常春藤解析英语【51】The Earth's Biggest Threat地球危（在线收听）

The Earth's Biggest Threat　地球危机──温室效应 by Levi King Global warming was once considered unlikely to be real. Recently, though, it has become widely accepted as fact. Scientists have calculated that the earth's atmosphere has gotten approximately 0.75 degrees Celsius warmer since 1900. This may not seem like much, but scientists predict an additional increase of between 1 and 7 degrees Celsius by the year 2100. This slight change could be enough to cause disasters such as extreme weather, crop failure, extinctions, melting glaciers, and rising sea levels. It's possible that natural phenomena like volcanoes, solar flares, and shifts in the earth's orbit could be causes of this change. However, scientists now believe that changes in the atmosphere are primarily to blame for the rise in temperatures. Light from the sun enters the earth's atmosphere and warms the air, land, and oceans. As heat radiates back through the atmosphere toward space, some of it is trapped by gases and continues to warm the earth. This is called the greenhouse effect, and the gases that trap the heat are greenhouse gases. Without the greenhouse effect, life couldn't exist on earth. However, rising levels of greenhouse gases are trapping more and more of the sun's heat. As people burn fossil fuels or clear forests, carbon dioxide, a greenhouse gas, is released into the atmosphere. As the oceans warm, water vapor, which is also a greenhouse gas, enters the atmosphere. This combination of pollutants and water vapor creates the powerful and dangerous cycle behind global warming. It is a cycle that, if active measures are not taken, could have serious and deadly consequences for all living things in the near future.

单字小铺 1.global warming n. 全球暖化 2.calculate vt. 估计；估算 3.atmosphere n. 大气层 4.Celsius n. 摄氏 Fahrenheit n. 华氏 5.predict vt. 预测 6.extreme weather　　极端气候 7.crop failure n. 作物欠收 8.extinction n. 灭绝 9.glacier n. 冰河 10.solar flare n. 太阳闪焰（太阳表面一种光度突然迅速增强的变化） 11.orbit n. 运行轨道 & vi. 绕轨道运行 12.primarily adv. 主要地 13.trap vt. 陷于，困住 14.greenhouse effect n. 温室效应 15.greenhouse gas n. 温室气体（尤指二氧化碳或甲烷） 16.exist vi. 存在 17.fossil fuel n. 化石燃料 18.carbon dioxide n. 二氧化碳 19.water vapor n. 水汽，水蒸气 20.combination n. 混合物；结合 21.consequence n. 结果 词组小铺 in the near future　　不久之后，不久的将来 = in the not too distant future

精解字词词组 1.threat n. 威胁 pose a threat to...　　对……构成∕造成威胁 例: The tiger that escaped from the zoo poses a threat to people in the area. （那只逃出动物园的老虎对该区民众造成威胁。） 2.approximately adv. 大约 注意: approximately 为修饰数量形容词的副词，此类副词常见的尚有 about、around、some、roughly 等。 例: I'm expecting approximately 10 people to come to the party. （我预期约有十个人来参加派对。） 3.additional a. 额外的 an additional + 数字　　额外的……（数目） = an extra + 数字 例: We need an additional five volunteers for the charity event. （我们还需要五名义工加入这项慈善活动。） 4.shift n. 改变；轮班 on shift　　轮班 work night shifts　　值晚班 例: The person who was on shift last night forgot to lock the doors when he left. （昨晚值班的人离开时忘记锁门了。） 5.sb be to blame for...　　某人该为……负责 blame sb for sth = blame sth on sb 因某事责备某人；将某事归咎于某人 例: Grady insists that he is not to blame for the mess in the classroom. （葛兰迪坚称自己不应该为教室的混乱负责。） 例: Don't blame me for your problems. I'm trying to help you. （别把你的问题怪到我头上。我正在想办法帮你。） 6.radiate vi.（光、热）散发，放射 例: The campers all sat and enjoyed the heat radiating from the fire. （露营者全坐在火堆旁取暖。） 7.take measures (to V)　　采取行动∕措施（做……） 例: Mr. Jones vowed to take firm measures to prevent cheating. （琼斯老师誓言采取严密措施防范考试作弊。）

中文翻译 全球暖化一度被认为不可能成真。然而近来却是广为大众所接受的事实。科学家算出自 1900 年起，地球的大气层温度已经上升摄氏 0.75 度。变化似乎不大，但科学家预测，到了 2100 年，气温会再上升摄氏 1 至 7 度。改变虽小，却足以造成诸多灾难，像是极端气候、作物欠收、物种灭绝、冰河融化和海平面上升。 像火山、太阳闪焰和地球轨道的改变等自然现象都有可能造成这种变化。然而，现在科学家相信大气层改变才是气温上升的元凶。太阳的光线进入大气层后使空气、地表和海洋的温度上升。有些热能在折射回太空的途中被气体困住，使地球温度持续升高。这种现象称为温室效应，而困住热能发散的气体称为温室气体。 少了温室效应，地球上就不会有生命存在。但是，温室气体含量上升困住了愈来愈多的太阳热能。当人类燃烧化石燃料或砍伐森林，二氧化碳（温室气体的一种）遂被释放到大气层。随着海洋温度上升，水汽（也是一种温室气体）也进入大气层。污染物和水汽两者便是造成全球暖化、强大而危险循环的主因。如果我们不积极做为，这种循环对所有生物造成严重且致命后果的日子将不远矣。