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 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 (www.worldwatch.org).

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 generalizations 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.

“In all, climate pressures on human migration cannot be denied,” said Hunter. “Yet new data and research are shedding light on the complexities underlying migration decision making, as well as providing more precise estimates of vulnerable populations. Future estimates of potential climate-related migration must take these insights into account.”

 

Around the world, environmental change interacts with existing challenges, including persistent impoverishment, unsustainable livelihoods, and population pressures. Such challenges can encourage relocation in some cases, but constrain it in others. Research suggests that when climate-related movement does occur, much of it will be short distance and within national borders, as opposed to international. And, like much environmentally influenced migration, people’s movements may be cyclical as opposed to permanent. More-rapid climate change, however, could increase both the overall number of individuals who are affected and the desperation brought on by a lack of viable livelihood alternatives.

Further highlights from the report:

• Over half of Africa’s urban residents are in cities located in arid zones vulnerable to water scarcity and lacking the infrastructure and resources needed to improve resilience and lessen potential outmigration.

• Researchers estimate that some 20 million people in the United States will be affected by sea-level rise by 2030.

• Research focused on urban vulnerability in Africa, Asia, and South America estimates the population at risk of climate change in two zones expected to experience serious impacts: low-level coastal zones, which are vulnerable to flooding and related health risks (such as cholera and diarrheal diseases), and arid drylands, where urban residents are often not adequately served by distribution systems even if water is plentiful.