As 11,000 scientists from around the world unite to declare a global climate emergency, a terrifying warning from the past predicts sea levels could rise 11 feet within a century if the world fails act.
The research comes from scrutinising what has happened to the Earth in the last warm period 125,000 years ago.
Scientists saw melting ice in Antarctica flooded the oceans in a warm age that lasted 10,000 years.
The result in the 21st century would be much of the coastline currently mapped would disappear under the deluge, rendering huge tracts of land under water and cities uninhabitable.
Millions forced from homes
Millions would become homeless and driven to look for shelter on higher land.
The evidence comes from examining fossil coral and sediments beneath the Red Sea.
And the shock is temperatures that triggered the melting of the ice caps were just one degree more than they are now.
The scientists say the Antarctica ice cap is already receding at a fast rate and the world may reach a point of no return if governments do not wake up and take notice by reducing emissions and taking other action to save the environment.
Rising oceans could displace up to 480 million people.
“This research shows that Antarctica, long thought to be the “sleeping giant” of sea-level rise, is actually a key player. Its ice sheets can change quickly, and in ways that could have huge implications for coastal communities and infrastructure in future,” said team scientist Eelco Rohling, of the Australian National University.
“Earth’s cycles consist of both cold glacial periods – or ice ages – when large parts of the world are covered in large ice sheets, and warmer interglacial periods when the ice thaws and sea levels rise.
“The Earth is presently in an interglacial period which began about 10,000 years ago. But greenhouse gas emissions over the past 200 years have caused climate changes that are faster and more extreme than experienced during the last interglacial. This means past rates of sea-level rise provide only low-end predictions of what might happen in future.”