Tipping The Icebergs: What Losing The Greenland Ice Sheet Means For The Planet
Scientists studying one of the world’s biggest ice sheets made a shocking observation this month that underscores how much Earth’s climate has changed.
For the first time in recorded history, rain fell on the highest point in Greenland. The discovery comes as policymakers grapple with the United Nations’ recent landmark report on global warming, which said climate change is accelerating and driving an increase in extreme weather.
Josh Willis, the lead scientist on NASA’s Oceans Melting Greenland, spent his summer flying around the ice sheet in Greenland. Willis says he felt “stunned” to hear about rain falling 10,000 feet in the sky at the summit in the supposed “land of snow.”
Clouds often block scientists’ views of the ice sheets below, but Willis recently flew over a large area of melt on a clear day.
“There were giant lakes, hundreds of tiny rivers carrying this water around,” he says. “And our captain of the airplane, who’s been flying over Greenland for a quarter of a century, remarked he’d never seen anything this big this high on the plateau this late in the year.”
This concerning level of melt usually only occurs once in 100 years — but it has happened three times in the last 20 years, Willis says. And the frequency will continue as the planet warms.
Danish researchers have estimated that enough ice melted in July on the ice sheet to cover all of Florida in two inches of water. This year marks one of the biggest melt years ever for Greenland, Willis says.
“In the last 15 years or so, [Greenland has melted] 5 trillion tons of ice. And that’s enough to raise global sea levels by almost an inch,” he says. “So what’s happening on this island is really affecting the entire planet.”
Greenland is roughly three times the size of Texas and contains enough water in ice to raise sea levels by about 24 feet. The ice sheet, which is 10,000 feet thick in some areas, impacts the entire planet’s climate and sea levels, he says.
When Greenland’s ice sheets melt, the water travels all across the world, he says.
“If you think about it, the oceans cover two-thirds of the planet’s surface and we’re literally raising that surface by an inch or so every decade or two,” Willis says. “That means we’re literally reshaping our entire planet.”
The UN report says that over the next two decades, the planet will heat up by at least 1.5 degrees Celsius compared to the late 19th century levels. Greenland will continue melting at an expedited rate as the planet’s atmosphere and oceans warm, he says.
These outcomes aren’t part of a faraway future that won’t come for decades from now — it’s already happening, he says.
“It’s shocking to realize the footprint that humans have on our planet,” he says. “When you get in an airplane and you fly for two hours and there’s two miles of ice underneath you, the whole time you think about the fact that we’re causing that to melt. It’s disappearing right in front of us.”
Scientists believe tipping points in the climate like runaway ice melt exist, Willis says, but they don’t know when to expect such events.
“We’re pushing our climate toward the edge of a cliff but we can’t see how close we are to the edge,” he says. “That’s the scariest part.”
This article was originally published on WBUR.org.
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