Use of US croplands for biofuels increases greenhouse gases through emissions from land-use change
Use of US croplands for biofuels increases greenhouse gases through emissions from land-use change
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DOI：
10.1126/science.1151861
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发表时间：
2008-02-29
期刊：
影响因子：
56.9
通讯作者：
Yu, Tun-Hsiang
中科院分区：
文献类型：
--
作者：
Searchinger, Timothy;Heimlich, Ralph;Yu, Tun-Hsiang
大多数先前的研究发现，用生物燃料替代汽油将减少温室气体排放，因为生物燃料通过原料的生长来固碳。这些分析未能计算出全球农民因价格上涨而将森林和草原转变为新农田以取代用于生产生物燃料的谷物（或农田）时产生的碳排放量。通过使用全球农业模型来估算土地利用变化带来的排放量，我们发现以玉米为原料的乙醇非但没有节省 20%，反而在 30 年内使温室气体排放量增加了近一倍，并在 167 年内增加了温室气体排放。如果在美国玉米土地上种植来自柳枝稷的生物燃料，排放量会增加 50%。这一结果引起了人们对大型生物燃料指令的担忧，并凸显了利用废物的价值。
Most prior studies have found that substituting biofuels for gasoline will reduce greenhouse gases because biofuels sequester carbon through the growth of the feedstock. These analyses have failed to count the carbon emissions that occur as farmers worldwide respond to higher prices and convert forest and grassland to new cropland to replace the grain ( or cropland) diverted to biofuels. By using a worldwide agricultural model to estimate emissions from land- use change, we found that corn- based ethanol, instead of producing a 20% savings, nearly doubles greenhouse emissions over 30 years and increases greenhouse gases for 167 years. Biofuels from switchgrass, if grown on U. S. corn lands, increase emissions by 50%. This result raises concerns about large biofuel mandates and highlights the value of using waste products.