Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate...
-
Upload
derrick-davidson -
Category
Documents
-
view
212 -
download
0
Transcript of Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate...
![Page 1: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/1.jpg)
Causes and Effects of Global Warming
Kerry Emanuel
Program in Atmospheres, Oceans, and Climate
Department of Earth, Atmospheric and Planetary Sciences
MIT
![Page 2: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/2.jpg)
Program
• History of earth’s climate
• A little climate science
• Forcings and feedbacks
• Possible effects of climate change
![Page 3: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/3.jpg)
The Snowball Earth (~500 mya)
![Page 4: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/4.jpg)
Climate of The Eocene (~50 mya)
![Page 5: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/5.jpg)
Ice Cover, Last Glacial Maximum (~18,000 years ago)
![Page 6: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/6.jpg)
Paleo reconstructions of temperature change over the last 2000 years
Year
Instrumental Record
![Page 7: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/7.jpg)
Some Characteristics of Climate Science
• Described by some as the most difficult scientific problem ever faced
• Draws on all the major scientific disciplines:– Chemistry, geology, atmospheric science,
oceanography, solar physics, orbital mechanics, biology
– Climate prediction also requires understanding of economics, politics, human psychology
• Very much a frontier science
![Page 8: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/8.jpg)
John Tyndall (1820-1893)
The Greenhouse Effect
Jean Baptiste Joseph Fourier(1768-1830)
![Page 9: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/9.jpg)
Tyndall’s Discovery:
Oxygen (O2) and Nitrogen (N2), which together comprise about 97% of the atmosphere, are transparent to solar and infrared radiation
If that’s all there were, it would be easy to calculate our global mean surface temperature, and it would be about 0 F.
![Page 10: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/10.jpg)
But certain trace gases interact strongly with radiation:
H20 (water vapor)
CO2 (carbon dioxide)
CH4 (methane)
Clouds also interact strongly with radiation. Together, they yield:
288 60sT K F
![Page 11: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/11.jpg)
Essence of the Greenhouse Effect:
The Earth’s surface receives radiation both directly from the sun and from the atmosphere and clouds within it. It must therefore get warm enough to emit enough radiation to balance both sunlight and back radiation from the atmosphere.
![Page 12: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/12.jpg)
Climate Forcing
• Varying Sunlight• Varying composition of atmosphere
![Page 13: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/13.jpg)
Climate Forcing
by Orbital Variations
Milutin Milanković, 1879-1958
![Page 14: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/14.jpg)
Climate Feedbacks
![Page 15: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/15.jpg)
Climate Elements and Feedbacks
![Page 16: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/16.jpg)
If the Only Feedback Were Temperature, Doubling Carbon Dioxide would Increase Surface Temperature by about 1.1 oC.
![Page 17: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/17.jpg)
Causes of Recent Climate Change
![Page 19: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/19.jpg)
![Page 20: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/20.jpg)
Variation in carbon dioxide and methane over the past 20,000 years, based on ice core and other records
![Page 21: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/21.jpg)
![Page 22: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/22.jpg)
Distribution of temperature change, 1901-2005
![Page 23: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/23.jpg)
Projected Warming:
![Page 24: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/24.jpg)
Does Any of this Matter?
![Page 25: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/25.jpg)
Possible Benefits of Warming:
• Fewer deaths from exposure • More vigorous plant growth• Increase of arable land at high latitudes• Increased mining potential in current
permafrost regions• Arctic waterways become navigable• Reduced heating costs
![Page 26: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/26.jpg)
Warming Risks
• Rising sea level• Concentration of rainfall into fewer but more
intense events...more drought, floods• Increased incidence of some diseases• Increased production of allergens• Increased mortality from heat waves• Increased consumption of electricity• Possible increase in violent storms• Ocean acidification, increased species
extinctions
![Page 27: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/27.jpg)
28
(Source: WBGU after David Archer 2006)
Past Sea Level vs. Temperature
![Page 28: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/28.jpg)
Arctic Minimum Sea Ice Extent
![Page 29: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/29.jpg)
![Page 30: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/30.jpg)
31
Changes in Precipitation
EEA2008
Observations: trend 1961-2006
Model simulation
Southern EuropeIs drying out
![Page 31: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/31.jpg)
32
Heat Stress
Kältestress
leicht
extreme
high
moderate
slight
mäßig
hoch
extrem
Mortality and heat stress (8. August 2003, 13 UTC)
15,000 †
7,000†
4,000 †
2,000 † 2,000
†
4,000 †
1,500 †
Mortality data: Earth Policy InstituteHeat Stress: Deutscher Wetterdienst
Summer 2003, greatest natural disaster
in Europe
ca. 35.000 fatalities
© 2007 Geo Risks Research, Munich Re
Heat Waves
![Page 32: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/32.jpg)
33
observationsHadCM3 Medium-High (SRES A2)
2003
2040s
2060sTe
mp
erat
ure
an
om
aly
(wrt
196
1-90
) °
C
Heat Waves
![Page 33: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/33.jpg)
Hurricane Power is Changing in Concert with Tropical Ocean Temperature
![Page 34: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/34.jpg)
Effect of Increased Potential Intensity on Hurricane Katrina
![Page 35: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/35.jpg)
![Page 36: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/36.jpg)
37
The Oceans are Turning Sour Acidification through CO2
threatens marine life
Plankton
Coral Reefs
![Page 37: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/37.jpg)
Summary
• Earth’s climate has changed radically and often abruptly through time
• Primary culprits:– Changing insolation, through solar evolution and
orbital variations– Changing concentrations of trace greenhouse
gases– Changing concentration of aerosols: Volcanic
eruptions
• Evidence for human-induced climate change now very compelling
![Page 38: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/38.jpg)
• Many climate processes remain poorly understood. Past abrupt climate change remains enigmatic and future abrupt state transitions cannot be ruled out
• The culture of climate science is overly reliant on large, complex models. The field is in need of a fresh approach and an influx of original thinkers
![Page 39: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/39.jpg)
Observed annual rate of increase of CO2
Rate of increase of CO2 if all remained in atmosphere
![Page 40: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/40.jpg)
Estimates of Global Mean Surface Temperature from the Instrumental Record
![Page 42: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/42.jpg)
Contributions to net radiative forcing change, 1750-2004:
![Page 43: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/43.jpg)
Global Climate Models: How Good Are They, and What
Do They Tell Us about The Future?
![Page 44: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/44.jpg)
Global Climate Modeling
• General philosophy:– Simulate large-scale motions of atmosphere,
oceans, ice– Solve approximations to full radiative transfer
equations– Parameterize processes too small to resolve– Some models also try to simulate
biogeochemical processes– First GCMs developed in 1960s
![Page 45: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/45.jpg)
Equations solved by discretizing to finite volumes
![Page 46: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/46.jpg)
Unresolved physical processes must be handled parametrically• Convection• Thin and/or broken clouds• Cloud microphysics• Aerosols and chemistry (e.g.
photochemical processes, ozone• Turbulence, including surface fluxes• Sea ice• Land ice• Land surface processes
![Page 47: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/47.jpg)
Climate Elements and Feedbacks
![Page 48: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/48.jpg)
Global mean temperature (black) and simulations using many different global models (colors) including all forcings
Same as above, but models run with only natural forcings
![Page 49: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/49.jpg)
Ensemble of climate models, Scenario A1b
![Page 50: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/50.jpg)
Dealing with Climate Change
• Winners and losers• Difficult but necessary cost-benefit
analysis• Still large uncertainty in climate
projections• Small but difficult-to-quantify risk of
major climate shifts (e.g. collapse of Greenland ice sheet)
![Page 51: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/51.jpg)
52Hansen, 2007
Atmospheric lifetime of CO2 is centuries long
![Page 52: Causes and Effects of Global Warming Kerry Emanuel Program in Atmospheres, Oceans, and Climate Department of Earth, Atmospheric and Planetary Sciences.](https://reader035.fdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35bf6/html5/thumbnails/52.jpg)
Strategies
• Reduce emissions– gasification of coal—potential CO2 capture– alternative sources– nuclear, wind, etc.– unlikely to effect major reductions– Fcous on non-CO2 greenhouse gases
• Carbon sequestration• Other geoengineering
– technically feasible, $20-30 billion/year– Side effects, e.g. reduced precipitation
• Adaptation