6.1.1 Global Warming

Global Warming & Greenhouse Gases

Greenhouse Effect Constant temperature: incoming solar energy = outgoing solar energy Greenhouse gases found in the troposphere absorb some of the infrared radiation (heat) radiated by the earth’s surface. Gas molecules vibrate more  heat

Temperature and Carbon Dioxide Concentration .

Greenhouse Gases** Water Vapor (varies) Carbon Dioxide (50%) Methane (16%) Nitrous Oxide (6%) CFCs (20%) Ozone (8%) Miller p.449

Water Vapor Most abundant natural greenhouse gas. Contributes to heating of the ocean surface and the lower atmosphere. Higher temps = more evaporation = rising of water vapor = more warming.

Carbon Dioxide (CO2) Present naturally (0.037%). Increased since Industrial Revolution Combustion of fossil fuels (coal, natural gas & petroleum). For every kg of fossil fuels burned 3kg is released. Deforestation Fewer forests = less absorption of CO2.

Methane (CH4) More effective (30x) absorber of long wave radiation than CO2. Sources Landfills Agriculture: intestines of cattle and sheep Wetlands, swamps, bogs Coal mines and natural gas Is being added to the atmosphere faster than it can be broken down. Increase correlates with population increase.

Nitrous Oxide (N2O) Agriculture Source Consequence of anaerobic dentrification processes Fertilizing land Industrial source: High temperature combustion of fossil fuels.

CFC’s and other Halocarbons Concerns: Live long and contribute to warming and greenhouse effect Also deplete ozone Absorb 10,000 times more radiation than CO2 Sources: Foam Cleaners Aerosol sprays Coolants for refrigeration and air conditioning

Consequences

Melting Ice Caps

Spread of human disease:

global conveyor belt

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Island Inundation

Habitats are becoming compromised

Methane bubbles trapped in lake ice in early autumn Credit: Katey Walter; courtesy of Nature

The Debate

Ways to Reduce Greenhouse Gas Emissions 1. Do not burn fossil fuels: Use renewable energy sources: Wind power Solar power Geothermal energy Alternatives don’t emit greenhouse gases.

2. Replanting Forests. 3. Recycling and reuse.

4. Legislation: Stricter transportation laws Carbon Tax Carpool & HOV lanes (High Occupancy Vehicles) Use Mass transit High-mileage standards

Sea Level and Coastal Areas Increased deaths from heat and disease Disruption of food and water supplies Spread of tropical diseases to temperate areas Increased respiratory disease and pollen allergies 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 from more frequent, intense, and heavy rainfall in some areas Weather Extremes Increased deaths More environmental refugees Increased migration Human Population

Action CO2 Reduction Drive fuel-efficient car, walk, bike, car pool, and use mass transit Use energy-efficient windows refrigerator Insulate walls and ceilings Reduce garbage by recycling and reuse Caulk and weatherstrip windows and doors Insulate hot water heater Use compact fluorescent bulbs Set water heater at no higher than (120° F) Wash laundry in warm or cold water Use low-flow shower head 9 kg (20 lbs) per gallon of gasoline saved Up to 4,500 kg (10,000 lbs) per year Up to 1,400 kg (3,000 lbs) per year Up to 900 kg (2,000 lbs) per year 450 kg (1,000 lbs) for 25% less garbage per year Up to 450 kg (1,000 lbs) per year 230 kg (500 lbs) per year per bulb for each 6° C (10° F) reduction Up to 230 kg (500 lbs) per year for 2 loads a week Up to 140 kg (300 lbs) per year