Transcript Royal Society 03_01_2007 - Academy Presidents` Forum

Global Climate Change: Challenges for
Scientists and Scientific Institutions
December 6, 2008
Ralph J. Cicerone, President
National 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
342
105
68
H2O, CO2, O3
390
327
169
90
16
Calculating the Surface
Temperatures of Planets
S(1 - a) = sTe4
for Earth, S = 1368 W/m2, a = 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
for Venus
WRONG
Actual Te = 730K
WRONG!!
Greenhouse effect and clouds, high pressure
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
Global Methane Release Rates
Gas Production
45 Tg/yr (8.3%)
Coal Mining
35 Tg/yr (6.5%)
Enteric Fermentation
80 Tg/yr (14.8%)
Clathrate Decomposition
5? Tg/yr (0.9%)
Landfills
40 Tg/yr (7.4%)
Termites
40 Tg/yr (7.4%)
Freshwaters
5 Tg/yr (0.9%)
Biomass Burning
55 Tg/yr (10.2%)
Wetlands
115 Tg/yr (21.3%)
Boreal: 20 – 60 Tg/yr
Rice Paddies
110 Tg/yr (18.5%)
Total = 540 Tg/yr
Oceans
10 Tg/yr (1.9%)
Cicerone & Oremland, 1988
2004 Radiative forcing from well-mixed greenhouse gases
1.8
Radiative Forcing
(Watts per square meter)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
CO2
CH4
N2O
CFC12
CFC11
Source: NOAA ESRL Global Monitoring Division
Other
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-andmud-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)
Global Carbon Cycle Management
Anthropogenic
Emission
7.2 GtC / y
ex: 2.4-2.8℃ rise from PI
Dangerous Level 425～440ppm
2ppm/y
How to control
the tap
to avoid risk
Present
380ppm
industrialization
280ppm
Pre-Industrial
Feedback
CO2 in Atmosphere
Absorption
3.1 GtC/ y
Ocean 2.2
Land 0.9
Adapted from Nishioka, NIES, Japan
World Primary Energy Consumption, 1970-2030
Transitional and Emerging Economies
Mature Market Economies
Quadrillion Btu
800
700
600
500
400
300
200
100
0
History
Projections
702
654
607
559
511
463
284
347
365
90
95
398
308
244
207
1970 75
80
85
2000 05
10
15
20
25
30
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
World Primary Energy Consumption, 1970-2030
Transitional and Emerging Economies
Mature Market Economies
Quadrillion Btu
800
700
600
500
400
300
200
100
0
History
Projections
702
654
607
559
511
463
284
347
365
90
95
398
308
244
207
1970 75
80
85
2000 05
10
15
20
25
30
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?
____________ ?
Science Academies Can:
 Convene Individual Scientists
 Analyze and Report on All Issues
 Interact with Local Leaders
 Represent the Nation Internationally
©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

Side Effects of Concern:
= 50TgS/year
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.
An Approach to Geoengineering?
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.
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 warming
pH 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 =
[
Emissions
Unit Produced
] [
X
Units Consumed
Person
]
X
[Population]