ZAccording to Monday’s study, ombie from Greenland’s massive ice sheet can eventually increase global sea level by about 10 inches (27 cm) alone.
The term “zombie” or “doomsday ice means that ice which is not being fed by the larger glaciers is attached to thicker ice areas, but it isn’t getting any more. That’s because the parent glaciers are getting less replenishing snow. The study’s co-author William Colgan is a glaciologist with the Geological Survey of Denmark.
“It’s dead ice. It’s just going to melt and disappear from the ice sheet,” Colgan said in an interview. “This ice has been consigned to the ocean, regardless of what climate (emissions) scenario we take now.”
Study lead author Jason Box, a glaciologist at the Greenland survey, said it is “more like one foot in the grave.”
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The unavoidable ten inches in the study is more than twice as much sea level rise as scientists had previously expected from the melting of Greenland’s ice sheet. Journal article Nature Climate ChangeAccording to some estimates, it may reach up to 30 inches (78cm). By contrast, last year’s Intergovernmental Panel on Climate Change report projected a range of 2 to 5 inches (6 to 13 centimeters) for likely sea level rise from Greenland ice melt by the year 2100.
Scientists looked at the ice as a balance for their study. In perfect equilibrium, snowfall in the mountains in Greenland flows down and recharges and thickens the sides of glaciers, balancing out what’s melting on the edges. But in the last few decades there’s less replenishment and more melting, creating imbalance. Study authors looked at the ratio of what’s being added to what’s being lost and calculated that 3.3% of Greenland’s total ice volume will melt no matter what happens with the world cutting carbon pollution, Colgan said.
“I think starving would be a good phrase,” for what’s happening to the ice, Colgan said.
One of the study authors said that more than 120 trillion tons (110 trillion metric tons) of ice is already doomed to melt from the warming ice sheet’s inability to replenish its edges. It would melt into water at 37 feet (11 metres) depth if concentrated in the United States.
This is the first time scientists calculated a minimum ice loss—and accompanying sea level rise—for Greenland, one of Earth’s two massive ice sheets that are slowly shrinking because of climate change from burning coal, oil and natural gas. Researchers used a well-known technique to calculate minimum committed Ice Loss, which was the same one that is used for mountain glaciers on the giant frozen island.
Pennsylvania State University glaciologist Richard Alley, who wasn’t part of the study but said it made sense, said the committed melting and sea level rise is like an ice cube put in a cup of hot tea in a warm room.
“You have committed mass loss from the ice,” Alley said in an email. ”In the same way most of the world’s mountain glaciers and the edges of Greenland would continue losing mass if temperatures were stabilized at modern levels because they have been put into warmer air just as your ice cube was put in warmer tea.”
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Although 10 inches doesn’t sound like much, that’s a global average. Some coastal areas will be hit with more, and high tides and storms on top of that could be even worse, so this much sea level rise “will have huge societal, economic and environmental impacts,” said Ellyn Enderlin, a geosciences professor at Boise State University.
Two outside scientists from the University of Buffalo, Leigh Stearns of University of Kansas and Sophie Nowicki of University of Buffalo, stated that time is the main unknown and the problem in the study. The researchers in the study said they couldn’t estimate the timing of the committed melting, yet in the last sentence they mention, “within this century,” without supporting it, Stearns said.
Colgan responded that the team doesn’t know how long it will take for all the doomed ice to melt, but making an educated guess, it would probably be by the end of this century or at least by 2150.
Colgan stated that this scenario is the best possible. In 2012 and 2019, there was an enormous melt year when the balance between adding and subtracting water ice was very out of equilibrium. Greenland melt, which could lead to 30 inches (78cm) sea-level rise if Earth goes through more years such as 2012. These two years are extreme right now but would not have happened 50 years ago if Earth was experiencing normal years, he stated.
“That’s how climate change works,” Colgan said. “Today’s outliers become tomorrow’s averages.”
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