The melting of the ice sheet at the end of the last ice age could have caused sea levels to rise 10 times higher than the current rate, said a study published Thursday by a team led by scientists at Durham University in the UK.
Based on geological records, researchers estimate that oceans around the world rose 3.6 meters (11.8 feet) per century over a period of 500 years about 14,600 years ago.
The findings raise a red flag about the current potential for rapid sea level rise, which could swamp coastal cities and densely populated deltas around the world.
The team found that the sea level rise event, about 18 meters, could have come mainly from melting ice sheets in the northern hemisphere and not from Antarctica as previously thought.
Scientists say their work could provide “vital clues” about the future melting of the ice sheet and rising sea levels due to climate change.
“We found that most of the rapid sea level rise was due to melting ice in North America and Scandinavia, with a surprisingly small contribution from Antarctica,” said study co-author Pippa Whitehouse of the study. of Geography at Durham University.
“The next big question is what caused the melting of the ice and what impact did the massive flow of melted water have on the ocean currents in the North Atlantic.
“That is very much on our minds today – any disruption to the Gulf Stream, for example due to the melting of the Greenland ice sheet, will have significant consequences for the UK climate.”
Current models used by many climate scientists estimate that global sea levels could rise by 1 to 2 meters by the end of this century.
Researchers in Durham used detailed sea level geological data and state-of-the-art modeling techniques to reveal the sources of the dramatic five-century sea level rise event.
Compared to the melting of an ice sheet twice as large as Greenland, it has flooded large areas of lowlands and disrupted ocean circulation, with effects on the global climate, they said.
“Our study includes new information from lakes around the coast of Scotland, which have been isolated from the ocean due to landslides following the retreat of the British ice sheet, allowing us to confidently identify sources of melted water,” added co-author Yucheng Lin, too. of the geography department of Durham.
Identifying the source of the meltwater will help improve the accuracy of climate models that are used to replicate the past and predict changes in the future, the team added.
They noted that the findings were particularly timely, as the Greenland ice sheet melts rapidly and contributes to rising sea levels and changes in global ocean circulation.
In 2019, Greenland dumped more than half a trillion tonnes of ice and melted water, accounting for 40% of total sea level rise that year.
© Agence France-Presse