Post on 08-Aug-2020
Global Warming Spring 2013
Lecture 18 1
UCSD Physics 12
2×Q
UCSD Physics 12
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Keeling, a researcher at Scripps Institute for Oceanography, started measuring atmospheric CO2 from Mauna Loa in Hawaii in 1958. Besides the annual photosynthetic cycle, a profound trend is seen.
400 ppm = 400 parts-per-million = 0.04% by volume
Q
2.0 ppm/yr
1.85 ppm/yr reference
just passed 400 ppm for first time in millions of years
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Global Warming Spring 2013
Lecture 18 2
UCSD Physics 12
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O2
H2O H2O
H2O, CO2 H2O, CO2
Atmospheric absorption
above the atmosphere
at ground level but the thermal emission is farther out in infrared (IR)
UCSD Physics 12
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Global Warming Spring 2013
Lecture 18 3
UCSD Physics 12
Spring 2013 9 Q
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Spring 2013 11 Often called the “hockey stick” curve
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4 2 0
-2 -4 -6 -8
-10
300
275
250
225
200
175
Note: Greenland’s ice sheet is 110,000 years old: melted in last interglacial period.
Today’s CO2 level!!
Global Warming Spring 2013
Lecture 18 4
UCSD Physics 12
Spring 2013 13 from http://www.pewclimate.org/global-warming-basics/slr.cfm
UCSD Physics 12
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Note: this is a good example of real data: lots of measurements from different scientists around the world all pointing to similar (and sensible) results. Note also error bars.
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Global Warming Spring 2013
Lecture 18 5
UCSD Physics 12
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UCSD Physics 12
Spring 2013 18 Q
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Global Warming Spring 2013
Lecture 18 6
UCSD Physics 12
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UCSD Physics 12
Spring 2013 22 plots from 2001 IPCC assessment
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UCSD Physics 12
Spring 2013 24 current rate is 3 mm/year → about a foot per century
Global Warming Spring 2013
Lecture 18 7
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A note of significance: none of these have yet stabilized as of 2100. Even the green curve (eliminating CO2 emissions by 2100) is still steadily climbing. This effect won’t play out until 2300 at least.
UCSD Physics 12
Spring 2013 26 2×Q
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UCSD Physics 12
Spring 2013 28 4×Q
Global Warming Spring 2013
Lecture 18 8
UCSD Physics 12
Spring 2013 29