Then there’s the legal problem. The guiding document of international refugee law, the 1951 UN Convention on the status of refugees, defines them as people who have left their home country and can’t return because of a “well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion.” Rising sea levels, droughts, and severe superstorms don’t fit into that definition.

There’s also the requirement of government persecution, but in most cases it’s not the government that’s persecuting people, it’s the climate. A court case in New Zealand tried to extend these protections to a family from the small island nation of Kiribati, arguing the danger from climate change back home amounted to persecution. The courts repeatedly rejected that argument, though, and the family was deported in September.

The gap in the international framework might not cause chaos now, while the effects of climate change are still ramping up. But climate-induced migration is only going to increase in the years to come. The International Organization for Migration says the most common estimate is 200 million environmental migrants by 2050.