Scientists detect critical threshold in Greenland after century of global warming
As the surface of the ice is exposed to higher temperatures, it leads to more melting, height reductions and accelerated loss of mass. Reuters
The melting of part of an ice sheet in Greenland is nearing tipping point and further environmental damage could follow, researchers said.
Analysis of the Jakobshavn drainage basin revealed that the central-western Greenland ice sheet is reaching a stage from which it cannot recover.
Data indicated that a critical threshold has been reached after a century of accelerated melting.
“We might be seeing the beginning of a large-scale destabilisation, but at the moment we cannot tell, unfortunately,” said Dr Niklas Boers from the Potsdam Institute for Climate Impact Research, one of the two authors of the research.
“So far, the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet.”
Dr Boers and Martin Rypdal from the Arctic University of Norway concluded that this part of the Greenland ice sheet is losing stability, and is very close to tipping into a state of accelerated melting, PNAS said on Monday.
Should that scenario play out, it will not be possible to save the sheet even if the Arctic warming trend was halted in the coming decades.
An ice sheet can only maintain its size if the loss of mass from melting is replaced by snow falling on to its surface. The warming of the Arctic disrupts that cycle.
As the surface of the ice is exposed to higher temperatures, it leads to more melting, height reductions and accelerated loss of mass.
After a point, this process cannot be reversed because a much colder climate would be needed for the ice sheet to regain its original size.
"We need to monitor the other parts of the Greenland ice sheet more closely, and we urgently need to better understand how different positive and negative feedback might balance each other, to get a better idea of the future evolution of the ice sheet," Dr Boers said.
The work is part of the Tipes project, co-ordinated and led by the University of Copenhagen in Denmark and the Potsdam institute in Germany.
Updated: May 18, 2021
The melting of part of an ice sheet in Greenland is nearing tipping point and further environmental damage could follow, researchers said.
Analysis of the Jakobshavn drainage basin revealed that the central-western Greenland ice sheet is reaching a stage from which it cannot recover.
Data indicated that a critical threshold has been reached after a century of accelerated melting.
“We might be seeing the beginning of a large-scale destabilisation, but at the moment we cannot tell, unfortunately,” said Dr Niklas Boers from the Potsdam Institute for Climate Impact Research, one of the two authors of the research.
“So far, the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet.”
Dr Boers and Martin Rypdal from the Arctic University of Norway concluded that this part of the Greenland ice sheet is losing stability, and is very close to tipping into a state of accelerated melting, PNAS said on Monday.
Should that scenario play out, it will not be possible to save the sheet even if the Arctic warming trend was halted in the coming decades.
An ice sheet can only maintain its size if the loss of mass from melting is replaced by snow falling on to its surface. The warming of the Arctic disrupts that cycle.
As the surface of the ice is exposed to higher temperatures, it leads to more melting, height reductions and accelerated loss of mass.
After a point, this process cannot be reversed because a much colder climate would be needed for the ice sheet to regain its original size.
"We need to monitor the other parts of the Greenland ice sheet more closely, and we urgently need to better understand how different positive and negative feedback might balance each other, to get a better idea of the future evolution of the ice sheet," Dr Boers said.
The work is part of the Tipes project, co-ordinated and led by the University of Copenhagen in Denmark and the Potsdam institute in Germany.
Updated: May 18, 2021
Greenland ice sheet melting may soon pass point of no return, study warns
‘We might be seeing the beginning of a large-scale destabilisation,’ scientist warns
Samuel Osborne@SamuelOsborne93
THE INDEPENDENT UK
The Greenland ice sheet contains enough water to raise global sea level by seven meters - a change which would displace millions of people
(Sean Gallup/Getty Images)
Part of the Greenland ice sheet could soon cross the point of no-return after which the rate of melting outpaces the rate of snow fall, scientists have warned.
Scientists analysing arctic data said the situation could soon reach a “tipping point” and warned that they “urgently” need to understand how the effects of melting affect each other.
The Greenland ice sheet contains enough water to raise the global sea level by seven metres, a change which would displace millions of people.
‘We might be seeing the beginning of a large-scale destabilisation,’ scientist warns
Samuel Osborne@SamuelOsborne93
THE INDEPENDENT UK
The Greenland ice sheet contains enough water to raise global sea level by seven meters - a change which would displace millions of people
(Sean Gallup/Getty Images)
Part of the Greenland ice sheet could soon cross the point of no-return after which the rate of melting outpaces the rate of snow fall, scientists have warned.
Scientists analysing arctic data said the situation could soon reach a “tipping point” and warned that they “urgently” need to understand how the effects of melting affect each other.
The Greenland ice sheet contains enough water to raise the global sea level by seven metres, a change which would displace millions of people.
Losing it is expected to add to global warming and disrupt major ocean currents, monsoon belts, rainforests, wind systems and rain patterns around the world.
However, the researchers said their data is not as comprehensive as they would like, meaning they cannot make solid conclusion
Dr Niklas Boers, from Potsdam Institute for Climate Impact Research in Germany, said: "We might be seeing the beginning of a large-scale destabilisation but at the moment we cannot tell, unfortunately.
"So far, the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet."
He explained how an ice sheet can only maintain its size if the loss of mass from melting and calving glaciers is replaced by snow falling onto its surface.
The warming of the Arctic disturbs this mass balance because the snow at the surface often melts away in the warmer summers.
Melting will mostly increase at the lower altitudes, but overall, the ice sheet will shrink from a mass imbalance.
As this happens, a positive feedback mechanism kicks in - meaning as the ice sheet surface lowers, its surface is exposed to higher average temperatures, leading to more melting and the process repeats until the entire ice sheet is gone.
Beyond a critical threshold, researchers say, this process can not be reversed because, with reduced height, a much colder climate would be needed for the ice sheet to regain its original size.
Dr Boers, and his colleague Dr Martin Rypdal from the Arctic University of Norway, have found the data shows that the critical threshold has at least regionally been reached due to the last 100 years of accelerated melting.
They add an increase in melting will possibly be compensated, at least partly, by more snowfall as precipitation patterns over the ice sheet will change due to the changing ice sheet height.
However, if the Greenland ice sheet as a whole moves into accelerated melting there will be severe consequences for the entire planet.
Dr Boers added: "We need to monitor also the other parts of the Greenland ice sheet more closely, and we urgently need to better understand how different positive and negative feedbacks might balance each other, to get a better idea of the future evolution of the ice sheet."
The research has been published in Proceedings of the National Academy of Sciences of the United States of America (PNAS).
However, the researchers said their data is not as comprehensive as they would like, meaning they cannot make solid conclusion
Dr Niklas Boers, from Potsdam Institute for Climate Impact Research in Germany, said: "We might be seeing the beginning of a large-scale destabilisation but at the moment we cannot tell, unfortunately.
"So far, the signals we see are only regional, but that might simply be due to the scarcity of accurate and long-term data for other parts of the ice sheet."
He explained how an ice sheet can only maintain its size if the loss of mass from melting and calving glaciers is replaced by snow falling onto its surface.
The warming of the Arctic disturbs this mass balance because the snow at the surface often melts away in the warmer summers.
Melting will mostly increase at the lower altitudes, but overall, the ice sheet will shrink from a mass imbalance.
As this happens, a positive feedback mechanism kicks in - meaning as the ice sheet surface lowers, its surface is exposed to higher average temperatures, leading to more melting and the process repeats until the entire ice sheet is gone.
Beyond a critical threshold, researchers say, this process can not be reversed because, with reduced height, a much colder climate would be needed for the ice sheet to regain its original size.
Dr Boers, and his colleague Dr Martin Rypdal from the Arctic University of Norway, have found the data shows that the critical threshold has at least regionally been reached due to the last 100 years of accelerated melting.
They add an increase in melting will possibly be compensated, at least partly, by more snowfall as precipitation patterns over the ice sheet will change due to the changing ice sheet height.
However, if the Greenland ice sheet as a whole moves into accelerated melting there will be severe consequences for the entire planet.
Dr Boers added: "We need to monitor also the other parts of the Greenland ice sheet more closely, and we urgently need to better understand how different positive and negative feedbacks might balance each other, to get a better idea of the future evolution of the ice sheet."
The research has been published in Proceedings of the National Academy of Sciences of the United States of America (PNAS).
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