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IMA The Scientific Case for Anthropogenic Warming, II Math and Climate Seminar

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IMA The Scientific Case for Anthropogenic Warming, II Math and Climate Seminar
Math and Climate Seminar
IMA
The Scientific Case for Anthropogenic
Warming, II
Richard McGehee
Joint MCRN/IMA Math and Climate Seminar
Tuesdays 11:15 – 12:05
streaming video available at
www.ima.umn.edu
Anthropogenic Warming
Seminar on the Mathematics of Climate
IMA, MCRN, School of Mathematics
September 18, 2012
Anthropogenic Warming
What Determines the Earth’s Temperature?
Heat Balance
Where is Public Opinion?
Mired in politics.
outgoing (infrared)
 T 4  (1   ) S
Is the globe warming?
where T = surface temperature (ºK)
Yes, but, from a geologic perspective, not so much.
S = solar influx (W/m2)
What determines the Earth’s temperature?
solar incoming (visible)
α = albedo (reflectivity)
σ = the Stefan-Boltzmann constant
What is the role of human activity?
How big is the problem?
For current values ,
T  255K  18C  0 F
Why isn’t the Earth a Snowball?
Anthropogenic Warming
What Determines the Earth’s Temperature?
Anthropogenic Warming
What Determines the Earth’s Temperature?
Why isn’t the Earth a Snowball?
The Greenhouse Effect!
Joseph Fourier, Mémoires de l'Académie des
Sciences de l'Institut de France, t. vii. 1827.
Svante Arrhenius, "On the Influence of Carbonic
Acid in the Air upon the Temperature of the
Ground," Philosophical Magazine and Journal of
Science (Fifth Series) 41, pp. 237-276, 1896.
Gary Stix, Scientific American September 2006, pp.46-49
1
Anthropogenic Warming
Anthropogenic Warming
What Determines the Earth’s Temperature?
What Determines the Earth’s Temperature?
Heat Balance
Remember Lake Vostok?
Historical Overview of Climate Change Science, IPCC AR4, p.96
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_CH01.pdf
http://svs.gsfc.nasa.gov/vis/a000000/a000900/a000996/index.html
Anthropogenic Warming
Anthropogenic Warming
What Determines the Earth’s Temperature?
What Determines the Earth’s Temperature?
Antarctic Temperature Data
Antarctic Temperature Data
2
1.5
kiloyear bp
350
300
250
200
150
100
50
1
0
4
2
0
-2
-4
-6
-8
-10
0.5
0
-0.5
delta deg C
400
temperature
450
-1
-1.5
-8000
-7000
-6000
-5000
-4000
-3000
-2000
-1000
0
1000
-2
2000
year
Petit, et al, Nature 399 (June 3 1999), pp.429-436
Petit, et al, Nature 399 (June 3 1999), pp.429-436
Anthropogenic Warming
Anthropogenic Warming
What Determines the Earth’s Temperature?
What Determines the Earth’s Temperature?
Atmospheric CO2 (Vostok data)
400
400
350
350
300
300
atmos CO2 (ppm)
atmos CO2 (ppm)
Atmospheric CO2 (Vostok data)
250
200
150
200
150
100
‐450
250
100
‐400
‐350
‐300
‐250
‐200
time (Kyr)
‐150
‐100
‐50
0
‐450
‐400
‐350
‐300
‐250
‐200
‐150
‐100
‐50
0
time (Kyr)
2
Anthropogenic Warming
Anthropogenic Warming
What Determines the Earth’s Temperature?
What Determines the Earth’s Temperature?
Vostok Data
Atmospheric CO2 & Temperature (Vostok data)
CO2 (ppm)
150
4
200
250
300
350
400
2
0
temperature
Current
conditions
are well
outside the
range
recorded in
the ice core
data.
-2
Ice Core
Today
-4
-6
-8
-10
Pam Martin, University of Chicago, 2010
Anthropogenic Warming
Anthropogenic Warming
What Determines the Earth’s Temperature?
What Determines the Earth’s Temperature?
Vostok Data
Boron Isotope Data
CO2 (ppm)
150
200
250
300
350
400
15
10
temperature
5
Ice Core
trend
imbalance
0
-5
-10
-15
Zachos, et al, "Trends, Rhythms, and Aberrations in Global Climate 65 Ma to Present". Science 292 (2001), 687.
Anthropogenic Warming
What Determines the Earth’s Temperature?
Hansen, et al, Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J. 2 (2008)
Anthropogenic Warming
What Determines the Earth’s Temperature?
http://www.carleton.edu/departments/geol/DaveSTELLA/Carbon/long_term_carbon.htm
3
Anthropogenic Warming
What Determines the Earth’s Temperature?
Anthropogenic Warming
What Determines the Earth’s Temperature?
The Earth’s Carbon Cycle
Silicate Weathering
Rainwater containing dissolved CO2 falling on silicate rocks
replaces a silicon atom with a carbon atom, ultimately producing
calcium carbonate (limestone) and silicon dioxide (quartz). For
example, calcium silicate (Wollastonite):
CaSiO3  CO2  CaCO3  SiO2
Under volcanic conditions, the carbon atom is replaced by a
silicon atom, completing the long term carbon cycle.
CaCO3  SiO2  CaSiO3  CO2
Sigman & Boyle, Nature 207 (2000), p.860
Anthropogenic Warming
What Determines the Earth’s Temperature?
Anthropogenic Warming
What Determines the Earth’s Temperature?
The Short-Term Carbon Cycle
Hansen, et al, Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J. 2 (2008)
Couplings Between Changes in theClimate System and Biogeochemistry, IPCC AR4, p.513
Anthropogenic Warming
Anthropogenic Warming
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_CH07.pdf
The Mauna Loa Observatory
Where is Public Opinion?
Mired in politics.
Is the globe warming?
Yes, but, from a geologic perspective, not so much.
What determines the Earth’s temperature?
Physics! Solar heating plus the carbon cycle.
What is the role of human activity?
How big is the problem?
http://www.climate.noaa.gov/images/about_climate/greenhouse_maunaloa.jpg
4
Anthropogenic Warming
Anthropogenic Warming
Atmospheric CO2 (Vostok data)
Mauna Loa Atmospheric CO2
400
390
400
380
350
atmos CO2 (ppm)
370
ppm
360
350
340
300
250
200
330
150
320
100
310
‐450
300
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010
‐400
‐350
‐300
‐250
‐200
‐150
‐100
‐50
0
time (Kyr)
2015
year
http://scrippsco2.ucsd.edu/data/data.html
Anthropogenic Warming
Did human activity cause the problem?
Carbon isotope ratios and
atmospheric oxygen depletion
indicate that the increase in
atmospheric CO2 comes from
burning fossil fuels.
Anthropogenic Warming
Did human activity cause the problem?
Models with and without
human activity.
Changes in Atmospheric Constituents and in Radiative
Forcing, IPCC AR4, Chap. 2, p.138
Understanding and Attributing Climate Change, IPCC
AR4, Chap. 9, p.684
http://ipccwg1.ucar.edu/wg1/Report/AR4WG1_Print_CH02.
pdf
http://ipccwg1.ucar.edu/wg1/Report/AR4WG1_Print_Ch09.
pdf
Anthropogenic Warming
Anthropogenic Warming
The IPCC Fourth Assessment Report
Where is Public Opinion?
Mired in politics.
Is the globe warming?
Yes, but, from a geologic perspective, not so much.
What determines the Earth’s temperature?
Physics! Solar heating plus the carbon cycle.
What is the role of human activity?
We are adding CO2 to the atmosphere.
How big is the problem?
http://nobelprize.org/nobel_prizes/peace/laureates/2007/
5
Anthropogenic Warming
Anthropogenic Warming
The IPCC Fourth Assessment Report
The IPCC Fourth Assessment Report
Global Mean Temperature Predictions
Prediction Methodology
Global Climate Projections, IPCC AR4, p.753
Summary for Policy Makers, IPCC AR4, p. 14
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_CH10.pdf
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf
Anthropogenic Warming
Anthropogenic Warming
The IPCC Fourth Assessment Report
The IPCC Fourth Assessment Report
Surface Temperature Predictions
The Last Interglacial Period
Global average sea level was likely between 4 and 6 m higher during the
last interglacial period, about 125,000 years ago, than during the 20th
century, mainly due to the retreat of polar ice. Ice core data suggest that
the Greenland Summit region was ice-covered during this period, but
reductions in the ice sheet extent are indicated in parts of southern
Greenland. Ice core data also indicate that average polar temperatures at
that time were 3°C to 5°C warmer than the 20th century because of
differences in the Earth’s orbit. The Greenland Ice Sheet and other arctic
ice fields likely contributed no more than 4 m of the observed sea level
rise, implying that there may also have been a contribution from
Antarctica.
Technical Summary, IPCC AR4, p. 58
Technical Summary, IPCC AR4, p. 72
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf
Anthropogenic Warming
Anthropogenic Warming
The IPCC Fourth Assessment Report
The Last Interglacial Period
Antarctic Temperature Data
kiloyear bp
400
350
300
250
200
150
100
50
0
4
2
0
-2
-4
-6
-8
-10
temperature
450
Technical Summary, IPCC AR4, p. 57
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf
Petit, et al, Nature 399 (June 3 1999), pp.429-436
6
Anthropogenic Warming
Anthropogenic Warming
How big is the problem?
How big is the problem?
Vostok Data
The USA in the Ice Free Earth
Computer Simulation, Clarence Lehman, Univ. Mn. 2006
CO2 (ppm)
150
200
250
300
350
400
15
10
temperature
5
Ice Core
trend
imbalance
0
-5
-10
-15
Anthropogenic Warming
Anthropogenic Warming
How big is the problem?
Summary
The Modern Ice Free Earth
Computer Simulation, Clarence Lehman, Univ. Mn. 2006
Where is Public Opinion?
Mired in politics.
Is the globe warming?
Yes, but, from a geologic perspective, not so much.
What determines the Earth’s temperature?
Physics! Solar heating plus the carbon cycle.
What is the role of human activity?
We are adding CO2 to the atmosphere.
How big is the problem?
Not big. Yet. ...
Sea level rises 63 meters.
Anthropogenic Warming
Solution
http://icanhascheezburger.com/2009/01/13/funny-pictures-eliminate-ur-carbon-footprint/
7
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