Thread by @rebeccawdell

You may have noticed that some genuinely insane things are happening at the bottom of the world:
-Temp 70F (40C) above normal in Antarctica
-Temp 50F (30C) above normal in the Arctic
-Collapsing ice shelves in East Antarctica
This is unprecedented!

Let’s discuss. 🧵

I’ve been following this more closely than a general interest in the climate apocalypse would warrant, as (fun fact) I used to be a cryosphere scientist. If you’re really bored, you can find my thoughts on how to model icebergs in @AMSJPO and other fine publications.

@AMSJPO Two weeks ago, Dome C (one of the coldest places on earth) was 70F warmer than normal. That's still not warm enough to directly melt any ice, but based on the last 30y of records, that’s 7 std deviations above normal, or something that happens about once per BILLION YEARS.

@AMSJPO However, @RARohde (who made the plot above) has a good argument why it might be less freakish than that, perhaps only a once per 200y event. Either way, it’s not normal.

https://twitter.com/RARohde/status/1506962967388119051

@AMSJPO @RARohde This one crazy temperature happened in the context of really high temps across both poles. Antarctica overall was 9F/5C warmer than average and the Arctic overall was 6F/3C above average. Globally, we’ve only had a 2F/1C increase in average temperature.

apnews.com/article/climat…

@AMSJPO @RARohde And, just for giggles it was 50F/30C above average at the North Pole.

Santa’s workshop is melting.

@AMSJPO @RARohde The crazy high T in Antarctica probably contributed to the collapse of the Conger Ice Shelf, shown in these before/after photos courtesy of @WHOI.

whoi.edu/press-room/new…

@AMSJPO @RARohde @WHOI Conger is not an important ice shelf. I had to look up where it was (circled below). What’s concerning about it is that it’s in the part of the cryosphere that we kinda thought was okay, at least for now: East Antarctic Ice Sheet (EAIS).
Source: earth.gsfc.nasa.gov/cryo/data/pola…

@AMSJPO @RARohde @WHOI On ice sheets: they sit on continents and flow toward the ocean. Ice shelves are extensions of sheets floating on the ocean at the coast. Icebergs are bits of sheets that break off and float away. Sea ice is ocean water that got cold enough to freeze.

@AMSJPO @RARohde @WHOI Melting ice sheets cause sea-level rise—all the other ice is already in the ocean. But the other kinds of ice protect the sheets: shelves buttress sheets and sea ice reduces waves that erode shelves. So collapsing ice shelves is not a good sign for ice sheets or sea level rise.

@AMSJPO @RARohde @WHOI We spend a lot of time worrying about the West Antarctic Ice Sheet—it’s sitting on ground below sea level, large parts of it are probably unstable, it’s ice shelves are crumbling, it even has a thing we call the Doomsday Glacier (aka Thwaites). It’s the problem child.

@AMSJPO @RARohde @WHOI EAIS is supposed to be much more stable—sitting above sea level, getting more snow than it’s losing in icebergs. It also has about 50m (165ft) of sea level stored up. No one thinks it could collapse quickly (in years or decades), but Conger’s collapse made me pretty queasy.

@AMSJPO @RARohde @WHOI When I left the lab almost 10y ago, I was shocked by how even *very* sophisticated climate policy experts were mostly unaware of the dramatic and accelerating changes in the world’s frozen places. It’s almost certainly worse than you think.

Update: @RARohde has tentatively declared the 70F/40C event the most anomalous temperature anywhere in the instrumental record. He has a very measured discussion of the potential sources of human influence on this event:

https://twitter.com/RARohde/status/1508392075737415680

Also this. It says "Concordia Station reached the highest temperature ever registered at the meteorological station." Life in a remote Antarctic station can be grim on many levels, so it's important to take every opportunity for a little silliness.

https://twitter.com/PeteScientist/status/1506001406603444230