Environmental Science Ch 13 Study Guide-KEY 1) Define Climate-the average weather conditions in an area over a long period of time. 2) What factors determine the Earth’s climate? Name all six.-1) latitude, 2) atmospheric circulation patterns, 3) oceanic circulation patterns, 4) the local geography of an area, 5) solar activity, and 6) volcanic activity. 3) Define Latitude-the distance north or south from the equator and is expressed in degrees. 4) What is located at 0° latitude? Equator 5) Why is latitude important and how does it affect the climate? Because the amount of solar energy an area of the Earth receives depends on its latitude. 6) What part of the Earth receives the most amount of solar energy? The Equator The least? The Poles 7) Describe what happens to the amount of daylight during both the summer and winter at the poles (Both north and south). At 45° north and south latitude, there is as much as 16 hours of daylight each day during the summer and as little as 8 hours of sunlight each day in the winter. At the North Pole in the winter, there is 24 hours of darkness. At the North Pole in the summer, there is 24 hours of daylight. It is the opposite at the South Pole. 8) Why does cold air sink? Because it is denser than warm air. What happens as warm air rises? It expands and cools as it rises. 9) What does warm air hold more of, than cold air can? Water vapor 10) What causes wind? Solar energy heats the ground, which warms the air above it. This warm air rises, and cooler air moves in to replace it. 11) Other than sunlight, areas near the equator also receive a lot of what? Rain 12) Define prevailing winds-Winds that blow predominantly in one direction throughout the year. 13) Ocean currents have a great effect on climate because water holds large amounts of heat. 14) Surface ocean currents are mostly caused by what? Winds and the rotation of the Earth 15) Define El Nino-the periodic occurrence in the eastern Pacific Ocean in which the surface-water temperature becomes unusually warm. Winds push warm water eastward and rain follows into the southern U.S. 16) Define La Nina-the periodic occurrence in the eastern Pacific Ocean in which the surface water temperature becomes unusually cool. 17) Mountains create rain shadows. What is a rain shadow? Describe in detail how one is created. Warm air from the ocean blows east, hits the mountains, and rises. As the air rises, it cools, causing it to rain on the western side of the mountain. When the air reaches the eastern side of the mountain it is dry. This effect is known as a rain shadow. 18) What gas is released into the upper atmosphere during volcanic eruptions? Sulfur dioxide 19) What is the Earth’s current tilt on its axis? (in degrees) 23.5° 20) Define ozone layer-the layer of the atmosphere in which ozone absorbs ultraviolet solar radiation. 21) How many oxygen atoms make up ozone? Three 22) What does CFC stand for and what applications did they used to have? Chlorofluorocarbons- They were used in coolants for refrigerators and air conditioners and in cleaning solvents. They were also used as a propellant in spray cans of everyday products such as deodorants, insecticides, and paint. 23) Why are CFC’s bad? They destroy ozone molecules in the stratosphere. 24) Define ozone hole-a thinning of stratospheric ozone that occurs over the poles during the spring. 25) In what year was the ozone hole discovered? 1979 26) What happens when the amount of ozone in the atmosphere decreases? More UV light is able to pass through the atmosphere and reach Earth’s surface. This can lead to an increase in what type of cancer? Skin cancer 27) What do ecologists study or look at as an environmental indicator? The health of amphibian populations 28) What did the Montreal Protocol do or propose? It sharply limited the production of CFCs 29) How long can CFC molecules remain active in the atmosphere? 60 to 120 years 30) Describe the Greenhouse Effect-Sunlight streams through the atmosphere and heats the Earth. As this heat radiates up from Earth’s surface, some of it escapes into space. The rest of the heat is absorbed by gases in the troposphere and warms the air around the Earth. This process of heat absorption is called the greenhouse effect. 31) Define greenhouse gas-a gas composed of molecules that absorb and radiate infrared radiation from the sun. 32) What are the major greenhouse gases? (Name five)- 1) water vapor, 2) carbon dioxide, 3) CFCs, 4) methane, and 5) nitrous oxide. 33) What do many scientists think will happen if the amount of greenhouse gases continues to rise? More greenhouse gases in the atmosphere will result in an increase in global temperature (global warming). 34) Define global warming-A gradual increase in the average global temperature that is due to a higher concentration of gases such as carbon dioxide in the atmosphere. 35) What do some scientists believe in regards to global warming? Some scientists believe that the warming is part of natural climatic variability. 36) What is it that these scientists point out in order to argue against global warming? They point out that widespread fluctuations in temperature have occurred throughout geological time. 37) Why are scientists currently not able to make accurate models about global warming? Because climatic patterns are too complex and too many variables must be taken into account to be solved, even using today’s fastest computers. 38) What would happen if the global temperature increased, what would happen to the ice and sea levels? If the global temperature increased, the amount of ice and snow at the poles would decrease (melt), causing sea levels around the world to rise. 39) When the temperatures are high, what group(s) of people does the heat affect the most? Very young and very old people 40) What would happen to crops if the temperature were to increase? There would be a decrease in crop yields. 41) The International Panel on Climate Change (IPCC) reported that the temperature increased by 0.6ºC during the 20th century. 42) What is the Kyoto Protocol? An international treaty in which developed countries that signed the treaty agree to reduce their emissions of carbon dioxide and other gases that may contribute to global warming by the year 2012. 43) Did the United States sign the Kyoto Protocol in 2001? No 44) What factors make it difficult to slow global warming? Economic, political, and social factors faced by different countries.