Polar Portal found that ice melt on Tuesday in Greenland was enough to cover the entire state of Florida under two inches of water. It is the largest melting event on the massive island of ice so far this summer. The melting so far this year has not been as extreme as in 2019, but a heatwave currently underway is making up for the lost time.
Greenland lost more than 8.5 billion tons of surface mass on Tuesday, and 18.4 billion tons since Sunday, according to the Denmark Meteorological Institute. While this week’s total ice loss is not as extreme as a similar event in 2019 — a record melt year — the area of the ice sheet that’s melting is larger.
“It’s a significant melt,” Ted Scambos, a senior research scientist at the National Snow and Ice Data Center at the University of Colorado, told CNN. “July 27th saw most of the eastern half of Greenland from the northern tip all the way to the southern tip mostly melted, which is unusual.”
As human-caused climate change warms the planet, ice loss has increased rapidly. According to a recent study published in the journal Cryosphere, Earth has lost a staggering 28 trillion tonnes of ice since the mid-1990s, a large portion of which was from the Arctic, including the Greenland ice sheet.
“In the past decade, we’ve already seen that surface melting in Greenland has become both more severe and more erratic,” said Thomas Slater, a glaciologist at the University of Leeds and a co-author on that report. “As the atmosphere continues to warm over Greenland, events such as yesterday’s extreme melting will become more frequent.”
A significant 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. Melting its ice sheet completely would eventually raise global sea level by 7 metres.
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. Uncertainties in the research meant it might already be at the point of no return, or be about to cross it in the coming decades, the scientists said. However, even if the tipping point was crossed, it did not mean that the entire ice sheet was doomed, they said, because there might be a stable state for a smaller ice sheet.
“We’re at the brink, and every year with CO2 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.”
The Greenland ice sheet has been one of the largest sources of sea-level rise since the early 2000s. However, basal melt has not been included explicitly in assessments of ice-sheet mass loss so far. Here, we present the first estimate of the total and regional basal melt produced by the ice sheet and the recent change in basal melt through time. We find that the ice sheet’s present basal melt production is 21.4 +4.4/−4.0 Gt per year, and that melt generated by basal friction is responsible for about half of this volume. We estimate that basal melting has increased by 2.9 ± 5.2 Gt during the first decade of the 2000s. As the Arctic warms, we anticipate that basal melt will continue to increase due to faster ice flow and more surface melting thus compounding current mass loss trends, enhancing solid ice discharge, and modifying fjord circulation.
Meanwhile, in British Columbia.
This is a Creative Commons article. The original version of this article appeared here.