L. Goddard

aos.princeton.edu

L. Goddard

The

“Global Warming”

Discussion

An American Perspective

Lisa Goddard

International Research Institute for Climate & Society

The Earth Institute, Columbia University

7 Sept 2012 Philander Symposium


7 Sept 2012 Philander Symposium


7 Sept 2012 Philander Symposium


Climate Variability & Change Globally

65%

13%

Temperature

Most of the variability in the

globally-averaged temperature

is contained in the slowly

varying “climate change”

component.

21%

7 Sept 2012 Philander Symposium

(Greene et al., EOS, 2010)

http://iridl.ldeo.columbia.edu/maproom/.Global/.Time_Scales


Multi‐Model Mean Changes

(2080‐2099)‐(1980‐1999)

Stippling placed over

regions where

multi‐model mean

exceeds 1 inter‐model

standard deviation

7 Sept 2012 Philander Symposium

IPCC AR4, WG1, Figure 10.9


R. Seager, et al, 2007, Science

Precipitation (Blue) and Evaporation (Green) over the SW U.S.

from 20 th Century Simulations and 21 st Century Projections

“If these models are correct… levels of aridity of

the recent multiyear drought… will become the new

climatology of the American Southwest within a

time frame of years to decades.”

7 Sept 2012 Philander Symposium


Observed Changes in 20 th C Precipitation

12%

21%

65%

7 Sept 2012 Philander Symposium


Observed Changes in 20 th C Precipitation

12%

3%

21%

17%

65%

76%

7 Sept 2012 Philander Symposium


Observed Changes in 20 th C Precipitation

12%

3%

21%

17%

65%

76%

7 Sept 2012

Philander Symposium


Information Needs

… for the science and for society

• Characterization of past observations

– How large are the decadal-scale fluctuations and interannual

variability compared to trends?

• Attribution

– Will the “current trend” continue?

– What/Who is “responsible”?

• Prediction/projection

– Impact of increasing GHGs + evolution of low-frequency [natural]

fluctuations in the climate system?

– How do these slow changes affect risks of climate impacts from

year-to-year variability?

7 Sept 2012 Philander Symposium

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