Climate change could touch off rising seas, droughts, floods, and other major calamities by the middle of the century, triggering migrations that could “vastly exceed” the scope of anything before, says a major new report from international researchers. While the report does not provide specifics on the numbers of potentially uprooted, estimates from other reports it cites range from 25 million to 50 million by 2010, to almost 700 million by 2050, according to the report from Columbia University's Center for International Earth Science Information Network (CIESIN), the United Nations University, and CARE International.

 

“Climate is the envelope in which all of us lead our daily lives,” says coauthor Alexander de Sherbinin, a geographer at CIESIN. “This report sounds warning bells. We usually categorize the poor as the ones who will suffer most—but richer societies will potentially lose as well.”

 

The researchers caution that the effects of climate change are hard to sort from connected factors, including political and economic conflicts, extreme weather events, population growth, human destruction of ecosystems, and overuse of farmland. But they say the phenomenon will eventually play a dominant role by exacerbating all of these problems, and is already having harmful effects. “In Search of Shelter: Mapping the Effects of Climate Change on Human Migration and Displacement” is based on a first-time global survey of environmental change and migration, the researchers say.

 

Among some of the findings, the report predicts that the breakdown of ecosystem-based economies, including subsistence herding, farming, and fishing will be the dominant driver of forced migration. It also says climate change will increase the frequency and intensity of natural hazards such as cyclones, floods, and droughts. It projects that rains in parts of Mexico and Central America, for instance, will drop as much as 50 percent by 2080.

 

What’s more, sea-level rise directly threatens the existence of some 40 countries. Saltwater intrusion, flooding, and erosion could destroy agriculture in the densely populated Mekong, Nile and Ganges deltas. Some Pacific island nations including the Maldives are already considering prospects for total relocation, it notes. The report states that most migrants will probably move within their own countries, or to countries next door. Many will be poor, and many will be unable to move far enough to improve their lots. It says that ripples from resulting conflicts and collapses will hit richer countries.

 

“Societies affected by climate change may find themselves locked into a downward spiral of ecological degradation, towards the bottom of which social safety nets collapse, while tensions and violence rise,” says a statement from CARE. “In this all-too plausible scenario, large populations would be forced to migrate as a matter of immediate survival.”

 

The report says it is vital that countries reach an agreement to stem greenhouse gases during this December's United Nations Framework Convention on Climate Change. But even if this deadline is met, most scientists say some amount of climate change is now inevitable, the report adds. To mitigate resulting migrations, the report recommends that nations prioritize the most vulnerable populations and invest there in defensive measures, including irrigation technology that uses less water; low-till agriculture; economic diversification; and official systems to manage natural disasters. “New thinking and practical approaches are needed to address the threats that climate-related migration poses to human security and well-being,” says coauthor Koko Warner, head of the UN University's Institute for Environment and Human Security.