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- 1. Global Warming. Extreme Climatic Conditions. Potential Impacts of Global Warming. Acid Rain.
- 2. Global Warming An increase in the near surface temperature of the Earth. Global warming has occurred in the distant past as the result of natural influences, but the term is most often used to refer to the warming predicted to occur as a result of increased emissions of greenhouse gases. Scientists generally agree that the Earth’s surface has warmed by about 1 degree Fahrenheit in the past 140 years.
- 3. GLOBAL CLIMATE CHANGE AND GLOBAL WARMING • The use of fossil fuels, including coal and petroleum-based fuels, causes the release of gases, including carbon dioxide, methane, chlorofluorocarbon gases, and nitrous oxide. Gases that arise from natural sources and anthropogenic activities such as the burning of fossil fuels may accumulate in the atmosphere. Sometimes these gases are referred to as greenhouse gases, owing to the fact that in sufficient concentrations in the atmosphere, they may have the effect of trapping heat and causing the earth’s temperature to rise. • Contributing to the greenhouse effect is deforestation, which decreases the capacity of trees and the forest ecosystem to reduce the amount of CO2 in the atmosphere. When deforestation occurs, biodiversity is reduced, resulting in the loss of plants that someday might yield valuable medicines and other products. Deforestation often is the result of burning huge swaths of land, further adding to air pollution.
- 4. Potential Impacts of Global Warming • The potential consequences of global warming include disturbances in the native habitats of plant and animal species. • Another possible end result could be the production of an environment that is conducive to the growth of vector-borne diseases, growth of organisms in the ocean that cause foodborne seafood poisoning, and exacerbation of the effects of air pollution. • Global warming, which has been linked to extreme climatic conditions such as heat waves, droughts, and monsoons, may cause disruption of the food supply and dwindling of food resources, especially in developing areas.
- 7. Extreme Climatic Conditions • Higher average ambient air temperatures are likely to induce more vigorous cycles of evaporation and precipitation. Indeed, a trend of increasing climate variability and extreme precipitation events has been observed over the past century, and recent models strongly correlate this trend with anthropogenic production of greenhouse gases. • Among significant episodes of heat-related mortality, two of particular note occurred: in Chicago, Illinois (US), and in France. The July 12 to July 16, 1995, heat wave in Chicago caused the daily high temperatures to rise to the range of 93°F to 104°F; the city had a record high temperature of 119°F on July 13. The resulting high temperatures were responsible for 465 deaths that were certified as heat-related during the period of the heat wave. • During August 2003, a blistering heat wave descended on France, causing a death toll of almost 15,000. 81 Many of the deaths occurred among the elderly after temperatures reached the low 100s Fahrenheit (low 40s Celsius) in a country where it is uncommon to use air conditioning. One account indicated that “Morgues and funeral parlours coped with an overflow of victims. Refrigerated storerooms were set up; and temporary workers hired to collect bodies from private homes and hotels.
- 8. Acid Rain The term acid rain refers to the precipitation of acidic compounds formed when components of air pollution (e.g., SO2 and NOx ) interact with other components in the air such as water, oxygen, and oxidants. Eventually the acid rain settles on the earth, creating abnormally high levels of acidity that are potentially damaging to the environment, wildlife, and human health. (17) How does Acid Rain affect Humans and the Environment - YouTube
- 9. Factors influencing climate Uneven heating of the earth’s surface by the sun. Air is heated much more at the equator, where the sun’s rays strike directly, than at the poles, where sunlight strikes at a slanted angle and spreads out over a much greater area. Rotation of the earth on its axis. As the earth rotates around its axis, its equator spins faster than its polar regions. As a result, heated air masses rising above the equator and moving north and south to cooler areas are deflected to the west or east over different parts of the planet’s surface. Properties of air, water, and land. Heat from the sun evaporates ocean water and transfers heat from the oceans to the atmosphere, especially near the hot equator. This evaporation of water creates giant cyclical convection cells that circulate air, heat, and moisture both vertically and from place to place in the atmosphere.
- 11. Greenhouse Gases Warm the Lower Atmosphere • Small amounts of certain gases, including water vapor (H2O), carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), in the atmosphere play a role in determining the earth’s average temperatures and its climates. These greenhouse gases allow mostly visible light and some infrared radiation and ultraviolet (UV) radiation from the sun to pass through the atmosphere. • The earth’s surface absorbs much of this solar energy and transforms it to longer-wavelength infrared radiation (heat), which then rises into the lower atmosphere. Some of this heat escapes into space, but some is absorbed by molecules of greenhouse gases and emitted into the lower atmosphere as even longer-wavelength infrared radiation. • Some of this released energy radiates into space, and some warms the lower atmosphere and the earth’s surface. This natural warming effect of the troposphere is called the greenhouse effect.
- 12. Biomes • Scientists have divided the world into several major biomes—large terrestrial regions characterized by similar climate, soil, plants, and animals, regardless of where they are found in the world. The variety of terrestrial biomes and aquatic systems is one of the four components of the earth’s biodiversity.
- 14. Humans Have Disturbed Most of the Earth’s Land The human species dominates most of the planet. In many areas, human activities are impairing some of the ecological and economic services provided by the world’s deserts, grasslands, forests, and mountains. According to the 2005 Millennium Ecosystem Assessment, about 62% of the world’s major terrestrial ecosystems are being degraded or used unsustainably, as the human ecological footprint intensifies and spreads across the globe. This environmental destruction and degradation is increasing in many parts of the world.
- 16. Questions? Essentials of Ecology P. 140-159
Editor's Notes
- #7: Climate change impacts a wide-range of health outcomes. This slide illustrates the most significant climate change impacts (rising temperatures, more extreme weather, rising sea levels, and increasing carbon dioxide levels), their effect on exposures, and the subsequent health outcomes that can result from these changes in exposures.