Heather Price, Ph.D Program on Climate Change University of Washington Global Climate Change
Heather Price, Ph.D
Program on Climate Change
University of Washington
Global Climate Change
The science
• Thousands of peer-reviewed scientific papers• Intergovernmental Panel on Climate Change (IPCC)• Major peer reviewed reports in 1990, 1996, 2001,
2007• Conclusions:
– “An increasing body of observations gives a collective picture of a warming world and other changes in the climate system.”
– “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.”
Temperature and CO2 vary together over glacial cycles
Source: Cuffey and Vimeux, Nature 412:523, 2001.
TemperatureCO2
Humans are altering atmospheric chemistry
Carbon dioxide (CO2): up 32% Methane (CH4): up 150%2004
Charles Keeling
Ralph Keeling
These changes are huge compared to the past
2011 CO2 = 390 ppmCarbon dioxide (CO2): up 32%
2004
Humans are altering atmospheric chemistry
Where in the world does CO2 come from?
2010 and 2005 tied for the warmest years on record. The 10 warmest years on record have all occurred since 1998. In the last century, Earth's lower atmosphere has warmed by more than half a degree Celsius (1.2 degrees F). Global sea level has risen 10 to 25 cm during the past 100 years, currently rising 0.08-0.12 inches per year (2.0-3.0 mm per year).
How has the climate already changed:
Source: Hadley Center http://www.met-office.gov.uk/research/hadleycentre/
1998
How has the world warmed?Greatest warming is occurring in Polar regions: Alaska, Greenland, Antarctica
Arctic ice thickness is down by 40%.
• Sea ice data acquired from submarines 1993-1997 and 1958-1976. • Mean ice thickness has decreased by 1.3 meters, from 3.1 to 1.6 meters.
Source: D.A. Rothrock, Y.Yu and G.A. Maykut, Thinning of the Arctic sea-ice cover, University of Washington, Seattle, 1999.
North Pole Sea Ice Extent Then and Now
1928
2000
The South Cascade glacier retreated dramatically in the 20th century
Courtesy of the USGS glacier group
Spruce Forests killed by Pine Beetle
Kenai Peninsula, Alaska:70 to 80 percent of the trees have died
Ask the scientists:
1. Have mean global temperatures risen compared to pre-1800s levels?
2. Has human activity been a significant factor in changing mean global temperatures?
• 90 percent of scientists said yes to the first question and 82 percent said yes to the second
• 97 percent of climate scientists said yes to both questions
• 47 percent of petroleum geologists said yes to the second question
Natural Climate Influence Human Climate Influence
All Climate Influences
By 2050 scientists expect 1 degree Celsius (2 degrees F) increase By 2100, climate models predict another 1.5-6 degree Celsius increase (3-11 degree F) Climate models also predict an additional 40-60 cm (~half meter) sea level rise by 2100 Sea level rise of 1 meter would endanger 90% of Japan’s sandy beaches
and much of Southern Florida, flooding Miami and the entire Everglades.
What do scientists predict for the future:
The main Northwest impact: less snow
April 1
Columbia
Basin
Snow
Extent
Impacts of hydrologic (water) changes
• Less snow, earlier melt means less water in summer – irrigation
– urban uses
– fisheries protection
– energy production
• More water in winter– energy production
– floodingNatural Columbia River flow at the Dalles, OR.
ChinaThe Bad News:• 80 % of energy from Coal• 16 of the worlds 20 most polluted cities• Respiratory illness is #1 killer in China• Pollution transports to Japan and beyond
The Good News:• Stronger fuel efficiency standards than USA: many US SUV’s will not be legal in China 2008• National law: at least 10% power from renewable energy by 2020 (same proposal was rejected by USA Congress last month)
Solar output varies - but not much
Figure courtesy of NOAA National Geophysical Data Center
Outline
• Observed changes in atmospheric composition• Understanding changes in global average
temperature• Global consequences of climate changes• Some issues here in the Northwest-loss of snow
pack• Policy dimensions… Why the ancient city of
Kyoto is a dirty word in middle America.
By 2000 Kilimanjaro: 82% of its ice had melted and is projected will be gone by 2015
Mt Kilimanjaro in 1912
Kilimanjaro, 2009