Doomsday update just dropped:

[teach1st]

39. I think it's important to read the article

From what I can see, most of the tweets center around this Rolling Stone article:

https://www.rollingstone.com/politics/politics-features/doomsday-glacier-thwaites-antarctica-climate-crisis-1273841/

Here you see the problem. Even predicting how the crackup of the ice shelf will impact the flow of the glacier is difficult to estimate.

And this is only one of the uncertainties that scientists face when trying to predict whether or not Miami will be underwater by 2100. There is further uncertainty in exactly where and when the ice will fracture, how much warm water will be pushed up beneath the glacier by changing winds and ocean currents, how the character of the bed the glacier rests on will speed up or slow down the glacier’s slide into the sea. Whether the bed is hard rock or muddy till can have a big impact on the velocity of the glacier, just as the texture of snow affects how fast you ski down a mountain. “Ice is alive,” says Pettit. “It moves and flows and breaks in ways that are difficult to anticipate.”

Paradoxically, the more scientists learn about what’s going on at Thwaites, the more divergent the latest climate models have become about its future. Consider the results of two models by highly respected scientists published side by side in Nature earlier this year. One model suggests that Thwaites stays fairly stable until temperatures rise above 2 C of warming. Then all hell breaks loose. Thwaites begins to fall into the sea like a line of dominoes pushed off a table and soon takes the rest of the West Antarctic ice sheet with it. And once the collapse begins, according to this model, it will be impossible to stop — at least on any human time scale. In a century or so, global sea levels could rise 10 feet, which would swamp South Florida and Bangladesh and many other low-lying regions of the world.

In the other model, global sea level rise only differs by 4½ inches between a 1.5 C global temperature rise and a 3 C temperature rise (which is a little above where we are headed with under current emissions scenarios). And much of that comes from increased melt in Greenland and mountain glaciers. As for Antarctica, the paper says explicitly: “No clear dependence on emissions scenario emerges for Antarctica.”

If Thwaites breaks up in five years (which seems like a worse-case scenario), it doesn't look like a sudden sea rise follows immediately. Still, we need to be working hard on reducing warming. Our children's and grandchildren's lives depend on it.