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Greenland ice sheet set to trigger almost a foot in sea ​​level rise


Climate change caused by human activities set in mass ice loss movement in Greenland that could not be stopped even if world stopped greenhouse gas emissions today, according to new the study was published on Monday.

finds in Nature climate change project what is now inevitable that 3.3 percent of the Greenland ice sheet will melt – equal to 110 trillion. tons of ice, the researchers said. What will happen trigger almost a foot of global sea ​​level rise.

Forecasts more worse than other forecasts, although they use different guesses. Although the study did not specify a time frame for melting and sea level rise suggested by the authors a lot of of maybe play out between present and year 2100.

“The point is that we need to plan for this ice as if it was not there on ice sheet in near futurewithin century or so.” – William Colgan, study co-author who research ice sheet from its surface with his colleagues at the Geological Survey of Denmark and Greenland, said in video interview.

“Each study has bigger numbers than last. It’s always faster than predicted,” Colgan said.

One reason what new research looks worse than other conclusions just be easier. He tries to calculate how a lot of ice Greenland has to lose as it readjusts to a warmer climate. On the contrary, sophisticated computer simulations of how the ice sheet will behave under future scenarios for global emissions made less alarming predictions.

BUT one-sole rise in global sea ​​level rise would have serious consequences. If sea levels along the US coast were to rise on average of 10 to 12 inches by 2050, a recent report from the National Oceanic and Atmospheric Administration. found, most destructive floods would take place five times both frequent and moderate floods becomes 10 times how often.

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Another countries low-lying island states and developing, like Bangladesh – even more vulnerable. These countries that have done little to fuel higher temperatures now thawing the Greenland ice sheet, not enough billions of dollars it will accept to adapt to rising seas.

papers lead author, Geological Survey of Denmark and Greenland scientist Jason Box, collaborated with scientists from institutes in Belgium, Denmark, Finland, Norway, Netherlands, Switzerland and USA assess the degree of ice loss already blocked in human activity.

Just last yearUnited Nations Intergovernmental Panel on Climate change, which usually predicts lower numbers for total loss of ice from Greenland towards the end of in century – projected around half foot of sea ​​level rise from Greenland via year 2100 at the top level. This scenario assumed that people would radiate a large amount of greenhouse gases for another 80 years.

current study, in contrast does not affect in any additional greenhouse gas emissions or indicate when melting will take place, comparison with the UN report is imperfect.

Conclusion that 3.3 percent of Greenland, in effect, already Losses represent “the bare minimum, the lower bound,” Box said. Research suggests things could be a lot worse, especially if world continues to burn fossil fuels, and if in 2012 set a record for Loss of ice in Greenland is becoming more like norm.

But this aspect of research offers hope: even if more sea ​​level rise blocked in than previously thought cutting emissions fast limiting warming to close to 1.5 degrees Celsius (2.7 degrees Fahrenheit) will prevent the situation from worsening further.

Scientists watching the lake of runoff of glacial melt water under the Greenland ice sheet in July 2018. This research could help better understand global sea rise. (Video: Sam Doyle and Tom Chudley)

Greenland is the world’s largest island and is covered with sheet of ice that, if completely melted, could raise sea levels by more than 20 feet. Is not in doubt – no fact what in past warm periods in Earth history, the ice sheet was much smaller than it is today. There has always been a question how a lot of ice will melt when the temperature rise – as well as how fast.

The melting speed has increased in in past two decades, and Greenland is the largest source of ice cover rate of global sea ​​level rise surpassing the contribution of both the larger Antarctic ice sheet and the mountain glaciers around world. Greenland lies in The Arctic is getting hotter faster than others of in world.

Higher arctic temperatures cause large sums of ice on The surface of Greenland is thawing. While the island’s ocean glaciers also drop huge icebergs with the acceleration of pace, it is this surface melting that turns into gushing icy rivers, disappearing lakes and giant waterfalls that dissolve into crevices, causes the biggest ice losses.

In the past, scientists have tried to determine what the ongoing melting of Greenland means. for in global sea ​​level across the complex computer simulations. They are model the ice itself, the ocean around it and future climatic on different trajectories of emissions.

AT general, models gave modest figures. For example, according to latest The IPCC estimates that the most “probable” loss of Greenland by 2100 under a very high emission scenario is about 5 inches. of sea ​​level rise. This represents the disappearance of about 1.8 percent of Greenland total weight.

Most models and scripts produce something much lower. In a low emission scenario that world trying to reach right now, the IPCC report suggests that Greenland will only raise sea levels by a few inches. rise on in century’Send.

new research “receives high numbers compared to other studies,” said Sophie Nowicki, an expert on Greenland at the University at Buffalo who contributed to the IPCC report. However, Novitsky noted that one reason the number is so large that the study only considers last 20 years – who have seen strong warming – like current the climate to which the ice sheet is now adapting. Taking 40-year period will give a lower resultNovitsky said.

“This fixed number is little known and is actually quite hard evaluate because of long scale response time of ice sheet,” Novitsky said.

Box, for for its part, claims that models on which the IPCC report is based are “like facsimile of reality”, without sufficient detail to reflect how Greenland is really changing. Those computer models has recently generated considerable controversy with one research group charging they do not adequately track Greenland current high levels of ice loss.

The alarm message was brought by scientists back from the ice caves of Greenland

In Greenland, the processes that cause ice to fall off large glaciers are often occur hundreds of meters below sea ​​surface in narrow fjords where warm water can splash in the underwater ice in complex movements. In some cases, these processes may simply be playing out in too small scale for in models to capture.

Meanwhile, while this clear what’s hot air the ice cover is melting from the surface, the consequences of all this water flows off the ice sheet – and sometimes through and under it – raises additional questions. A lot of of the water disappears into crevasses called mulins and flows along invisible paths through the ice to the sea. How much it causes the ice itself is slippery and staggers forward remains discussed and may occur on a smaller scale than what models capture.

“Individual moulins, they are not in in modelsColgan said.

new research evaluates future in a simpler way. He tries to calculate how big loss of ice from Greenland already dictated by physics, given current Arctic climate.

Ice cover – like ice cube, but on a much larger scale – always in process of melting or growing in response to ambient temperature. But with good body the size of Greenland – imagine the whole state of Alaska covered with ice it one up to two miles thick – adjustment required a lot of time. This means that losses can be almost inevitable, even if it hasn’t actually happened yet.

However, the ice shield will leave clues when it shrinks. As the thawing progresses, according to scientists, the change will manifest itself in the near future. location called snow line. This is the dividing line between great height, bright white parts of an ice sheet that accumulates snow and mass even in summer, and darker, lower areas that melt and release water into the sea. This line moves every yeardepending on on how warm or cool summer, tracking how a lot of of Greenland is melting in given period.

new research States that in in current climate, medium location of snow line should move inward and upward, leaving a smaller area in which ice could accumulate. This would result in a smaller ice sheet.

“They say that the climate we already there is in process of edge burning of ice,” said Ted Scambos, an ice sheet expert at the University of Colorado in Boulder who not work on paper.

Scambos, however, said it could take much longer than 80 years for 3.3 percent of the ice cover has melted: the study says “most” of the change could happen by 2100.

“A lot of of the change they predicted would happen in it’s a century but to get [that level of retreat] it will take several centuries more possibly,” he said.

Future ice losses will be more than amount if global warming continues to come – as it will. If a massive melt year of 2012 became the norm for for example, this is probably lead up to about two and a half half feet of perfect at sea level risestudy says.

Pennsylvania State University professor Richard Alley, an ice sheet expert, said that fact that researchers remain not sure about how the ice sheets of the planet will change and rise global sea ​​levels shows in need for more research.

” problems are very complex, will not be resolved by wishful thinking and have not yet been resolved business“As usual,” he said.

But alley added what is this clear what more we let the planet warm up, more the seas will rise.

“[The] rise maybe a little less than usual forecasts, or a little more, or a lot more, but not much less,” Ellie said.

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Tyler Hromadka
Tyler Hromadka
Tyler is working as the Author at World Weekly News. He has a love for writing and have been writing for a few years now as a free-lancer.

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