By RTCC Staff
The Greenland ice sheet is more sensitive to long term climate change than previously thought, according to a new study.
The new research, published in the journal Nature Climate Change, estimates the threshold in global temperature rise leading to the complete melt of the ice sheet between 0.8-3.2°C and the best estimate at 1.6°C.
This compares to previous studies which put the best estimate at 3.1°C – with a range between 1.9-5.1°C.
The study also found the time it takes for the ice on Greenland to be lost is strongly dependant on the levels of warming.
For example, with a 2°C rise, the ice sheet could melt within around 50,000 years, while at an 8°C rise this could be as little as 2,000 years,
“The more we exceed the threshold, the faster it melts,” said Alexander Robinson, the report’s lead-author. “This is not what we call a rapid collapse. However, compared to what has happened in our planet’s history, it is fast. And we might already be approaching that critical threshold.”
The report authors, from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid warned that the world has already witnessed a temperature rise of almost 0.8°C already.
The aim of the study was to address the so called ‘tipping point’ of the Greenland ice sheet – which if reached would mean irreversible melting.
It found that for significantly large temperature anomalies the Greenland Ice Sheet would continue to melt even if temperatures dropped back below the threshold.
“Our study shows that under certain conditions the melting of the Greenland ice sheet becomes irreversible. This supports the notion that the ice is a tipping element in the Earth system,” says Andrey Ganopolski of PIK.
“If global temperature significantly overshoots the threshold for a long time, the ice will continue melting and not regrow – even if the climate would, after many thousand years, return to its pre-industrial state.”
This is due to the feedback between the climate and the ice sheet, say the researchers.
The ice sheet is over 3000 metres thick and thus elevated into cooler altitudes. When it melts the surface comes down to lower altitudes and higher temperatures and therefore melts quicker.
The ice also reflects solar radiation back into space. As the area cover decreases more radiation is absorbed adding to Greenland’s regional warming.