Greenland’s largest ice cap is melting at a much faster rate than expected, a new study has revealed, suggesting it will add six times more water to sea level rise than previously thought. And the trend may not be limited to Greenland, scientists worry.
The study used GPS measurements and computer modeling to estimate the amount of ice lost due to climate change Greenland Northeast Ice Flow (NEGIS), a major ice flow that drains ice and meltwater from Greenland’s ice-covered inner basin.
Calculations have revealed that, since 2012, the melting of NEGIS has accelerated so much that by the end of this century it will add more than 0.5 inches (1.3 centimeters) of water to the world’s ‘ocean. This is equivalent to the total value of the last 50 years of Greenland’s contribution to the sea level rises.
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Acceleration of NEGIS ice melt started after Zachariae Isstrøm glacier that protected the coastal part of the ice stream broke in 2012, allowing warmer seawater to penetrate deeper inland. The new data revealed that the wave of rapid ice thinning triggered by this incident spread much farther upstream than previously thought. Scientists were able to measure thinning up to 186 miles (300 kilometers) from the northeast coast of Greenland where NEGIS meets the ocean.
“Many glaciers have been accelerating and thinning near the margin over the past few decades – GPS data has helped us detect how far these nearshore changes are spreading,” co-author Mathieu Morlighem, professor of earth sciences at Dartmouth College in New Hampshire, said in a statement. (opens in a new tab). “If this is correct, the contribution of ice dynamics to overall mass loss in Greenland will be larger than current models suggest.”
Morlinghem added that similar trends could be underway in other parts of the Greenland Ice Sheet, as the whole system could be much more sensitive to changes occurring in coastal areas than previously thought. .
The study found that the melting acceleration continued even throughout the winter of 2021 and summer of 2022, which were unusually cold in Greenland, suggesting that the process will be quite difficult to Stop.
“We can see that the whole basin is thinning and the surface velocity is accelerating,” said Shfaqat Abbas Khan, a researcher at the University of Denmark and first author of the new study, in the same statement. “Each year, the glaciers we have studied have retreated further inland, and we expect this to continue for decades and centuries to come. Under current climate forcing, it is difficult to conceive how this decline could stop.”
If confirmed, the findings will have implications for current sea level rise forecasts, which predict a sea level rise of 8 to 38 inches (22 to 98 cm) by the end of the century. . Actual sea level rise is likely to be much greater, the authors concluded, with catastrophic consequences for people in low-lying and coastal areas around the world.
“We predict profound changes in global sea level, more than currently predicted by existing models,” said Eric Rignot, professor of Earth system science at the University of California, Irvine, who is also co- author of the article. statement. “Data collected from the vast interior of ice sheets, such as that described in our research, helps us to better represent the physical processes included in numerical models and in turn provides more realistic projections of global sea level rise. the sea.”
The study was released as countries negotiated at the 27th Conference of the Parties to the United Nations Framework Convention on Climate Change (COP27) in the Egyptian coastal city of Sharm el-Sheikh. The summit, which builds on the outcomes of last year’s COP26 climate change meeting in Glasgow, Scotland, seeks to identify solutions for a wide range of climate-related emergencies, including the energy crisis and the increasing severity of extreme weather events.
The study (opens in a new tab) was published in the journal Nature on November 9.
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