Annual snowfall was no longer enough to make up for what was being lost. That melting is already causing global seas to rise about a millimetre on average per year.
Ohio State University glaciologist Ian Howat said: "Greenland is going to be the canary in the coal mine, and the canary is already pretty much dead at this point."
Last week the peer-reviewed State of the Climate report, which has contributions from scientists around the world, said 2015, 2016 and 2019 were the three hottest years since records began in the 1800s.
The Bulletin of the American Meteorological Society reported that the past decade, 2010 to 2019, was the warmest for the world - 0.2C higher than 2000-2009. Each decade since 1980 had been successively warmer than the one before.
Just over a week ago, researchers reported that the last fully intact ice shelf in the Canadian Arctic had collapsed. The 4000-year-old and 187sq km Milne Ice Shelf on the north-western edge of Ellesmere Island lost 43 per cent of its area at the end of July.
"Above-normal air temperatures, offshore winds and open water in front of the ice shelf are all part of the recipe for ice shelf break-up," the Canadian Ice Service said.
The polar sea ice was at its lowest extent for July in 40 years. The northern summer in the Canadian Arctic this year has been 5C above the 30-year average, glaciology professor Luke Copland, of the University of Ottawa, said.
The background climate threat is always reminding us that it is still lurking behind the virus danger in the foreground. The pandemic keeps showing us that changes to address a major crisis can be achieved, but are also difficult to do so.
Even countries focused on science-based responses and national strategies have struggled at times. We have seen people's desire to return to normal can be counter-productive. And rebuilding after a massive hit requires skilled and wise leadership.
But the opportunity hidden within the pandemic disaster is apparent to many.
In July, the European Union's recovery deal included 550 billion euros for green projects over the next seven years. US presidential candidate Joe Biden's climate plan, is being pitched as a jobs programme. It means that should he win, climate projects will be part of legislation put forward as a priority in 2021.
Millions of jobs and investment dollars will be needed for economic recovery, and a good proportion could be green jobs. Money is going to have to be spent anyway, so it had best be spent on achieving different, multiple goals at once.
And because recovery is urgent, and will still be the priority next year, it provides political cover to prioritise climate concerns.
Those concerns are also urgent, but have struggled to attract the political will needed - and the types of actions the pandemic has shown can be possible.
