A turbulent melt-river pours a million tons of water a day into a moulin, where it flows down through the ice to ultimately reach the ocean. Ted GiffordsI’m standing at the edge of the Greenland ice sheet, mesmerized by a mind-blowing scene of natural destruction. A milewide section of glacier...
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What’s going on with the Greenland ice sheet? It's losing ice faster than forecast and now irreversibly committed to at least 10 inches of sea level rise
Alun Hubbard, Professor of Glaciology, Arctic Five Chair, University of Tromsø
Wed, December 28, 2022 at 11:03 AM EST
I’m standing at the edge of the Greenland ice sheet, mesmerized by a mind-blowing scene of natural destruction. A milewide section of glacier front has fractured and is collapsing into the ocean, calving an immense iceberg.
Seracs, giant columns of ice the height of three-story houses, are being tossed around like dice. And the previously submerged portion of this immense block of glacier ice just breached the ocean – a frothing maelstrom flinging ice cubes of several tons high into the air. The resulting tsunami inundates all in its path as it radiates from the glacier’s calving front.
Fortunately, I’m watching from a clifftop a couple of miles away. But even here, I can feel the
seismic shocks through the ground.
Despite the spectacle, I’m keenly aware that this spells yet more unwelcome news for the world’s low-lying coastlines.
As
a field glaciologist, I’ve worked on ice sheets for more than 30 years. In that time, I have witnessed some gobsmacking changes. The past few years in particular have been unnerving for the sheer rate and magnitude of change underway. My revered textbooks taught me that ice sheets respond over millennial time scales, but that’s not what we’re seeing today.
A study published Aug. 29, 2022, demonstrates – for the first time – that Greenland’s ice sheet is now so out of balance with prevailing Arctic climate that it no longer can sustain its current size. It is irreversibly committed to retreat by at least 59,000 square kilometers (22,780 square miles), an area considerably larger than Denmark, Greenland’s protectorate state.
Even if all the greenhouse gas emissions driving global warming ceased today, we find that Greenland’s ice loss under current temperatures will
raise global sea level by at least 10.8 inches (27.4 centimeters). That’s more than current models forecast, and it’s a highly conservative estimate. If every year were like 2012,
when Greenland experienced a heat wave, that irreversible commitment to sea level rise would triple. That’s an ominous portent given that these are climate conditions we have already seen, not a hypothetical future scenario.
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