Flooded farmland has already forced thousands of Bangladeshis to higher ground, but that's just the tip of the iceberg, so to speak, of the numbers of people who will need to move because of climate change in the coming decade, according to a report released by the Center for International Earth Science Information Network (CIESIN) at Columbia University, the United Nations University and CARE International today.

As climate change alters weather patterns—hastening desertification in some places and sopping others—increases the strength of natural disasters—from cyclones to landslides—and raises sea levels world wide, it will make many areas and livelihoods untenable, say the authors.

"Climate is the envelope in which all of us lead our daily lives," Alexander de Sherbinin, a geographer at CIESIN, said in a statement. "This report sounds warning bells."

The International Organization for Migration (IOM) estimates that by 2050, about 200 million people will have been uprooted by climate change.  A sea level rise of 3.28 feet (1 meter) could affect 23.5 million people on the low-lying Ganges, Mekong and Nile river deltas alone, according to the report.

But it's not only the poor or rural who will likely be affected. If projections are on target, "large populations would be forced to migrate as a matter of immediate survival," CARE's climate-change coordinator Charles Ehrhart said in a statement. And that could start a "downward spiral of ecological degradation, toward the bottom of which social safety nets collapse, while tensions and violence rise," affecting both rich and poor, he said.

To safeguard against that outcome, the report authors recommend that countries reduce greenhouse gas emissions, provide more eco-friendly methods to farmers and workers, and come up with plans to make sure those most vulnerable to climate change—especially the poor—will retain rights and security.

The Maldives, a low-slung island country especially threatened by climate change's rising tides, has already heeded previous similar advice and pledged to go carbon neutral by 2020. In fact, the president has said he wants to buy a new country.

Map showing the Nile River delta with a sea level rise of 1 meter (dark blue) and urban areas (hatched) courtesy of Center for International Earth Science Information Network/Columbia University