class #35: friday, november 19, 2010 1 class #35: friday, november 19 human influences on climate

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More observations of global warming Widespread retreat of nonpolar glaciers Thinning of arctic sea ice—40% Decreased N Hemisphere snow cover Increase of global mean sea level Longer growing season in NH Shortened duration of ice cover on NH lakes Class #36: Monday, November 22,

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Class #35: Friday, November 19, Class #35: Friday, November 19 Human Influences on Climate Class #36: Monday, November 22, Global Warming is a fact!!! Over the past 2 decades the global average surface temperature has increased noticeably. A trend involves a steady change in one directionupward for global average temperature. Not every location and/or every region shows the identical pattern. More observations of global warming Widespread retreat of nonpolar glaciers Thinning of arctic sea ice40% Decreased N Hemisphere snow cover Increase of global mean sea level Longer growing season in NH Shortened duration of ice cover on NH lakes Class #36: Monday, November 22, 4 5 6 7 8 9 10 Feedback: change leads to change leads to more change Positive feedback mechanism: reinforces (enhances) the original trend (change) Negative feedback mechanism: damps out an existing trend (change) Example of a positive feedback mechanism: warming, evaporation, water vapor, warming Class #36: Monday, November 22, More climate feedback mechanisms Example of a negative feedback mechanism: warming, evaporation, water vapor, cloud, cooling Another positive feedback mechanism: Called the ice/albedo feedback mechanism Cooling, more ice, higher albedo, more cooling Warming, less ice, lower albedo, more warming Class #36: Monday, November 22, Class #36: Monday, November 22, Forest fires produce carbon monoxide Fig. 15-3, p. 444 Class #36: Monday, November 22, Air Pollution Air pollutants are aerosol particles (liquids and solids) and gases that, in high concentrations, seriously affect the lives of people and animals, harm plants, or threaten ecosystems. Air pollutants can come from natural sources (volcanoes, forest fires, dust storms) or human activities (anthropogenic sources) Class #36: Monday, November 22, Anthropogenic sources of air pollution Transportation: motor vehicles, aircraft, ships Energy generation: electricity generation Industry: smelting, dry cleaning, manufacturing Home heating Carbon dioxide can be considered a pollutant Class #36: Monday, November 22, Primary air pollutants Emitted directly by sources Carbon monoxide, a gas, incomplete combustion, can cause death in small concentrations, emitted by vehicles and defective heating devices Lead, a particulate, brain damage, in some paints and treated gasoline, outlawed now Class #36: Monday, November 22, More primary air pollutants Oxides of sulfur, sulfur dioxide and sulfur trioxide, respiratory irritant, emitted in burning fossil fuels containing sulfur Oxides of nitrogen, nitric oxide and nitrogen dioxide, pulmonary problems, emitted by high-temperature combustion of fossil fuels in transportation and electric energy generation Class #36: Monday, November 22, More primary air pollutants Hydrocarbons, also called volatile organic compounds, or VOCs Some are carcinogens Are made up of hydrogen and carbon Emitted by motor vehicles, dry cleaning Particulates, small particles Smallest are most dangerous to lungs Class #36: Monday, November 22, Secondary air pollutants Are produced in chemical reactions with primary air pollutants Present harder-to-solve problems than primary air pollutants Include acid deposition and photochemical oxidants (smog)/ozone Class #36: Monday, November 22, Acid deposition Can be acid rain, snow, fog, dew, or dry Formed when oxides of nitrogen and sulfur combine with water vapor or liquid water to produce nitric acid and sulfuric acid In water, allows toxic heavy metals to leach out and contaminate drinking water Damage to structures, make lakes toxic Class #36: Monday, November 22, Fig. 15-4, p. 445 Class #36: Monday, November 22, pH level of rain in 2001 Fig. 15-5, p. 446 Class #36: Monday, November 22, Photochemical oxidants/smog/ozone Irritates eyes, nose, throat; causes coughing chest pain, and shortness of breath, aggravates asthma and bronchitis Forms when sunlight acts on a combination of hydrocarbons, oxides of nitrogen, and oxygen Ozone is the main component, with PAN and formaldehyde Class #36: Monday, November 22, Table 15-1, p. 445 Class #36: Monday, November 22, Table 15-2, p. 445 Class #36: Monday, November 22, Fig. 15-7, p. 448 Class #36: Monday, November 22, Fig. 15-6, p. 447 Class #36: Monday, November 22, Fig. 15-8, p. 449 Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Class #36: Monday, November 22, Fig. 15-1, p. 442 Class #36: Monday, November 22, Fig , p. 465 Class #36: Monday, November 22, Primary air pollutants Emitted directly by sources Carbon monoxide, a gas, incomplete combustion, can cause death in small concentrations, emitted by vehicles and defective heating devices Lead, a particulate, brain damage, in some paints and treated gasoline, outlawed now Class #37: Monday, November 29,