英语： Unit22 lesson 1 教学课件（北师大版选修 8 ）Lesson 1Global Warming Lesson 1Global Warming Appreciation of a film trailerWords previewconsensusbeyondclaimrelevantraybouncepinn. 一致的意见prep. 超出vt. 声称adj. 有关的n. 光线vi. 反弹vt. 固定agriculturecoincidencecondemndroughtfederalreservationsacrificeWords previewn. 农业n. 巧合vt. 宣判死刑 , 注定毁灭n. 旱灾adj. 联邦的n. 保留 , 存疑vt., vi. 牺牲 , 献出advocaterecyclesubstitutethreatenpancakehurricaneWords previewvt. 主张 , 提倡vt. 回收利用n. 代替品 , 代用品vt. 威胁n. 薄煎饼n. 飓风Expressions previewbeyond one’s controllook aheadrefer toin turnlead totake actionahead of超出……的控制，不受……的控制展望未来指 , 意即依次引起 , 导致采取行动在……前面Look at the pictures and what do you know about global warming. The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor, carbon dioxide, nitrous oxide, and methane, for example) trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. Because of how they warm our world, these gases are referred to as greenhouse gases. The Greenhouse EffectThe Greenhouse Effect Without this greenhouse heating, the Earth's average temperature would be only about -73 C (-100 F); even the oceans would be frozen under such conditions, such as the Moon and the Mars. MarsMarsMoonMoonWhat Are Greenhouse Gases? Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases . O...
