| A | B |
|---|
| a form of oxygen that has 3 oxygen atoms instead of 2 | ozone |
| plants must have this molecule to produce food | carbon dioxide |
| water in the form of gas | water vapor |
| harmful substances in the air, water, or soil | pollutants |
| brown haze that forms in cities | photochemical smog |
| a process in which a layer of warm air prevents rising air from escaping | temperature inversion |
| formed when nitrogen and sulfur oxides combine with water | nitric and sulfuric acid (acid rain) |
| they cause about 1/2 of the air pollution in the cities | cars and trucks |
| the thickness of a tree ring | depends on the length of the warm growing season |
| huge sheets of ice covered parts of Earth's surface | ice age |
| the rise in average temperatur of the troposphere over the last 120 yrs. | 0.5 degrees Celcius |
| atmospheric gases that trap solar energy | greenhouse gases |
| 3 greenhouse gases | Water vapor, carbon dioxide , methane |
| human activites that add to greenhouse gases hence warming earth | burning of fossil fuels |
| farmers in cool areas could plant more | possible advantage of global warming |
| Dust bowls, increase in hurricanes, floods from melting ice | Possible negative effects of global warming |
| blocks out harmful ultraviolet radiation | ozone layer |
| These have been damaging the ozone layer | chemicals produced by humans, esp. CFCs |
| The chemicals that are the major cause of ozone depletion | CFCs |
| 3 factors possibly changing earth's climate | change of earth's position relative to sun,movement of continents,changes in sun's energy output |
