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