The office of the United Nations High Commission for Refugees estimates that rising seas, intensifying droughts, and other extreme weather events will uproot 250 million people by 2050. Like most other refugees, climate refugees are expected to come largely from developing nations in Africa, Asia, and South America. But unlike those escaping war and persecution, climate refugees have few legal protections.

"The 1951 Refugee Convention's definition of 'refugee' does not include people who are fleeing environmental stress," says Alice Thomas, the climate displacement program manager at the non-profit group Refugees International. To date, no individual has been able to successfully claim asylum on the grounds that they are fleeing climate change, Thomas says, though some have tried.

And there is another climate reality, according to Thomas, that is rarely recognized: the fact that most climate-affected migrants will not be leaving their countries.

"International migration is really complex. Most people, the poorest people, can't afford to migrate internationally," she says. "There needs to be focus on these what we call 'trapped populations,' people who are too poor to even move and escape climate effect."

A 2018 World Bank report suggests that these trapped populations might number over 140 million people by 2050. That's why Thomas says countries worldwide need an internal migration policy. Such policies should help people who need to move and resettle within their own nation so they are not stateless. Smart climate change adaptation policies may even make it possible so that people don't have to move in the first place.

This article is part of our Climate Justice collection. Learn more about climate justice, or read the full article about climate migrants by Bhanu Sridharan at Pacific Standard.