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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?. 1000 years of “proxy” surface temperatures, 100+ from thermometers. - PowerPoint PPT Presentation
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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
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