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Global Climate Change: Challenges for Scientists and Scientific Institutions
December 6, 2008
Ralph J. Cicerone, PresidentNational Academy of Sciences
OUTLINE Greenhouse Effect
Greenhouse Gases from Human Activities
Rising Temperatures, Sea Level and Ice Losses
World Energy Needs and Fossil Fuels
Roles for Scientists and Science Academies
Geoengineering ?
237
105
342
68
169
390
327 90
16
H2O, CO2, O3
Calculating the Surface Temperatures of Planets
for Venus
Actual Te = 730K WRONG! Greenhouse effect and clouds, high pressure
S(1 - e
for Earth, S = 1368 W/m2, = 0.3, so we calculate
Te = 255K (- 18 ºC or - 32 ºF) WRONG !
Greenhouse effect & clouds are needed
for Mars
Te = 240 to 250K (large day/night swings) OK
Greenhouse effect is very small, low pressure
WRONG !
WRONG !
OK !
Global CO2 Emission Estimates 1750 - 2005
CITE AS: Marland, G., T.A. Boden, and R. J. Andres. 2007. Global, Regional, and National CO2 Emissions. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.
Weiss et. al. ALE/GAGE Web site
Clathrate Decomposition 5? Tg/yr (0.9%)
Termites40 Tg/yr (7.4%)
Freshwaters5 Tg/yr (0.9%)
Wetlands115 Tg/yr (21.3%)Boreal: 20 – 60 Tg/yr
Oceans10 Tg/yr (1.9%)
Rice Paddies110 Tg/yr (18.5%)
Biomass Burning55 Tg/yr (10.2%)
Landfills40 Tg/yr (7.4%)
Global Methane Release Rates
Coal Mining35 Tg/yr (6.5%)
Gas Production45 Tg/yr (8.3%) Enteric Fermentation
80 Tg/yr (14.8%)
Cicerone & Oremland, 1988Total = 540 Tg/yr
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Ra
dia
tiv
e F
orc
ing
(Wa
tts
pe
r s
qu
are
me
ter)
CO2 CH4 N2O CFC12 CFC11 Other
Source: NOAA ESRL Global Monitoring Division
2004 Radiative forcing from well-mixed greenhouse gases
Frohlich and Lean (2005): Recent analyses of satellite measurements do not indicate a long-term trend in solar irradiance
(the amount of energy received by the sun)
www.giss.nasa.gov/gistemp(updated from Hansen et al., 2001)
Last 50 Years Surface Temperature Change Based on Linear Trends (oC)
Sea Level Change
Source: University of Colorado at Boulder http://sealevel.colorado.edu/
South Cascade Glacier 1955
South Cascade Glacier 2006
Meltwater stream flowing into a moulin in the ablation zone of the Greenland ice sheet. Accelerations of ice flow in summer are closely related to variations in air temperature and surface melting, and indicate that meltwater quickly travels through 1000 m of ice and enhances basal sliding. These observations reveal a mechanism for dynamic response of ice sheets to climate change.
[Photo: R. J. Braithwaite]
Warming increases mass-loss from “self-lubricating” ice sheets
• In places, ice rests on a water-and-mud-lubricated “pancake griddle”, in other places on a bumpy bedrock “waffle iron”; these can be mapped through two miles of ice, but job far from done;
• In places, ice is “self-lubricating”--surface meltwater plunges to bottom to make it more slippery, so warming may bring faster flow, but depends on griddle vs. waffle iron character.
Zwally et al., 2002, Science
Where we’re headed: Heat waves Extreme heat waves in Europe, already 2X more frequent because of global warming, will be “normal” in mid-range scenario by 2050
Black lines are observed
temps, smoothed &
unsmoothed; red, blue, &
green lines are Hadley Centre simulations w
natural & anthropogenic forcing; yellow is natural only.
Asterisk and inset show 2003 heat wave that killed 35,000.
Stott et al., Nature 432: 610-613 (2004)
Pre-Industrial 280ppm
380ppm
425 ~ 440ppm
Present
Dangerous Level
Global Carbon Cycle Management
Anthropogenic Emission 7.2 GtC / y
Absorption3.1 GtC/ y
How to control the tap
to avoid risk
industrialization
CO2 in Atmosphere
Ocean 2.2 Land 0.9
2ppm/y
ex: 2.4-2.8 rise from PI℃
Feedback
Adapted from Nishioka, NIES, Japan
0
100
200
300
400
500
600
700
800
1970 75 80 85 90 95 2000 05 10 15 20 25 30
Transitional and Emerging Economies
Mature Market Economies
World Primary Energy Consumption, 1970-2030
Quadrillion BtuHistory Projections
207244
284308
347 365398
463511
559607
654702
Sources: History 1970-1975: Energy Information Administration, International Energy Database, April 22, 2008. History, 1980-2005: Energy Information Administration, International Energy Annual 2005 (http://www.eia.doe.gov/iea). Projections: International Energy Outlook 2007, DOE/EIA-0484(2007) (http://www.eia.doe.gov/oiaf/ieo).
Solutions Require: Research on Climate
Actions for Mitigation
Actions for Adaptation
Climate Change Mitigation and Adaptation
Mitigation = Reduce Pace and Amount of Climate Change Caused by Humans
Adaptation = Reduce Adverse Impacts on Human Well-being from Climate Changes that Occur
0
100
200
300
400
500
600
700
800
1970 75 80 85 90 95 2000 05 10 15 20 25 30
Transitional and Emerging Economies
Mature Market Economies
World Primary Energy Consumption, 1970-2030
Quadrillion BtuHistory Projections
207244
284308
347 365398
463511
559607
654702
Sources: History 1970-1975: Energy Information Administration, International Energy Database, April 22, 2008. History, 1980-2005: Energy Information Administration, International Energy Annual 2005 (http://www.eia.doe.gov/iea). Projections: International Energy Outlook 2007, DOE/EIA-0484(2007) (http://www.eia.doe.gov/oiaf/ieo).
International Bodies Are Needed for Consensus
Examples:
IPCC Reports, IAC Energy Report, United Nations Framework Convention on Climate Change
Yet, each country needs its own scientists to evaluate data, to assess scientific understanding.
Article 2, UN Framework Convention on Climate Change (1992)
Who Should Define "Dangerous" ?
scientists?
elected leaders?
____________ ?
Convene Individual Scientists
Analyze and Report on All Issues
Interact with Local Leaders
Represent the Nation Internationally
Science Academies Can:
©2007 Nature Publishing Group
Inject Sulfur into Earth’s Stratosphere ?
• S gases convert to sulfate particles. Fine particles stay aloft for one year or more, as shown by stratosphere-penetrating volcanoes.
• Assuming global spreading ---
5 TgS/year could cause 4W/m2 of cooling
cost = $125 billion/year ??.
Optical depth of particles = 0.04 (some whitening of sky with reddish, violet sunsets) Current emissions of S from fossil-fuel burning = 50TgS/year
Side Effects of Concern: ozone losses ? Other unknown effects?
Continuous operations required.
(from Crutzen and several other scientists)
• Modify to Inject only over Arctic Region?
Geoengineering to Counter Climate Change
Motivations Expressed by Proponents
Apparent inadequacy of efforts to limit emissions of GG’s
Hopes for Low-cost engineering interventions
Largest Concerns Expressed by Opponents
Inadvertent side effects (examples)
Unwarranted encouragement for technological fixes will decrease commitment to mitigation efforts.
Oceanic acidification will continue.
Encourage and Formalize Research
Peer-reviewed publications in scientific journals.Calculations: State principles, display equations and assumptions, analyze sensitivities and side effects. Suggest experiments.
Peer-reviewed research-grant programs.
Sessions at major scientific meetings.
An Approach to Geoengineering?
Discourage Implementation: A Moratorium
Scientists define criteria and conditions for eventual experiments.Seek small-scale demonstrations and rigorous monitoring, linked with predictive calculations.
International teams.
Mechanisms for Public Oversight.
Withhold participation and endorsement unless/until conditions are met.
An Approach to Geoengineering?
Immediate action with multiple benefits.
Energy efficiency would: decrease our dependency on foreign oil improve our national security decrease our trade deficit decrease local air pollution increase our national competitiveness encourage development of new products for
global markets decrease household energy costs while also
slowing the increases of CO2 and CH4 !
Oceans acidifying as well as warmingpH history and “business as usual” projection
Red line is global annual average; blue lines show ocean-to-ocean and seasonal variation.
Surface ocean pH has already fallen by 0.1 pH unit. Projected additional changes are likely to have large impacts on corals and other ocean organisms that make skeletons/ shells from calcium carbonate.
Population, Excessive Consumption, or Technology?
CO2 Emissions = [ Unit Produced ] X [ Person ] X [Population]Emissions Units Consumed