Earth’s sea levels should be nine meters higher than they are — and dramatic melting in Antarctica may soon plug the gap, scientists warn.

They say global temperatures today are the same as they were 115,000 years ago, a time when modern humans were only just beginning to leave Africa.

Research shows during this time period, known as the Eemian, scorching ocean temperatures caused a catastrophic global ice melt. As a result, sea levels were six to nine meters higher than they are today.

But if modern ocean temperatures are the same as they were during the Eemian, that means our planet is “missing” a devastating sea rise.

If oceans were to rise by just 1.8 meters, large swathes of coastal cities would find themselves underwater, turning…