Deforestation in the Amazon. (Credit: iStockphoto)

ScienceDaily (Sep. 4, 2010) — Global agricultural expansion cut a wide swath through tropical forests during the 1980s and 1990s. More than half a million square miles of new farmland — an area roughly the size of Alaska — was created in the developing world between 1980 and 2000, of which over 80 percent was carved out of tropical forests, according to Stanford researcher Holly Gibbs. “This has huge implications for global warming, if we continue to expand our farmland into tropical forests at that rate,” said Gibbs, a postdoctoral researcher in the Department of Environmental Earth System Science, who led the study. Gibbs and colleagues at several other universities analyzed Landsat satellite data and images from the United Nations to reach their conclusions. Theirs is the first study to map and quantify what types of land have been replaced by the immense area of new farmland developed across the tropical forest belt during the 1980s and 1990s. While this huge increase was happening within the tropics, agricultural land in the non-tropical countries actually decreased in area. The study was published in the online Early Edition of the Proceedings of the National Academy of Sciences. The United Nations Food and Agriculture Organization estimates that to keep pace with increasing demand, global agricultural production will have to keep increasing, possibly even doubling by 2050. That would likely lead to millions of additional acres of tropical forest being felled over the next 40 years. …

Most new farmland in tropics comes from slashing forests, research shows