Climate Change Climate is what we expect, weather is what we get. ~Mark Twain

Climate Average weather conditions of the Earth or a particular area Main focus: temperature & precipitation Minimum period: 3 decades

Climate Change: Historical Radioisotopes in rocks & fossilsrocks Plankton & radioisotopes in ocean sediments Pollen from the bottom of lakes & ponds Tree rings Ice cores Regular temperature measurements (1861)

Climate Change

Climate Change: Historical Volcanic Emissions Changes in solar input Impacts by meteors Changes in air & ocean circulation

Climate Change: Human Activities Significant increase in greenhouse gases (CO 2, CH 4, & N 2 O) since mid-1700s –Industrial revolution –Burning fossil fuels –Deforestation –Agriculture

Carbon dioxide (CO2) Year Parts per million Fig. 18.4a, p. 450

Methane (CH 4 ) Year Parts per million Fig. 18.4b, p. 450

Year Parts per million Fig. 18.4c, p. 450 Nitrous Oxide

Year Index (1900 = 100) Carbon dioxide Methane Nitrous oxide Fig. 18.5, p. 451

Intergovernmental Panel on Climate Change (IPCC) Earth’s lower atmosphere is warming Most increase in gases are due to human activities Combo of human induced changes to air composition & temperature of the atmosphere are beginning to change the Earth’s climate Increased greenhouse gas conc. will likely trigger a significant climate disruption this century Climate disruption will have ecological, economic, & social effects

IPCC (2010) 1906–2005: Ave. temp increased about 0.74˚C 1970–2009: Annual greenhouse emissions from human activities up 70% warmest decade since 1881 Past 50 years: Arctic temp rising almost twice as fast as the rest of the earth Melting of glaciers and increased floating sea iceMelting of glaciers Last 100 years: sea levels rose 19 cm

Key Players in Climate Change Carbon Dioxide Waste Heat Solar Input Oceans Cloud Cover

CO2 Emissions Role Mainly burning of fossil fuels –Burning forest (agriculture) –Deforestation 1850: 285 ppm 2010: 389 ppm 2050: 560 ppm Tipping point: 450 ppm

Carbon Emitters (2009) Total 1.China 2.United States 3.European Union(27) 4.Indonesia 5.Russia Per Capita 1.Australia 2.United States 3.Canada 4.Netherlands 5.Saudi Arabia

Heat Waste Burning fossil fuels Main sources –Combustion engines –Power plant –Lights

Solar Input No correlation between increased solar input & increase temperatures Since 1975 –Troposphere warmer –Stratosphere cooler

Oceans Carbon Sink –Absorbs 25=30% of anthropogenic CO 2 –Cooler temps = increased absorption Warmer Oceans –Average temp = increase ⁰ C –Less CO 2 absorptions Ocean Acidity –Increased 30% in last 200 years –Affects: coral bleaching, phytoplankton populations, & ability to absorb CO 2

Cloud Cover Increase temp = increased evaporation = increase in clouds Low clouds: decrease surface temp High clouds: increase surface temp

Climate Change Possible Effects…

Droughts Severe/prolonged droughts affect 30% of Earth Consequences: –Increased wildfires –Decrease in water –Decrease in agriculture

More Ice & Snow Melt

Arctic Temperatures have risen at twice the rate Mountain glaciers affected by: –Average snowfall –Average temperatures Mountain glaciers supply water to rivers

Permafrost Melt Releases methane

Permafrost Melt

Sea Level Rising Prediction: meter rise by 2100

Sea Level Rise Effects Degradation of coastal estuaries & wetlands Disruption of coastal fisheries Coastal flooding –Shanghai –New York –Miami –Bangkok –Calcutta Area floods with one meter rise

Sea Level Rise Effects Flooding of low-lying barrier islands Area floods with one meter rise

Sea Level Rise Effects Flooding of agriculture lowlands & deltas Saltwater contamination of freshwater

Extreme Weather Increase Heat waves Hurricanes –increase 0.8°C = increase in storms by 1/3 –Intensity increase by 45% Flooding/droughts increase

Threat to Biodiversity Most susceptible areas: –Coral reefs –Polar seas –Coastal areas –Tundra Organisms with limited ranges & temperature tolerance

Agriculture Regions of farming may shift –Decrease at tropics & subtropics –Increase in northern latitudes Low productivity because of low soil quality

Human Health Temperature related death increase Increase in insects, molds, & microbes

Climate Change What can we do…

Difficult to do... Global issue Long term political issue Impacts are not distributed evenly Proposed solutions disrupt economies & lifestyles

Ways to Manage Greenhouse Gases Improve energy efficiency Increase use of renewable resources Stop deforestation Shift to more sustainable agriculture

Collect Greenhouse Gases Massive tree planting Restore wetlands Plant perennials on degraded land Preserve and restore natural forests Stimulate phytoplankton growth

Government Involvement Strictly regulate CO 2 and CH 4 Carbon tax on fossil fuelsCarbon tax Cap and trade approach Increase subsidies to encourage energy efficiencyefficiency

Kyoto Protocol 1997 treaty to slow climate change Reduce CO 2, CH 4, & N 2 O emissions by 5.2% by 2012 Not signed by US