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Jonathan Amos @jcdamos.bsky.social · 4d

Ooops! It's happened again. The remnants of iceberg A23a have been caught on another Taylor Column, this time above the NorthWest Georgia Rise to the north of South Georgia BOT. The fragments have spun around and around for more than a month now.

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Jonathan Amos @jcdamos.bsky.social · Sep 2

Fab first data from the UK-supplied Microwave Sounder on the new Metop weather satellite. MWS combines obs from the old MHS & AMSU instruments. MWS measures the temperature and water content sitting at different altitudes. Fundamental data needed by computer models' for medium range forecasts.

European Space Agency @esa.int · Sep 2

🌎 Fresh data just in from space: the first results from the Microwave Sounder and Radio Occultation Sounder onboard @eumetsat.int’s MetOp-SG-A1 satellite are here, after less than a month in orbit: esa.int/Applications...

📸Eumetsat

First glimpse of MetOp-SG-A1 Microwave Sounder data.

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Jonathan Amos @jcdamos.bsky.social · Aug 30

Really clear view today of Iceberg A23a's big fragmentation event. Going back through the data, I think it happened on the 25th/26th. Image from NASA/Terra/Modis. Each new fragment is probably big enough to get a US National Ice Center designation. Likely A23g, A23h and A23i.

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Jonathan Amos @jcdamos.bsky.social · Aug 29

OK, the US National Ice Center was being a bit more generous than me. It logged A23a at 2,371 sq km. For comparison, the current title holder of the "world's biggest iceberg" is A15a at 3,070 sq km, grounded in the Amery Sea off East Antarctica.

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Jonathan Amos @jcdamos.bsky.social · Aug 29

🚨🚨🚨Boom! Iceberg A23a looks to have undergone a major fragmentation event in the past 24 hours. I count at least three "daughter" bergs (g, h and i ?). Further satellite imagery will confirm. The last intact measurement I made was ~2,250 sq km. @bas.ac.uk

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Jonathan Amos @jcdamos.bsky.social · Jul 15

Iceberg A23a update. It's lost another couple of large chunks in the past few days. Are we getting close to a major fragmentation event? Likely so.

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Jonathan Amos @jcdamos.bsky.social · Jul 7

In case you were wondering... Iceberg A23a seen cruising around South Georgia today by Meteosat 12. The old berg still has an area of 2,846 sq km.

Iceberg A23a on 7/7/25 Eumetsat/Meteosat 12

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Jonathan Amos @jcdamos.bsky.social · Jun 15

Iceberg D15a, grounded in the Amery Sea, is now officially "the world's biggest iceberg".

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Jonathan Amos @jcdamos.bsky.social · Jun 15

Sentinel-1 has finally got a clear view of iceberg A23a (13/6/25). The berg is much diminished as it skirts around South Georgia. And the US National Ice Center has updated its stats: A23a is now only the world's second biggest berg at 829.79 sqNM, or 2846,11 sqKM.

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Jonathan Amos @jcdamos.bsky.social · Jun 4

You can see the original grounded position in this BBC map. The berg is following the expected track, riding the prevailing current and hugging the continental shelf. It could always ground again. But if not, it should sweep around SG and go north.

Grounded position of iceberg A23a in early March off the coast of South Georgia

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Jonathan Amos @jcdamos.bsky.social · Jun 4

The movement of iceberg A23a over the past seven days. It's moved about 80km to the southeast of the position where it grounded off the coast of South Georgia in early March. Zoomed in animation from Meteosat-12.

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Jonathan Amos @jcdamos.bsky.social · Jun 1

And I'm pretty sure now that A23a is no longer the "World's Biggest Iceberg". D15a is larger in my view. But only the US National Ice Center can make that determination and its listing doesn't yet reflect this.

Nasa Worldview measurement of iceberg A23a

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Jonathan Amos @jcdamos.bsky.social · Jun 1

Somebody's got itchy feet! Iceberg A23a has moved in the past couple of days. It grounded close to South Georgia back at the beginning of March. But the erosion and melting since then has clearly allowed it to break free. Does it now reground or sweep off around the island?

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Reposted by Jonathan Amos

Mark Parrington @mparrington.bsky.social · May 30

Latest #CopernicusAtmosphere AOD forecast (from 30/05 00 UTC) shows smoke plume from devastating (&growing) Canadian #wildfires continuing across the Atlantic with hazy skies for Europe over next few days atmosphere.copernicus.eu/charts/packa... @copernicusecmwf.bsky.social @ecmwf.int

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Jonathan Amos @jcdamos.bsky.social · May 30

With days shortening at South Georgia (it's about 8 hours from sunrise to sunset), optical satellite coverage in the region is getting more restricted. Not so for Meteosat, which images the Europe/Africa hemisphere regardless of season. Hence we get a few views of iceberg A23a. Still grounded.

Meteosat view of South Georgia and iceberg A23a. 30/5/25

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Reposted by Jonathan Amos

Ian Hall @ianhall.bsky.social · May 8

I can't shake the feeling that these ideas are getting far more attention than their credibility and maturity warrant!

Cutting global greenhouse gas emissions as soon as possible is the key to tackling global warming.

www.thetimes.com/uk/science/a...

Hope to halt climate change by thickening Arctic sea ice

The government has outlined how it will spend £57 million on research on geo-engineering projects designed to cool the planet

www.thetimes.com

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Reposted by Jonathan Amos

Nagissa Mahmoudi @nagissa.bsky.social · May 8

How little we’ve seen: A visual coverage estimate of the deep seafloor | Science Advances www.science.org/doi/10.1126/...

How little we’ve seen: A visual coverage estimate of the deep seafloor

In decades of deep-sea exploration, humans have observed only 0.001% of the deep seafloor, leaving 66% of planet Earth unseen.

www.science.org

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Jonathan Amos @jcdamos.bsky.social · May 6

There was a spectacular view of iceberg A23a on 3 May. Clear skies over the berg and South Georgia. By my measurement, A23a is no longer the world's biggest iceberg. At ~2850 sq km, it's now bested by D15a - but only just. The US National Ice Center will be the final judge on the matter.

Iceberg A23a on 3 May. Copernicus / Sentinel-3

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Reposted by Jonathan Amos

Rob Larter @polarrobs.bsky.social · May 2

This is almost unbelievable. It's now May and there is still virtually no new sea ice forming in the Bellingshausen Sea (lower left region in image).
Image showing sea ice concentration derived from AMSR satellite data is by Institute of Environmental Physics, University of Bremen, Germany.

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Reposted by Jonathan Amos

British Antarctic Survey 🐧 @bas.ac.uk · Apr 25

The Penguin Book of Penguins!

Coming later this year: a beautifully illustrated book about the world’s most beloved bird, written by British Antarctic Survey’s Peter Fretwell @ptfretwell.bsky.social

What better day to reveal the cover the #WorldPenguinDay? ⬇️

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Jonathan Amos @jcdamos.bsky.social · Apr 24

Everybody loves a good iceberg story, as @helen-amanda.bsky.social keeps telling me.

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Jonathan Amos @jcdamos.bsky.social · Apr 24

And see this version of the story from my old BBC pals Georgina Rannard and Mark Poynting because it’s got some great graphical work from the ever excellent Erwan Rivault www.bbc.co.uk/news/article...

Iceberg tracks found off UK coast could shed light on Antarctica

Deep tracks gouged in the seafloor off the coast of Scotland could help us understand Antarctica today.

www.bbc.co.uk

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Reposted by Jonathan Amos

James Kirkham @jdkirkham.bsky.social · Apr 24

Icebergs? The size of a city? 90 miles from the UK? Must be a joke, right?

No! Our new paper in @natcomms.nature.com shows massive tabular icebergs broke off the UK in the last ice age before the UK’s ice shelves disintegrated from climate warming.

🧵

www.nature.com/articles/s41...

@bas.ac.uk

Change in iceberg calving behavior preceded North Sea ice shelf disintegration during the last deglaciation - Nature Communications

Massive tabular icebergs broke off of the UK during the last ice age. The widespread break-up of the ice shelves which produced these giant icebergs can be traced to around 18,000 years ago, and likel...

www.nature.com

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Jonathan Amos @jcdamos.bsky.social · Apr 24

Mickey's recent GRL paper on trends/extremes in big Antarctic bergs is here: doi.org/10.1029/2024...
And you can read the Kirkham paper in Nature Comms here: doi.org/10.1038/s414...
And yours truly with the lead story on New Scientist online here: newscientist.com/article/2477... 😎

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Jonathan Amos @jcdamos.bsky.social · Apr 24

This underscores thinking about Antarctica. Large calvings like A23a are not necessarily a sign of instability. “Rather, ice shelves disintegrate via death by a thousand cuts. We should be concerned when we stop seeing the large calving events,” Mickey MacKie tells me.

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