Half of the way to the first tipping point that will melt the Greenland ice sheet has already been covered.
That shows a new study.
The director of studies warns.
Potsdam – The Greenland Ice Sheet covers an area of 1.7 million square kilometers in the Arctic.
Researchers know that if it melts completely, the global sea level will rise by about seven meters.
Between 2003 and 2016, the ice sheet lost about 255 gigatonnes of ice per year, much of it in the southern part.
But one thing is unclear: How quickly can the ice sheet melt away completely?
In order to determine this, researchers are trying to determine the tipping points of the ice sheet - at which limit values does the behavior of the system change so much that it can no longer be reversed?
Previous studies have shown that global warming of between one and three degrees Celsius is considered the limit at which the ice will melt irreversibly.
A new study now shows two more tipping points for the Greenland ice sheet: If 1,000 gigatons of carbon were released into the atmosphere, the southern side of the ice sheet melts.
At around 2500 gigatons, almost the entire ice sheet disappears.
Humanity is currently around 500 gigatons, according to a statement on the study.
Specifically: Half of the way to the first tipping point has already been covered.
Climate change: “Risk of crossing the first tipping point”
"The first tipping point is not far from today's climate conditions, so we risk exceeding it," warns study leader Dennis Höning, a climate researcher at the Potsdam Institute for Climate Impact Research in a statement.
And warns: "Once we begin to slide, we will fall off the cliff and will no longer be able to climb up." The study was
published in the journal
Geophysical Research Letters .
The glaciers are melting – How climate change is changing the earth
The glaciers are melting – How climate change is changing the earth
To arrive at their conclusion, Höning's research team used a complex model of the entire Earth system, as well as a model of the behavior of ice sheets.
With the help of simulations over 20,000 years and carbon emissions between 0 and 4000 gigatons, the research group approached their result and determined the two new tipping points.
Greenland Ice Sheet: Study reveals tipping points
They are so dangerous because at some point the process can no longer be stopped.
As the ice sheet melts, its surface sinks deeper and is exposed to higher temperatures.
These temperatures ensure that the ice melts faster and the ice warms up even faster.
The only halfway positive news is that global temperatures must have been elevated for centuries or more to trigger this effect, the release says.
However, if the critical values are exceeded, the ice sheet will melt inexorably - not even reducing carbon emissions to pre-industrial levels can save the ice sheet.
“We cannot continue carbon emissions at the same rate much longer without risking exceeding the tipping points,” stresses Höning.
"Most of the ice melt won't happen in the next 10 years, but it won't be too long before we won't be able to work against it." (
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