Broccoli UU-UNO April 2010

8/9/2019 Broccoli UU-UNO April 2010

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Global warming?

Winter 2009-2010

2010snowiest month onrecord)


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Temperature anomalies during 2009-10 winter

Source: J. Hansen, NASA/GISS


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Weather vs. Climate

Source: ClimateStations.comSource: Climate Prediction Center


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Source: NASA/Goddard Institute for Space Studies


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Northern Hemisphere Temperature Reconstructions

global mean surface temperaturewas higher during the last few decades of the 20th century than during any comparableperiod during the preceding four centuriesthe Northern Hemisphere was warmer during thelast few decades of the 20th century than during any comparable period over the

preceding millennium National Research Council


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Source: Polar Research Group,Univ. of Illinois


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Changes in glacier mass


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Intergovernmental Panel on Climate Change

The Intergovernmental Panel on Climate Change isthe leading body for the assessment of climatechange, established by the United NationsEnvironment Programme (UNEP) and the WorldMeteorological Organization (WMO) to provide theworld with a clear scientific view on the current

state of climate change and its potentialenvironmental and socio-economic consequences.

The IPCC is a scientific body. It reviews andassesses the most recent scientific, technical andsocio-economic information produced worldwiderelevant to the understanding of climate change. Itdoes not conduct any research nor does it monitorclimate related data or parameters. Thousands of

scientists from all over the world contribute to thework of the IPCC on a voluntary basis. Review isan essential part of the IPCC process, to ensure anobjective and complete assessment of currentinformation. Differing viewpoints existing withinthe scientific community are reflected in the IPCCreports.


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balance of evidence suggests

Climate Change 1995The Second Assessment of theIntergovernmental Panel on Climate Change (IPCC)

likelyto have

Climate Change 2000

The Third Assessment Report of the IPCC

Climate Change

The IPCC Scientific Assessment (1990)

since the mid-20th century is very likelydue to theobserved increase in anthropogenic greenhouse gas

Climate Change 2007The Fourth Assessment Report of the IPCC


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What Are Climate Models?


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Coupled Climate Model Schematic


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Blue: NaturalPink: Natural + Human-induced


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Future Emissions Scenarios


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Projections of Future Climate


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Source: NOAA Geophysical Fluid Dynamics Laboratory

Simulating Future Climate Change


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Potential Climate Change Impacts


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Global Impacts of Climate Change

There will be some winners, but more losers

Densely populated coastal regions will face increasedpressures from sea level rise and more extreme weather

Poor communities and stressed ecosystems will suffer most, as they

Report by IPCC Working Group II on Impacts, Adaptation and

Vulnerabilitywas released on 6 April 2007. Some of thehighlights from this report:


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Why Is Global Sea Level Rising?

Thermal expansionWarmer water is less densethan colder water.

Melting of glaciers andice capsWater released by the meltingof ice on land adds to thevolume of the oceans. Melting

and calving of Greenland andAntarctic ice sheets dependson the details of how the iceflows).


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Thermal expansionWarmer water is less densethan colder water.

Melting of glaciers andice capsWater released by the meltingof ice on land adds to thevolume of the oceans. Melting

and calving of Greenland andAntarctic ice sheets dependson the details of how the iceflows).


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Surface melt area in Greenland

Source: Konrad Steffen


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Global mean sea level changes


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Sea level projection based on empirical relationshipbetween temperature and sea level

Source: Vermeer and Rahmstorf, Proc. Nat. Acad. Sci., 2009


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Source: The Providence Journal

Source: The Courier News

March 13, 2010:

Extensive flooding in central NewMarch 2010 wettest March on recordstatewide.

March 30, 2010:

Record flooding in Rhode Island;

Patuxet River crests 5 feet aboveprevious record flood; March 2010wettest month on record atprecipitation.


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Warmer

MoreEvaporation

Warmer

More

Precipitation


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Stippled areas are where more than 90% of the models agree in the sign of the change.

Relative changes in precipitation (%) for the period 20902099, relative to 19801999.

Simulated Changes in Precipitation


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Mid-range climate scenario Nine model average (2080-2099

relative to 1980-1999). Figure courtesy of Claudia Tebaldi

Index of change in precipitation intensity

(amount / wet day)


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Index of change in number of

consecutive dry days

Mid-range climate scenario Nine model average (2080-2099

relative to 1980-1999). Figure courtesy of Claudia Tebaldi


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New Brunswick, NJ, April 16, 2007

John Munson/The Star-Ledger

and flooding due to the greater water-holding capacityof a warmer atmosphere. This has already been

observed and is projected to continue because in awarmer world, precipitation is concentrated into more


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Climate change in the news


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Northern Hemisphere Temperature Reconstructions

global mean surface temperaturewas higher during the last few decades of the 20th century than during any comparableperiod during the preceding four centuriesthe Northern Hemisphere was warmer during thelast few decades of the 20th century than during any comparable period over thepreceding millennium National Research Council


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Public opinion about global warming

Source: Pew Research Center for the People and the Press, Oct. 2009


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Global Warming Not A Top Priority

Source: Pew Research Center for the People and the Press, Jan. 2009


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Climate change is not the result of malevolence.

Climate change does not violate longstanding culturaltraditions.

Climate change is perceived as a future rather than animmediate threat.

Climate change proceeds gradually.

Source: Daniel Gilbert, Harvard University, Los Angeles Times, July 2006


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Historical carbon emissions by country


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Future Emissions Scenarios

All scenarios showincreasing emissionsduring next severaldecades

Some scenarios showdecreased emissionsin latter half of 21st

century

Even with aggressivereductions in emissions,CO2 would rise to 2xpreindustrial levels


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The Atmospheric CO2 Balance

Human-produced emissions of CO2

Uptake of CO2 by ocean,

vegetation, and solid earth


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Climate impact depends on cumulative emissions

Source: Zickfield et al., Proc. Nat. Acad. Sci., 2009


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More warming is in the pipeline

Warming to date

-

Future emissions


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1.6

Billions of Tons

Carbon Emittedper Year

Historicalemissions Flat path

0

8

16

1950 2000 2050 2100

Stabilization Wedges

16 GtC/y

Goal: In 50 years, sameglobal emissions as today

Source: Carbon Mitigation Initiative, Princeton University


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Energy Efficiency &

Conservation (4)

CO2 Capture

& Storage (3)

StabilizationTriangle

Renewable Fuels

& Electricity (4)

Forest and Soil

Storage (2)

Fuel Switching

(1)

15 Wedge Strategies in 4 Categories

Nuclear Fission (1)

2007 2057

8 GtC/y

16 GtC/y

Triangle

Stabilization

Source: Carbon Mitigation Initiative, Princeton University


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Not just a scientific question.

Policymakers must balance a variety of considerations.

Your opinion counts just as much as mine.

There are no easy answers.

centuries in the future.

What Should We Do About Global Warming?

Documents

Broccoli UU-UNO April 2010