甘蔗可降低周围环境气温
文章来源:未知 文章作者:enread 发布时间:2011-04-18 03:10 字体: [ ]  进入论坛
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Brazilians are world leaders in using biofuels for gasoline(汽油) . About a quarter of their automobile1 fuel consumption comes from sugarcane, which significantly reduces carbon dioxide emissions2 that otherwise would be emitted from using gasoline. Now scientists from the Carnegie Institution's Department of Global Ecology have found that sugarcane has a double benefit. Expansion of the crop in areas previously3 occupied by other Brazilian crops cools the local climate. It does so by reflecting sunlight back into space and by lowering the temperature of the surrounding air as the plants "exhale4(呼气) " cooler water. The study is published in the 2nd issue of Nature Climate Change, posted on-line April 17. The research team, led by Carnegie's Scott Loarie, is the first to quantify the direct effects on the climate from sugarcane expansion in areas of existing crop and pastureland of the cerrado, in central Brazil.

The researchers used data from hundreds of satellite images over 733,000 square miles—an area larger than the state of Alaska. They measured temperature, reflectivity (also called albedo), and evapotranspiration—the water loss from the soil and from plants as they exhale water vapor5.

As Loarie explained: "We found that shifting from natural vegetation to crops or pasture results in local warming because the plants give off less beneficial water. But the bamboo-like sugarcane is more reflective and gives off more water—much like the natural vegetation. It's a potential win-win for the climate—using sugarcane to power vehicles reduces carbon emissions, while growing it lowers the local air temperature."

The scientists found that converting from natural vegetation to crop/pasture on average warmed the cerrado by 2.79 °F (1.55 °C), but that subsequent conversion6 to sugarcane, on average, cooled the surrounding air by 1.67 °F (0.93°C).

The researchers emphasize that the beneficial effects are contingent7(因情况而异的) on the fact sugarcane is grown on areas previously occupied by crops or pastureland, and not in areas converted from natural vegetation. It is also important that other crops and pastureland do not move to natural vegetation areas, which would contribute to deforestation.

So far most of the thinking about ecosystem8 effects on climate considers only impacts from greenhouse gas emissions. But according to coauthor Greg Asner, "It's becoming increasingly clear that direct climate effects on local climate from land-use decisions constitute significant impacts that need to be considered core elements of human-caused climate change."



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1 automobile rP1yv     
n.汽车,机动车
参考例句:
  • He is repairing the brake lever of an automobile.他正在修理汽车的刹车杆。
  • The automobile slowed down to go around the curves in the road.汽车在路上转弯时放慢了速度。
2 emissions 1a87f8769eb755734e056efecb5e2da9     
排放物( emission的名词复数 ); 散发物(尤指气体)
参考例句:
  • Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
  • Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。
3 previously bkzzzC     
adv.以前,先前(地)
参考例句:
  • The bicycle tyre blew out at a previously damaged point.自行车胎在以前损坏过的地方又爆开了。
  • Let me digress for a moment and explain what had happened previously.让我岔开一会儿,解释原先发生了什么。
4 exhale Zhkzo     
v.呼气,散出,吐出,蒸发
参考例句:
  • Sweet odours exhale from flowers.花儿散发出花香。
  • Wade exhaled a cloud of smoke and coughed.韦德吐出一口烟,然后咳嗽起来。
5 vapor DHJy2     
n.蒸汽,雾气
参考例句:
  • The cold wind condenses vapor into rain.冷风使水蒸气凝结成雨。
  • This new machine sometimes transpires a lot of hot vapor.这部机器有时排出大量的热气。
6 conversion UZPyI     
n.转化,转换,转变
参考例句:
  • He underwent quite a conversion.他彻底变了。
  • Waste conversion is a part of the production process.废物处理是生产过程的一个组成部分。
7 contingent Jajyi     
adj.视条件而定的;n.一组,代表团,分遣队
参考例句:
  • The contingent marched in the direction of the Western Hills.队伍朝西山的方向前进。
  • Whether or not we arrive on time is contingent on the weather.我们是否按时到达要视天气情况而定。
8 ecosystem Wq4xz     
n.生态系统
参考例句:
  • This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
  • We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。
TAG标签: climate carbon sugarcane
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