Sea levels could rise by at least 6 meters (20 feet) in the long term, swamping coasts from Florida to Bangladesh, even if governments achieve their goals for curbing global warming, a study published Thursday said.
Tracts of ice in Greenland and Antarctica melted when temperatures were around or slightly higher than today in ancient thaws in the past 3 million years, a U.S.-led international team wrote in the journal Science.
And the world may be headed for a repeat even if governments cut greenhouse gas emissions to limit global warming to a United Nations goal of 2 degrees Celsius (3.6 Fahrenheit) above pre-industrial times.