Climate-induced migration often for short distances, cyclical, not global

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 likely impact of climate change  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 new analysis conducted by Lori Hunter, associate professor of sociology at the University of Colorado at Boulder, for the Worldwatch Institute's Vital Signs Online service.

Recent research has added nuance to the scientific understanding of the potential connections between climate change and human migration. Previous studies over the past two decades relied largely on descriptive data and simplistic assumptions to put forward at-times alarmist estimates of future numbers of "environmental refugees," ranging from 150 million to 1 billion people. But such broad-sweeping generalisations mask several central issues that are important in the development of appropriate policy responses. These include:

Environmental drivers, such as changing climatic patterns, are rarely the only factor leading to migration. Rainfall shortages and heat waves interact, for example, 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 resources.

Environmentally-related migration is not new: migration has represented a livelihood strategy for millennia. In low-lying Bangladesh, for example, migration has long served as an adaptive strategy. Over two-thirds of Bangladeshis work in agriculture, forests, or fisheries - all livelihoods that depend on environmental conditions. Natural disasters plague rural Bangladesh with regular exposure to flooding as well as crop failure due to rainfall deficits, and food insecurity abounds.

Migration comes with costs - social, financial, and otherwise. People tend to be attached to their homelands, their cultures, and their ways of life, so it is likely that they will seek to remain close to home, and to maintain their accustomed patterns, to the extent possible.