Greenland’s rapidly melting ice sheet will cause a massive rise in sea levels with potentially dire consequences over the course of this century as temperatures continue to rise, according to a study published Monday. The melting of “zombie” ice from the massive Greenland ice sheet will eventually raise global sea levels by at least 27 centimeters (10 inches) alone. The “zombie”, or doomed ice is still attached to thicker areas of the sheet, but is no longer fed by larger glaciers. The study in the journal Nature Climate Change said sea-level rise could reach 78 centimeters (30 inches) – enough to leave huge areas of low-lying coastline and flood and storm surges. This should serve “as an ominous forecast for Greenland’s 21st century warming course,” the authors said. In contrast, last year’s report by the Intergovernmental Panel on Climate Change (IPCC) predicted a range of 6-13 cm (2-5 inches) of possible sea level rise from the melting of the Greenland ice sheet by the year 2100. The glaciologists found that regardless of any future pollution from fossil fuels, warming to date will cause the Greenland ice sheet to lose 3.3% of its volume, raising sea levels by 27.4cm. Lead study author Jason Box, a glaciologist at the Greenland Survey, said it’s “like one foot in the grave”. Co-author William Colgan, a glaciologist at the Geological Survey of Denmark and Greenland, said: “This ice has been sent to the ocean regardless of climate. [emissions] scenario we are following now”. Icebergs seen at the mouth of the Jakobshavn ice fjord during sunset near Ilulissat, Greenland [Hannibal Hanschke/Reuters]
“Radically different” methodology
The theory the researchers used was originally developed to explain changes in Alpine glaciers, Box said. This is true if more snow accumulates on top of a glacier, it causes the lower areas to expand. In that case, the reduced snow shrinks to the lower reaches of the glacier as it re-equilibrates, he said. Box said the methods his team used were “radically different” from computer modeling, but could complement that work to predict the effects of sea-level rise in the coming decades. He said that while climate change poses more immediate threats, such as food security, the accelerating rate of sea level rise will become a huge challenge. “It’s kind of decades in the future when it’s going to force its way onto the agenda because it’s going to start displacing people more and more,” Box said. The Greenland Ice Sheet is currently the main factor in the swelling of Earth’s oceans, according to NASA [File: Lucas Jackson/Reuters] This is the first time scientists have estimated minimal ice loss—and accompanying sea-level rise—for Greenland, one of Earth’s two giant ice sheets slowly shrinking due to climate change from burning coal, oil and natural gas. The world has warmed an average of nearly 1.2 degrees Celsius (2.4 Fahrenheit) since the pre-industrial era, unleashing a catalog of effects from heat waves to more intense storms. Under the Paris climate agreement, countries agreed to limit temperature rise to 2C (4.0F). But in its climate impact report this year, the IPCC said that even if warming were to stabilize at 2C to 2.5C (35.6F to 36.5F) “coastlines will continue to reshape for millennia, affecting at least 25 megacities and suffocating low-lying areas’, which were home to up to 1.3 billion people in 2010. Colgan said his research team doesn’t know how long it will take for all of the doomed ice to melt, but makes a scientific guess that it would likely be by the end of this century or at least by 2150.
