Rain fell on the highest level on the Greenland ice sheet final week for the primary time on report, one other worrying signal of warming for the ice sheet already melting at an growing fee, scientists stated on Friday.
“That’s not a healthy sign for an ice sheet,” stated Indrani Das, a glaciologist with Columbia University’s Lamont-Doherty Earth Observatory. “Water on ice is bad. … It makes the ice sheet more prone to surface melt.”
Not solely is water hotter than the standard snow, it is also darker — so it absorbs extra daylight relatively than reflecting it away.
That meltwater is streaming into the ocean, inflicting sea ranges to rise. Already, melting from Greenland’s ice sheet –the world’s second-largest after Antarctica’s — has triggered round 25% of worldwide sea stage rise seen over the previous couple of many years, scientists estimate. That share is anticipated to develop, as international temperatures enhance.
The rain fell for a number of hours on the ice sheet’s 3,216-metre summit on Aug. 14, the place temperatures remained above freezing for round 9 hours, scientists on the US National Snow and Ice Data Centre stated.
Temperatures on the ice cap almost by no means carry above freezing, however have now performed so 3 times in lower than a decade.
In whole, 7 billion tonnes of rain fell throughout Greenland over three days, from Aug. 14 by way of Aug. 16 — the biggest quantity since data started in 1950.
The rain and excessive temperatures triggered in depth melting throughout the island, which suffered a floor ice mass loss on Aug. 15 that was seven instances above the typical for mid-August.
The record-breaking rain is the most recent in a string of warning indicators about how local weather change is affecting Greenland’s ice sheet.
Greenland skilled a large melting occasion in late July, when sufficient ice melted in a single day to cowl the US state of Florida in 2 inches (5 cm) of water.
That melting occasion and final week’s rain have been each brought on by air circulation patterns which meant heat, moist air quickly coated the island.
“This alarming rain at the summit of Greenland is not an isolated event,” stated Twila Moon, deputy lead scientist with the US National Snow and Ice Data Centre.
Along with rising floods, fires, and different extremes, it’s one among many “alarm bells” signalling the necessity to cut back greenhouse fuel emissions, she stated.
“We really have to stay laser-focused on adapting, as well as reducing the potential for those to become truly devastating.”