Agricultural land use and its Earth system implications

点击翻译按钮获取中文摘要

Agricultural land use presents a dilemma. On the one hand, humans derive valuable resources such as food, fiber, and freshwater through land use. On the other hand, land use and cover change is a major driver of global environmental change, which may, in turn, jeopardize our continuing ability to derive resources in the future. Over the last 40 years, most of our global increase in food production has come through agricultural intensification (i.e., extracting higher production per unit of land by using new varieties of crops and more inputs such as irrigation and fertilizers) rather than through extensification (expanding area under production). There is a raging debate, mainly among the conservation community, about the benefits of intensification versus extensification. On the one hand, extensification allows for "wildlife friendly" farming. But intensification, by using less land overall, may allow us to "spare land for nature". However, this debate also has significance for other environmental issues, which has not been widely recognized. While extensification results in carbondioxide emissions (through deforestation), and biodiversity loss, intensification can cause nitrous oxide emissions (another potent greenhouse gas), and freshwater depletion and pollution. So either option presents a different suite of environmental problems. My research program aims to examine the tradeoffs between crop production and the global environment in the content of the intensification-extensification debate. I propose to develop global data sets and modeling tools necessary to address this challenge. I also propose to do more focussed work in the Brazilian Amazon, India, and Canada, three case-study regions chosen to consider a range of farming systems and environmental problems, to examine the historical tradeoffs that have already been made and explore potential future tradeoffs.