Extract from ABC News
Scientists say rain falling on Greenland's highest point for the first time on record is another worrying sign of warming for the ice sheet, which is melting at an increasing rate.
Key points:
- Greenland's highest point recorded several hours of rain and temperatures above freezing last week
- Melting on the ice sheet was seven times greater last week than the mid-August average
- Enough ice melted from Greenland in July to cover an area 2.5 times the size of Tasmania in 5cm of water
The world's second-largest ice sheet, behind Antarctica, had several hours of rainfall on August 14 at its 3,216-metre summit.
In total, 7 billion tonnes of rain fell across Greenland over three days, from August 14-16 — the largest amount since records began in 1950.
Indrani Das, a glaciologist with Columbia University's Lamont-Doherty Earth Observatory, said rain on the ice cap was a bad sign.
"That's not a healthy sign for an ice sheet," she said.
"Water on ice is bad. It makes the ice sheet more prone to surface melt."
Greenland also recorded temperatures above freezing, which is rare.
The temperature was above freezing for around nine hours and is the third time it has risen above freezing in the past decade.
The rain and high temperatures triggered extensive melting across the island, which suffered a surface ice mass loss on August 15 that was seven times above the average for mid-August.
The record-breaking rain is the latest in a string of warning signs about how climate change is affecting Greenland's ice sheet.
Greenland experienced a massive melting event in late July, when enough ice melted in a single day to cover an area roughly 2.5 times greater than Tasmania with 5cm of water.
That melting event and last week's rain were both caused by air circulation patterns which meant warm, moist air temporarily covered the island.
"This alarming rain at the summit of Greenland is not an isolated event," according to Twila Moon, deputy lead scientist with the US National Snow and Ice Data Center.
Along with rising floods, fires, and other extremes, it is one of many "alarm bells" signalling the need to reduce greenhouse gas emissions, she said.
"We really have to stay laser-focused on adapting, as well as reducing the potential for those to become truly devastating."
In April last year, Marco Tedesco, research professor at Columbia University's Lamont-Doherty Earth Observatory, told Reuters that ice which had been built up over several millennia was being destroyed in just decades.
He said Greenland had contributed around 25 per cent of all sea level rises in the last few decades, with that number expected to rise to 40 per cent by 2100 if carbon emissions continue to grow.
Reuters
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