Global warming: New estimates on Greenland meltdown

A 2006 NASA satellite image shows Greenland covered by ice except at its fringes.

Previous estimates on temperature thresholds might be too high

By Summit Voice

SUMMIT COUNTY — A global temperature increase of 1.6 degrees Celsius could be enough to trigger an irreversible meltdown of the Greenland ice sheet, according to a team of European researchers.

Previous research suggested a temperature increase between 1.9 to 5.1 degrees Celsius would lead to a Greenland meltdown. The new study estimates that a temperature increase of half as much could lead to the point of no return.

The scientists with the Potsdam Institute for Climate Impact Research and the Universidad Complutense de Madrid used a new climate model incorporating regional climate data and climate feedback associated with changes in snowfall and melt.

The simulation proved able to correctly calculate both the observed ice-sheet of today and its evolution over previous glacial cycles, thus increasing the confidence that it can properly assess the future. All this makes the new estimate of Greenland temperature threshold more reliable than previous ones.

Logically, the researchers said that, the warmer it gets, the faster the ice will melt. A business-as-usual scenario, with no significant reductions in greenhouse gases, could result in up to 8 degrees of warming, with up to 20 percent of the Greenland ice sheet melting with 500 years and complete meltdown in 2000 years. Climate science skeptics will be quick to point out that sea ice around Greenland has grown to a greater extent than in the past few winters, but that doesn’t obviate the long-term trend of ice loss from the Greenland ice sheet. Substantial melting of land ice could contribute to long-term sea-level rise of several meters and therefore it potentially affects the lives of many millions of people.

“This is not what one would call a rapid collapse,” said Alexander Robinson, lead-author of the study  published in Nature Climate Change. “However, compared to what has happened in our planet’s history, it is fast. And we might already be approaching the critical threshold.”

if global warming is limited to 2 degrees Celsius, complete melting would take about 50.000 years. Still, even within this temperature range, often considered a global guardrail, the Greenland ice sheet is not secure.

“Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice sheet is a tipping element in the Earth system,” said team-leader Andrey Ganopolski of the Potsdam Institute for Climate Impact Research. “If the global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow, even if the climate … returns to its pre-industrial state,” Ganopolski said.

Ganopolski explained some of the feedback loops that could affect the rate of melting:

The ice sheet is over 3000 meters thick and thus elevated into cooler altitudes. When it melts its surface comes down to lower altitudes with higher temperatures, which accelerates the melting. Also, the ice reflects a large part of solar radiation back into space. When the area covered by ice decreases, more radiation is absorbed and this adds to regional warming.



10 thoughts on “Global warming: New estimates on Greenland meltdown

  1. Looking at the time span, one can understand why there are climate deniers. They will be all dead by the rime this event comes to fruition, so it really doesn’t matter. Of course, they can also admit that their position has eroded, that they now embrace new findings, and indeed, the Earth is in a stage of climate change. Of course, why wouldn’t they?

    1. Sooooooo you are basing your comment of the study, which you probably haven´t even read, on a single data (1 sec of one day of the year)??? Wow dude, please enlighten my ignorance with your superior knowledge.

  2. Because of your in-depth research, I see that you, Bob, have a large following on this issue. I’m guessing that some of your following is from scientists and political party wonks in addition to your average readers who want to be informed.

    As an average reader, I’m always on the side of taking care of our planet, and I believe that global climate change is largely because of human folly that could be corrected if we cared enough. (Maybe you don’t agree, but I think an argument could even be made that ice is melting and oceans are rising partly because many massive undersea volcanoes are triggered by disturbances from deeper oil drilling.)

    But, if Greenland’s ice sheet is 3,000 meters thick, and humans wouldn’t see any difference for 500 years, I see why it sounds to some like a silly thing to worry about today. And I hate to say that I understand how the deniers can make the argument seem like a non-issue to short-term thinkers.

    When scientists prove to voters that beachfront houses are losing value this year because the ocean is creeping closer to them, and animals are suffering today, and next week’s tornadoes and floods are triggered by climate change, then global warming will be an issue to the average person out there.

    1. There are already numerous studies out on global warming economic impacts to coastal communities, for example:

      Plus, some Pacific island nations are talking about wholesale relocation, at a huge cost to themselves and the international community.

      And you’re right. Some people don’t get the long-term picture; others, like Steve Goddard, deliberately obfuscate to confuse short-term seasonal or annual variations in weather with long-term climate trends.

  3. i do not think global warming matters during a global recession/ depression. think of this. you have a family of 5 , three kids and a mother and father. all that matters to them is food and shelter for their kids. then you have families in which they are worried about keeping their job. and do you guard against inflation , or the current problem , “deflation” . i know for myself , even if global warming is true , i could care less. the number one priority is to fix the social problems such as war and peace , unemployment , medical care for all. all of this is not for the united states to fix , but is the responsibility of the united nations. have a good day!!!!!

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