Global Climate Change

History of Earth ’ s Climate Life appeared ~3.8 billion years ago Life appeared ~3.8 billion years ago Photosynthesis began billion years ago Photosynthesis began billion years ago –Produced oxygen and removed carbon dioxide and methane (greenhouse gases) –Earth went through periods of cooling ( “ Snowball Earth ” ) and warming

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

Global Atmospheric Concentration of CO 2

The Sun ’ s energy passes through the car ’ s windshield. This energy (heat) is trapped inside the car and cannot pass back through the windshield, causing the inside of the car to warm up. Example of the Greenhouse Effect

Greenhouse gases are the gases present in the atmosphere which reduce the loss of heat into space and therefore contribute to global temperatures through the greenhouse effect. The term greenhouse gas is applied to, in order of relative abundance: water vapor, carbon dioxide, methane, nitrous oxide, ozone and CFCs.atmosphere greenhouse effectwater vaporcarbon dioxide methanenitrous oxideozone CFCs

GLOBAL WARMING is the PREDICTION that Earth ’ s average surface temperature will increase by 1 o C-3.5 o C by the year is the PREDICTION that Earth ’ s average surface temperature will increase by 1 o C-3.5 o C by the year 2050 due to a build-up of greenhouse gases in the atmosphere. CLIMATE CHANGE is a broader term that refers to long-term changes in climate, including average temperature and precipitation. is a broader term that refers to long-term changes in climate, including average temperature and precipitation. What’s the difference between “global warming” and “climate change”?

How Global Warming Works Fossil fuels (coal, oil, natural gas) Carbon Dioxide (CO 2 )

Past Temperatures Measurement Proxy – a method that approximates a particular measurement (e.g., temperature) Proxy – a method that approximates a particular measurement (e.g., temperature) –Ice cores –Pollen records –Plant macrofossils –Sr/Ca isotope data –Oxygen isotopes from speleothem calcite (stalactites and stalagmites)

Disruption of food and water supplies Spread of tropical diseases 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 aquifers with salt water Sea Level and Coastal Areas Disappearance of some forests Increased fires from drying Loss of wildlife habitat and species Forests Decreased water quality Increased drought Increased flooding Water Resources 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 More intense hurricanes, tornadoes, and violent storms Weather Extremes Increased deaths More environmental refugees Increased migration Human Population

Effects

Solutions: Dealing with the Threat of Climate Change 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  Do nothing  Do more research before acting  Act now to reduce the risks from climate change

“ When an activity raises threats of harm to human health or the environment, precautionary measures should be take even if some cause and effect relationships are not fully established scientifically. ” Wingspread Conference, Precautionary Principle

Setting goals (Health indicators) Taking preventive action in the face of uncertainty Shifting the burden of responsibility to the proponents of an activity (Who benefits?) Exploring a wide range of alternatives to possibly harmful actions (Is it necessary?) Increasing public participation in decision making (transparency of information & environmental justice) Central components

 In 1992 Earth Summit in Rio de Janeiro 106 developed nations committed to reduce greenhouse gases to 1990 levels by the year This was not a requirement so most countries did not achieve this goal.  In 1997 in Kyoto, Japan the Kyoto Treaty was signed by 161 nations. Developed countries will cut greenhouse emissions. Developing countries are exempt. Emissions trading would be allowed. By, 2008 US has not ratified treaty because developing countries are exempt and coal, oil, steel, chemical and automobile companies opposed treaty because it would be devastating to the economy and workers.

What ’ s being done now to reduce our emissions? Solar PowerWind PowerFuel-Efficiency

We can stop global warming!

What can you do to help solve the problem?

Simple Things To Do Turn off your computer or the TV Turn off your computer or the TV when you ’ re not using it. when you ’ re not using it. Take shorter showers. Heating water uses energy. Keep rooms cool by closing the blinds, shades, or Keep rooms cool by closing the blinds, shades, or curtains. curtains. Turn off the lights when you leave a room. Use compact fluorescent bulbs. Use compact fluorescent bulbs.

Be Bulb Smart—Use CFLs Incandescent Compact Fluorescent 500 lbs. of coal What’s the difference? 1,430 lbs. CO 2 pollution avoided $30 saved

Simple Things To Do Dress lightly when it ’ s hot instead of turning up Dress lightly when it ’ s hot instead of turning up the air conditioning. Or use a fan. the air conditioning. Or use a fan. Dress warmly when it ’ s cold instead of turning Dress warmly when it ’ s cold instead of turning up the heat. up the heat. Offer to help your parents keep the air filters on Offer to help your parents keep the air filters on your AC and furnace clean. your AC and furnace clean. Walk short distances instead of asking for a Walk short distances instead of asking for a ride in the car. ride in the car. Plant a tree. Plant a tree. Recycle.