Extreme Temperature Diary- Friday December 17th, 2021/Main Topic: Antarctic Thwaites Glacier Is in Danger of Collapsing…Why We Should Be Very Worried

The main purpose of this ongoing blog will be to track planetary extreme, or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials). 😉

Antarctic Thwaites Glacier Is in Danger of Collapsing…Why We Should Be Very Worried

Dear Diary. If you live on or near a coast anywhere on the planet, by now you realize that sea level is very slowly creeping upward, relative to one lifetime. Due to this slow rate of rise at no more than a few millimeters per year, most areas are able to adapt. What if something were to happen to the Earth’s cryosphere (or frozen surface) such that sea levels all of a sudden within a few years jumped by several feet? Well, then there would be true catastrophe.

It’s becoming apparent that such jumps have indeed occurred in the Earth’s distant past. One jump may be in the planet’s not too distant future, perhaps in the lifetime of those living through most of this century, stemming from the more rapid melting of Antarctic ice. Let’s see if Thwaites becomes a household name should that most unstable Antarctic glacier start to collapse into the sea.

Here is more from the Washington Post:


Climate and Environment

Crucial Antarctic ice shelf could fail within five years, scientists say

An ITGC field site on Thwaites Glacier. (Peter Davis/British Antarctic Survey)

By Sarah Kaplan December 13, 2021 at 2:49 p.m. EST

Scientists have discovered a series of worrying weaknesses in the ice shelf holding back one of Antarctica’s most dangerous glaciers, suggesting that this important buttress against sea level rise could shatter within the next three to five years.

Until recently, the ice shelf was seen as the most stable part of Thwaites Glacier, a Florida-sized frozen expanse that already contributes about 4 percent of annual global sea level rise. Because of this brace, the eastern portion of Thwaites flowed more slowly than the rest of the notorious “doomsday glacier.”

But new data show that the warming ocean is eroding the eastern ice shelf from below. Satellite images taken as recently as last month and presented Monday at the annual meeting of the American Geophysical Union show several large, diagonal cracks extending across the floating ice wedge.

These weak spots are like cracks in a windshield, said Oregon State University glaciologist Erin Pettit. One more blow and they could spiderweb across the entire ice shelf surface.

“This eastern ice shelf is likely to shatter into hundreds of icebergs,” she said. “Suddenly the whole thing would collapse.”

The failure of the shelf would not immediately accelerate global sea level rise. The shelf already floats on the ocean surface, taking up the same amount of space whether it is solid or liquid.

But when the shelf fails, the eastern third of Thwaites Glacier will triple in speed, spitting formerly landlocked ice into the sea. Total collapse of Thwaites could result in several feet of sea level rise, scientists say, endangering millions of people in coastal areas.

Two major Antarctic glaciers are tearing loose from their restraints, scientists say

“It’s upwardly mobile in terms of how much ice it could put into the ocean in the future as these processes continue,” said Ted Scambos, a glaciologist at the University of Colorado Boulder, and a leader of the International Thwaites Glacier Collaboration (ITGC). He spoke to reporters via Zoom from McMurdo Station on the coast of Antarctica, where he is awaiting a flight to his field site atop the crumbling ice shelf.

“Things are evolving really rapidly here,” Scambos added. “It’s daunting.”

Pettit and Scambos’s observations also show that the warming ocean is loosening the ice shelf’s grip on the underwater mountain that helps it act as a brace against the ice river at its back. Even if the fractures don’t cause the shelf to disintegrate, it is likely to become completely unmoored from the seafloor within the next decade.

Other researchers from the ITGC revealed chaos in the “grounding zone” where the land-bound portion of the glacier connects to the floating shelf that extends out over the sea. Ocean water there is hot, by Antarctic standards, and where it enters crevasses it can create “hot spots” of melting.

Without its protective ice shelf, scientists fear that Thwaites may become vulnerable to ice cliff collapse, a process in which towering walls of ice that directly overlook the ocean start to crumble into the sea.

This process hasn’t been observed in Antarctica. But “if it started instantiating it would become self-sustaining and cause quite a bit of retreat for certain glaciers” including Thwaites, said Anna Crawford, a glaciologist at the University of St. Andrews.

Models developed by Crawford suggest that Thwaites could exhibit this kind of runaway collapse, though it’s unlikely to happen in the immediate future.

“But what we’re seeing already is enough to be worried about,” she said. “Thwaites is kind of a monster.”

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More on climate change

After two weeks of talks in Glasgow, diplomats from almost 200 countries reached an agreement to ramp up their carbon-cutting commitments, phase down fossil fuels and increase aid to poor countries on the front lines of climate change. Read the full text of the agreement here, with annotations.

More reporting from COP26: Five big takeaways from COP26 | Countries’ climate pledges built on flawed data, Post investigation finds | Nations reach agreement to speed climate action, but world remains off target

More on the causes and effects climate change: How we know global warming is real | How climate change is making parts of the world too hot and humid to survive | The undeniable link between weather disasters and climate change

More on climate change solutions: Tracking Biden’s environmental actions | The world’s biggest plant to capture CO2 from the air just opened in Iceland | Toronto is home to the world’s largest lake-powered cooling system. Here’s how it works. | Harnessing the energy of the ocean to power homes, planes and whisky distilleries

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Here are some of Thursday and Friday’s “ET’s:

Here is more climate and weather news from Friday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:

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Guy Walton “The Climate Guy”

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