As deserts expand, sea levels rise and other climate impacts make some regions uninhabitable, tens of millions of people will be displaced from their homes.
They won't be alone.
Thanks to human-caused climate change, countless plants and animals will also need to move in order to survive. But as disruptive as climate migration will be for humans, many of our fellow inhabitants of Earth will not have the options that will be open to us.
That could be particularly true for plant species adapted to living in the Arctic — a region warming twice as fast as any other on Earth. At a certain point, they will not be able to move any farther north to find places safe from competition by shrubs and trees well adapted to warmer temperatures. That's because they'll simply run out of land before hitting the Arctic Ocean and surrounding waters.
For plants adapted to living in the particularly harsh climate of mountainous areas in the Arctic, the prospect of a warming environment is particularly daunting: They can try migrating up mountainsides, but they will eventually reach the top and have nowhere else to go.