Write a one sentence overview on what we will learn today based on this picture.

Climate Change:Fitting the pieces together

Present day observations

Past Data: How do we know?

Is current climate change unusual?

National Research Council, 2006

1000 years of “proxy” surface temperatures, 100+ from thermometers

Hadley Centre, 2003

Surface, balloon, & satellite temperatures agree

Climate ModelingNOAA’s New Supercomputer “Gala”

The smoking gunEssentially all of the observed climate-change phenomena are consistent with the predictions of climate science for GHG-induced warming.

No alternative “culprit” identified so far – no potential cause of climate change other than greenhouse gases – yields this “fingerprint” match.

A credible skeptic would need to explain both what the alternative cause of the observed changes is and how it could be that GHGs are NOT having the effects that all current scientific understanding says they should have. (No skeptic has done either thing.)

Temperature increases are nonuniform: higher mid-continent, highest of all in far North. (These are observations, not modeling results.)

J. Hansen et al., PNAS 103: 14288-293 (26 Sept 2006)

2001-2005 mean ∆Tavg above 1951-80 base, °C

Evaporation & precipitation are increasing

NCDC, 2000

Effect is not uniform; most places getting wetter, some getting drier.

GLACIERS ARE MELTING

Muir Glacier, Alaska, 1941-2004

NSIDC/WDC for Glaciology, Boulder, compiler. 2002, updated 2006. Online glacier photograph database. Boulder, CO: National Snow and Ice Data Center.

August 1941 August 2004

Coastal glaciers are retreating

is the MELTING OF THE ARCTIC.

New predictions

Satellite observationsMean IPCC predictionMost likely change

(melt)IPCC range

Actual observed melting

it has melted nearly 80 YEARS ahead of when

scientists predicted

YEAR

% c

han

ge in

ice

cover

WEATHER IS BECOMING MORE EXTREME

MAJOR FLOODS PER DECADE

Australia fires spark calls for CLIMATE

ACTION“ ”- Washington Post, March 1, 2006

The trend has been upward everywhere.

Wildfires by continent & decade from 1950

Running, Science, 18 August 2006

This works in part through soil moisture

Australia suffers worst drought in

1,000 years “ ”

- Guardian UK, Nov 7, 2008

Burma cyclone death toll rises above

43,000. “ ”

- USA Today, May 15th, 2008

SEA LEVELS ARE RISING

Three Year Average

Satellite Altimetry

Year

Sea L

evel C

han

ge (c

m)

1993-2003 ≈ 35 mm = 3.5 mm/yr; compare 1910-1990 = 1.5±0.5 mm/yr.

Sea-level is rising

mm

ACIA, 2004

Further evidence of changing climateAs expected in a warming world, observations overrecent decades also show…

Evaporation & rainfall are increasing;

Coastal glaciers are retreating;

Mountain glaciers are disappearing;

Permafrost is thawing;

Sea ice is shrinking;

Greenland is melting;

Sea level is rising;

Species are moving.

What changes climate?

Changes in:Sun’s outputEarth’s orbitDrifting continentsVolcanic eruptionsGreenhouse gases

Climate forcing agents in the industrial era. “Effective” forcing accounts for “efficacy” of the forcing mechanism.Source: Hansen et al., JGR, 110, D18104, 2005.

Effective climate forcings 1750-2000Correlating various lines of evidence has reduced uncertainties

Units are watts per square meter alteration in global-average atmospheric radiation flow

WARMING

COOLING

Earth’s Atmosphere

THE GREENHOUSE EFFECT

“Greenhouse effect” Increasing greenhouse gases trap more heat

Atmosphere Matters!

Greenhouse gases

Nitrous oxide

Water

Carbon dioxideMethane

Sulfur hexafluoride

CO2 CONCENTRATIONS ARE OFF THE CHARTS

CO2 in PPM

TEMPERATURE

Years

Part

s p

er

Million

C

O2

TODAY: 387ppm

550ppm? More?

EARLY 1900S

LAST ICE AGE

Where we’ll be mid-century if we keep this up

390ppm CO2

today:

Why should we care?

OCEANS ARE ACIDIFYING

Sea Levels Are

RISING

Coral reefs are dying

impacts

LOCAL LIVELIHOODS

Each year there is a two-week Conference of the Parties (COP) to discuss the terms of the Kyoto Treaty

COP 12 Montreal, Canada 2005

1988: The IPCC was created to “provide

the decision-makers and others interested in climate change with an objective source of information about

climate change”

this all began 20 years ago

KYOTO PROTOCOL 1997Ratified TreatyDidn’t Ratify

Signed, Ratification PendingNo Position

AND IMPLEMENTING AND IMPLEMENTING

A A THOUSAND THOUSAND

DIFFERENT DIFFERENT SOLUTIONSSOLUTIONS

SOURCES• BBC World Service Poll -

http://www.globescan.com/news_archives/bbc_climate/

• Hansen, James, et al. Target Atmospheric CO2: Where Should Humanity Aim? Submitted April 7, 2008.

• The IPCC 4th Assessment Report - www.ipcc.ch

• Baer, Paul, Tom Athanasiou and Sivan Kartha. "The Right to Develop in a Climate Constrained World: The Greenhouse Development Rights Framework"

• The United Nations Framework Convention on Climate Change

• NASA - www.nasa.gov

• RealClimate.org

• Climate Safety - www.climatesafety.org

• New Scientist - www.newscientist.com