Energy and Human Ambitions on a Finite Planet, 2021a

9 Climate Change 150
140
CO2 ppmV annual contribution
1.50
1.25
1.00
0.75
0.50
0.25
2100: 0.0 ppm V /yr
coal
oil
gas
cumulative CO2 ppmV contribution
0.00
1800 1850 1900 1950 2000 2050 2100
year
130
120
110
100
90
80
70
60
50
40
30
20
10
Total: 235 ppm V
coal
oil
gas
0
1800 1850 1900 1950 2000 2050 2100
year
Figure 9.13: CO 2 rise if immediately reversing
fossil fuel use in an ambitious decline
reaching zero by the year 2100. The accumulation
would come to 235 ppm v at the
end, which is almost twice the current level
(1.9 times). The associated temperature rise
would be 2.6 ◦ C.
100
1.50
2050: 0.0 ppm V /yr
90
Total: 169 ppm V
CO2 ppmV annual contribution
1.25
1.00
0.75
0.50
0.25
coal
oil
gas
cumulative CO2 ppmV contribution
0.00
1800 1850 1900 1950 2000 2050 2100
year
80
70
60
50
40
30
20
10
coal
oil
gas
0
1800 1850 1900 1950 2000 2050 2100
year
Figure 9.14: CO 2 rise if we mounted a superaggressive
weaning of fossil fuels, completed
by the year 2050. In this extreme case,
the total CO 2 emission would be 169 ppm v ,
or 37% more than we have produced to date.
The associated temperature rise would be
2 ◦ C.
contribution to the atmosphere would be an increase of 169 ppm v , which
is 37% more than we have emitted to date. Adding another ∼ 40%, then,
seems like the best we could hope to see, but possibly accompanied by
serious hardships in adapting. The radiative forcing associated with this
scenario is 2.5 W/m 2 , corresponding to ΔT ≈ 2 ◦ C.
Try replicating!
9.4 Climate Change Consequences
Turning up the thermostat on the planet results in too many effects to
chronicle here. Obviously, the climate is impacted—in terms of storm
frequency <strong>and</strong> intensity, rainfall, snowfall <strong>and</strong> water supply, season
durations, <strong>and</strong> the ability of plant <strong>and</strong> animal species to adapt to the
changes. The timescale over which we are changing the climate is far
faster than evolution can track, except for microbial life <strong>and</strong> maybe
insects, whose shorter generational turnover permits a more dynamic
response. <strong>Human</strong>s are late arrivals to a long evolutionary sequence,
which laid a foundation to support our lives in complex interconnected
© 2021 T. W. Murphy, Jr.; Creative Commons Attribution-NonCommercial 4.0 International Lic.;
Freely available at: https://escholarship.org/uc/energy_ambitions.