Illustration for article titled Great, Now We Have to Worry About Sunny Skies Melting Greenlands Ice Sheet

Greenland is some of the world’s most-distressed real estate. In recent years, it’s been subject to bizarre fires, and its ice sheet has been cracking up and melting down due to rising temperatures. Now, new research adds to the growing list of calamities the second-biggest stash of ice on the planet faces: sunny skies.

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The findings, published Thursday in The Cryosphere, show that last summer’s record melt wasn’t just the result of extreme heat that turned the ice sheet liquid. Instead, bizarrely sunny skies actually locked in over the island, and the resulting watery mess shows the way that climate change can overlap with other threats, putting the world at risk.

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The summer of 2019 was one for the record books. There was the aforementioned weird fire on an island largely covered by ice. In June, said ice saw a huge melting spike that was a precursor to an even bigger spike in late July and early August. The latter meltdown saw the island shed an astounding 12.5 billion tons of ice in the span of a single day. Here’s where I could make a comparison, but even that wouldn’t help you make sense of how much ice that is. (Seriously, can you picture 2.5 billion African elephants? Because I sure can’t.)

All told, the new findings show that Greenland surface mass balance—a metric that factors in snowfall coming in and melting ice going out—dropped a record 320 billion metric tons in 2019 compared to the 1981-to-2010 average. That’s even worse news when you consider the island prior to was already losing six times more ice than it was in 1980. All told, 96 percent of the ice sheet’s surface saw melt in 2019. And while heat certainly played a role, the fresh research shows that freaky clear skies amplified the impacts.

The main driver for the clear skies was a ridge of high pressure that parked itself over the island. While weather patterns usually move from west to east in the northern hemisphere, the summer 2019 high-pressure system that helped melt Greenland was tied to the same pattern that baked Europe with record-setting heat.

The strong area of high pressure essentially shunted storms around Greenland, but not over it. Meanwhile, the clear skies helped heat things up on the ground, which in turn helped sustain the high-pressure system and lack of clouds. Of the 92 days last summer, 63 were dominated by high pressure over the ice sheet. It’s a vicious feedback loop that we’ve seen play out in other locations, like California during its multiyear drought.

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The pressure system was basically like a kid with a magnifying glass—but instead of killing ants, it cooked the ice. The situation was compounded by low snowfall prior to melt season, which usually adds a layer of protection. White, fresh snow reflects incoming sunlight, keeping the ice under it from melting. Without that, snow sullied by dust, wildfire soot, and other crud absorbs that heat and worsens the whole situation.

While the new research doesn’t tie the persistent sunny skies to climate change, previous research has found that these types of stuck weather patterns are becoming more common due to climate change. Regardless of whether climate change played a role in locking in the weirdly clear conditions over Greenland, it’s not a phenomenon that climate models include. The new paper makes the case that models need to better incorporate these types of weather patterns to truly understand just how endangered the ice is.

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For me, though, the takeaway is the world needs to get off fossil fuels now rather than waiting to find out how bad things could get.

Managing editor, Earther

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