Fiercer weather and worsening wildfires drove more than 20 million people from their homes over the last decade — a problem set to worsen unless leaders act swiftly to head off surging climate threats, anti-poverty charity Oxfam said Monday.

Much of the displacement caused by cyclones, floods and fires appeared temporary and in some cases due to better efforts to evacuate people ahead of danger, Oxfam researchers said.

But its "sheer scale" was a surprise, said Tim Gore, Oxfam's climate policy leader, with island nations like Cuba, Dominica and Tuvalu seeing on average close to 5 percent of their people out of their homes in any given year.