If the poles are the world's early-warning system for climate change, the alarm bells are ringing.
After a record-warm winter during a record-warm year, plus almost a decade of the warmest years in known history, Greenland's ice sheet has set yet another dangerous record: It began melting two months early.
That really shouldn't be happening.
Greenland's ice sheet — one of the greatest storehouses of freshwater on Earth — grows during the winter. Then, starting around June, it loses some of that ice accumulation in a melt season.
However, new data shows that, as of April 11, over 12% of the ice sheet had started melting. The three earliest dates for an early melt covering more than 10% of the ice sheet happened in May (in 2010, 1990, and 2006).
The findings come from the Danish Meteorological Institute (DMI), which tracks ice in Greenland.
DMI scientists were so shocked by the data that they thought it might be wrong. On-the-ground measurements later confirmed it all, though.
"Even weather stations quite high up on the ice sheet observed very high temperatures on Monday," Robert Fausto, a scientist with the Geological Survey of Denmark and Greenland said in a DMI statement, which we learned about from The Guardian.
According to Fausto, these stations recorded temperatures of almost 38 degrees Fahrenheit. "That would be a warm day in July, never mind April," he added.
Maps released by DMI show this dramatic change in ice cover. The leftmost image shows melt water, in red, on April 10. The map right next to it shows melt water for April 11.
And the chart on the far right shows how ice melt has progressed in years past (the dark gray line shows the average trend). While there's certainly a lot of yearly variation (shown in light gray shading), nothing even touches the near-vertical, bright blue line demonstrating where we are today.
Just so we're clear: The Greenland Ice Sheet is 656,000 square miles. If we laid it over the US, it would cover 80% of everything east of the Mississippi River.
It contains 8% of the world's fresh water, and if it melts, sea levels could rise as much 20 feet.
The last record melt season, the Washington Post reports, was in 2012. The ice sheet lost 562 billion tons of freshwater mass. Sea levels worldwide over rose by over a millimeter.
That may not sound like a lot — but earlier estimates had pegged the pace of rising seas at about 2 mm per year, or a little less than a tenth of an inch.
We're more than on track to exceed that, confirming recent predictions that we're going to have to adjust our expectations of the rate of climate change upward — particularly the rate of warming and sea-level rise — by a troubling amount.
