Environmental refugees tend to stay local.

• Position: Climate Change

Recent reports, as well as extreme weather events such as Superstorm Sandy, suggest that climate change, and particularly sea-level rise, may be occurring faster than earlier anticipated. This has increased public and policy discussions about climate change's likely impacts on the movement of populations, both internally and worldwide. Research suggests that, when climate-related migration does occur, much of it is short distance and within national borders, as opposed to international, according to analysis conducted by Lori Hunter, associate professor of sociology at the University of Colorado, Boulder.

Previous studies over the past two decades largely have relied on descriptive data and simplistic assumptions to put forward, at times, alarmist estimates of future numbers of "environmental refugees," ranging from 150,000,000 to 1,000,000,000 people, but such broad-sweeping generalizations mask several central issues that are important in the development of appropriate policy responses. These include:

* Environmental drivers, such as changing climatic patterns, rarely are the only factor leading to migration. Rainfall shortages and heat waves interact, for instance, with persistent impoverishment and land degradation, as well as political and economic pressures. In addition, in many regions women's inability to limit their family size, combined with the unmet demand for family planning, results in unsustainable population pressures on local and natural...