A part of the Greenland ice sheet is on the brink of a tipping point, after which accelerated melting would become inevitable even if global heating was halted, according to new research. Rising temperatures caused by the climate crisis have already seen trillions of tonnes of Greenland’s ice pour into the ocean.
The new analysis detected the warning signals of a tipping point in a 140-year record of ice-sheet height and melting rates in the Jakobshavn basin, one of the five biggest basins in Greenland and the fastest-melting. The prime suspect for a surge in melting is a vicious circle in which melting reduces the height of the ice sheet, exposing it to the warmer air found at lower altitudes, which causes further melting. The study shows destabilisation of this ice sheet is under way.
It might already be at the point of no return, or be about to cross it in the coming decades, the scientists said.
“We’re at the brink, and every year with CO emissions continuing as usual exponentially increases the probability of crossing the tipping point,” said Niklas Boers at the Potsdam Institute for Climate Impact Research, Germany, who conducted the research with Martin Rypdal from the Arctic University of Norway. “It might have passed [the tipping point], but it’s not clear. However, our results suggest there will be substantially enhanced melting in the near future, which is worrying.” He continued, “We might be seeing something that is happening in many parts of Greenland, but we just don’t know for sure, because we don’t have the high-quality data for other parts.”
Large-scale melting of the Greenland ice sheet would have long-term global consequences, beyond rising sea levels. It could halt the Gulf Stream ocean current, with potential knock-on effects on the Amazon rainforest and tropical monsoons.