A new study has warned that melting ice sheets in northeastern Greenland could cause sea levels to rise by half an inch by the end of the century.
This equates to the contribution of the entire Greenland ice sheet over the past 50 years, which means that the rate of ice loss has been significantly underestimated.
Researchers from Denmark and the US have used satellite data and numerical models to examine ice loss from cover since 2012.
They found that it could contribute up to six times more to global sea level rise by 2100 than is currently predicted by climate models.
Lead author Shfaqat Abbas Khan, of the Technical University of Denmark, said: “The models are mostly tuned to the observations at the front of the ice sheet, which is easily accessible and where obviously a lot happens. اشياء.
“Our data shows us that what we see happening in the foreground goes back to the center of the ice sheet.”
Researchers from Denmark and the United States have used satellite data and numerical models to examine the ice loss on the sheet since 2012. Pictured: A satellite image from August 2021 showing the rupture of the Zakaria glacier
A: 2007 ice velocity map. The black dashed line indicates the combined drainage of the two glaciers. The blue box indicates the enlarged area. B: Image of a configuration of a satellite receiving station, which consists of an antenna, a receiver (in the orange box) and a solar panel (in the upper part of the box). All of them are located on a platform about 2 meters above the ice surface. A: A satellite image showing NEGIS and the two glaciers. The color indicates the surface velocity derived from the satellite. The positions of the three space stations are marked with yellow boxes
Dr Khan added: ‘We can see that the whole pelvis is thinning and the surface velocity is increasing.
“Each year, the glaciers we studied retreat inland and we expect this to continue for decades and centuries to come.
“With the current impact on the climate, it is difficult to imagine how this decline can be stopped.”
The North East Greenland Ice Stream (NEGIS) is a fast-moving ice area within the ice sheet.
About 12% of the inner layer of the aquifer drains from two offshore outlet glaciers: the Nioghalvfjerdsfjord Gletscher and Zachariae Isstrøm.
In 2012, the intrusion of warm ocean currents into the ice shelf of the Zacharias Esstrom Glacier caused it to collapse.
This event is believed to have boosted NEGIS productivity since then, but it’s unclear exactly how much.
This means that the extent of ice thinning from the glacier is also uncertain, as are its contributions to sea level rise.
For their study, published today in natureThe international team used GPS navigation satellites to study the extent of accelerating ice flow spreading inland.
The satellites measure the ice speed using three receiving stations located on the ice flow, between 56 and 118 miles (90 and 190 km) inside the glacier.
Co-author Eric Regno, of the University of California, Irvine, said, “Data collected from the vast interiors of the ice sheets help us better represent the physical processes embedded in numerical models and thus provide more realistic sea level predictions. global go up.
The satellites collected data from 2016 to 2019, which was combined with data on surface elevations and flow accelerations from 2012.
All these measurements were ultimately used to improve the friction laws for a numerical model capable of predicting future ice loss.
The ice was found to have thinned to 10 feet (three meters) since 2011 and stretched for at least 124 miles (200 kilometers) inland. From the coast of Greenland.
Pictured: Loosening along the flow line from April 2011 to April 2021
Models suggest that this relief will continue at an accelerating pace throughout this century and raise sea levels by as much as 15.5mm (0.6in).
Co-author, Dr Matthew Morlighem, of Dartmouth College, said: “The Greenland ice sheet is not necessarily more stable than we thought, but it may be more sensitive to changes along the coast.
“If true, the contribution of ice dynamics to the overall mass loss in Greenland would be greater than current models suggest.
“It is possible that what we find in northeastern Greenland is happening in other areas of the ice sheet.”
The study found that the ice has thinned to 10 feet (3 meters) since 2011 and has extended for at least 124 miles (200 km) inland from the coast of Greenland. Left: lake and river on the Zacharias glacier, northeastern Greenland. Right: a meltwater river on the Zaccaria glacier
Additionally, despite the cold winter of 2021 and summer of 2022, the NEGIS glaciers continued to retreat.
Northeast Greenland is described as an “arctic desert” due to its low rainfall, which means the ice sheet is not sufficiently supplied to compensate for its melting.
The researchers say that as technology advances, we may find that our current estimates of sea level rise will need to be corrected upward.
They hope their study of how the upstream sections of glaciers are related and their melting will help with these future predictions.
