Program on Food Security and the Environment, Stanford University, Stanford, CA 94305, USA.
Proc Natl Acad Sci U S A. 2010 Sep 21;107(38):16732-7. doi: 10.1073/pnas.0910275107. Epub 2010 Aug 31.
Global demand for agricultural products such as food, feed, and fuel is now a major driver of cropland and pasture expansion across much of the developing world. Whether these new agricultural lands replace forests, degraded forests, or grasslands greatly influences the environmental consequences of expansion. Although the general pattern is known, there still is no definitive quantification of these land-cover changes. Here we analyze the rich, pan-tropical database of classified Landsat scenes created by the Food and Agricultural Organization of the United Nations to examine pathways of agricultural expansion across the major tropical forest regions in the 1980s and 1990s and use this information to highlight the future land conversions that probably will be needed to meet mounting demand for agricultural products. Across the tropics, we find that between 1980 and 2000 more than 55% of new agricultural land came at the expense of intact forests, and another 28% came from disturbed forests. This study underscores the potential consequences of unabated agricultural expansion for forest conservation and carbon emissions.
现在，全球对粮食、饲料和燃料等农产品的需求是推动发展中国家大部分地区耕地和牧场扩张的主要因素。这些新的农业用地是取代森林、退化森林还是草原，对扩张的环境后果有很大影响。尽管这种一般模式是已知的，但仍没有对这些土地覆盖变化进行明确的量化。在这里，我们分析了联合国粮食及农业组织创建的丰富的、泛热带分类 Landsat 场景数据库，以研究 20 世纪 80 年代和 90 年代农业扩张的途径，并用这些信息来突出未来可能需要进行的土地转换，以满足日益增长的农产品需求。在整个热带地区，我们发现，在 1980 年至 2000 年期间，超过 55%的新农业用地是从完整的森林中开垦出来的，另有 28%来自受干扰的森林。这项研究强调了不加控制的农业扩张对森林保护和碳排放的潜在影响。
