Environmental Problems, Their Causes, and Sustainability 1

Agriculture• Shifts in food-growingareas• Changes in crop yields• Increased irrigationdemands• Increased pests, cropdiseases, and weedsin warmer areasWater Resources• Changes in water supply• Decreased water quality• Increased drought• Increased flooding• Snowpack reduction• Melting of mountaintopglaciersForests• Changes in forest compositionand locations• Disappearance of some forests,especially ones at high elevations• Increased fires from drying• Loss of wildlife habitat and speciesBiodiversity• Extinction of someplant and animal species• Loss of habitats• Disruption of aquatic lifeNASASea Level and Coastal Areas• Rising sea levels• Flooding of low-lying islands andcoastal cities• Flooding of coastal estuaries, wetlands,and coral reefs• Beach erosion• Disruption of coastal fisheries• Contamination of coastal aquiferswith salt waterWeather Extremes•Prolonged heat wavesand droughts• Increased flooding frommore frequent, intense,and heavy rainfall insome areasHuman Population• Increased deaths fromheat and disruption offood supplies• More environmentalrefugees• Increased migrationHuman Health• Decreased deaths from cold weather• Increased deaths from heat and disease• Disruption of food and water supplies• Spread of tropical diseases totemperate areas• Increased respiratory disease andpollen allergies• Increased water pollution fromcoastal flooding• Increased formation ofphotochemical smogFigure 21-13 Winners and losers. Projected effects of a warmer atmosphere for the world. Most of these effectscould be harmful or beneficial depending on where one lives. Current models of the earth’s climate cannotmake reliable projections about where such effects might take place at a regional level and how long theymight last. (Data from Intergovernmental Panel on Climate Change, U.S. Global Climate Change ResearchProgram, U.S. National Academy of Sciences)According to the IPCC, the largest burden of theharmful effects of moderate global warming will fallon people and economies in poorer tropical and subtropicalnations without the economic and technologicalresources needed to adapt to its harmful impacts.In 2003, scientists at the World Health Organizationestimated that each year about 150,000 people—mostly children in developing countries in Asia andAfrica—die prematurely from side effects of globalwarming ranging from increases in malaria to malnutrition.They estimated that this death toll could doubleby 2020. Some researchers estimate that by the end ofthis century the annual death toll from global warming• Less severe winters• More precipitation in some dry areas• Less precipitation in some wet areas• Increased food production in some areas• Expanded population and range for some plantand animal species adapted to higher temperaturesFigure 21-14 Winners: Possible beneficial effects of a warmeratmosphere for some countries and people.http://biology.brookscole.com/miller14475