1 climate change science kathryn parker u.s. environmental protection agency rocky mountain national...
TRANSCRIPT
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Climate Change Science
Kathryn ParkerU.S. Environmental Protection Agency
Rocky Mountain National Park
March 21, 2007
July 1932 July 1988
Glacier National Park, Montana
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What is the greenhouse effect?
– Greenhouse gases effectively ‘trap’ heat
– Without them, the Earth would be ~ 60ºF cooler and life, as we know it, would not exist
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Recent CO2 Concentrations
– In the early 1960s, Charles Keeling began the first continuous recording of CO2 levels in the atmosphere atop Mauna Loa, Hawaii
http://www.aip.org/history/climate
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Human Influence on the Atmosphere
in the Industrial Era
CO2 up 35%
CH4 up 151%
N2O up 18%
Different symbols denote ice core data for several sites in Antarctica and Greenland
Source: IPCC WG I (Science) Summary for Policy-Makers, Third Assessment Report, 2001.
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Who’s responsible for these emissions?
• Electricity, transportation, and industry biggest emitters
• When considering electricity distribution, homes and business account for a lot more
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Global CO2 Emissions
Data courtesy of Carbon Dioxide Information Analysis Center, DOE
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*Today
CO2 concentration is closely correlated with temperature
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Historic CO2 Concentrations
Source: IPCC WGI Third Assessment Report, 2001.
*Today
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Is the Earth warming?
– Earth’s surface has warmed by about 1.4 º F since 1860
– Most of this warming occurred post 1950
– Most of the warming of the last 50 years is very likely the result of human activities
Source: Climate Research Unit, Univ. of East Anglia & UK Met. Office Hadley Centre, 2005.
(Relative to 1961-1990 Mean)
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• Eleven of the twelve years in the period 1995-2006 rank among the 12 warmest since 1850
• 2006 annual average temperature was warmest on record in U.S.
• Warming since the middle 1970s is now about 1°F
• Most areas have warmed
– Greatest warming: Over land, northern high latitudes, nights, winter– Observed increase in warm extremes, decrease in cold extremeSource: NASA, 2006.
How much is the Earth warming?
11Source: Compilation of 10 peer reviewed reconstructions, Wikipedia, 2006.
It is likely warmer now than it has been in at least 2000 years.
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Are greenhouse gases causing the Earth to
warm?
"Most of the observed increase in globally averaged temperatures since the mid-20th century is very likely due to
the observed increase in anthropogenic greenhouse gas concentrations.“ – IPCC, 2007
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Additional Evidence of Warming Climate
• Earlier spring melting of ice on rivers and lakes
• Winter snow cover in the Northern Hemisphere is decreasing
• Increased ocean heat content is causing sea level to rise around the world
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Arctic sea ice is thinning and decreasing in extent.
• Arctic is warming twice as fast as rest of the world
• Arctic warming has worldwide implications
• Indigenous people, animals and vegetation are affected
• May open new shipping routesSource: NASA, 2005
Sea Ice Minimum 2005Sea Ice Minimum 1979
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Summer melting in Greenland has increased
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Tropical and temperate mountain glaciers are
melting• In Montana’s Glacier National Park, 27
glaciers remain of 150 in 1850
• Researchers have documented rapid mountain glacier retreat in Greenland, the European Alps, the Himalayas, Ecuador, Peru, Venezuela, New Guinea, and East Africa, among other places
Qori Kalis Glacier, Quelccaya Ice Cap, Peru, are shown between 1978 (top) and 2002. The glacier retreat during this time was 1,100 meters.
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What about the future?
– Greenhouse gases and temperatures will very likely continue to increase
– There are important uncertainties about future emissions and how the climate will respond to them
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Sea Level will continue to rise
• 1 to 3 foot rise possible by end of century
• Will continue to rise even if temperatures stop rising
• May rise more if warming accelerates melting of glaciers
Source: UK Met Office,Hadley Centre, 2002. http://www.met-office.gov.uk/research/hadleycentre/pubs/talks/sld036.html
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Extreme Event Projections
• Higher maximum temperatures and more hot days and heat waves over land areas
• Higher minimum temperatures and fewer cold days, frost days and cold waves
Source: IPCC SPM, Third Assessment Report, Climate Change 2001: The Scientific Basis, 2001.
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Extreme Event Projections
• More intense precipitation events over many areas
• Increase summer continental drying and associated risk of drought
• Increase in tropical cyclone peak wind and precipitation over some areas
Source: IPCC SPM, Third Assessment Report, Climate Change 2001: The Scientific Basis, 2001.
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For More Information
www.epa.gov/climatechange
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Questions
Kathryn Parker, USEPA, Climate Change [email protected]
Karen Scott, USEPA, Climate Change [email protected]
Thank you!