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Yale Scientific



VOL. 94 NO. 4 • $6.99







The Greta Thunberg Effect

Hannah Huang

Researchers explore some of the social and psychological reasons why climate activists like Greta

Thunberg are so impactful.

10 Making Buildings More Energy Efficient

Could Save Lives

Bella Xiong

Buildings comprise a major source of the air pollution that is detrimental to our health. However,

a few efforts could help us decrease pollution emission, Yale researchers report.

12 Cook Stoves and Pollution Mortality

Risha Chakraborty and Arushi Dogra

A team of researchers quantified the relationship between pollution-related health impacts and

income in India, highlighting the immediate need to address pollution inequity.

15 The Temperature Toil

Angelica Lorenzo and Anna Calame

Recent research from SUNY Buffalo and the Yale School of Public Health points to a potential

relationship between exposure to extreme temperature and a greater number of mental healthrelated

emergency room visits.

18 The New Rumpelstiltskin: Spinning

Wood Into Plastic

Lucas Loman and Kayla Yup

Researchers at the Yale School of the Environment, University of Maryland and the University of

Wisconsin-Madison have created a biodegradable plastic alternative, using natural wood as their

raw material.

2 Yale Scientific Magazine December 2021 www.yalescientific.org


More articles online at www.yalescientific.org & https://medium.com/the-scope-yale-scientific-magazines-online-blog









How can Physics Teach Us About Climate Change? • Katherine Moon • 4

Mirror Mirror on the Wall... Is One Mirror Image Better Than Us All? •

Sherry Wang • 4

Cleave the Chlorine! • Sydney Hirsch • 6

Atmospheric Rivers • Crystal Liu • 7

Climate Change and Evolution • Isabel Trindade • 38

Can You Learn More Than a Fifth Grader? • Odessa Goldberg • 38

Unpacking the Cell's UPS • Alexandra Paulus • 39

Food Addiction Across Demographics • Lauren Chong • 39

A Tiny Molecule's Big Role in Brain Development • Neil Kadian • 40

Breaking Bonds with Computer Models • Madison Houck • 41

Cow Toilets 101 • Jack Litke • 21

The Fault in Our Stars • Ethan Olim and Anavi Uppal • 22

Wildfires and Ocean Blooms • Krishna Dasari and Nathan Wu • 24

Rationing Breaths • Catherine Zheng and Sophia Li • 26

The Bacterial Birth of 'Living Medicine' • Simona Hausleitner • 37

Scope: Positive Progress or Harmful Haste? • Annabel Wallace • 28

Undergraduate Profile: Elea Hewitt ('22) • Sophia David • 30

Alumni Profile: Paul Hanle ('75) • Sophia Burick • 31

Science in the Spotlight: Our Biggest Experiment by Alice Bell • Tori Sodeinde • 32

Science in the Spotlight: EVST 219: Philosophical Environmental Ethics •

Lucy Gilchrist • 33

Into the Newsroom: The Yale Program on Climate Change

Communication • Hannah Han • 34

Counterpoint: Do Hospitals Really Do No Harm? • Hannah Shi • 35

From the Archives: Yale Scientific Summer 1980 • 36

Synapse Essay Contest: When Sound Meets Chemistry • Marian Caballo • 42


December 2021 Yale Scientific Magazine 3




By Sherry Wang

By Katherine Moon



This year, the Nobel Prize in Physics was awarded to

three scientists, Syukuro Manabe, Klaus Hasselmann,

and Giorgio Parisi, for their contributions to the

understanding of complex systems. They each pioneered

research on modeling Earth’s climate and the nature of disorder

in physical systems. By awarding the prize to climate scientists

for the first time, the committee conveyed a clear message:

climate change study is a rigorous form of scientific research.

So, how have scientists used physics to analyze climate change?

In the 1960s, Manabe, now a climatologist at Princeton

University, created mathematical models of the Earth’s climate

to demonstrate how increased levels of carbon dioxide in the

atmosphere raise the surface temperature. German meteorologist

Hasselmann furthered the study by linking climate to the weather

as a chaotic system, ultimately supporting that human activity,

such as the generation of carbon dioxide emissions, is responsible

for the change in climate. Both models are now foundational to

the current understanding and research of climate change.

Meanwhile, Parisi, an Italian physicist at the Sapienza University of

Rome, focused on quantum field theory, a framework to construct

models of subatomic particles. He used this to discover patterns

from underlying disorder and fluctuations in complex systems. The

idea of analyzing irregularities in a complex system is analogous to

evaluating numerous variables in the Earth’s climate.

Physics teaches us about climate change through mathematical

models and complex systems. These physicists’ recognition by the Nobel

Committee emphasizes the rigorous scientific foundation underlying

the study of climate change, ultimately prompting us to take action. ■

The chemistry of molecule-making is quite particular:

sometimes, a reaction produces two mirrored versions

of a molecule, but only one remains sufficient for a

given application. In processes such as drug development,

using the wrong mirror image can have devastating biological

effects. Some catalysts can speed up a chemical reaction while

producing one mirror version preferentially over the other.

Historically, these catalysts have been made with toxic metals.

But the 2021 Nobel Prize in Chemistry was awarded to two

scientists—Benjamin List of the Max-Planck Institute for Coal

Research and David MacMillan of Princeton University— who

developed organic catalysts that are mirror image-selective,

helping to make reactions more environmentally friendly.

List discovered that the amino acid proline could replace the

function of metal catalysts while producing the more favored

mirrored version of a molecule. At the same time, MacMillan

designed small organic molecules that, like proline, had

catalytic functions and could generate one mirrored version

of a molecular product over the other. MacMillan officially

coined the term for this process: “asymmetric organocatalysis.”

This method of catalysis is eco-friendly: it decreases the

need to use toxic metals as catalysts and also decreases the

time of reaction. Approximately thirty-five percent of the

world’s gross domestic product depends on catalysis, so the

creation of a more efficient and environmentally sustainable

tool has major benefits. Production of the preferred mirrored

version through organocatalysis has revolutionized the field of

chemistry, one reaction at a time. ■

4 Yale Scientific Magazine December 2021 www.yalescientific.org

The Editor-in-Chief Speaks



This summer, the UN’s Intergovernmental Panel on Climate Change released a

landmark report with bleak findings: that human activity is an “unequivocal”

culprit in warming our atmosphere; that even if we drastically reduce our

carbon emissions, temperatures will continue to rise by at least 1.5 degrees Celsius;

and that these rising temperatures will cause severe weather, which we have already

previewed in our increasingly strong storms, long draughts, and ever-raging wildfires.

This November, world leaders gathered at COP26, a UN climate conference. Dozens

of countries vowed to institute meaningful policy combating climate change—though

youth climate activists protested that these proposals were far from enough.

This issue of Yale Scientific is themed Environmental Science and Justice. As the last

one helmed by our 2021 masthead, we’re interested in how issues of the environment

embody key themes our publication has addressed this past year.

Science uncovers and innovates. It helps us identify parts of our ecosystem, aspects

of our lives, or segments of society most harmed by environmental degradation.

It also develops alternatives to our most harmful activities and provides us with

potential means to mitigate the worst effects of climate change.

But science cannot be untangled from humanity, who will ultimately feel the pain

of environmental degradation.The global response to climate change is social and

political, shaped by how government officials, activists, and everyday individuals

internalize the scientific evidence presented to them. And as extensive research can

corroborate, long, long histories of injustice mean that those most socioeconomically,

racially, or otherwise oppressed in society suffer most in environmental crises.

Environmental justice, a movement distinctly aware of these inequalities, with roots

in Black and Indigenous activism, must shape any response moving forward.

Even as environmental crises loom, life moves on. In this issue we also look at areas of

science not directly related to the environment. An article from Scope, our interdisciplinary

online blog, investigates the COVID-19 pandemic’s effect on science research publishing

(p. 28). We also feature work by high schooler Marian Caballo, winner of this year’s

Synapse essay contest, who shows us that the future of science journalism is bright (p. 42).

As always, and especially for the last issue of this masthead, I am grateful for

our readers and for the massive team that makes our publication. Thank you for

critically engaging with science and all its impacts—for the past year, for the many

years before, and for the many years this publication will see in the future. Whatever

fate our planet might face in the meantime, science, and science journalism, will

undoubtedly help shape it. Let’s make sure it’s for the better.

About the Art

Isabella Li, Editor-in-Chief

This cover appears chaotic from the

outset, but only represents a sliver of

the countless environmental issues

plaguing the world today. While

wildfires as well as air and ocean

pollution are crucial problems, this

semester’s issue delves into many more

injustices, their nuances, and ideas on

how to ameliorate them.

Sophia Zhao, Cover Artist


December 2021 VOL. 94 NO. 4



Managing Editors

News Editor

Features Editor

Special Sections Editor

Articles Editor

Online Editors

Copy Editors

Scope Editors

Newsletter Editor


Production Manager

Layout Editors

Art Editor

Cover Artist

Photography Editor



Operations Manager

Advertising Manager

Subscriptions Manager


Synapse Presidents

Synapse Vice Presidents

Synapse Outreach Coordinators

Synapse Events Coordinator


Web Manager

Web Developer

Web Publisher

Social Media Coordinator

Web Designer


Lauren Chong

Rayyan Darji

Krishna Dasari


Ann-Marie Abunyewa

Hannah Barsouk

Breanna Brownson

Sophia Burick

Anna Calame

Risha Chakraborty

Allison Cho

Sophia David

Arushi Dogra

Chris Esneault

Sarah Feng

Lucy Gilchrist

Odessa Goldberg

Hannah Han

Simona Hausleitner

Alex Dong

Elisa Howard

Malia Kuo

Sydney Hirsch

Madison Houck

Abigail Jolteus

Neil Kadian

Catherine Kwon

Gina Lee

Sophia Li

Cathleen Liang

James Licato

Jack Litke

Crystal Liu

Lucas Loman

Angelica Lorenzo

Katherine Moon

Ethan Olim

Isabella Li

James Han

Hannah Ro

Jenny Tan

Cindy Kuang

Nithyashri Baskaran

Maria Fernanda Pacheco

Meili Gupta

Cathleen Liang

Alex Dong

Brianna Fernandez

Hannah Huang

Christina Hijiya

Tai Michaels

Beatriz Horta

Ishani Singh

AnMei Little

Catherine Zheng

Elaine Cheng

Sophia Zhao

Crystal Xu

Blake Bridge

Jared Gould

Brian Li

Sophia Zhuang

Lauren Chong

Alice Zhang

Sophia Li

Blake Bridge

Jared Gould

Athena Stenor

Anavi Uppal

Sophie Edelstein

Matt Tu

Brett Jennings

Eten Uket

Megan He

Siena Cizdziel

Dhruv Patel

Anavi Uppal

Kayla Yup

Alexandra Paulus

Noora Said

Hannah Shi

Anasthasia Shilov

Tori Sodeinde

Connie Tian

Isabel Trindade

Annabel Wallace

Sherry Wang

Jenny Wong

Nathan Wu

Bella Xiong

Lucy Zha

David Zhang

Lana Zheng

The Yale Scientific Magazine (YSM) is published four times a year by Yale

Scientific Publications, Inc. Third class postage paid in New Haven, CT

06520. Non-profit postage permit number 01106 paid for May 19, 1927

under the act of August 1912. ISN:0091-287. We reserve the right to edit

any submissions, solicited or unsolicited, for publication. This magazine is

published by Yale College students, and Yale University is not responsible

for its contents. Perspectives expressed by authors do not necessarily reflect

the opinions of YSM. We retain the right to reprint contributions, both text

and graphics, in future issues as well as a non-exclusive right to reproduce

these in electronic form. The YSM welcomes comments and feedback. Letters

to the editor should be under two hundred words and should include the

author’s name and contact information. We reserve the right to edit letters

before publication. Please send questions and comments to yalescientific@

yale.edu. Special thanks to Yale Student Technology Collaborative.


The Environmental Issue



Single-atom palladium

as a catalyst for the

removal of chlorine

from polluted water



Anthropogenic pollutants—that is, those released by

human activities—are toxic and can pose serious risks

to human and ecological health. Chlorinated phenolic

compounds (CPs), often used in pesticides, herbicides, and various

other chemical products, are one such type of pollutant. These

compounds need to be removed from water systems by a process

known as hydrodechlorination. Conventional treatment methods

such as filtration, however, are not effective. As a result, scientists

have begun to explore electrocatalysis as an alternative technique

to cleave the chlorine from phenol, ridding systems of CPs.

Palladium-based catalysts offer a promising solution to catalyze

or promote this reaction. However, palladium (Pd) is a costly

material, and past experimentation with Pd nanoparticles (Pd nano


has demonstrated various limitations in dechlorination efficiency. A

team of researchers at Yale, including post-doctoral fellow Dahong

Huang and senior professor Jaehong Kim, devised an electrocatalytic

technique utilizing single-atom palladium (Pd 1

) that circumvents

both the cost and mechanistic issues posed by Pd nano

. Their efforts, in

collaboration with Brookhaven National Laboratory, yielded a system

fourteen times more efficient than Pd nano

at the atomic scale.

The researchers’ experiment consisted of mounting the Pd

single-atom catalyst (SAC) onto a reduced graphene oxide (rGO)

support, which allows for rapid electron transfer and sufficient

distribution of the SAC. Unlike Pd nano

loaded onto an analogous

support, in which many Pd atoms sit under the surface, all of the

palladium atoms on the Pd 1

/rGO are available for reaction. Thus,

the atomic efficiency of Pd 1

can reach one hundred percent.

In addition, Pd 1

uses less palladium than Pd nano

, making it costefficient

as well. In fact, it costs only seventeen cents to cover a square

meter of rGO with the palladium SAC, whereas Pd nanoparticles

run around thirty-seven dollars per square meter. This dramatic

reduction in cost is vital in the context of water treatment, as the

broader objective of this research seeks to find efficient and costeffective

ways to treat large volumes of water.

In previous research involving palladium-induced catalysis, scientists

also noticed that the catalyst could be deactivated by the products of

hydrodechlorination. This result was seen in experimentation with

Pd nano

, wherein the chloride released by the reduction reaction clung to

the palladium surface and prevented further catalytic activity. Kim and

his team recognized, however, that single-atom palladium circumvents

this “poisoning effect” since the unsaturated nature of the SAC allows

any adsorbed chloride to be released quickly and the reaction to

progress unhindered. The researchers demonstrated this phenomenon

experimentally. Throughout the electrocatalytic reaction, in which

chlorines were removed from the phenolic compounds, the chloride

ion concentration in solution remained close to one hundred percent,

indicating that the Pd 1

/rGO surface had not adsorbed chloride after

dechlorination of the phenols.

Additionally, phenol was the only product in solution, highlighting

the selectivity of this mechanism. “Imagine you have a pollutant like

chlorophenol in water and you’re trying to treat it. But water also

has a lot of other stuff in it. You don’t want your reduction power

to reduce the rest of the organics in water. We want a treatment

scheme that selectively destroys the pollutant, and this palladium

single atom-based material can selectively target reducing chlorocompounds,

which is the ultimate goal,” Kim said.

The presence of electron metal support interactions (EMSI)

between the Pd 1

atoms the rGO support promotes the catalytic

reaction. Electrons flow through the palladium-oxygen bonds and

transfer directly to what is adsorbed on the Pd 1

, whether it be a

chlorophenol (direct reduction) or a proton. In the latter, atomic

hydrogen is formed to reduce the chlorophenol, a process termed

indirect hydrogenation. With previous methods using Pdnano, two

atoms of hydrogen formed H 2

and thus failed to contribute to the

electrocatalytic hydrodechlorination. Pd 1

avoids this issue due to

its limited adsorption sites and spatial separation.

Kim’s research demonstrates the potential of palladium SACs in

becoming a prominent part of water treatment solutions. Before

considering the broader applications, however, there are many

smaller-scale steps to be taken in this line of work. “We need to

continue to test this material for a wide range of scenarios. At the

same time, we are not claiming that [palladium] is the best material,”

Kim said. “There are many other options for the metal as well as the

substrate, and we do not know what the best is.”

Future studies may continue to test the long-term stability

of SACs and optimize its properties for a given reaction,

ultimately working to detoxify environmental systems. “You

have just seen the tip of the iceberg,” Kim said. ■

6 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue




How global warming

influences the stability

of water vapor streams


Not all rivers run on land. Atmospheric rivers (ARs)

are pathways of intense water vapor transport in the

extratropics, the mid-latitude areas beyond the tropics.

Seung Hun Baek and Juan Lora at Yale’s Department of Earth and

Planetary Sciences examined new models to evaluate the past and

future influences of human activity on AR fluctuations.

An AR can be advantageous or detrimental depending on

its strength. The Scripps Institution of Oceanography at the

University of California San Diego categorizes ARs based on a

five-level scale, ranging from “weak” to “exceptional” in strength

and “beneficial” to “hazardous” in impact. An AR of level two

(Moderate) can help replenish low reservoirs after a drought,

but ARs of four and five (Extreme and Exceptional) often lead

to heavy precipitation and floods.

Higher temperatures can strengthen ARs by increasing the

amount of water vapor in the air. Two important factors that

affect temperature are the warming effects of greenhouse gases

(GHGs) and the cooling effects of industrial aerosols, such as

smoke and particulate air pollutants. Baek and Lora showed that

there was little human-induced change in AR characteristics

from 1920-2005, as the effects of GHGs canceled out those of

aerosols. Compared to natural variability, human activity only

caused statistically significant changes in the North Atlantic and

the Southern Pacific, and these changes were small in scale.

However, when the scientists applied the same framework to

project future changes, they saw a drastically different picture.

Relative to the historical evaluation, they predicted far more

vigorous ARs from 2005-2080, simulating a roughly twentymillimeter

per month rainfall increase in many regions and over

one hundred percent more frequent extreme precipitation over

much of Europe. These natural disasters can lead to flooding,

property losses, and casualties.

Baek and Lora used the Representative Concentration Pathway

of 8.5 watts per square meter (RCP8.5) in their prediction model.

The RCPs were proposed by the United Nations Intergovernmental

Panel on Climate Change (IPCC) in its Fifth Assessment Report.

They represent a series of GHG concentration scenarios, and RCP8.5

corresponds to “very high GHG emissions.” In 2014, the IPCC stated

that without additional efforts to constrain emissions, the baseline



condition would fall between RCP6.0 and 8.5. “[RCP8.5] is certainly

pessimistic, but it is possible and very worth thinking about, as we’ve

been following that trajectory relatively closely,” Lora said. Plus,

the models stay conceptually valid regardless of the numbers. “If

greenhouse gases went up less, the intensification of atmospheric

rivers would be less. But qualitatively it will still go up,” Baek said.

The researchers also evaluated the altitude of changes in AR

characteristics. Changes at a higher altitude, although smaller in

magnitude, closely mirror those at a lower altitude. “Mid-latitude

weather systems have a vertical structure that goes from the surface

up into the troposphere, so we want to understand how these [AR]

changes occur in the vertical direction as well,” Lora said.

With such large experiments came numerous challenges.

Collecting and analyzing the data was an especially arduous

task. “Atmospheric rivers use daily data, so it’s pretty high

resolution temporally. I think we analyzed or generated

something like twenty terabytes of data.” Baek said.

Lora, on the other hand, expressed words of gratitude. “Yale

maintains very good computing capabilities. [During the pandemic,]

we are lucky as computational scientists in that we run simulations

and analyses on computers that we can access remotely,” he said.

It is astonishing that industrial aerosols, an important air

pollutant, can cool the atmosphere. Can humans make use of

this property? Indeed, solar geoengineers have been considering

injecting aerosols into the stratosphere. This field has received

much attention recently, but its implementation is currently far

from reality due to its many unknown consequences. “Think

about the mass extinction event that killed the dinosaurs. A large

proportion of that was probably due to aerosols blocking the Sun.

So maybe it’s not [a path] we want to go down,” Lora said.

In future studies, the scientists hope to examine the influence

of global patterns, such as the El Niño–Southern Oscillation, on

atmospheric rivers. Several regional studies have observed these

phenomena, but simulations like the one in this paper can help

paint a global picture. The scientists also aim to elucidate the impact

of individual forcings, or perturbations to the Earth system, on

atmospheric rivers—not only to gain an insight on this elaborate

system, but also to shed light on the possible effects of solar

geoengineering and other human modifications to the atmosphere. ■

December 2021 Yale Scientific Magazine 7


The Environmental Issue





Studying what makes an

ordinary teenager so

extraordinarily impactful



Zooming with me from across the pond

in London, Anandita Sabherwal, a

PhD student at the London School of

Economics, explained how she arrived at the

topic of her latest publication in the Journal

of Applied Social Psychology.

“I was very interested in the idea of

social identity and social reference, and

who acts as a social reference when it

comes to climate activism,” she said.

Sabherwal had been sitting in her adviser’s

office, bouncing research ideas around with

him. Together, they came to the realization

that they should study the effect that Greta

Thunberg has had on climate activism.

That idea, coupled with a collaboration

with the Yale Program on Climate Change

Communication (YPCCC), led to their

recent paper, “The Greta Thunberg Effect:

Familiarity with Greta Thunberg predicts

8 Yale Scientific Magazine December 2021

intentions to engage in climate activism in

the United States.”

Thunberg, a teenage activist from Sweden,

has inspired countless people of all ages

from across the globe to both care about

and act against climate change. Sabherwal

and her colleagues wanted to know what

makes a young, seemingly ordinary

teenager so influential in convincing

people to partake in collective actions like

contacting government representatives,

donating time and money, and attending

strikes and protests—actions that help a

larger group and not just themselves.

Living, Learning, and Collaborating

Across Continents

Sabherwal’s interest in studying how

people react to communication about

climate change is driven by the many places

she’s lived in. Born and raised in India, she

saw how the water shortage crisis forced

women to walk ever-farther distances to get

water, even driving some farmers to suicide.

While studying at Yale-NUS College in

Singapore, she participated in a study abroad

program at Pomona College, where she was

surprised by how highly politicized climate

change is in the US—a characteristic that

she thinks is more exaggerated here than

anywhere else she’s lived. “Different political

groups don’t even agree on whether climate

change is worth discussing as a problem or

looking for solutions for, and that blew my

mind,” she said.

Now a new PhD student at the London

School of Economics, she has observed

that although people in the UK want to act,

there is an intention-action gap. “People


The Environmental Issue


want to do something, but they also don’t

want to sacrifice a lot of their privileges and

ways of life to get to that point,” she said.

From India to Singapore to the US to

the UK, she has seen and studied firsthand

how countries differ in how they

are affected by and deal with climate

change. “I realized that this would be

an amazing thing to study because

socially and psychologically, there is a

lot to unpack here,” she said. “Why do

different groups react so differently to the

same information? How do they adapt

differently based on their social status

and class? What impacts do they face?”

Sabherwal and her colleagues sought

to establish whether increased exposure

to Thunberg was predictive of increased

motivation to participate in collective

action against climate change. They also

wondered if collective efficacy—the idea

that working as a group can bring about

the accomplishment of specific goals—

was behind this effect.

The UK researchers first attempted

to study the Greta Thunberg Effect in a

sample of adults drawn heavily from the

East and West Coasts of the US; however,

their efforts were foiled by how well

people already knew Thunberg. “People

were already so exposed to her that when

we did an experiment exposing people

to Greta, it had no effect,” Sabherwal

said. “Everyone in our control group

knew Greta just as equally. People were

much more aware of Greta and much

less polarized on her than was nationally

representative.” Then, an encounter with

a former labmate from Sabherwal’s time

at Pomona led to the opportunity to

collaborate with the YPCCC.

YPCCC conducts annual surveys on

the US population and, fortunately, had

data that were more representative of

people’s opinions on climate change and

Thunberg. YPCCC’s data solved the

problem that UK researchers had run

into earlier. Moreover, because of how

politicized climate change is in the US,

there was a wide range of opinions on

climate change, which made the US data

an interesting sample on which to test the

researchers’ hypotheses.

What is So Special About Thunberg?

In the study, after participants were

asked how familiar they were with


Thunberg, they were also asked questions

measuring their belief in collective efficacy

(how likely was it that a group of ordinary

citizens, working together, could affect

the actions of government or businesses)

and questions measuring their intent to

engage in collective actions (how likely

the individual was to vote for a candidate,

attend a rally, listen to a speech, etc.).

As expected, they found that familiarity

with Thunberg induces people’s sense of

efficacy: they feel like if they work along

with others, they can make an impact.

This is because Thunberg has modeled

both collective action—leading and

supporting climate strikes, for example—

and worldwide impact, such as speaking

at high-profile events like United Nations


Surprisingly, there was no difference

in the Greta Thunberg Effect across age

groups. The researchers had hypothesized

that her impact would be more apparent

in younger people, but they were glad

to see that she impacted all age groups


What also stood out about Thunberg

was her appeal across the political

spectrum in the US. “Generally, if a leader

appeals to one political segment, they

backfire with the other political segment.

It’s not that the effect is just lowered.

It backfires,” Sabherwal said. “But we

found that Greta was also appealing to

conservatives, even if to a lesser extent

compared to liberals.” In light of these

findings, she posits that Thunberg’s

emphasis on intergenerational justice and

her lack of clear alignment to a specific

political party underlie her success.

Finally, to Sabherwal, Thunberg’s

humility and relatability allow her to

connect with the general public. Leaders

are typically elite in some way, whether

it be in educational background, power,


or wealth. Academic experts, government

leaders, and wealthy people are examples

of the types of elite leaders that abound

in the arena of climate change activism.

Elite leaders, however, can alienate

people in the general population for the

exact reasons they are conspicuous in the

first place. “Sure, Jeff Bezos can donate

twenty million dollars to climate change

research. I can’t do that,” Sabherwal said.

“But by always conveying that she’s just

like us, Greta has been able to be a leader

that we can look up to and say, ‘If Greta

can do it, we can do it too.’”

Fighting Anxiety with Action

As a researcher whose entire day is spent

focusing on climate change and seeing

how reluctant people are to change their

behavior, thinking about the future can be

anxiety-inducing, Sabherwal admitted.

But when a person like Thunberg says

there is still time to change, it gives her

great solace. “Greta inspired me to take

care of my anxiety by taking action, by

doing something about it, which I think

is a message she consistently gives,”

Sabherwal said. “Because unless you act,

it’s very easy to get overwhelmed by the

state of climate change right now.”

Sabherwal believes in Thunberg’s

unique power. “Most of us will change

because we know that the social norm has

changed. But there are a few individuals

that will change the social norm, and

that’s how societies change,” Sabherwal

said. As her recent study reveals, the Greta

Thunberg Effect is real and impactful.

Hopefully, it will continue to change

people’s minds, their actions, and our

society for the better because—to use one

of Thunberg’s trademark phrases—our

house is on fire, and we’re running out of

time to save it. ■


HANNAH HUANG is a sophomore in Davenport College. In addition to writing for YSM, she volunteers

with HAVEN Free Clinic and is part of the Davenport College Council.

THE AUTHOR WOULD LIKE TO THANK Anandita Sabherwal for her time and enthusiasm about her


Sabherwal, A., Ballew, M. T., Linden, S., Gustafson, A., Goldberg, M. H., Maibach, E. W., Kotcher, J. E.,

Swim, J. K., Rosenthal, S. A., & Leiserowitz, A. (2021). The Greta Thunberg effect: Familiarity with Greta

Thunberg predicts intentions to engage in climate activism in the United States. Journal of Applied Social

Psychology, 51(4), 321–333. https://doi.org/10.1111/jasp.12737

December 2021 Yale Scientific Magazine 9


The Environmental Issue





Even before the pandemic, people spent

about ninety percent of their time

indoors. Given how many hours we

spend in these spaces, it is important to think

about how changes in building design or

operation impact indoor air quality.

The burning of fossil fuels contributes

to global warming by accumulating large

quantities of carbon dioxide and particulate

matter smaller than 2.5 microns in the

atmosphere. The latter is a pollutant with

one of the largest health effects—despite

its minuscule size, it can both cause

and exacerbate cardiovascular diseases,

respiratory diseases, and cancer.

While many factors contribute to emissions

of carbon dioxide and particulate matter—

wildfires and cars, for example—a major

source of air pollution originates from

buildings and building-related operations.

According to the US Energy Information

Administration, residential and commercial

buildings consume forty percent of all energy

in the US. This issue makes buildings an

important target for measures that increase

energy efficiency and reduce carbon dioxide

and pollution emissions.

Drew Gentner, Yale professor of Chemical

& Environmental Engineering, and Kenneth

Gillingham, professor of Economics, along

with their colleagues from Yale's Solutions

for Energy, Air, Climate & Health Center,

embarked on a necessary interdisciplinary

investigation. In their new study, published in

Science Advances in August, the researchers

used the Yale-NEMS (National Energy

Modeling System) model, which models the

effects of various building energy efficiency

scenarios they designed based on literature.

Leveraging their perspectives on the dynamics

How improving the energy efficiency

of buildings can impact air quality

of air pollution in indoor and outdoor spaces,

they investigated scenarios that could impact

carbon dioxide emissions associated with

energy use and energy-related emissions of

outdoor pollutants.

The project was motivated by the desire

to both improve human health and help us

tackle climate change. “It is not a new issue,

and we have known for a long time how

important it is, but quantifying the effects of

strategies to address climate change is more

relevant now than ever,” Gillingham said.

Energy Efficiency Scenarios

Gentner and Gillingham’s study

evaluated how energy efficiency measures

could improve building tightness, a

measure of outward and inward air

leakage in buildings. These energy

efficiency measures included changes to

infiltration, natural ventilation, and heat,

ventilation, and air conditioning (HVAC)

recirculation adoption. The researchers'

goal was to explore ways to reduce energy

losses associated with air leakage from

indoors to outdoors, and vice versa.

To do so, they created two scenarios:

“Intermediate EE” and “Optimistic EE.” The

“Intermediate EE” scenario provides close

to twenty percent increased efficiency on all

building appliances and equipment. In this

scenario, the annual efficiency improvement

from better building shells—which separate

the building’s interior spaces from its

exterior spaces—can achieve cumulative

improvements of more than fifty percent. The

“Optimistic EE” scenario is a more idealistic

model, allowing for fifty percent increased

efficiency in appliances and equipment, along

with more than sixty percent of cumulative

annual efficiency improvement from

increasing the quality of building shells.

These two scenarios are based on possible

future energy efficiency improvements

for building services and shell structure

materials. Shell structure materials are

used to secure the building composition by

transmitting applied forces on the surface.

The energy efficiency improvements

address space heating and cooling, water

heating, lighting, refrigeration, and culinary

services for residential and commercial

facilities. They also address building shell

efficiency improvements in the residential,

commercial, and industrial sectors for both

existing and new structures.

Another focus was improving

recirculation with filtration, which can

help mitigate indoor concentrations of

particulate matter. Considering how

energy efficiency is greatly related to

the emission of energy productionrelated

pollutants, these two scenarios

also provide estimates for how many

premature deaths in the United States

would be avoided in each case.

Using the outputs of the Yale-NEMS

model, along with the building energy

efficiency scenarios, the researchers

evaluated how concentrations of

particulate matter could change indoors as

a function of building tightness. The study

examined how the two building energy

efficiency scenarios would impact air

quality across the entire US housing stock.

The researchers explored the

interconnectivity of outdoor and indoor

air quality by looking at the changes in

infiltration while also considering the

10 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue


variations in indoor emissions across

houses in the US. These emissions are

closely related to cooking activities,

and the resulting concentrations are

impacted by the presence of particle

filtration—which, in turn, is related to

building HVAC systems.

Compared to the reference case of the

energy efficiency scenarios, the Yale-NEMS

model predicted that decreasing energyconsuming

activities could improve general

outdoor air quality. On a larger scale,

it also shows that indoor air quality

related to building energy efficiency

improvements depend largely

on indoor emissions and home

design characteristics. According

to the research team’s findings

and interpretation, by 2050, both

efficiency scenarios could yield a

six to eleven percent reduction in energyrelated

carbon dioxide emissions and an

eighteen to twenty-five percent reduction

in the main particulate matter emissions.

Ultimately, following the energy-saving

scenarios could reduce outdoor emissions,

potentially saving 3,700 to 7,800 lives per

year in the United States by 2050.

A Call to Action

Unfortunately, the study’s findings also

show that energy efficiency improvements

could negatively impact indoor air quality

in some homes. Due to lower air exchange

rates, infiltration caused by tightening the

building shell for energy efficiency gains

might result in greater exposure to indoor

contaminants in some buildings. The

observed changes in indoor air quality show

that it is essential to increase awareness

of indoor particulate matter emissions.

Because of this, indoor air filtration

improvements should also accompany

energy efficiency improvements. This might

be especially significant for low-income

housing, which tends to have inadequate

indoor air filtration due to the usage of

more health-damaging materials.

Still, even after accounting for changes

in indoor air quality, the thousands of

premature deaths that could be avoided

by improving the energy efficiency of

buildings should not be neglected.

Overall, estimates of public health

improvements reveal the urgency of

reducing the outdoor air or outdoor

pollutant emissions associated with energy


u s e .

“Attention to

ventilation strategies, indoor emissions,

and investments in interior air recirculation

systems with filtration, such as betterperforming

filters in HVAC systems,

require careful consideration from a policy

standpoint and can help to minimize

potential negative effects on indoor air

quality,” said Gentner. This could help to

improve indoor air quality even further,

preventing even more premature deaths.

Making buildings more energyefficient

can help us move toward a more

environmentally safe future. Going forward,

individuals also have an opportunity to

consider how personal housing choices can

affect air pollution. By choosing a more

environmentally sustainable option of

housing, for example, thousands of premature

deaths may be avoided each year. “This study


p r o v i d e s

guidance to

policymakers who are trying to

understand what it would mean to have

intensive energy efficiency improvements. It

tells us what the benefits could be, but also

what additional efforts are needed to achieve

the benefits,” said Gillingham.

To address climate change, we must

pay close attention to the impacts of

air pollution. This requires considering

emissions from a variety of sources.

Whether it is through improving

building efficiency, reducing air pollution

emissions, or changing personal choices,

each of us has a role to play. A tremendous

amount of work remains to be done, but

scientists like Gentner and Gillingham are

using what they know to combat climate

change by initiating conversations that

could lead to policy changes. ■

BELLA XIONG is a junior Neuroscience major in Trumbull college. In addition to writing for YSM, she

directs the Yale Helix Incubator and works for the Yale Medical School as a research assistant. Her research

involves using machine learning to predict patient outcomes after suffering an intracranial hemorrhage..




K. T. Gillington., P. Huang., C. Buehler., J. Peccia., D. R. Gentner. (2021, August 20). The climate and health

benefits from Intensive Building Energy Efficiency Improvements. Science Advances. Retrieved November 6,

2021, from https://www.science.org/doi/10.1126/sciadv.abg0947.

Xing, Y.-F., Xu, Y.-H., Shi, M.-H., & Lian, Y.-X. (2016, January). The impact of PM2.5 on the human respiratory

system. Journal of thoracic disease. Retrieved November 6, 2021, from https://www.ncbi.nlm.nih.gov/


December 2021 Yale Scientific Magazine 11


The Environmental Issue



Poorer Indian households face death from

pollution more than the rest of the world


Nowhere is the diversity in the

impacts of climate change more

obvious than in India. There,

great disparities in people’s access to

pollution-causing technologies ultimately

culminate in stark differences in health

and lifespan. Pollution is the single

greatest environmental cause of premature

mortality worldwide, but the proportion

of Indian babies and moms dying from it

vastly exceeds the global average.

While researchers have long studied

the tie between emission origin and

pollution spread, as well as the impacts

of this pollution on human health, these

disciplines had historically remained

unconnected. The question of why

families located in specific areas of India

disproportionately felt the impacts of

atmospheric pollution lingered.

To correlate the hotspots of

pollution-based premature mortality

with proximity to emission-causing

technologies in India, Narasimha

Rao, an associate professor at the Yale

School of the Environment, assembled

a team of researchers from Yale and

the International Institute for Applied

Systems Analysis with different areas

of expertise. Serving as climate justice

advocates, they sought to understand

the income-specific impacts of pollution

and to propose policies to address these

interconnected disparities in India.

The Integration of Models

Climate change models have existed as

long as climate data has been collected—for

nearly two centuries. The need for research

correlating specific emissions to public

health issues might seem obvious—after all,

while the causes of pollution inequity have

gone uninvestigated, pollution’s inequitable

health impacts have been theorized for

as long as we have known pollution to be

detrimental to health. However, as Rao

acknowledged, there has been a historical

lack of research in this field. “In science,


Professor Narasimha Rao of the Yale School of the


you can only ask the questions you can

answer, and this fell through the cracks of

intersection boundaries,” Rao said.

Prior to this study, Rao, as a footprinting

climatologist, lacked the tools to link

emissions to health markers, such as

respiratory illnesses and premature

mortality. Similarly, those working on

the health impacts of emissions did not

have the tools to understand the spatial

distribution of atmospheric pollution

according to location and consumption of

fuels and technologies. While many climate

researchers have thought about linking

these two areas, the fact that separate tools

are involved in creating each model meant

there was previously no way to pursue

the connection. Rao’s novel insight was to

devise an analytical framework where the

results from the emissions contribution

model would provide data to fuel the health

and socioeconomic impacts model, and

vice versa.

The linked contribution and impact model

Rao’s team created was a culmination of many

smaller models with different purposes, each

exchanging information with the others.

Rao worked on the aspect of the model

that linked spatial distributions of “point

sources”—people and industries—across

a region to the emissions from that region.

His team had a good understanding of

point sources’ emission generation patterns,

including the usage of fuels involved in

12 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue


transportation, heating, or making food in

cook stoves, and those that were indirectly

wasteful, such as generating food waste and

running electricity.

Once his team localized emissions

to these point sources, an atmospheric

model was implemented to reflect realistic

weather patterns, including air flows

and temperature changes, and deduce

the ultimate stabilized concentrations

of pollutants. Finally, an impact model

linked the pollutant concentrations

to individual exposure and mortality,

demarcated by age, sex, socioeconomic

status, and proximity to urban centers.

The impact model also mapped the

socioeconomic characteristics of people

and inferred their future energy demands;

for example, rising disposable income could

mean that individuals would buy more

polluting technologies, such as new fridges

or cars, or less polluting technologies,

such as gas stoves instead of biomass

stoves. These results would in turn provide

feedback to the emissions model. Thus,

the cyclical nature of the model pipeline

ensured that both the emissions and health

impacts could be modulated over time.

Not only was the model predictive over

time, but it was also highly generalizable

across global regions. “You can change out

the data and you’d represent a different part

of the world,” Rao said. Since the underlying

algorithm remained the same, it was simply

a matter of “plugging in” different data

points—adding or removing emissioncausing

technology contributions, changing

the population distribution, changing the

atmospheric characteristics—and “chugging”

to customize the model for any region.

The team chose to look at India as the

first application of the model because India

has a mix of income levels and polluting

technologies that makes the source and

extent of pollution unclear. The model

provided clear evidence for what might

have been superficially obvious: poorer

households in India disproportionately

face the impacts of pollution. The

pollution inequity is jarring—in fact,

the poorest decile of the population in

the country faces a mortality risk that is

nine times greater than that of the richest

decile in the country.

More importantly, the model highlighted

the exact sources of pollution that were


Pollution from cookstoves contributes to the premature deaths of nearly a million Indian mothers and babies.

causing families of lower socioeconomic

status to suffer premature mortality. The

most lethal sources of pollutant emissions

in India are biomass-burning cook

stoves, which cause indoor air pollution

and are primarily used by poorer, rural

Indian families who cannot afford

liquid petroleum gas stoves—the typical

choice for richer, urban-based families.

According to Rao, pollution from cook

stoves leads to nearly one million deaths

of Indian babies and mothers every year.

Moreover, the ambient air pollution that

is produced by public services such as

transportation and electricity generation far

exceeds any benefits these families receive

from these services. While they do not

consume electricity or use transportation

to the same magnitude as richer families,

poorer families face asymmetrically

exaggerated mortality risks.

The Role of Government

Climate researchers and public health

officials alike have recognized that this grim

narrative of inequity in pollution-attributed

mortality cannot continue. What policies

can be passed to address this disparity?

In Rao’s ideal world, addressing

pollution in its totality and switching

from pollution-causing fossil fuels to

clean energy within the next ten years is

imperative. “Biomass cook stoves need

to go away, since the health impacts of

indoor air pollution completely dwarf the

ambient air pollution,” Rao said. However,

poorer Indian households wouldn’t be able

to afford and reliably use clean fuels unless

the government provided it to them.

The government has taken a necessary

first step. “In the past decade, aggressive

policies have provided a free stove and a

free gas cylinder to fifty million households

in India," Rao said. "The problem is, the

fuel has continued to be expensive, so they

haven’t used those new stoves as much.

It's just a governance failure: we need

to make sure that the fuel is cheap.” He

acknowledged that some policies could

cause market failures or require public

investments. But since poorer people

suffer most from the exorbitant price of

clean fuels, the onus to provide cheap,

clean fuel is on the government.

According to Rao, one of the more feasible

solutions is to use targeted emissions

policies, where the costs of emission are

apportioned to the consumers of fuels. This

would incentivize lower fuel usage and in

turn decrease ambient air pollution.

The proposals don’t stop there. “We

need to address food waste and garbage

disposal in cities and areas that are affluent,


December 2021 Yale Scientific Magazine 13


The Environmental Issue

where most of the consumption waste is and wide. Accordingly, he joins the gamut implementation remains a challenge.

coming from. We need to create the policy

instruments for the costs to flow to the

right people,” Rao said. Such policies, along

with governments ensuring that clean fuels

are accessible to poorer households, could

reduce exposure to air pollutants.

By providing free stoves to a significant

proportion of India’s population, the Indian

government has shown that it has the capacity

to provide clean energy to poorer households.

It also seems like it has the capacity to

implement targeted emissions policies.

of an increasing force of researchers, who by

writing policy reports, publishing academic

papers, and making data available to nongovernmental

organizations, are increasingly

influencing governmental decisions.

“I like to think of myself as an academic

activist, as having the privilege of generating

[scientific] insights," he said. "I see it as

an obligation on my part to make those

insights available as broadly as possible.”

Clearly, “solving climate change” or

“fixing pollution” is much easier said

Nevertheless, Rao and his team shed

some much-needed light on the social

ramifications of pollution inequity and

mortality. Their work points to targeted

emissions policies and biomass cook stove

replacement policies as necessary, even

inevitable, solutions.

As scientists and climatologists continue

to embrace their roles as policy influencers

and activists, governmental inaction will

no longer remain an option. In this way,

Rao’s ideal world—one in which pollution

But capability doesn’t always translate than done. Even though the technology inequity is vanquished—just might

to action. “Unfortunately, the cliche is that to reduce emissions exists, its equitable become a reality. ■

there needs to be strong political support

for it. There is a cost that has to be paid,”

Rao said. And according to him, that is ART BY BREANNA BROWNSON

not something that scientific research

alone can repair. “Understanding people’s

dependence on the fuels, the nature of the ABOUT THE AUTHORS RISHA CHAKRABORTY AND ARUSHI DOGRA

lack of reliability of the fuel supply, and the

RISHA CHAKRABORTY is a first-year Neuroscience major prospect in Saybrook College. In addition

political economy of the fuel price setting to writing for YSM, Risha plays trumpet for the Yale Precision Marching Band and Undergraduate

and subsidies are essential,” he said.

Jazz Collective, volunteers for HAPPY (Hypertension Awareness and Prevention Program at Yale), and

Because of the results of the model, researches Parkinson’s Disease at Chandra Lab in the School of Medicine.

scientists now know the contributors and ARUSHI DOGRA is a sophomore in Jonathan Edwards College, prospectively majoring in MCDB and

victims of pollution, both geographically HSHM. Outside of YSM, Arushi is on the board of the Yale Hunger and Homelessness Action Project,

and in terms of socioeconomic is involved in Health & Education Advocates for Refugees, and conducts immuno-oncology research in

characteristics. For meaningful change the Katz Lab in the School of Medicine.

to occur, governments and the public THE AUTHORS WOULD LIKE TO THANK Dr. Narasimha Rao for his time and enthusiasm about his research.

must also internalize these findings. Rao’s FURTHER READING

current personal goal is to improve global Rao, N. D., Kiesewetter, G., Min, J., Pachauri, S., Wagner, F. (2021). Household contributions to and impacts

understanding of how to diffuse clean fuels from air pollution in India. Nature Sustainability, 4(10), 859–867.

and sustainable energy technologies fast

14 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue






Today, climate change is not only at our doorstep—it’s in our living rooms, on our kitchen tables, and even in

our pockets, through near-constant coverage on television news, newspapers, and social media. Climate stories

are often accompanied by aggressive images: wind- and rain-battered palms, neighborhoods swallowed up by

churning floodwaters, forests consumed by flames, disturbingly vibrant thermal maps.

While these photographs impactfully illustrate the physical devastation wrought by extreme weather, recent research

suggests they may fail to capture a less visible but key consequence of climate change: its impact on mental health.

Studies conducted by Eun-hye Yoo, associate professor of geography at SUNY Buffalo, and Kai Chen, assistant professor

of epidemiology at the Yale School of Public Health, identified a possible link between extreme temperatures and increased

mental health-related emergency room (ER) visits. Such an association, though still subject to further research,

may have meaningful implications for how we think about climate change.


December 2021 Yale Scientific Magazine 15


The Environmental Issue


From left to right: Pin Wang; Yiqun Ma (PhD candidate); Lingzhi Chu (PhD candidate); Chengyi Lin (PhD

student); Kai Chen.

A Gap in the Literature

While climate research has increased

significantly over the past two decades,

not all ramifications of the impending

crisis have been investigated equally.

Yoo and Chen are seeking to address a

consequential gap in the literature: the

effect of extreme temperature, both hot

and cold, on mental disorders. To that end,

they co-authored two studies with other

collaborators on potential associations

between extreme temperature events and

ER visits for mental health reasons in New

York State. While the first study examined

a wider array of mental disorders,

the second study investigated specific

conditions, such as anxiety disorders,

mood disorders, substance abuse, and

dementia, as reasons for ER visits.

Though prior studies suggesting probable

links between heat and negative mental

health outcomes have been conducted,

the field remains relatively sparse in

comparison to the larger body of climate

research. To account for this, Yoo points

to the fact that psychologists are primarily

interested in analyzing individual

behaviors, while epidemiologists engage

almost exclusively with population-level

data. As a result, overlap between research

in environmental epidemiology and

mental disorders is relatively rare.

For their part, these two researchers

come to the field from different

backgrounds—Chen, an environmental

health epidemiologist, has long harbored

an interest in the health implications of

climate change, while Yoo’s area of expertise

is geographic information science and

spatial statistics. Nevertheless, they share

a deep concern for this under-investigated

correlation, and the two enjoy an amiable

relationship, each quick to credit the other

for their unique contributions to the study.

Exploring the Effects of Extreme


To investigate the relationship between

exposure to extreme temperature and risk

of increased ER visits, the researchers

employed a time-series analysis. Timeseries

models, a common type of statistical

analysis, use a series of data points

collected at fixed time intervals to make

a prediction or estimate an association.

In Yoo and Chen’s studies, the model

consisted of two time series—temperature

and ER visits—which both varied daily.

“What we do in this model is try to find

an association between these two timeseries,”

Chen said. “But in the meantime,

there are a lot of other things going on

that may influence this relationship, so we

need to use our model to control them.”

Data on daily ER visits for mental health

disorders were collected from the New York

State Department of Health and compared

to climate and air pollution data obtained

from the National Center for Environmental

Information Climate Data Online System.

The ER records, dating from January 2009

to December 2016, included demographic

information like race, age, and sex, as

well as the primary diagnosis code, which

the researchers used to identify mental

disorders in ER patients. Daily precipitation

and minimum, average, and maximum

temperatures were examined as part of the

temperature time-series. Separate timeseries

analyses were conducted in ten labor

market regions in New York State, and a

meta-analysis was performed to pool the

result the whole state.

Notably, the model was designed to

consider any delayed effects on mental

health caused by temperature exposure.

While a lag period of seven days was used

to identify short-term exposure effects

on increased ER visits, their analysis

also evaluated this exposure-response

relationship for a longer period of

twenty-one days.

Climate Consequences for Mental


The first study, which focused solely

on Erie and Niagara counties, indicated

a strong positive association between

maximum temperature and increased ER

visits for mental illness. Significant risk was

observed at temperatures above twenty-nine

degrees Celsius and below eight degrees

Celsius. Across all lag periods, heat effect

was found to elevate one’s risk of visiting

an ER for mental illness. For maximum

daily temperatures under eight degrees

Celsius, the researchers observed a delay of

zero to fourteen days between exposure to

extreme cold temperatures and increased

ER visit risk. In other words, the cold

effect on ER visits was not always evident

until up to fourteen days after exposure to

temperatures below eight degrees Celsius.

However, neither precipitation nor air

pollution were found by this study to alter

the observed temperature-mental illness


Though the first study suggested

that extreme temperatures may induce

adverse mental health effects for people

16 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue


of all ages and races, it also indicated

a disproportionate effect for certain

subpopulations. Youth and elderly

populations, defined as ages zero to

nineteen and over sixty-four, respectively,

seemed more susceptible to heat effects.

Additionally, the model suggested greater

risk of ER visits for African Americans

ages fifty to sixty-four exposed to intense

heat as compared to other racial groups

in the same age category. Some posit that

the observed vulnerability of African

Americans, the elderly, and young people

to extreme temperatures may reflect

disparities in access to healthcare, housing,

and technology on a larger, societal scale.

To examine how differences in geography,

climate, and population impacted

exposure-response relationships, the

researchers expanded the study to include

ten different labor regions in New York

State. Unlike in the first study, they did not

find short-term exposure to extreme cold

to be associated with increased ER visits for

any mental disorder. However, the findings

did suggest a positive association between

maximum daily temperatures above 27.07

degrees Celsius and elevated risk for ER

visits. Diverging from the findings of the

first study, no racial group or age cohort

was observed to be more vulnerable to the

effects of heat than any other group.

The varying results between

northwestern New York counties and

New York State as a whole suggest that

the results of any particular analysis

are subject to geographic and climatic

limitations and that further expansion

of the study is required to make more

generalizable conclusions. Foremost,

both studies support the researchers’

hypothesis that extreme temperatures

increase one’s risk for visiting the ER for

mental health reasons.

New Possibilities for Public Health

Measures currently in place to

protect the public from the effects of

severe weather include radio warnings

of impending extreme temperatures,

required heating systems in New York

housing, and publicly available cooling

and heating centers in urban areas.

Unfortunately, such efforts often fail to

meet the needs of the most vulnerable

populations. Cooling and heating


centers are rarely adequate in number or

capacity in low-income, under-resourced

neighborhoods, the very areas where

they are needed most. Additionally,

unlike heating systems, air conditioning

in housing is not necessitated under

New York law. This places an additional

financial burden on tenants and, in many

cases, effectively removes their access to

such systems altogether.

Chen cautioned that while improving

existing measures is necessary, as

they provide immediate support to

vulnerable groups, adaptive actions

like air conditioning are ultimately

“double-edged swords.” Air conditioning

increases energy demand and emissions,

thus exacerbating climate change. Chen

and Yoo pointed instead to research

suggesting that the cultivation of green

spaces in so-called “heat islands,” urban

areas that retain high levels of heat, can

reduce temperatures naturally. By adding

green spaces, communities can promote

better mental and physical health without

compromising the environment.

Ultimately, however, most climate

research indicates that effective prevention

of climate change will require efforts on

a much larger, societal scale, including

the commitment of governments and

corporations to achieve net zero emissions.

An Expansive Research Landscape

Yoo and Chen know that their work

is far from done. For all the questions

this study answers, it raises just as many


new ones. Both highlighted the need

for future research to intimately involve

psychologists. “While we were working

on this study, I had a lot of conversations

with psychologists,” Yoo said. “We have

a lot of interesting hypotheses that need

to be verified, but in some cases, this

is hard to do with population data…

We need to combine population-level

studies with cohort studies.”

Yoo emphasized that future studies

should investigate new or more diverse

populations in different climatic regions

to better understand the variation

observed between the county- and statelevel

studies as well as discrepancies in

outcomes between subgroups.

Chen expressed particular interest in

further exploring how and why shortterm

exposure to extreme temperatures

can exacerbate more long-lasting, chronic

conditions. “That’s something we don’t

know much about,” Chen said. “There

must be something, through biological or

societal mechanisms, that can explain how

temperature [has this effect]. This is paving

the way for more research on this topic.”

As climate change accelerates, it seems

that the urgency of Yoo and Chen’s

research will only become more apparent.

Without a proper understanding of

how extreme temperature events might

increase potential for severe mental

health episodes, we cannot be adequately

prepared for the full range of climate

consequences. After all, as the oftrepeated

climate activism saying goes, the

climate is changing—why aren’t we? ■



ANNA CALAME is a junior in Davenport College studying the history of science, medicine, and public

health. Outside of her work with the YSM, Anna is involved with Yale UAID, YaleBleeds, and the club

tennis and climbing teams.

ANGELICA LORENZO is a sophomore in Grace Hopper College majoring in Biomedical Engineering.

In addition to writing for YSM, Angelica is a percussionist in the Yale Symphony Orchestra, serves as

Professional Development Chair for the Yale Society of Women Engineers, climbs with YCT, and does

tissue engineering research in the Pober Lab.

THE AUTHORS WOULD LIKE TO THANK Professors Chen and Yoo for discussing their research


Yoo, E. H., Eum, Y., Gao, Q., & Chen, K. (2021). Effect of extreme temperatures on daily emergency room

visits for mental disorders. Environmental Science and Pollution Research, 1-14.

Yoo, E. H., Eum, Y., Roberts, J. E., Gao, Q., & Chen, K. (2021). Association between extreme temperatures

and emergency room visits related to mental disorders: A multi-region time-series study in New York,

USA. Science of The Total Environment, 148246.

December 2021 Yale Scientific Magazine 17


The Environmental Issue





A sustainable

solution to


urgent waste




Avocado seeds, lobster shells, fish scales,

red algae, cactus leaves… and now, wood.

What do these items have in common?

As it turns out, researchers around the world

have turned to all these unexpected materials to

develop biodegradable alternatives to plastic.

Petrochemical plastics are plastics derived

from crude oil and natural gas. Such nonrenewable

resource-based plastics have pervaded

modern life—they can be found everywhere,

from fertilizers to packaging to clothing, and

are cemented as an integral part of society.

According to the International Energy Agency,

petrochemical feedstock now accounts for twelve

percent of oil demand around the world. But it is

not the quantity alone that renders plastic a global

issue—instead, it is the lack of biodegradability.

18 Yale Scientific Magazine December 2021 www.yalescientific.org


how could a balance

between degradability and

durability be achieved?

A potential solution may lie in

bioplastics, alternative materials

that use different biomass feedstock

to create bio-based plastics that are

biodegradable. A breakthrough study on

the creation of bioplastic from natural

wood was recently published in Nature

Sustainability, co-authored by Yuan

Yao, assistant professor of industrial

ecology and sustainable systems at the

Yale School of the Environment (YSE),

and Liangbing Hu, a professor at the

Center for Materials Innovation at the

University of Maryland.

The quest for a biodegradable plastic

to combat the billions of metric

tons of plastics accumulating in the

environment has led to the creation

of these bioplastics. Currently,

petrochemical plastics last for hundreds

to thousands of years due to the stable

long polymer chains they contain,

such as those found in polyethylene,

polystyrene, and polyvinyl chloridebased

plastics. Because previous

efforts to produce bioplastics have

been associated with the use of toxic

chemicals, weak mechanical strength,

and poor water stability, researchers

started to wonder: how could a balance

between degradability and durability

be achieved?

In this study, the research team reports

a method of fabricating lignocellulosic

bioplastic that not only demonstrated

recyclability and biodegradability, but

also dramatically improved durability.

“There are many people who have tried

to develop these kinds of polymers in

plastic, but the mechanical strands are

not good enough to replace the plastics

we currently use, which are made mostly

from fossil fuels,” Yao said in a Yale

School of the Environment News article.

Overall, their bioplastic showcases high

mechanical strength as well as improved

water and thermal stability.

Building Better Bioplastic

To create bioplastics, researchers

typically extract lignin and cellulose,

two organic polymers responsible for

plant structure, from wood. The team

performed a process called in situ lignin

regeneration, whereby instead of isolating

lignin and cellulose, they homogenized

wood powder, or made it uniform, to

form a high-density, viscous slurry.

Next, deep eutectic solvent (DES)—a

group of biodegradable and recyclable

substances—was used to dissolve lignin

and break apart the hydrogen bonds

between cellulose fibers. Water was then

added to the slurry for lignin regeneration

from the DES. Finally, the DES was

removed from the mixture through a

filtration and washing process, leaving

behind a stable cellulose-lignin material.

Through a simple casting process, the

team fabricated bioplastic films.

In sharp contrast to cellulose film,

lignocellulosic bioplastic was found to

be considerably more resistant to water

The Environmental Issue


damage. The researchers demonstrated

that it absorbed water at a much slower

rate than standard cellulose film. As a

result, lignocellulosic bioplastic samples

maintained their shape well past thirty days

of being submerged in water, far beyond

the point at which cellulose film degraded.

While the durability of lignocellulosic

bioplastic is critical for its large-scale

use, the most important characteristic

of this new bioplastic was its ability to

break down under the right conditions.

When the researchers subjected it

to an outdoor environment, they

found that exposure to sun, wind,

and rain was enough to completely

break it down within five months. For

comparison, PVC—a commonly-used

synthetic plastic—subjected to identical

conditions remained unchanged. “That

[characteristic] is what really makes

this plastic good: it can all be recycled

or biodegraded," Yao told the Yale

School of the Environment News. "We’ve

minimized all of the materials and the

waste going into nature.”

The more sustainable production

process of lignocellulosic bioplastic, in

addition to the material's impressive

physical properties, makes it a promising

replacement for less environmentally

friendly petrochemical plastics. This

bioplastic follows a closed-loop cycle

in which microorganisms in soil can

naturally degrade the material. Typical


December 2021 Yale Scientific Magazine 19


The Environmental Issue

plastics take hundreds of years to

decompose in nature, filling up landfills

and potentially leaching toxic chemicals

into groundwater; in contrast, this type of

bioplastic breaks down far more quickly

and poses less risk to communities and

nature in the process. The lignocellulosic

bioplastic can also be recycled.

Barbara Reck, a senior research

scientist at the Yale School of the

Environment, characterized the project’s

findings as an impressive innovation.

“A bioplastic is fully degradable under

regular outdoor conditions, offering

an opportunity to reduce putting a

much-needed end to the accumulation

of at least some plastics in the natural

environment,” she said.

The Future of Bioplastics


Synthetic plastics p ose a major threat to e cosystems once they are disp osed of, f illing up

landfills and polluting waterways.

a product that has a large environmental could elucidate the connection between

The environmentally friendly, closedloop

impact because of its persistence to the growth cycle of forests to the

cycle used to create this bioplastic one that might potentially be relatively manufacturing process of this bioplastic.

signals hope for a future where strong, benign,” Ashton said.

Such advances in the processability and

biodegradable bioplastics can be In determining a sustainable functionality of wood could motivate

produced from resource-abundant, production network, the team has better forest management practices

sustainable, and renewable biomass. continued to research how scaling up in addition to realizing the lower

Hu told the Yale School of the manufacturing for this bioplastic could environmental impact of using wood as

Environment News that the malleability impact forests. The issue with using wood a sustainable material.

of this bioplastic will allow for several byproducts is that large-scale production Considering our far-reaching reliance

applications. From being molded into a may require massive amounts of wood, on plastic in society, the discovery of

film for use in plastic bags to being shaped which could negatively impact forests a biodegradable, durable bio-based

for use in automobile manufacturing, this and local ecosystems.

plastic is worth its weight in gold.

bioplastic may help solve our society’s According to Yao, the research team In this way, the researchers are like

current dependence on plastic.

is responding to this potential issue Rumpelstiltskin—spinning something

Because this lignocellulosic bioplastic by working with a forest ecologist to valuable out of a natural material in

is made of biomass feedstock, its build forest simulation models, which ways we never thought possible. ■

production would entail the use of local

materials rather than nonrenewable

fossil fuels, which would further ABOUT THE AUTHORS

mitigate environmental damage. “It is

very promising to see the flexibility LUCAS LOMAN AND KAYLA YUP

in the biomass feedstocks used for LUCAS LOMAN is a sophomore Environmental Engineering major in Morse College. In addition

this process,” Reck said. “One can to writing for YSM, Lucas serves in the Energy and Environment Center of the Yale Policy

imagine a decentralized production Institute, as well as Yale Design for America’s Garden Club of New Haven project.

network that uses predominantly local KAYLA YUP is a first-year in Pierson College interested in studying Biomedical Engineering.

materials, which in turn would keep the Outside of YSM, Kayla serves as a copy editor for the Yale Herald, writes for the Yale Daily News,

overall environmental impacts [of the

and works for the Peabody Museum.

lignocellulosic bioplastics] rather low.” THE AUTHORS WOULD LIKE TO THANK Dr. Barbara Reck and Dr. Mark Ashton for providing

Yao’s team’s work on using wood as a commentary.

substitute for plastic presents significant

substitution potential for petroleum

derived plastics. Mark Ashton, Morris K.

Jesup Professor of Silviculture and Forest

Ecology and the Director of the Yale


Anusewicz, J. (25 March 2021). Turning Wood Into Plastic. Yale School of the Environment News.

Xia, Q., Chen, C., Yao, Y., Li, J., He, S., Zhou, Y., ... & Hu, L. (2021). A strong, biodegradable and recyclable

lignocellulosic bioplastic. Nature Sustainability, 1-9.

Xiao, S., Chen, C., Xia, Q., Liu, Y., Yao, Y., Chen, Q., Hartsfield, M., Brozena, A., Tu, K., Eichhorn, S. J., Yao, Y.,

Forests, further emphasized the benefits Li, J., Gan, W., Shi, S. Q., Yang, V. W., Lo Ricco, M., Zhu, J. Y., Burgert, I., Luo, A., … Hu, L. (2021). Lightweight,

of using bioplastic over petrochemical strong, moldable wood via cell wall engineering as a sustainable structural material. Science, 374(6566),


plastics. “[Bioplastic usage can] mov[e]

20 Yale Scientific Magazine December 2021 www.yalescientific.org



The Environmental Issue




Like those in all animals, the internal biological processes of

cattle create byproducts that must be peed, pooped,

or (rather notoriously) farted out. Collected waste

from the world’s 1.5 billion cows creates a mess for farmers

and scientists alike. In addition to the potent greenhouse

gases released from their farts, the solid and liquid waste

generated by these famously flatulent ruminants can

pollute water systems, reduce air quality, and contribute to

global warming. Urine contains nitrogen, which is naturally

converted into nitrous oxide, a greenhouse gas three-hundred

times more powerful than carbon dioxide. Globally, cattle urine

accounts for nearly 1.6 percent of greenhouse gas emissions.

Scientists from New Zealand and Germany think they may have

discovered a solution: toilet-training cows.

Lindsay Matthews, a researcher at the University of Auckland

and the project’s leader, has considered the possibility for a long

time. In a 2007 radio interview on the harmful environmental

effects of cow waste, the interviewer humorously suggested that

Matthews train cows to use the loo. The interviewer, thinking his

wacky suggestion would whiz by without much more than a laugh,

was shocked to hear that Matthews thought it possible.

Influenced by American behavioral psychologist B.F. Skinner,

Matthews and his team developed a backward-chaining—that is,

working backwards from the goal—three-step process for training cows.

First, they established a specially constructed latrine as the correct

place to “void.” Individual calves were given a diuretic and led into

the latrine. Every time a calf urinated, they were rewarded with either

a molasses drink or crushed barley—“Ben and Jerry’s [for] cattle,”

described Matthews. Training sessions, which lasted for no more than

forty-five minutes, were continued until the calves turned to receive the

reward after urination eighty percent of the time, or until eight or ten

sessions had been completed. At this stage in the training, Matthews

and his team were unsure whether they had only conditioned the

calves to expect reward upon urination, or whether they had also

established the latrine as the correct location for urination.

Next, the calves were allowed to roam freely in a segment outside

the latrine. Calves that moved into the latrine to micturate—that’s

jargon for urinate—were rewarded, while “accidents” outside the

latrine were punished with a three-second water spray. Calves

were considered sufficiently trained after three consecutive correct

urinations occurred during a session. By the end of the study,

eleven of sixteen calves were declared successfully trained.

Finally, a second section was opened leading to the latrine, forcing

the calves to control their reflexes over an extended time period

and distance. Remarkably, successfully trained calves urinated in

the latrine approximately seventy-two percent of the time without

any corrective intervention from the experimenters.

Matthews and his team hope that their research findings will be

implemented by large and small-scale operations around the world.




that there will be s o m e

difficulties in scaling-up

the training, but

he thinks that modern technology exists to enable training on a large

scale. He suggests that young calves—who require more attention

than adult cows and can be kept individually—be monitored and

rewarded using machine vision. Maintaining the correct behavior

will require careful design and strategic positioning of the latrines,

but Matthews is optimistic that “[they] can crack it.”

Matthews suggests that punishment for urination outside may

not be required for training. During the training process, some of

the calves were successfully trained without the three-second water

spray. Of the calves that were punished, most immediately stopped

urinating, entered the latrine, and finished their business. “The

latent behavior was already there,” Matthews said, “The calves just

needed a reminder for it to be correctly expressed.”

The calves are like “kids who know the toilet, [and] know the

routine. They just get so distracted,” Matthews said.

He also thinks that training processes that reward for correct

behavior inherently punish incorrect behavior: the absence of a

reward during incorrect behavior is itself corrective. Matthews

and his team will further explore this possibility in the future, as

eliminating the punisher will facilitate training on a large scale.

Matthews’ research has demonstrated that these “dopey”

ruminants are actually quite intelligent. Through training, they

can gain an interoceptive awareness of their urinary systems

and learn to control their reflexes—often faster than an infant.

And we have a lot to gain when we don’t underestimate cows’

brainpower: Capturing eighty percent of cow urine will reduce

ammonia emissions by fifty-six percent and significantly reduce

the release of nitrous oxide. ■

December 2021 Yale Scientific Magazine 21


The Environmental Issue



Light pollution and the rise of

satellite megaconstellations



Far above the rush of everyday life, past our

fragile atmosphere, and across millions of miles

of space, billions of stars glow. While bright city

skylines already make it difficult for people in

urban areas to enjoy this beautiful night sky,

a new source of light pollution is on the rise:

satellite megaconstellations, also known as

satcons. Satcons are collections of thousands

of artificial satellites launched by commercial

companies, and they are lighting up the

night sky. Researchers from the University of

Regina, University of British Columbia, and

University of Toronto at Scarborough recently

collaborated on a predictive model for the

damage satcons will ultimately cause to their

research and to the night sky.

In the last few years, researchers have seen the

impacts of satcons grow both in their research

and in their everyday lives. Astronomer

Samantha Lawler moved to Saskatchewan in

2019 for a faculty position at the University

of Regina and was able to see the Milky Way

from her home for the first time. But she saw

something else as well: a growing number of

satellites whizzing by due to Starlink, a satellite

constellation operated by SpaceX with the

stated goal of providing worldwide internet

service. “I knew from my calculations that

this [was] going to be a big problem for a lot

of areas of research in astronomy,” Lawler said.

Astronomers often collect data by using

telescopes to take pictures of the sky in different

wavelengths of light, such as visible, infrared,

and radio. However, the recent increase in

satcons has resulted in an increasing number

of images being contaminated by satellite

streaks. While this can currently be corrected

for by taking several images of the same patch

of sky, this restorative measure will become

increasingly unreliable as more satcons are

launched and more images are contaminated.

Even telescopes in space aren’t immune to

22 Yale Scientific Magazine December 2021


satellite contamination—the historic Hubble

Space Telescope has to contend with it as well.

The future James Webb Space Telescope will

be one of only a few telescopes free from their

influence, due to its more distant orbits.

The brunt of the impact of satcons will likely

be felt by astronomers who study the skies in

visual wavelengths. As images become more

and more filled with satellite streaks, they will

contain fewer and fewer pixels of data that are

actually useful to researchers. For example, the

Vera Rubin observatory, a nearly $500 million

facility in Chile, has predicted that thirty

percent of its images will be severely impacted

by satellite trails. “The same science goals [in

visual astronomy] can happen, but they’re

going to take longer,” Lawler said.

Other types of astronomical research will feel

the impact of satcons as well. Near Earth object

observations, which involve monitoring for

asteroids potentially dangerous to our planet,

will become much more difficult as satellites

are mistaken for asteroids. Radio astronomy

will also be hit hard as commercial satellites

begin making noise at frequencies currently

reserved for research.

In most fields of astronomy, it will

simply take more data over more time to

reach the same findings. But getting access

to telescopes and observatories to take

data is already incredibly competitive for

researchers. “It just means that fewer people

are going to be able to get science results. We

don’t actually know what we’re going to miss,

and that’s pretty sad,” Lawler said.

To get an idea of the damage satcons will

cause, Lawler and two other researchers created

a model based on reflectivity estimates and

launch filings to the Federal Communications

Commission (FCC). Their model allows

anyone curious to enter a latitude, time of

day and year, and several other factors, and

view an estimate of what satcons will affect

their night sky. It is freely available at http://


In creating this model, researchers faced the

major challenge of modeling the reflectivity

of satellites without specification information

from the companies. As such, they used a

classic physicist trick: modeling every object as a

sphere. This allowed for surprisingly successful

predictions, creating data that matched with

observations better than more complicated

attempts. They also had to balance countless

other complex factors, including distribution

models for orbits. But their work will pay off:

such an accurate model will be extremely useful

to other researchers going forward.


It’s worth questioning how this problem

could be fixed instead of simply modeled

better. At first glance, there seems to be an

easy solution: regulate the corporations

launching the satcons. But unfortunately,

no regulations currently exist for low Earth

orbit. At the moment, industry is voluntarily

having some discussions about the issue:

this July, the National Science Foundation

hosted SATCON 2, a conference to facilitate

conversations between astronomers and

satellite operators. But “it just became

incredibly clear during the meeting: you

[corporations] don’t have to be here. You

don’t have to talk to us,” Lawler said.

Companies are ultimately under no

obligation to respect the night skies, and

never will be without a major change in

international regulation, which would take

years to implement. Meanwhile, SpaceX

continues to rapidly launch satellites into

space. “My hopes are not enormously high

that [regulation] will happen fast enough,”

said Hanno Rein, an astrophysicist at

University of Toronto at Scarborough.

Satcons are also causing enormous

environmental problems. Their launches

release an incredible amount of carbon into

the atmosphere.

And that’s not the end of the damage they

can cause. SpaceX alone plans to have 42,000

satellites that will be replaced every five years,

meaning that they will have to deorbit more

than twenty satellites per day. These satellites

will burn up in Earth’s atmosphere, depositing

six tons of aluminum and other materials into

our upper atmosphere daily and wreaking

untold environmental havoc.

One measure could help prevent this fate:

the global recognition of low Earth orbit as an

environment. This would force environmental

impact assessments to be conducted for these

satellites, giving governments a better idea of

their potential damage to the atmosphere.

The Environmental Issue


While researchers would much rather

return to their preferred areas of study,

satcons are not going away—so unfortunately,

neither is research into their effects, including

their climate and environmental impacts. For

example, teams have begun to look into what

huge quantities of deorbiting satellites might

imply for Earth’s atmospheric chemistry.

Research may also need to examine the

biological implications for animals that rely

on the night sky for navigation.

Astronomers will continue working

to mitigate the effects of satcons on their

research, including attempting to lower the

numbers of satellites launched. Additionally,

they will advocate for satellites to be launched

into orbits minimally destructive to research.

Finally, they will aim to make satelliteimpacted

research as useful as possible—

for example, work is being done to perfect

algorithms to remove satellite damage

from images. “Someone could describe it as

chemotherapy for your images. It’s not great,

not ideal, but it’s better than nothing,” Lawler

said, attributing the phrase to astrodynamicist

Moriba Jah at the University of Texas Austin.

Unfortunately, while these strategies help

mitigate the damage wrought by satcons, they

can never fully undo it.

The benefits brought by Starlink and

other satcon services are certainly worthy of

acknowledgment. But only a tiny fraction of the

world’s population will be able to afford these

services—Starlink internet service currently

costs $99 a month, plus a $499 upfront cost.

This creates a familiar system where wealthy

countries reap the rewards of technological

advancement while the entire world feels its

negative consequences. A tiny portion of the

Earth will gain faster internet service, and an

even tinier portion will line their pockets. But

untold volumes of astronomical research—

and perhaps more tragically, the sheer beauty

of the clear night sky—will be lost to all. ■


The Milky Way rising above the Paranol Observatory in Chile. The Paranol Observatory is one of many that

will soon have to contend with heavy interference from satcons.

December 2021 Yale Scientific Magazine 23


The Environmental Issue






From September 2019 to March

2020, Australia experienced one

of the worst recorded wildfire

seasons in its history. Spanning 18.6

million hectares, the wildfires were

responsible for massive ecological

and socioeconomic damage. Around

three billion animals were estimated

to have been displaced or killed,

causing a severe loss of biodiversity

that will prove difficult to recuperate

from. Furthermore, 715 million tons

of carbon dioxide and various aerosols

were released into the atmosphere over

the course of the bushfires, the effect of

which was felt around the world.

Despite the undeniably catastrophic

effects of these fires, their unprecedented

nature provided researchers with a

unique opportunity to study the global

impacts of wildfires—including their

previously under-studied consequences

for marine ecosystems. The researchers

hope that further research on this topic

can help us better predict and respond to

wildfires and their effects in the future.

Scientists Weiyi Tang and Joan

Llort, helming an international team

of researchers under biogeochemist

Nicholas Cassar and climatologist Richard

Matear, were intrigued by the relationship

between two known phenomena:

wildfires drag nutrients like iron into

the atmosphere, and iron deposition

can trigger phytoplankton blooms in

water given the right conditions. Further

motivated by the limited research on the

marine effects of wildfires, the scientists

used data from the bushfires to determine

their effects on phytoplankton blooms in

the South Pacific Ocean.

“[The bushfires] provided us with a

unique opportunity to see how and if

such wildfires could have an impact on


The Australian bushfires ravaged entire ecological systems, causing a terrible loss of biodiversity.

ocean ecosystems downwind. Very often

in science it’s very difficult to detect the

signal from the noise, but here we had an

unprecedented wildfire event, and so this

was a unique opportunity,” Cassar said.

To measure aerosols produced by

wildfires, the team used black carbon

aerosol optical depth (AOD) data

provided by the Copernicus Atmospheric

Monitoring Service (CAMS). Black

carbon AOD cannot actually be

measured directly, but is rather estimated

from overall AOD, which is in turn

measured spectroscopically by satellites

in the atmosphere. This data reflects

the concentration of all aerosols in a

given air column—not just black carbon

aerosols produced by fires. The CAMS

aerosol model uses meteorological

data to separate total AOD into many

subcategories, including black carbon,

dust, sulfate, and salt.

AOD values for these wildfires were

abnormal, reportedly over threehundred

percent higher than average

values since 2004. They indicated

eastward drift of black carbon into the

South Pacific Ocean, which was then

confirmed through modeling of air

trajectories from meteorological data.

To quantify phytoplankton growth

in the South Pacific, the team took

advantage of the fact that phytoplankton,

as photosynthetic organisms, produce

the green pigment chlorophyll a

(Chla). Chla concentrations could then

be estimated from publicly available

satellite observations as a proxy for

phytoplankton biomass. This satellite

data was subsequently confirmed by

marine floats deployed by Argo, an

international program that collects

ocean data with an array of below-thesurface

floats that occasionally surface

to transmit their data to satellites.

Just six months after the wildfires

started, Chla concentrations increased

by more than 150 percent compared

to historical concentrations in oceanic

regions along the path of aerosol

24 Yale Scientific Magazine December 2021 www.yalescientific.org

The Environmental Issue


transport. Furthermore, these increases

in concentration occurred just days to

weeks following spikes in black carbon

AOD, suggesting a connection between

wildfires and phytoplankton blooms,

and further revealing just how swiftly

events of this scale can impact the globe.

The international team also found that

aerosols collected at a station downwind

of bushfires had iron concentrations

over five times the median value of

concentrations observed at the same

station from 2016 to 2019, when smaller

wildfire events occurred. The formation

of blooms requires a variety of nutrients

and environmental conditions—iron

alone is not always sufficient. In this case,

the South Pacific Ocean likely had all the

sufficient conditions for phytoplankton

growth except for iron during the wildfire

season, meaning the iron deposits from

migrating aerosols were likely sufficient

to support the Chla concentration

increase observed in oceans. Thus, the

aerosols produced from the Australian

bushfires may provide an explanation for

the observed phytoplankton blooms in

the South Pacific.

Blooms can have varying ecological

effects depending on the type of

phytoplankton and the characteristics

of the body of water and environment.

In some scenarios, the blooms may,

in fact, benefit the climate. Through

photosynthesis, phytoplankton sequester

carbon dioxide from the atmosphere.

However, the authors have not yet been

able to determine if the carbon dioxide

sequestration is short-term, with carbon

dioxide quickly recycled back into the

atmosphere, or long-term, with carbon

dioxide exported to the deep ocean as

plankton biomass. In future wildfire

seasons, they hope to determine what

fraction of the carbon is sequestered

long-term by using sediment traps to

capture plankton biomass exported into

the ocean from blooms.

Further investigating long-term

sequestration effects will provide

important data that can be used to create

better climate models. Current climate

models do not sufficiently account for

the various and widespread effects of

wildfires. “You're expecting that the

frequency, the intensity, the duration

of some of these wildfires is going to

increase,” Cassar said. “And so, if we're


Phytoplankton blooms occur across the world, such as

here in the Baltic Sea, with varying ecological effects.

going to project our climate in the

future, we need to understand how these

wildfires also impact ocean ecosystems

because of their role in the carbon cycle.”

With further testing at other wildfire

sites and more detailed biogeochemical

analysis, the team hopes they can develop

a better understanding of the climaterelated

impacts of wildfires that would

facilitate future climate predictions.

Because the oceans are

global, and because no

one owns them, there's a

real strong international

collaboration culture in

this space.

—Richard Matear

Ultimately, this project would have

been impossible without international

cooperation. The majority of the data,

including black carbon AOD data and

Chla concentration data, was sourced

from organizations and projects

producing publicly available atmosphere

and ocean data. This collaborative datasharing

and type of cooperation is typical

in the field of oceanography. “Because

the oceans are global, and because no

one owns them, there's a real strong

international collaboration culture in

this space,” Matear said. Such a spirit

of collaboration provides a model for

future climate research—international

cooperation is necessary to address this

global issue.

With this project, the research team

revealed the dynamic, interconnected

nature of our climate and ecology. In

fact, Matear and other climatologists are

changing the language they use to reflect

this connectivity. “I’m going to use the

word ‘earth system’ rather than ‘climate,’”

Matear said. “That’s probably a big

change that’s happening in the climate

modeling space, just acknowledging that

climate and carbon cycle processes are

intimately linked and you probably don’t

want to separate them.”

Climatological trends that may seem

small on paper, such as a global increase

in temperature by just two degrees

Celsius, can have far-reaching and

catastrophic effects. As weather patterns

and natural phenomena become more

severe due to climate change, so too do

the impacts they have on regions around

the world, on species nearing extinction,

and on delicate climate systems.

Today, humans have become deeply

entangled in this environmental web.

“We're such a successful species that we're

impacting our climate. We're impacting

the temperature of the atmosphere and

the likelihood of droughts in some

regions, so I think there's a local and

global impact of our species that we have

to take into account,” Cassar said.

It is vital to understand how local

perturbations by humans can cause

drastic changes on a global scale. This

study reveals just how much we have

yet to uncover about the connectivity

of Earth’s natural and artificial systems.

Cassar, Matear, and their team, for

example, observed links between

wildfires and phytoplankton populations

thousands of miles away. Future research

into this issue will require searching for

more unexpected connections between

climate-related phenomena. ■


December 2021 Yale Scientific Magazine 25


The Environmental Issue





It’s in the very air we breathe.

Invisible gases, small but pervasive,

travel and lodge themselves in our

airways as we go through our daily

motions. The truth is, the air we breathe

is not equitable in its distribution.

Harmful pollutants such as nitrogen

dioxide (NO 2

) aggregate in particular

communities, leading to severe health

disparities and stark gradients in air

pollution maps. It has long been known

that low-income, urban neighborhoods

and communities of color experience

significantly worse air pollution

than higher-income, majority-white

neighborhoods. Sally Pusede’s group

from the University of Virginia took

this research a step further, conducting

a broad survey of the air pollution of

the United States and comparing it

with various external factors such as

days of the week and vehicle pollution

in order to locate specific drivers of the


This project combined environmental

research with environmental justice

policy in hopes of elucidating intercommunity

disparities. It focused on

nitrogen dioxide, NO 2

, an air pollutant

commonly released from road vehicles

and fossil fuel combustion reactions.

NO 2

is also a key factor in atmospheric

oxidation and secondary pollution, as it

reacts with other chemicals in the air to

form pollutants that are not otherwise

directly emitted into the atmosphere,

such as ozone and acid rain. NO 2


been previously shown to increase levels

of respiratory irritation and can lead to

hospitalization due to impaired lung

function and shortened life expectancy.

The researchers used data from the

TROPospheric Ozone Monitoring

Instrument (TROPOMI), a satellite

launched in 2017 that maps NO 2


almost daily, providing a high degree

of clarity for air pollutant emissions

at the city-level. “Prior to TROPOMI,

the satellite observations [regarding

NO 2

emissions] were too coarse to look

within a city, so you couldn’t go into a

city and look at how NO 2

is distributed.

With these finer scale observations,

we can now look at the steep gradients

within a city to the point where you can

look at a map of NO 2

and make out the

individual roads,” said Mary Angelique

G. Demetillo, a graduate student in

Pusede’s group.

With the TROPOMI data, they were

able to calculate mean NO 2


vertical column densities for each 1 x 1

km 2 area. Pusede’s group analyzed NO 2

data from 2018 to 2020 from fifty-two of

the largest cities, stopping right before

the start of the pandemic to eliminate any

changes in pollution caused by reduced

social activity. The cities sampled were

“urbanized areas,” so the data reflected

intra-urban, rather than suburban-urban,

differences. The data was classified by race,

ethnicity, and income to compare the air

pollution in low-income communities of

color to that of high-income, majoritywhite

neighborhoods and to quantify

inequalities in terms of NO 2


“All of the data that we used was publicly

available, so anyone can use it, and it’s just

a question of what’s the best method and

how can we integrate all of these types of

datasets together. For me, that challenge

is pretty exciting,” Demetillo said.

Previous research in this field had

already established these existing

disparities, but Pusede’s group

wanted to look into the drivers of

these disparities. In this paper, they

compared the data between weekends

and weekdays, and cross-referenced


Air pollution emissions from diesel vehicles contribute

to elevated nitrogen dioxide levels in the atmosphere.

26 Yale Scientific Magazine December 2021


The Environmental Issue



The global three-year running mean of NO 2

levels from 2010-2012 taken directly from the NASA worldview page.

this with patterns in diesel truck traffic,

allowing them to see what proportion

of the atmospheric disparities were due

to diesel truck emissions. While diesel

trucks make up between three and five

percent of vehicles at any given time,

they contribute thirty to fifty percent of

air pollution from NO 2

and many other

harmful chemicals and particles. “People

who live in impacted communities have

long known that diesel trucks are a

major contributor to disparities, but

what we contribute here is really sort of

the quantification of those [disparities]

and the ability to see those [disparities]

across cities and in so many cities at the

same time,” Pusede said. Data regarding

diesel truck emissions was taken from

the Fuel-Based Inventory from Vehicle

Emissions, which provides information

on emission rates and fuel use.

The results of this study indicate

that in general, the air pollution in

lower-income communities of color

is twenty-eight percent higher than

that of high-income majority-white

neighborhoods. Some of the cities with

the highest inequalities were Phoenix,

Arizona (where NO 2

pollution was

forty-six percent higher for lower

income communities of color) and Los

Angeles, California (where pollution

was forty-three percent higher).

Regarding diesel truck emissions

specifically, air pollution decreases by

sixty-two percent on weekends—in part

because more vehicles are parked on

the weekends. Despite this, disparities

still remain, as NO 2

pollution in lowerincome

communities of color only falls

by thirty-seven percent.


This study only used data from 2018.

"[Over time] broadly speaking, there

have been really large gains in air quality

across the country, but disparities have

persisted throughout this time,” Pusede


Just having this data in front of us

is not enough. Pusede’s group hopes

to influence policymakers with these

findings to induce changes that confront

and dismantle this inequality. And this

work doesn’t just relate to scientists.

“For sure it would take interdisciplinary

collaboration with people who work with

human activity data, urban planning,

maybe even historians to assess how the

placement of communities and roads

has contributed to the current-day air

pollution distribution,” Demetillo said.

These policies could take the form

of identifying specific areas in urban

regions that should be more highly

regulated for diesel truck traffic.

But even if diesel truck emissions were

effectively brought down to zero, there

would still be disparities in air pollution

from other sources. Thus, moving forward,

researchers must investigate other major

contributors to air pollution and its

unequal distribution, as well as patterns

affecting human exposure to it and the

causes of these disparities. Human activity

data shows us that patterns in activity

affect an individual’s exposure to pollution.

Meteorology affects the distribution

of NO 2

within the atmosphere, which

also affects our exposure to pollution.

Urban planning is a major factor in air

quality disparities, as the placement and

structuring of communities and roads

affects how pollution is distributed.

Closely analyzing satellite data is also

key to reducing inequality and lowering

air pollution. In this study, since the

data was so finely resolved spatially,

some temporal data was sacrificed: the

researchers used seasonal or annually

averaged data. However, they are now

looking into daily satellite observations,

which could provide more temporal data

regarding these disparities that their

current analysis could have missed.

Additionally, as NO 2

is not distributed

homogeneously in the horizontal

direction, there will be different levels

of exposure to NO 2

as you travel across

Earth’s surface. However, the satellite

data currently used takes an atmospheric

cross section that doesn’t account for

these horizontal gradients. Looking into

them with new satellite data will be yet

another important step forward in the

future of this research.


The Sentinel-5 Precursor satellite's mission is to measure

and monitor Earth's atmosphere. The TROPospheric

Ozone Monitoring Instrument (TROPOMI) is mounted

on the satellite and takes measures of atmospheric

nitrogen dioxide levels almost daily.

“I think an important part of this work

is incorporating local communities and

local governments into this work. Now

that we have a stronger technical grasp

on this data, we can better work with

those communities to address issues

that we might not even know they

are experiencing. I think their voices

and their perspectives would greatly

contribute to this work,” Demetillo said.

With more research into atmospheric

inequality with collaboration from

affected communities, policymakers,

and others in the field, we can look

forward to concrete changes to alleviate

disparities—as well as tackle pollution

as a whole. ■

December 2021 Yale Scientific Magazine 27


Science Communication







From individuals’ eagerness to escape

the stagnancy of life under stayat-home

mandates, to the global

sense of urgency to produce a vaccine for

COVID-19, a focus on time has defined

the pandemic. Families wondered for

how many more months they would

have to delay reunions with loved

ones. Parents, especially those without

access to childcare or homeschooling

resources, anxiously awaited the return

of in-person schooling. In contrast,

research progressed at warp speed as the

scientific community furiously worked

towards understanding COVID-19 and

developing a vaccine.

The World Health Organization’s

(WHO) global database of literature

on COVID-19 contains over 350,000

documents, demonstrating the sheer

quantity of work that has been completed

on the singular topic in just under two

years. While the number of publications

has massively increased, so has

communication between researchers, as

the threat of the pandemic eliminated

many of the formalities that previously

prevented the sharing of pre-published

materials. However, the removal of the red

tape in scientific publishing has resulted

in many retracted studies, deemed

unjustified or simply incorrect after

publication. Thus, a question emerges:

how the desire to share new discoveries,

especially those essential to saving lives,

can be balanced with the need to conduct

research ethically and effectively.

COVID-19 has revolutionized the

publication process, forging new

networks of communication that expand

scientific discussion but can also obscure

the purpose of scientific journals.

Preprint servers, which allow for the

upload of unpublished manuscripts, have

become increasingly popular sources of

information. MedRxiv, a server partially

owned by Yale University, contains nearly

twenty-thousand papers on SARS-CoV-2

alone. The allure of these sites is clear:

they remove the middle-men of formal

publishing, allowing information to be

more easily disseminated. Furthermore,

while the publishing process for peerreviewed

scientific journals was arduous

in previous years, many of these journals

have adjusted their methods since the

onset of the pandemic. Some of these

new practices change how information

is shared, like allowing the public to

have free access to coronavirus content,

28 Yale Scientific Magazine December 2021 www.yalescientific.org

Science Communication


increasing the spread of useful data with

relatively few drawbacks.

Other modifications to the publication

process, specifically the rushed review

of submitted materials, fundamentally

alter what type of information journals

present. In the context of the pandemic,

rushing publication or modifying

how information is shared could be

a necessary price to pay for sharing

updates as quickly as possible. Thijs

Kuiken, a veterinary pathologist in the

Netherlands, notified the WHO when he

realized how rapidly the COVID-19 could

spread upon reading a manuscript he was

reviewing for The Lancet in January of

2020 at the start of the pandemic. Taking

such action would previously have been

highly unconventional due to strict

regulations about sharing unpublished

material, but the journal editors and

authors of the study supported his

decision considering the danger of the

virus. “There are no clear guidelines

or agreements about how reviewers

of scientific manuscripts should deal

with such crucial information during

public health emergencies,” Kuiken

remarked to the journal Science, in

reflecting upon how urgent findings are

shared within the scientific community.

Kuiken’s comments speak to the dire

need for a revision in how information

is communicated in the pandemic age.

Publications have certainly started to

change their ways. Holden Thorp, the editorin-chief

of Science, described this new rate of

publication as unprecedented in a New York

Times article.“It’s the same process going

extremely fast,” Thorp commented.

Kim Tingley, author of the article,

cautioned that this speed might not be

all beneficial. “The strength of traditional

academic journals… is that they have

the expertise to interrogate the validity of

highly specialized experimental methods

and the accuracy of the resulting data,”

Tingley wrote. In rushing the traditional

steps of publication, journals must, to

some degree, lower the level at which

they examine the validity of submitted

studies. Without an updated definition

of the role of scientific publications,

there exists a dangerous dissonance in

which journals maintain their perceived

standing as sources of near absolute

scientific authority but actually publish

materials that haven’t been reviewed to

the fullest extent. Preprint platforms

and accelerated publication methods

have offered easier and faster access to

information, but these changes have

occurred so rapidly that the expected

quality of information published has yet

to be updated, making studies potentially

seem more reliable than they actually are.

The consequences of hasty publication

are perhaps most obvious in the example

of the Surgisphere scandal. In June of

2020, The New England Journal of Medicine

(NEJM) and The Lancet, widely regarded

as two of the most prestigious medical

journals, were forced to retract two papers

that sourced data from Surgisphere after

the company denied the publications

access to the results they had collected.

NEJM’s retracted piece used

Surgisphere resources to assert that

COVID-19 patients on angiotensinconverting

enzyme (ACE) inhibitors and

other blood pressure drugs were not at

higher risk for death. The Lancet article

pointed to remarkably increased death

rates in COVID-19 patients treated

with hydroxychloroquine based on

Surgisphere data sourced from multiple

countries. The high repute of these

journals led many to trust the information

in both articles. The World Health

Organization (WHO), for example,

paused its trial testing the efficacy

of hydroxychloroquine as a possible

treatment for COVID-19 infections after

The Lancet’s study pointed to increased

death rates resulting from the drug.

Data emerging from Surgisphere was

quickly questioned because, as explained

by an article in Science, it seemed unlikely

that “a tiny company without much

publishing experience in big data analysis,

could have collected and analyzed tens

of thousands of patient records from

hundreds of hospitals.” These concerns

should have prevented the article from

being published in the first place.

Unfortunately, the pressure of the

pandemic overcame proper examination

of sources in the case of the Surgisphere

scandal, resulting in grave misconduct.

The retracted Lancet paper, for example,

only added to confusion surrounding

hydroxychloroquine, the malaria drug

that former President Trump pointed to

as a cure for the coronavirus on Twitter

and in press conferences. Twitter later

labeled Trump’s tweets as misinformation

and removed them from the platform,

and the use of hydroxychloroquine

was later rejected as a treatment for

COVID-19. Still, the rush to publish

research on the drug and the following

retraction of said research complicated

the already chaotic discussion around

treatments for


While political discourse has

unfortunately seen a rise in disinformation

in recent years, the spread of false data is

far more concerning in journals such as

The Lancet, which are expected to only

publish papers with the highest degree of

scientific rigor. The ramifications of The

Lancet’s paper speak to the repeatedly

seen consequences of rushed publication

in the scientific community.

COVID-19 has drastically impacted

almost every aspect of the status quo,

including how scientific papers are

published. The destructive effects of

the pandemic have greatly complicated

journals’ aim both to share the everincreasing

updates on what we know

about COVID-19 and fully examine

each data point and source. Until a

balance can be struck between these two

goals, the onus will fall upon readers

to more critically examine what they

read, making scientific literacy more

important than ever. ■










December 2021 Yale Scientific Magazine 29



YC ’22


Senior Elea Hewitt described herself during her gap year as

the happiest she had been in years. Returning to Yale from a

year spent on her family’s Oregon ranch, she has fascinating

perspectives on the intersection between farming and agriculture,

social justice, and sustainable environmental practices.

Hewitt grew up in rural Oregon in the Willamette Valley on her

family’s farm. Homeschooled until high school, Hewitt looks

back fondly on her primary education. She was taught

by her mother and given freedom to let her interests

guide her learning, which often took place outside.

Now an Environmental Studies major at Yale,

Hewitt has observed the continued relevance of

things she learned early on. For example, she

was already familiar with some of the concepts

in her Economics of Natural Resources class

because of experiences in her early childhood.

A gap year gave Hewitt the opportunity to

connect with her family farm in a way that she

never did while busy in high school. She enjoyed

spending days outside, being active, and caring

for the animals. Beef and lamb are the farm’s main

products, but they also have chickens, turkeys, and a

few ducks. Hewitt highlighted that one of the joys of the

ranch is stewarding Navajo-Churro sheep and maintaining

relationships with other breeders to preserve both the

breed and a familial cultural practice.

Currently, Hewitt’s family is working

to convert pastureland into multitiered

agroforestry silvopasture,

which combines tiers of trees and

other plants with livestock. They

plant chestnut trees at the top, then

hazelnut trees, then berries and

vines. At the bottom, they plant

ground cover, such as mushrooms

and sorel. Animals graze between

rows of plants, eating their fallen food,

pruning them, and providing manure to

help them grow. This method of planting

maximizes production value, allowing for the

cultivation of more calories per square acre. Most

importantly, because each plant requires and replenishes different

resources, it helps restore the soil’s nutritional balance.

Imbalances in soil nutrition have become a problem on many

large-scale farms. Although it may seem that industrialized

agriculture is more efficient than smaller scale farms, this is only

the case for the first ten to fifteen years. Over longer timelines, it

becomes extremely wasteful, costly, and inefficient due to problems

with soil quality, water contamination, and transport cost.


Hewitt’s farming background has also made her aware of the

injustices that common industrial farming practices cause, to both

the planet and humans.

“Humans have lived on the planet for so long, but we’ve only

lived [in an industrialized way] way for two hundred years. It has

resulted in so much poverty and inequality. Industrial

agriculture is agribusiness, and there’s something

unethical about centering a business model

around something that is a basic need,”

Hewitt said. “However, due to the way

the agribusiness system developed

in America, there is little room for

a just transition at this point. An

overhaul centering Indigenous

and local agriculture production

pathways is necessary.”

Hewitt would like to see a

return to community-based food

production, with more people

involved in farming, more farmer’s

markets, and less reliance on food

sourced from afar. “I think society

would be a better place if more people

had experience with agriculture. I think there

is a disconnect from reality that exists today as a

result of peoples’ lived experiences which often center

around academic or non-physical work,” Hewitt said. “At the

end of the day, we have to remember that we’re human; we’re

animals. We have a body that was designed for work, and

it’s important to be well-rounded.”

Hewitt identified some changes she would like to

see here at Yale. First and foremost, she encourages

the university to hire more Indigenous faculty.

On the individual level, she wishes that each

Yale student could visit both the Yale Farm and

a landfill. Encouraging them to face a reality they

might not encounter on a daily basis, she believes such

experiences could leave a lasting impression, impacting

students’ future decisions. Hewitt also raised the idea of

creating a “climate credit,” which would require students to

gain environmental awareness, just as they are required to learn

about math or science. Elea expressed how this awareness is crucial;

ignoring it is no longer an option.

After college, Elea hopes to work on different types of farms,

work for a non-profit, and travel. She hopes to learn through these

diverse experiences before she eventually takes over her family’s

farm, where she will continue to implement Indigenous and

environmentally sustainable practices, working towards a more

socially just future. ■


30 Yale Scientific Magazine December 2021 www.yalescientific.org



PhD ’75


From curating exhibits at the Smithsonian to teaching judges

about the facts of climate change, Paul Hanle (PhD ’75) has spent

decades helping the public appreciate the importance of science.

Hanle came to Yale in 1969 with the intention of earning his PhD

in physics but changed directions soon after. “I was interested in

both physics and how physicists think, where their

ideas come from, and how the circumstances in

which they work enable science to develop,”

Hanle said. He focused his studies on the

History of Science & Medicine and was

awarded his PhD in 1975.

After his fourth year of studies, Hanle

won a fellowship at the Smithsonian

Institution. He was appointed as a

curator at the soon-to-open National

Air and Space Museum in 1974. One

of his proudest accomplishments was

overseeing the creation of the Air and

Space Smithsonian magazine. “It was

extremely exciting and gratifying to create

something brand new,” Hanle said.

Hanle had been bitten by the museum bug. He went on

to lead two museums—the Maryland Science Center and the Academy

of Natural Sciences of Philadelphia. As CEO of the Maryland Science

Center, Hanle pursued new, creative routes of communicating scientific

knowledge. For example, he helped lead the Museum Film

Network, which produced the IMAX film To the Limit—a film

exploring human physiology through athletics. “It was a very

powerful strategy for conveying scientific information,”

Hanle said. “The audience didn’t necessarily know

they were learning science.” As president of the

Academy, Hanle opened an exhibit on dinosaurs that

brought museum visitation to record highs. Hanle’s

ingenuity in his leadership at these museums created

meaningful opportunities for the general public to

engage with scientific thought.

Hanle went on to become the first president of the

Biotechnology Institute, an organization centered

around getting kids excited about modern bioscience.

Each year, the organization grants BioGENEius

awards to students who completed outstanding science

projects, honoring them at an annual convention attended

by thousands of representatives from biotechnology companies.

While working at the Biotechnology Institute, Hanle advised

President Barack Obama’s 2009 Educate to Innovate initiative,

a bipartisan effort to advance the level of STEM education

available to kids across the country. “It was successful in helping

to raise the profile of the issue and getting companies to realize

that they had a stake in STEM education,” Hanle said.



In 2011, Hanle shifted his work towards educating the public

about climate change. “In my view, it’s the greatest challenge to

humanity and the planet,” Hanle said. “It is truly existential.”

He became CEO of Climate Central, an organization focused on

communicating the scientific facts of climate change to the public.

One of their major projects involved getting local meteorologists

to incorporate information about the impact of climate

change on weather into their daily newscasts. “There’s a

maxim in communication about climate change—to

convey simple messages, repeated often, by trusted

messengers,” Hanle said. “Those three elements are

a very important way to reach people who might

otherwise not be reached.”

Climate Central’s impact is widespread;

figures generated by the organization illustrating

what rising sea levels would look like at iconic

places like the Gate of India and the White House

were used at the United Nations’ Climate Change

Conference in 2015 to emphasize to delegates the

dangers of rising temperatures.

In 2018, Hanle embarked on his latest effort: founding the

Climate Judiciary Project at the Environmental Law Institute.

The project’s mission is to educate judges about climate science

and its connection to environmental law. “I realized that a lot

of interesting things were happening in legal

cases around trying to hold emitters or

producers accountable for the effects

of climate change,” Hanle said. “It

seemed to me that one of the

crucial things we could do is to

educate these decision makers,

the judges, about the objective,

scientifically valid facts of

climate change.” The program

has received strong interest

from judges, and project

leaders are currently planning

to expand it internationally.

Hanle’s advice for getting people

to care about climate change is

simple: stick to the science. “If you

can convey the scientific facts objectively,

you might reach a broader audience,” Hanle

said. “That audience may include people who are not

necessarily sympathetic to social movements for climate action or

are even skeptics, but who might be convinced that there’s a really

serious problem about climate change that needs to be addressed

now.” Hanle’s work exemplifies how scientific communication and

education can be used to create positive change. ■


December 2021 Yale Scientific Magazine 31




What do whales, fizzy water, and a 364-foot Ferris wheel have to do

with the climate crisis? In her new book, Our Biggest Experiment:

The Epic History of the Climate Crisis, author and climate activist

Alice Bell answers this question and many more as she explores the climate

crisis from a unique perspective, focusing not only on the future of the planet

but also on the history of how we reached this critical point.

Devoting each chapter to a different aspect of environmental history, Bell explains

the first weather maps, the advent of electricity, and even the origins of the term “tree

hugger”—trust me, it’s not what you’re expecting. Starting with scientist and activist

Eunice Foote’s 1856 experiment positing the effect of increased carbon dioxide on

atmospheric temperatures, Bell weaves together the story of how humans began

shaping the Earth. The book highlights several little-known but influential climate

scientists, including Foote and Guy Calendar, the English scientist who linked

Earth’s rising temperatures to rising carbon dioxide concentrations in the 1930s.

When trying to find ways to combat climate change, certain ideas crop up time

and time again, like the idea of a technofix, a new technological approach to the

problem of climate change that tends to oversimplify the problem and distract

from the root problems. “It’s almost a magician’s trick. It’s a way of looking at

shiny new tech… and not old tech that’s destroying the world,” Bell told Yale

Scientific. Despite the excitement surrounding alluring new ideas like cloud

seeding and artificial volcanoes, we must exercise caution. “All technology’s kind

of a double-edged sword. We have to think of how we apply it, who’s in charge,

and what other technologies we need alongside it,” Bell said.

One single solution will not solve the crisis, and focusing on futuristic quick fixes

can distract from the basic problems that need to be addressed, like our dependence

on and overuse of unrenewable energy sources. Bell remains hopeful but pragmatic:

today, our future will depend more on minimizing, rather than totally reversing,

climate change. Keeping the world half a degree colder might sound inconsequential,

but in reality, it equates to countless lives, homes, and livelihoods saved.

Bell stresses the importance of developing a personal connection to the

environment and climate. It’s easy to become cynical and apathetic when

thinking of the climate crisis as an ambiguous, ominous tide of change, but

forging personal connections to the environment—whether through planting

trees, joining environmental action groups, or investing in renewable

energy—can remind us of the close relationship between our lives and the

environment. If you’re unsure where to begin, reading Bell’s book could be

a good start. “It’s hard to feel like you understand [the climate crisis], but I

understood it more because of the history, and so I wanted to share that with

other people,” Bell said. With a more complete understanding of the past, we

can hopefully begin building a more sustainable future. ■


Melting ice sheets in the Arctic are evidence of the changing climate’s

influence on environment, human lives, and the future of the planet.


32 Yale Scientific Magazine December 2021






Carbon emissions from power plants get trapped in the atmosphere,

creating a greenhouse effect that accelerates the planet’s warming.

Stephen Latham, JD, PhD, stumbled upon bioethics by happenstance in his

first job after law school. Now the director of Yale’s Interdisciplinary Center

for Bioethics, Latham is perhaps best known for his popular spring-term

course, Bioethics and Law. His new course this fall, Philosophical Environmental

Ethics, focuses on the philosophical questions relevant to the climate crisis.

First, Latham wants his students to understand the broad contours of the field

since the 1970s. “At that point, environmentalism was a fight against dumping stuff

into the water, or releasing stuff into the air,” Latham said. Early environmental

activists weren’t yet aware of greenhouse gases as a harbinger of climate change. They

decentralized human affairs in their discourse, focusing their concerns on animals

and ecosystems. Latham explained that the increasing visibility of the climate crisis

in the public and scientific imagination has shifted discussion back toward humans.

“Today, under pressure from the urgency of the need to do things about the climate,

people are thinking about how we can save the climate for ourselves,” Latham said.

Currently, most environmental discussions center on the extractive value of the

environment. “Philosophical environmental ethics raises slightly more technical

questions about how to value nature in itself,” Latham said. For example, the

“nonidentity problem” considers the responsibilities we have to future generations

who will only exist because of present-day choices about climate change. “If we

don’t do anything about climate change, people fifty years from now would be

looking back on us and saying, ‘You left us this horrible planet,’... but you could

point out to them that they only exist because we didn’t do anything about climate

change,” Latham said. Our current actions—or inactions—will decide who will

be left to reckon with the climate crisis in future years.

Topics in his course seem to beg for political action, and Latham hopes

his students will respond to the impulse. “I want people out there protesting

against more extraction of fossil fuels and in favor of renewable energy and

carbon capture and so on,” Latham said. However, he also realizes that the

ability to protest against climate change often comes from a place of privilege.

“It’s hard to say to someone who’s just getting by, ‘You have a moral obligation

to be thinking about climate change,’” Latham said.

But the target of Latham’s instruction are Yale students—privileged by their

education—who he hopes will leave his course equipped with the tools to address

climate change in their activism, careers, and personal lives. “I’m arming them

with arguments that they might be able to use in the future, whether it’s to a city

council or to their intransigent uncle over Thanksgiving dinner,” Latham said.

Trained as a lawyer and a scholar, Latham recognizes that the philosophical

perspective he can provide on environmental issues is only one piece of the puzzle.

Nevertheless, the ability to reason and write about our ethical responsibility to mend

the environment can help his students contribute to political and scientific action. ■



December 2021 Yale Scientific Magazine 33









For some Americans, the phrase “climate change” conjures

images of barren lands crippled by drought and forests

decimated by wildfires. For others, climate change is a distant

thought, a phenomenon entirely unrelated to human activity.

For over a decade, the Yale Program on Climate Change

Communication (YPCCC) has studied Americans’ changing

perceptions of climate change and provided critical public

opinion surveys for news outlets such as CBS, NBC, CNN, and

The New York Times. YPCCC was founded in 2007 and is directed

by Anthony Leiserowitz, a senior research scientist at the Yale

School of the Environment.

Leiserowitz’s journey into the realm of climate change

communication was unanticipated—a confluence of his seemingly

disparate interests and serendipity. As an undergraduate,

Leiserowitz majored in International Relations, studying Cold

War politics. But in 1990, he was offered a position at the Aspen

Global Change Institution, a research center in Colorado,

surrounded by snow-capped mountains and dense conifer forests.

For four years, Leiserowitz immersed himself in climate studies

among the world’s leading environmental scientists, learning

about carbon pollution and climate models.

However, Leiserowitz eventually grew frustrated with the narrow

focus on natural science. “The only reason we have [global warming]

is because of people [and their decisions],” Leiserowitz said. “This

isn’t a natural science problem. This is a human science problem.”

This realization would guide the rest of his career. Leiserowitz

devoted himself to studying human responses to the climate

crisis, earning a master’s and doctorate in Environmental Science,

Studies, and Policy at the University of Oregon. He then spent

four years at Decision Research, a research institute in Oregon,

where he studied public risk perceptions and decision making,

seeking the answers to pivotal questions concerning the climate

crisis: How do people perceive the natural and social worlds?

What are the psychological and political factors that shape human

decision-making? How do we better communicate climate change

and engage people in climate science?

Leiserowitz founded YPCCC in 2007, when he was hired

by the Yale School of Forestry and Environmental Studies—

recently renamed as the Yale School of the Environment. The Yale

Program includes psychologists, geographers, political scientists,

sociologists, and others who conduct studies on public opinion

and engagement. YPCCC has spearheaded research on public

attitudes regarding climate change in more than 120 countries,

including the United States, China, India, and Brazil. The program

has also partnered with governments, media organizations, and

companies, including Facebook and Google, supporting their

climate change communication goals.

Leiserowitz reiterated that all of our lives are entangled with the

burning of fossil fuels: they are woven into the clothes we wear,

the electronics we purchase, and the appliances we use. Every time

we buy a product, we contribute to climate change. Every time we

vote, we choose leaders who will either support or oppose climate

policies. Multiply this by seven-and-a-half billion people, and the

need for large-scale messaging becomes clear.

“One of the major shifts that we’ve seen change over the past ten

years is recognizing how important communication is as a way

to engage the broader society itself,” Leiserowitz said. YPCCC’s

research has found that many people perceive global warming as a

remote issue. “Many Americans continue to think of climate change

as a distant problem—that this is about polar bears, or maybe

developing countries, but not the United States, not my state, not my

community, not my friends, not my family, not me,” Leiserowitz said.

As a result, the issue is often psychologically distant, blending into

the noisy background of people’s lives, where it doesn’t seem salient.

To engage a national audience in climate change, Leiserowitz also

founded Yale Climate Connections (YCC). A climate change news

service and national radio program, YCC broadcasts a new oneand-half-minute

story about climate change every day on more

than 680 frequencies nationwide. YCC’s listeners are not just located

in liberal regions of the U.S.; in fact, two-thirds of its stations are

located in congressional districts that voted for former president

Donald Trump. YCC’s stories feature the voices of Americans from

all backgrounds—racial justice activists, religious leaders, business

owners, doctors, farmers—communicating that climate change is

harming Americans right here and now.

Currently, Leiserowitz is working to build a Global Center for

Climate Change Communication at Yale to foster international

research and public engagement, at a scale equal to the size of

climate change itself. ■

Editor’s Note: Elsewhere, we covered a research article coauthored by

YPCCC researchers. See page 8.

34 Yale Scientific Magazine December 2021 www.yalescientific.org






do no harm.” All doctors swear by the ancient

Hippocratic oath. But we must ask ourselves, do


hospitals really do no harm? The production,

distribution, and eventual disposal of medical drugs and

equipment are major contributors to climate change. In fact, if

global healthcare was its own country, it would be the fifth largest

emitter on the planet. The severity of healthcare’s carbon footprint

contradicts the values of a system centered around protecting

human health. Physicians are contributing, whether they realize it

or not, to one of the largest public health crises in human history.

Yale Professor Jodi Sherman provides a solution as to how

healthcare can strive to “do no harm” on a global scale. Her

research focuses on creating sustainability metrics that help

inform administrative and physician decision-making towards

more environmentally sustainable operations. Sherman’s

recent paper published in British Medical Journal introduces

the idea of “planetary healthcare,” which expands the principle

of “first, do no harm” beyond the patient to the environment.

In an interview with Yale Scientific, Sherman isolated three

ways in which physicians can adopt this planetary healthcare

lens: first, reduce emissions from healthcare services; second,

match the supply and demand of healthcare services; and

third, reduce the demand for healthcare services.

On the first point, healthcare emissions are often embedded

in the products and spaces physicians use when providing care.

By using sustainability metrics, physicians can select drugs,

equipment, and procedures that are less polluting yet still

produce the same clinical outcome. For example, Sherman’s

work on tracking the life cycle of anesthesia drugs reveals

that certain gases, such as desflurane and nitrous oxide, are

significantly higher contributors to emissions compared to

other clinically similar options. In addition to guiding clinical

practices, empowering physicians with the environmental

information associated with certain medicines and products

used in treatments helps them leverage organizational

purchasing power to influence a more eco-friendly industry.

Secondly, healthcare resources are often inappropriately

utilized, which creates unsustainable practices that fail to match

supply and demand. “In the U.S. over fifty percent of healthcare is

devoted to five percent of the population with advanced chronic

disease… there are also alarming statistics on how much we


spend on end of life [care] and it’s not frequently the care patients

would choose if they were better informed,” Sherman said. It is

necessary to both mitigate excessive resource consumption while

also maximizing high value, clinically effective treatment, which

ultimately leads to more positive environmental outcomes.

Finally, it is imperative that we reduce our demand for healthcare

resources. This involves directing care resources upstream and

incorporating non-pharmacological and lifestyle methods to

preventing disease. Medical services contribute to only twenty

percent of health and wellbeing, while the rest is attributed to social

and environmental factors. Integrative healthcare aims to address

this other eighty percent of human wellbeing by informing patients

of healthier life choices (such as reducing alcohol consumption)

and alternative pain management strategies (such as acupuncture

and meditation). Moreover, consistent primary care enables early

prevention, detection, and treatment, leading to better health

outcomes. As such, it is important to invest in primary care and

public health so that preventative measures can reduce the demand

for acute treatment of advanced disease down the line.

Several sectors must come together if we wish to achieve netzero

emissions in healthcare. With the COVID-19 pandemic,

the world witnessed global mobilization and cooperation

in healthcare unlike anything ever seen before. “While we

had an increased need for emergency care and critical care,

and obviously increased consumption of personal protective

equipment and other healthcare resources, the global medical

community came together quickly, sharing information,

redesigning models of care, increasing access to telehealth,

and moving towards a circular economy—meaning, keeping

materials in use for longer,” Sherman said. “This begs the

question, why are we not doing this routinely?”

The pressures of the pandemic forced physicians to challenge

the culture of disposability and excess consumption of resources

within medicine. Medical practitioners safely succeeded

at efforts to adapt practices, increase communication, and

become better stewards of healthcare resources, proving

that rapid change in response to a crisis is possible. Indeed,

the world is now faced with a global crisis more urgent than

anything we have dealt with before. The lives of all people and

the planet are at stake. Doctors swore to “do no harm.” It is

now time to “do no harm” to our environment. ■

December 2021 Yale Scientific Magazine 35

FROM THE ARCHIVES Yale Scientific Magazine, Summer 1980

36 Yale Scientific Magazine December 2021 www.yalescientific.org






Every year, millions of patients recover from life-threatening

surgeries and other medical procedures, only to get a

secondary infection caused by the presence of bacterial,

fungal, or viral particles on medical implants. In fact, the Centers

for Disease Control (CDC) estimates that healthcare-associated

infections account for an estimated 1.7 million infections

and 99,000 associated deaths each year in the United States

alone. Medical implants such as catheters, pacemakers, and

prosthetic joints act as ideal habitats for biofilms—bacterial

colonies that aggregate on smooth surfaces and remain

highly resistant to treatment with antibiotics.

In the past, the only methods for treatment involved

surgical removal of the implant or degradation of the

biofilm using enzymes, which often had toxic effects on

the human body. Researchers at Pulmobiotics, a spinoff

company from the Center of Genomic Regulation

in Spain, have recently developed a state-of-the-art

technique to solve this problem: “living medicine,” or the

introduction of genetically engineered bacteria to fight

the dangerous pathogens within the body.

In this technique, researchers decide on a “good

bacterium” to use, then remove specific genes

to eliminate the infectious or disease-causing

capability of the bacterium. They then equip the

bacteria with an engineered genetic platform

designed to secrete antibiofilm and bactericidal

enzymes—giving the bacteria the ability to

disintegrate or “fight” infectious biofilms.

Maria Lluch Senar, a biotechnologist who

formerly worked at the Center for Genomic

Regulation before founding Pulmobiotics

with her research partner Luis Serrano,

has been working with the bacterium

Mycoplasma pneumoniae for over ten

years in an attempt to characterize its

genome. Ultimately, the researchers sought to create a

bacterial chassis, a genetic framework that could house and support

exogenous DNA without interfering with the bacterium’s functional

purpose: targeting ventilator-associated pneumonia.

With a mortality rate of ten to fourteen percent, ventilatorassociated

infection is caused by pathogenic bacteria like

Staphylococcus aureus, which “grow in thick layers that are very

difficult to target by using conventional antibiotics because [the

antibiotics] cannot cross [the bacterial] barrier,” Senar said.

Thus, the lab aimed to engineer a bacterium that could fight

against biofilm infections: removing the pathogenic factors of M.

pneumoniae DNA while concurrently adding synthetic promoters

and sequences designed to destruct S. aureus biofilms in the lungs.



The researchers chose to use M. pneumoniae for their microbial

chassis due to several favorable biological characteristics. The

bacterium, for example, had known activity in lungs. “When you

want to engineer a live biotherapeutic, it is important to look

for bacteria that is naturally present, or already colonizing, the

target organ,” Senar said. M. pneumoniae also had a genetic

advantage: “The strain has a unique genetic code

that prevents gene transfer,” Senar said. Moreover,

M. pneumoniae’s slow division allowed for an

expanded production time scale in the lab and

provided additional control over the

bacteria’s replication rate in vivo.

Thus, if there was a major

problem with the delivery

system of the chassis, it

was easier to contain the

spread of bacterial growth

and remove the bacteria

from the patient’s lungs.

However, the biggest

advantage of M. pneumoniae

was its

lack of a cell wall. The immune

s y s t e m ’ s pathogen recognition mechanisms

often target bacterial cell walls; thus, this feature of M.

pneumoniae would allow it to escape immune recognition,

preventing host elimination of the microbial chassis. This also

allows for a combined treatment approach: after the bacterial

chassis secretes biofilm-dispersing agents, antibiotics and

bacteriolytic enzymes can be co-administered to attack the cell

wall of S. aureus without damaging M. pneumoniae.

The researchers delivered the biofilm-fighting genes

to M. pneumoniae with plasmids, circular pieces of DNA

that can be transferred from cell to cell. They assembled

the plasmids from DNA fragments of genes of interest

using the Gibson method, a molecular cloning technique. Of

interest, the researchers delivered genes that drove continuous,

localized production of dispersin B, a hydrolytic enzyme that

breaks down S. aureus bacterial cells, to provide long-term

disruption of the biofilms. After genetically engineering their

M. pneumoniae, the researchers tested their chassis in mice

models to verify its safety and efficacy.

The research team is also looking beyond S. aureus biofilms. Due

to the natural ability of M. pneumoniae to colonize the respiratory

tract, bacterial therapies hold important future potential in many

medical therapies. “The 21st century is becoming the century of

synthetic biology,” said Senar, highlighting genetic engineering’s

increasing potential to create novel treatments for a wide range of

diseases, from cancer to chronic obstructive pulmonary disease. ■

December 2021 Yale Scientific Magazine 37


Evolutionary Biology / Psychology

















Loss of biodiversity is just one of many grave consequences

due to climate change. Recent research sheds light on a

species’ capacity to escape extinction by evolving rapidly at

microgeographic scales. A study from the Skelly Lab of the Yale

School of the Environment replicated research from 2001 that

investigated how various populations of wood frogs, Rana sylvatica,

exhibited differing embryonic development characteristics in

response to factors associated with climate change.

The study sought to understand how certain species

could adapt to climate change. “Wood frogs are a great

study system because they form natural metapopulations

and are highly adapted to cold and therefore sensitive to

warming,” said A. Andis, a PhD candidate in the Skelly

lab. Results showed that embryos in 2018 developed at rates

fourteen to nineteen percent faster than those in 2001 on

average. Further, there was variation among embryonic

development rates across frog populations separated only

by small geographic differences, a pattern found in both

the 2001 and 2018 studies. Several environmental factors

attributed to climate change, including canopy cover and

pond temperature, influenced development rates.

“When it comes to predicting conservation outcomes into the

future, [scientists] tend to [ignore] the capacity for organisms

to adapt and variation within species and populations,” Andis

said. This study provides some hope that organisms can mediate

the effects of human environmental impacts. However, this

capacity is limited—“too much change, too quickly” still has

disastrous effects. Some species, unfortunately, may already

be approaching this rate limit or have passed it already, a

phenomenon known as “extinction debt.” ■

How much do you think you can learn in a year’s time? At

the Cognition and Development Lab at Yale, researchers

compared children’s and adults’ attitudes towards how

much knowledge they believed one could acquire in one year. The

research was driven by previous findings showing that children

are more optimistic than adults when it comes to knowledge

acquisition attitudes. Research scientist Kristi Lockhart sought

to see if shortened time frames, methods of learning, or types of

knowledge affected this attitude. Who was more optimistic?

Apparently, children. “Even though they made a distinction

of what they could learn [with different methods of learning]

if you look at some of their scores, they are still above average

[compared to] the adults,” Lockhart said.

But this optimism is not without its limits. Children ages

five to seven still believe two-year-olds are unable to learn

anything, making a bigger distinction between themselves and

the two-year-olds than themselves and adults. Additionally,

they distinguish themselves specifically, displaying a selfenhancement

effect; in other words, each child believes they

will be able to learn more than their peers.

But the question remains: why are the children so

optimistic? Lockhart has a few theories. First, this optimism

may be necessary to keep children motivated in schools. It

may not be unfounded, as adults routinely underestimate

how much children can learn. Conversely, children may

maintain this level of optimism because they don’t yet have

the metacognitive skills to consider the effort required by

knowledge acquisition. In early life, children seem to learn

without consciously exerting effort, potentially causing them

to view knowledge acquisition as easy. ■

38 Yale Scientific Magazine December 2021


Cellular Biology / Epidemiology

















Vesicular transport is a vital process that allows

proteins to travel from one location to another in

package-like vesicles. When a vesicle reaches its

target membrane, it has two fates. It can undergo full fusion,

in which the vesicle completely fuses with the membrane

to deliver its cargo. Alternatively, it can undergo kiss-andrun,

in which the vesicle connects with the membrane before

rapidly reclosing. Seong An, a research associate at the Yale

School of Medicine, discovered that bridge-like vesicle

tethers, such as exocyst complexes, play an unexpected role

in fusion mode selectivity.

To investigate the exocyst’s role in the tethering process,

An first mutated Exo70, an exocyst subunit, so that it could

no longer directly bind to the membrane. Unexpectedly, this

did not prevent tethering—instead, it promoted kiss-and-run

over full fusion. When membrane binding by the mutated

Exo70 was “rescued” using optogenetics, a technique that

uses light to control protein function, full fusion occurred.

Finally, An found that in the absence of the exocyst, vesicles

that were optogenetically tethered to the membrane merely

underwent kiss-and-stay, a version of kiss-and-run in which

the vesicle remains at the membrane after fusing. “The

evidence suggests that membrane binding by Exo70 is not

necessary for tethering but vital for the mode of vesicle

fusion,” An said.

Further research may shed light on cellular processes such

as cell migration, as full fusion events play a role in membrane

expansion. “Now that we’re able to observe vesicle tethering

in real time, we can study what kind of impact membrane

fusion has physiologically,” An said. ■

What does it mean to be addicted to food—and is

food addiction the same for everyone? According

to a new study by the Yale School of Medicine

and University of Minnesota Medical School, rates of food

addiction—the compulsive consumption of foods high in

sugar and fat, leading to symptoms of distress—differ across

demographic and weight groups.

In the study, participants reported their views on

healthcare and food consumption as well as their clinical,

demographic, and body-mass index (BMI) information.

Those who had food addiction symptoms such as distress or

impairment as a result of their eating habits were placed into

the food addicted category.

Statistical analyses revealed people with obesity and

females were more likely to report distress related to the

food addiction symptoms after controlling for symptom

frequency. “Women might experience more pressure

related to food and weight, and therefore, [are] more likely

to experience symptoms of distress from eating,” lead

researcher and Yale postdoctoral fellow Meagan Carr said.

“People who are overweight and obese experience stigma

and prejudice, and so it’s also possible that they might have

more reactions to food addiction.”

Carr emphasized the need for a better understanding of

food addiction. “The data show that it may be better to move

beyond focusing on people’s individual choices around food,

and instead think about environmental context and other

contributors,” Carr said. ■


December 2021 Yale Scientific Magazine 39






How retinoic acid

regulates the connectivity

of the prefrontal cortex


There are more synapses in the human brain than there are

stars in the Milky Way. The developing brain manages to

wrangle and organize over one hundred trillion neural

connections—many orders of magnitude greater than the number

of base pairs in our genome. Deciphering how the body constructs

such mind-bogglingly complex cellular structures might demystify

psychiatric diseases and the evolution of the brain. In a recent

study published in Nature, researchers from the Yale School of

Medicine identified a small signaling molecule, retinoic acid, that

plays a key role in the development of the prefrontal cortex.

Located in the front of the human brain, the prefrontal cortex

regulates complex behavior, personality expression, and decision

making. Compared to other animals, anthropoid primates

possess enlarged prefrontal cortices. To identify genes that are

uniquely upregulated in the prefrontal cortex, the researchers

analyzed transcriptome data—information regarding gene

expression across different brain regions—from databases

including BrainSpan and PsychENCODE. They identified 125

protein-coding genes that are upregulated in the human frontal

lobe, which includes the prefrontal cortex and motor cortex,

during mid-fetal development, when gene differentiation

becomes highly enriched. Of the 125 genes identified, many were

associated with the small signaling molecule retinoic acid.

“Since retinoic acid-regulated genes are enriched in the prefrontal

cortex, we decided to analyze these genes more closely,” said Mikihito

Shibata, a co-first author of the study and associate research scientist

in neuroscience at the Yale School of Medicine. Retinoic acid is a

signaling molecule involved in the development of a plethora of

anatomical structures, including the spinal cord, heart, liver, eye,

and limbs. By micro-dissecting brain tissue, the researchers found a

clear gradient of retinoic acid in the brains of mid-fetal humans and

macaques: high levels saturated the prefrontal cortex in the front

of the brain, then sharply dropped after the prefrontal cortex and

continued decreasing towards the back.

The researchers identified similar gradients of retinoic acidsynthesizing

enzymes and receptors and an enrichment of

retinoic acid-degrading enzymes in the regions surrounding

the prefrontal cortex. These findings indicate that expression of

retinoic acid receptors and synthesizing and degrading enzymes

localize the molecule’s activity to the prefrontal cortex.


But what happens when this network is disrupted? In mutant mice

that did not express retinoic acid receptors, retinoic acid signaling in

the prefrontal cortex decreased. When compared to normal mice,

these mutant mice expressed 4,768 genes differently in the mouse

equivalent of the prefrontal cortex. Intriguingly, many of these genes

are known to be responsible for synapse and axon development,

suggesting that retinoic acid regulates synapse and axon development

in mice. Levels of critical synapse proteins such as DLG4 and

synaptophysin were reduced, as well as the number of mushroom

dendritic spines, structures that receive inputs from other neurons.

Next, the researchers used diffusion tensor imaging (DTI), an

advanced MRI-based imaging technique, to observe the effect of

retinoic acid on long-range brain connections. In mutant mice

that did not express retinoic acid receptors, DTI identified a

reduction in connections between the mouse prefrontal cortex

and another brain region known as the thalamus.

The connection between the prefrontal cortex and thalamus is critical

for cognitive function, and abnormalities in the connection have been

implicated in psychiatric diseases such as schizophrenia. “Beyond

having an importance in understanding the evolution and development

of the prefrontal cortex, this paper has critical implications in the

way we conceptualize and possibly treat schizophrenia,” said Kartik

Pattabiraman, co-first author and a Child and Adult Psychiatry Fellow

in the Child Study Center at the Yale School of Medicine. “It’s thought

that schizophrenia is caused by disruption of the adolescent brain, but we

provide evidence that schizophrenia could instead be a developmental

disorder. To truly prevent it, we might have to intervene much earlier.”

On the other hand, in mice that did not express CYP26B1, an

enzyme that degrades retinoic acid, retinoic acid signaling expanded

beyond the prefrontal cortex. Connections between the thalamus and

the prefrontal cortex expanded to regions adjacent to the prefrontal

cortex, and the mouse prefrontal cortex developed characteristics

unique to the primate prefrontal cortex. Does this mean that

increasing neural retinoic acid activity could generate super intelligent

mice? “It’s probably more complex than that. But testing the behavior

of CYP26B1-deficient mice is a next step” Pattabiraman said.

In the future, Shibata and Pattabiraman are interested in

further exploring the role of retinoic acid, uncovering the

secrets of brain development and evolution, and identifying

new paradigms for clinical treatment. ■

40 Yale Scientific Magazine December 2021 www.yalescientific.org


What do fuel cells, water splitting, and artificial

photosynthesis have in common? They’re all vital

technologies in the fight to transition away from

fossil fuels towards a brighter, cleaner energy future. They also all

require a specific type of chemical reaction to work. This reaction,

called a proton-coupled electron transfer (PCET) reaction,

is widespread across energy studies, as well as in biological

systems. In this reaction, protons and electrons are transferred

either simultaneously or one at a time. Understanding PCET

reactions is fundamental to a better understanding of how to

improve cutting-edge sustainable technologies.

Robert E. Warburton, an Arnold O. Beckman Postdoctoral

Fellow at Yale University working in the Hammes-Schiffer group,

has approached this important problem using computational

modelling. While previously his collaborators in the Mayer

lab had collected experimental data on the PCET reactions,

computational modeling can give deeper insight into these

systems. “If we want to understand how to control the chemistry,

we need to know what happens in between that initial and final

stage that you see in an experiment. And a lot of times that

happens on very short timescales,” Warburton said.

His main research goal was to examine how different materials

require different amounts of energy to undergo a PCET

reaction. Each material has a unique property called band gap.

Band gap is associated with the difference in energy between

the highest and lowest electron levels within the material.

Warburton initially hypothesized that a larger band gap would

make a PCET reaction have a larger bond dissociation free

energy (BDFE), which measures how hard it is to break a bond.

Specifically, Warburton’s study focused on how defects in

materials could affect the reaction. Defects could cause the

material to react all at one site: PCET can occur at either low

electron levels or, in the case of a defect, high electron levels that

carry a positive charge. Typically, only one value is reported for

the BDFE, so it’s important to consider how the defects in the

material could impact its actual performance.

Some of the titanium oxide (TiO 2

) metal oxides transferred

the electron from the valence band, a lower electron energy level

where the outermost electrons of the material lay, and some

transferred the electron from the conduction band, a higher





A new approach for

understanding protoncoupled

electron transfer


Computational Chemistry


electron energy level to which some of these electrons jump. TiO 2

is an ideal material to study this because its conduction band has

a different orbital shape than the valence band. The conduction

band, more closely associated with titanium, has an electron

cloud, or orbital, that is shaped like a flower. The valence band,

more closely associated with oxygen, has an orbital that is shaped

like a peanut. Warburton’s model showed a significant difference

between the BDFE of the valence and conduction bands.

Although these results confirmed Warburton’s hypothesis, he and

his collaborators concluded that the model was too simple. While

there certainly was a relationship between the band gap and the

energy of the bond, that wasn’t the whole picture. “We saw the big

result that is interesting and compelling, but we don’t necessarily

have a straightforward answer as to why. So really the hard part

about this was doing the analysis and sensitivity,” Warburton said.

In order to have a more complete model, Warburton and his

colleagues incorporated another theoretical framework, called

Marcus theory. Marcus theory deals with the rearrangement of atoms

in the material during electron transfer. More specifically, an electron

transfer can only occur if there is enough energy to rearrange chemical

bonds in the surrounding environment to accommodate the transfer.

Including these effects in the model made it more complicated but

better able to explain experimentally observed behavior.

Warburton says his work is far from over. “All we’ve been

looking at so far is reaction energies and thermodynamics—

basically how favorable the processes are. Now we want to start

looking at the kinetics of these reactions, so how fast they go,”

he said. Further down the line, his results could one day help us

understand why there may be gaps between the theoretical and

actual performance of materials. Armed with this understanding,

engineers and scientists can choose the optimal material for green

technologies. Although this research seems incredibly specific,

the applications are far-reaching and could impact the way we

design green technologies in coming years.

Warburton’s postdoctoral research is supported by the Arnold

and Mabel Beckman Foundation through an Arnold O. Beckman

Postdoctoral Fellowship. This research study was also supported

as part of the Center for Molecular Electrocatalysis, an Energy

Frontier Research Center funded by the U.S. Department of

Energy, Office of Science, Basic Energy Sciences. ■

December 2021 Yale Scientific Magazine 41


Essay Contest Winner








42 Yale Scientific Magazine December 2021 www.yalescientific.org

Essay Contest Winner


Sound is powerful. I am personally moved

by the sounds of my favorite artists—

from the catchy tunes of Taylor Swift to

the chill-inducing crescendos of my favorite

Hans Zimmer film scores. But just as sound

waves can emotionally destroy us as humans

(causing surges in dopamine or even firing

up our cerebellums), recent experiments

have demonstrated acoustics' efficiency and

promise for manipulating tangible objects in

(literally) groundbreaking ways.

Acoustics—the “science concerned with the

production, control, transmission, reception,

and effects of sound”—is expansive and

interdisciplinary. Considered a branch of

physics, acoustics presents itself in biological

systems, technology, infrastructure, and even

human behavior. Acoustic manipulation is

most known for being emotional, shockingly

levitational, and, most unusually, chemical.

But how can sound—which seems so

uninterestingly ubiquitous—possibly be so

impactful on a molecular level?

The study of sonochemistry merges sound

and chemistry through the ultrasonic alteration

of chemical reactions. In 2013, professors

Manish Keswani and Reyes Sierraat at the

University of Arizona College of Engineering

used sound waves to destroy eleven million

liters of toxic chemical stockpile, breaking fireextinguishing

foam down to carbon dioxide

and water. The sonochemical process that

occurred was sonolysis: the employment of

ultrasonic waves to decompose a substance.

Ultrasounds vibrate at frequencies that

exceed the human upper limit of hearing

(greater than 20,000 Hz). When ultrasonic

waves propagate into liquids, they experience

alternating periods of rarefaction (lowpressure)

and compression (high-pressure)

cycles, like all sound waves. However, in the

low-pressure cycle, the intense ultrasonic

waves create small bubbles or “cavities.”

When the cavities can no longer absorb

or accommodate energy, they violently

implode—releasing high amounts of heat,

energy, and destructive free radicals (unstable

atoms best known for harmful oxidation

in humans). This process, termed acoustic

cavitation, goes on to affect proximate

substances in many ways. According to

Dr. Alexey Peshkovsky’s blog post on

sonomechanics, effects include “sterilization,

polymerization, desulfurization, long-chain

molecule degradation,” among others.

This phenomenon, which can decompose

stubborn toxins, is promising for

environmental preservation. In the case of the

fire-extinguishing foam experiment, the heat

energy from cavitation broke bonds keeping

the perfluoroalkyl sulfonates and carboxylates

(PFCs) intact. PFCS are incredibly difficult to

break down; the EPA has reported numerous

health concerns due to widespread human

exposure and observed toxicity in animal

models. Sonolysis is not only powerful enough

to destroy these persistent PFCs, but also

cost-effective for commercial use. Sonolysis

has also been used for water purification as it

rapidly degrades pollutants without producing

or using additional chemicals. Though this

use of sonolysis is not extremely developed

or widespread, studies have revealed it to be

a potentially effective and low-energy tool.

With experiments showing acoustic cavitation

reducing E. coli’s ability to divide, it may also

prove useful for bacterial eradication in oceans.

Commercial ultrasonic technologies have

existed since the 1970s. The instruments

set off random cavitation to clear debris

from jewelry, scientific samples, surgical

instruments, lenses, and even musical

instruments. Megasonic technology is

another option, employing higher frequency

waves to produce less dangerous and more

controlled cavitation. Since ultrasound also

has the ability to atomize liquids, it has been

used to disinfect hospital surfaces as well.

High-power ultrasound can pose dangers

to humans due to extreme temperatures

that may cause burns. Under professional

supervision, however, sonochemistry has

a reassuring safety record. In fact, medical

scientists and surgeons use sonolysis for

various applications, such as an FDAapproved

and non-invasive cavitation

procedure to eliminate fat (called ultrasonic

fat cavitation). Lithotripsy removes kidney

stones through ultrasonic cavitation as

shock waves break the kidney stones into

more-passable stones. If cavitation bubbles

are deliberately imploded next to diseased

tissue, they can also deliver drugs directly to

the blighted area. Ultrasonic technology even

has the ability to inject new DNA through

gene-loaded microbubbles through a process

called sonoporation. By embedding magnetic

particles into the bubbles, scientists can move

each gene-loaded bubble to targeted locations

electromagnetically. It can even combat

cancer: high-intensity focused ultrasound

(HIFU) is a non-invasive cancer therapy that

destroys cancerous tissue.

Sonochemistry has also proved to be

beneficial in nanomaterial synthesis, a

revolutionary process of creating extremely

small technology with applications in

healthcare, electronics, and beyond.

For example, Fe 3

O 4

NPs (magnetite

nanoparticles)—key for biomedical

applications like biosensors—can be formed

through ultrasound irradiation. Similarly,

sonochemistry has been used to form AuNPs

(gold nanoparticles). Gold nanoparticles,

both costly and difficult to make, are sought

after due to their ability to penetrate cell

membranes without causing damage.

Ultrasonic nanomaterial synthesis is generally

precise and cost-effective, eliminating the

need for complex equipment or facilities.

Thus, sonochemical synthesis may make

AuNPs more accessible if widespread.

Considering that nanomaterials are 100,000

times smaller than the width of a hair strand

and therefore require an arduous production

process, sonochemical synthesis methods will

only become more valuable as demand for

nanoparticles increases.

Sonochemistry has other miscellaneous uses.

Cavitation can emit light through a mysterious

phenomenon called sonoluminescence. In the

1990s, some scientists theorized that bubble

temperatures during sonoluminescence

exceed two million degrees Fahrenheit and can

therefore cause nuclear fusion. Though little

evidence supports this theory, the idea went on

to play a central role in the 1996 Keanu Reeves

science fiction film Chain Reaction. Food

engineers may also benefit from the wonders

of sonochemistry. One investigation showed

that the use of ultrasound as a processing aid

in yogurt can reduce production time by up to

forty percent. Ultrasonic cavitation has even

been used to brew tastier coffee by rupturing

the cell walls of coffee grounds to release more

triglycerides and caffeine at a faster rate.

So, as you jam out to the soul-crushing,

heart-squeezing sounds of your favorite

artists, recall that sound can have just

as much physical power—thanks to the

interdisciplinary study of sonochemistry. ■

Marian Caballo, a senior at Bronx High School

of Science, is the winner of the 2021 Yale Synapse

Essay Contest for high school students.


December 2021 Yale Scientific Magazine 43

YSEA’s 2021 Awardees for Outstanding Academic Achievement

Kudos to the YSEA Award Winners!

Your achievements inspire all of us in the Yale STEM community.

Your achievements inspire all of us in the Yale STEM community

Judith Rodin

YSEA Award for Meritorious Service to Yale University:

Judith Rodin, Ph.D. Professor of Psychiatry, School

of Medicine, and President Emerita, University of


In recognition of her outstanding service in a variety

of roles including Professor of Psychology, Psychiatry

and Medicine; Dean of the Graduate School of Arts and

Sciences; and as University Provost.

Susan Hockfield

YSEA Award for Distinguished Service to Industry, Commerce or


Susan Hockfield, Ph.D. Professor of Neuroscience and President

Emerita, Massachusetts Institute of Technology; Joint Professor of

Work and Organization Studies, MIT Sloan School of Management.

To honor her many contributions to industry and academia at Yale

as Professor Neurobiology; Dean of the Graduate School of Arts and

Sciences; and Provost; and as University President of MIT.

Jerry Chow

YSEA Award for Advancement of Basic and Applied


Jerry Chow, Ph.D. (Yale Physics 2010), Director of

Quantum Hardware Systems Development, Thomas J.

Watson Research Center.

For his work on quantum computing and architecture,

including quantum error correction and quantum

machine learning.


For contributing to Yale’s rich tradition in STEM.

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