Crack Network New To Science, Atmospheric River Rainfall Newest Greenland Ice Sheet Threats
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Paleoclimate studies show that Earth’s ice age cycles are slow build-ups to peak glaciation over millennia, with much more sudden phases of disintegration and collapse, when the rate of sea level rise spiked to as high as 16.4 feet per century in the most extreme cases in the paleoclimate record. Current research suggests that the warming caused by greenhouse gas emissions from a handful of highly developed countries during the last century could once again trigger similar phases of extreme sea level rise in coming centuries.
So what could melt a slab of ice that’s bigger than Alaska and up to 2 miles thick, holding enough water to raise average global sea level by 24 feet? Or perhaps more importantly, what could melt it fast? The second recent study, published in June in Nature Geoscience, shows a possible new mechanism that could accelerate ice sheet disintegration. There are vast networks of previously undetected micro-cracks on the Greenland Ice Sheet that may run hundreds of meters deep, carrying warm surface water to the interior of the ice sheet and melting it from within, said David Chandler, a postdoctoral researcher at the Bjerknes Centre for Climate Research in Bergen, Norway, and a co-author.
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Melting surface ice isn’t the only source of water on the Greenland Ice Sheet. Rainfall is playing an increasing role, and the amounts of rain now falling are “insane,” said Jason Box, a snow and ice climatologist at the Geological Survey of Denmark and Greenland and lead author of the third recent study, published in July by the Royal Meteorological Society documenting an increase of extreme rainstorms in Greenland. Box said his study, the study by Chandler on the ice cracks and Bierman’s new research on Greenland’s meltdown in Marine Isotope Stage 11 “add insight to an all-too-long list of factors not yet encoded in ice sheet models used to project future sea level rise.” The increased meltwater delivery from rainfall is an important aspect of the hydrofracturing processes that are cracking up the ice sheet, he added.
“Greenland Ice Sheet rainfall exemplifies how climatology has been undergoing a paradigm shift,” Box said in a video outlining the study results. “Our attention is now a lot less focused on the gradually upward creeping averages. Extremes in weather are increasingly disrupting our world and dominating the climate conversation.” His new study measured a 33 percent increase in rainfall on the Greenland Ice Sheet since 1991, and includes new readings of extreme rainfalls since gauges were installed at several climate stations in Greenland.
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https://insideclimatenews.org/news/31072023/greenland-ice-sheet-microcracks-atmospheric-rivers-tipping-points/
