Our data show us that what we see happening at the front reaches far back into the heart of the ice sheet. Shfaqat Abbas Khan, Senior Researcher in Geodesy at the National Space Institute
Climate models have greatly underestimated the ice loss from northern Greenland, warns the Technical University of Denmark. Greenland's glaciers have been shedding ice at record speed; this is no surprise since the Arctic is warming four to seven times faster than the rest of the planet.
The study, published in Nature, indicates that sea level rise will be significantly higher than thought. The revelations suggest that civilization is unprepared to deal with the coastal destruction that rising seas will unleash on Earth's coastlines.
From the presser:
By 2100, the Northeast Greenland Ice Stream will contribute six times as much to the rising sea level as previous models suggested, adding between 13,5 to 15,5 mm, according to the new study. This is equivalent to the entire Greenland ice sheet's contribution in the past 50 years. The research was carried out by researchers from Denmark, the United States, France, and Germany
That 0.61-inch of additional sea-level rise may not sound like much to worry about, but that comes on top of other new findings, such as Zombie Ice which occupies most of Greenland's margin, will contribute a minimum increase of ten inches. Increasing heatwaves, rainfall intensity, and frequency, which have stunned glacier scientists, are not factored into existing climate models.
"Our previous projections of ice loss in Greenland until 2100 are vastly underestimated," said first author Shfaqat Abbas Khan, Professor at DTU Space.
"Models are mainly tuned to observations at the front of the ice sheet, which is easily accessible, and where, visibly, a lot is happening."
The study is partly based on data collected from a network of precise GPS stations reaching as far as inland on the Northeast Greenland Ice Stream—located behind the Nioghalvfjerdsfjord Gletscher and Zachariae Isstrøm glaciers, one of Earth's most hostile and remote terrains. The GPS data were combined with surface-elevation data from the CryoSat-2 satellite mission and high-resolution numerical modeling.
"Our data show us that what we see happening at the front reaches far back into the heart of the ice sheet," said Khan.
"We can see that the entire basin is thinning, and the surface speed is accelerating. Every year the glaciers we've studied have retreated further inland, and we predict that this will continue over the coming decades and centuries. Under present day climate forcing, it is difficult to conceive how this retreat could stop."
An additional study has found that meltwater pouring into the oceans is churning the water in front of marine-terminating glaciers, "speeding the loss of glaciers like stirring ice cubes in a glass of water."
Greenland Is Disappearing Quickly, and Scientists Have Found a New Reason Why
The Greenland ice sheet is losing an average of around 250 billion metric tons of ice per year. These losses are speeding up over time, studies have found—and there are two main processes causing it.
Warm air temperatures cause melting to occur on the surface of the ice sheet—that process accounts for about half the ice Greenland loses each year. The other half comes from glaciers at the ice sheet’s edge crumbling into the sea.
Losses from these seaside glaciers have, until now, been mainly attributed to warm ocean waters licking at the edge of the ice. But the new research finds that rising air temperatures have a big influence as well.
Warm air causes the surface of the ice sheet to melt, and that meltwater then runs off into the ocean. When that happens, it churns up the waters—and that turbulence helps heat rise up from the depths of the ocean and warm up the waters coming into contact with the ice. That, in turn, melts the glaciers faster.
Lead study author Donald Slater, a scientist at the University of Edinburgh, likened the process to ice cubes in a glass of water. They clearly melt faster when the water is warmer. But they also melt faster when the water is stirred.
What happens in the Arctic doesn’t stay in the Arctic. I genuinely hope Democrats can hold the house and we can take even further action to brace ourselves against climate catastrophe. Every tenth of a degree matters.
Zachariae Isstrøm