Greenhouse Effect (E 3 ) Pages ) Definitions 2) Description 3) Greenhouse Gases 4) Greenhouse Gases Effect on Atmosphere

Definitions  Greenhouse Effect A heating effect occurring in the atmosphere because of the presence of greenhouse gases that absorb infrared radiation  Greenhouse Gases Molecules that contribute to the greenhouse effect and global warming by absorbing infrared energy emitted or reflected from the surface of the earth

Objective One: Describe the Greenhouse Effect  Earth’s Temperature Short wavelength sunlight  Some energy absorbed by surface  Remaining reflected off the surface=longer wave radiation Longer Wave Radiation (infrared)  Absorbed by greenhouse gases and reradiated  Greenhouse Gases 1 way filters:  Shortwave (visible & UV) can pass through, long wave (infrared) cannot Maintain Earth’s temperature (60)

“Enhanced” Greenhouse Effect  Global Warming The increase in the temperature of the Earth’s atmosphere since the Industrial Revolution. Believed to be a consequence of rising levels of greenhouse gases (CO 2 ) which are enhancing the greenhouse effect

Objective Two: List the main greenhouse gases and their sources, and discuss their relative effects GasH2OH2OCO 2 CH 4 N2ON2OO3O3 CFCs % Volume 0 − 43.7 × × × × × Relative Effectiveness ,00010,000 − 25,000 Contribution to Global Warming 50 − 60%15 − 18%6%12%8 − 14% Atmospheric Life (years) 200 − 5007 − − 15080

Main Sources  Water Vapor: H 2 O Evaporation from bodies of water; product of hydrocarbon combustion  Carbon Dioxide: CO 2 Combustion of fossil fuels, forest fires, decay of plants and animals  Methane: CH 4 Anaerobic decomposition of organic matter; from ruminant animals (cows & sheep by bacterial breakdown of cellulose), rice paddies, oil and gas fields

Main Sources (continued)  Dinitrogen Monoxide: N 2 O Bacterial action, use of nitrogen-based fertilizers  Ozone: O 3 Photochemical smog  Chlorofluorocarbons: CFCs In spray can propellants, old refrigerators and air conditioners, as solvents, production of plastic foams (no natural source)

Objective Three: Discuss the influence of increasing amounts of greenhouse gases on the atmosphere  3 main effects 1) Increase in temperature 2) 1% increase in precipitation 3) cm worldwide rise in sea levels o Melting of glaciers and ice caps o Physical expansion of H 2 O because of warmer temperatures o More changes as concentration of greenhouse gases increase

Additional Effects of Global Warming  Health Life cycles of pathogens and insects (like mosquitoes) are affected by climate Greater chance of malaria, etc.  Agriculture Effect on crop yields and geographic distribution of crops  Forests Insects and diseases may increase Increase in summer droughts would produce more forest fires Higher temps and more rain should help forests grow more rapidly

Global Warming Effects (continued)  Water Resources Decreased water quality due to flooding  Floods more likely due to more intense rainfall Droughts more severe due to increased evaporation and drier soil  Coastal Areas Raise the level of seas eroding beaches, inundation low lands, increasing coastal flooding  Species and Natural Areas Loss of cold water fish habitat Shift in ecological areas Loss of habitats and species Desertification