UNITED NATIONS — More than 65 million people are displaced from their homes, the largest number since the Second World War, and nearly 25 million of them are refugees and asylum seekers living outside their own country.

But that number doesn’t include people displaced by climate change.

Under international law, only those who have fled their countries because of war or persecution are entitled to refugee status. People forced to leave home because of climate change, or who leave because climate change has made it harder for them to make a living, don’t qualify.

The law doesn’t offer them much protection at all unless they can show they are fleeing a war zone or face a fear of persecution if they are returned home.