Global meat production is becoming increasingly industrialized, spatially concentrated, and geographically detached from the agricultural land base. This Policy Forum reviews the process of livestock industrialization and globalization, and its consequences for water, nitrogen, and species-rich habitats in meat- and feed-producing regions often vastly separated in space. It argues that pricing and other policy mechanisms which reflect social costs of resource use and ecological change are needed to re-couple livestock and land in producer countries, drawing on examples from Europe and the United States. It also argues that consumers can play an important role in setting a sustainable course.

Land use has generally been considered a local environmental issue, but it is becoming a
force of global importance. Worldwide changes to forests, farmlands, waterways, and
air are being driven by the need to provide food, fiber, water, and shelter to more than
six billion people. Global croplands, pastures, plantations, and urban areas have expanded
in recent decades, accompanied by large increases in energy, water, and fertilizer consumption, along with considerable losses of biodiversity. Such changes in land use have
enabled humans to appropriate an increasing share of the planet's resources, but they
also potentially undermine the capacity of ecosystems to sustain food production,
maintain freshwater and forest resources, regulate climate and air quality, and ameliorate
infectious diseases. We face the challenge of managing trade-offs between immediate
human needs and maintaining the capacity of the biosphere to provide goods and
services in the long term.

Global society is seriously threatened by the environmental impacts of human activities. Although the Millennium Ecosystem Assessment and the Intergovernmental Panel on Climate Change have been established to analyze biophysical aspects of global change, there is no equivalent effort to assess the role of individual behavior in creating those environmental threats. The authors of this Policy Forum propose the institution of a Millennium Assessment of Human Behavior to establish serious dialogues about what can and should be done. It would draw heavily on social scientists and would engage groups of citizens globally in public forums to explore the moral elements and the consequences of choices about environmental change.

Although no country to date has released a major genetically modified (GM) food grain crop, China is on the threshold of commercializing GM rice. This paper studies two of the four GM varieties that are now in farm-level pre-production trials, the last step before commercialization. Farm surveys of randomly selected farm households that are cultivating the insect-resistant GM rice varieties, without the aid of experimental station technicians, demonstrate that when compared with households cultivating non-GM rice, small and poor farm households benefit from adopting GM rice by both higher crop yields and reduced use of pesticides, which also contribute to improved health.

Improved understanding of the factors that limit crop yields in farmers' fields will play an important role in increasing regional food production while minimizing environmental impacts. However, causes of spatial variability in crop yields are poorly known in many regions because of limited data availability and analysis methods. In this study, we assessed sources of between-field wheat (Triticum aestivum L.) yield variability for two growing seasons in the Yaqui Valley, Mexico. Field surveys conducted in 2001 and 2003 provided data on management practices for 68 and 80 wheat fields throughout the Valley, respectively, while yields on these fields were estimated using concurrent Landsat satellite imagery. Management-yield relationships were analyzed with t tests, linear regression, and regression trees, all of which revealed significant but year-dependent impacts of management on yields. In 2001, an unusually cool year that favored high yields, N fertilizer was the most important source of between-field variability. In 2003, a warmer year with reduced irrigation water allocations, the timing of the first postplanting irrigation was found to be the most important control. Management explained at least 50% of spatial yield variability in both years. Regression tree models, which were able to capture important nonlinearities and interactions, were more appropriate for analyzing yield controls than traditional linear models. The results of this study indicate that adjustments in management can significantly improve wheat production in the Yaqui Valley but that the relevant controls change from year to year.