Climate Change and Ozone Loss Climate Change Review session Climate Change Review session Brian Kaestner and Dr. Richard Clements

Key Concepts  How does the Earth’s climate fluctuate  What factors affect climate  What are the possible effects of global warming  What can humans do about potential climate change

Past Climate Change  Past global temperatures  Recent trends in global temperatures Average temperature over past 900,000 years Thousands of years ago Present Average surface tem perature (°C) Average surface temperature (°C) Average temperature over past 130 years Year

Average temperature over past 900,000 years Thousands of years ago Average surface temperature (°C) Present

Temperature change over past 22,000 years Years ago Temperature change (°C) 20,00010,0002,0001, Now End of last ice age Agriculture established Average temperature over past 10,000 years = 15°C (59°F)

Temperature change over past 1,000 years Year Temperature change (°C)

Average temperature over past 130 years Year Average surface temperature (°C)

The Natural Greenhouse Effect  Greenhouse effect  Greenhouse gases Rays of sunlight penetrate the lower atmosphere and warm the earth's surface. The earth's surface absorbs much of the incoming solar radiation and degrades it to longer-wavelength infrared radiation (heat), which rises into the lower atmosphere. Some of this heat escapes into space and some is absorbed by molecules of greenhouse gases and emitted as infrared radiation, which warms the lower atmosphere. As concentrations of greenhouse gases rise, their molecules absorb and emit more infrared radiation, which adds more heat to the lower atmosphere. (a)(b)(c)

Carbon dioxide Temperature change End of last ice age Thousands of years before present Concentration of carbon dioxide in the atmosphere (ppm) –10.0 –7.5 –5.0 – Variation of temperature (˚C) from current level

Carbon dioxide (CO2) Year Parts per million

Methane (CH 4 ) Year Parts per million

Year Index (1900 = 100) Carbon dioxide Methane Nitrous oxide

Human Activities and Earth’s Climate Action -Increased use of fossil fuels Action -Increased use of fossil fuels -Deforestation Causes Global warming Causes Global warming Leads to -Melting icecaps and glaciers Leads to -Melting icecaps and glaciers -Coral reef bleaching

Projecting Future Changes in Earth’s Climate  Climate models  Apparent influence of human activities  Could be natural changes Year Observed Model of greenhouse gases + aerosols + solar output Temperature change (°C) from 1980–99 mean

Factors Affecting Changes in Earth’s Average Temperature  Changes in solar output  Changes in Earth’s albedo  Moderating effect of oceans  Clouds and water vapor  Air pollution Oceans 5% Bare sand 30–60% Grass 15–25% Clouds 50–55% Snow 80–90% City 10–15% Forest 5%

Antarctica Cold water melting from Antarctica's ice cap and icebergs falls to the ocean floor and surges northward, affecting worldwide circulation. Cold water melting from Antarctica's ice cap and icebergs falls to the ocean floor and surges northward, affecting worldwide circulation. Greenland

Today’s sea level Years before presentPresent 250,000200,000150,000100,00050,0000 –130 0 –426 0 Height above or below present sea level (meters) Height below present sea level (feet)

Present range Future range Overlap Climate zones Move miles Per 1Degree C Tree species Can migrate About 5 miles Per decade

Some Possible Effects of a Warmer World Increased deaths from heat and disease Disruption of food and water supplies Spread of tropical diseases to temperate areas Increased respiratory disease Increased water pollution from coastal flooding Human Health Rising sea levels Flooding of low-lying islands and coastal cities Flooding of coastal estuaries, wetlands, and coral reefs Beach erosion Disruption of coastal fisheries Contamination of coastal aquifiers with salt water Sea Level and Coastal Areas Changes in forest composition and locations Disappearance of some forests Increased fires from drying Loss of wildlife habitat and species Forests Changes in water supply Decreased water quality Increased drought Increased flooding Water Resources Shifts in food-growing areas Changes in crop yields Increased irrigation demands Increased pests, crop diseases, and weeds in warmer areas Agriculture Extinction of some plant and animal species Loss of habitats Disruption of aquatic life Biodiversity Prolonged heat waves and droughts Increased flooding More intense hurricanes, typhoons, tornadoes, and violent storms Weather Extremes Increased deaths More environmental refugees Increased migration Human Population

N S Waste less water Develop crops that need less water Move hazardous material storage tanks away from coast Prohibit new construction on low- lying coastal areas Stockpile 1 to 5 year supply of key foods Expand existing wildlife reserves toward poles Connect wildlife reserves with corridors

Solutions: Dealing with the Threat of Climate Change Options  Do nothing  Do more research  Act now to reduce risks PreventionCleanup Cut fossil fuel use (especially coal) Shift from coal to natural gas Transfer energy efficiency and renewable energy technologies to developing countries Improve energy efficiency Shift to renewable energy resources Reduce deforestation Use sustainable agriculture Slow population growth Remove CO 2 from smokestack and vehicle emissions Store (sequester CO 2 by planting trees) Sequester CO 2 underground Sequester CO 2 in soil Sequester CO 2 in deep ocean