Iceberg A23a today (17 Feb). A totally clear sky. Utterly stunning. Still refusing to die. Still 500 sq km in area. Image from the Modis instrument on the venerable Aqua satellite, another oldie that's still plugging away.

The landscape hidden beneath Antarctica's ice sheet has been mapped from space for the first time. Scientists used hi‑res satellite observations to track how the continent’s frozen surface bunches and dips as it moves over the rugged rock bed below. www.bbc.co.uk/news/article...

A small silver lining: Yes, NASA and NOAA did not do briefings for their global temp data sets released today. And they certainly do not emphasize the human causes. But they *did* release them. The work is still happening. data.giss.nasa.gov/gistemp/grap... www.ncei.noaa.gov/access/monit...

🌊❄️ When Antarctic glaciers collapse into the sea, they can trigger huge underwater tsunamis that mix the ocean, affecting ice loss, climate and ecosystems. The project I lead on this is now in the field and featured on Sky News: news.sky.com/story/underw... #Antarctic #OceanMixing #ClimateScience

One big paddling pool becomes three. Today's view of iceberg A23a (left) and a view from the end of December (right). Notice how the raised rim effect, holding in surface meltwater, has re-established on all three main segments of the broken berg. A23a is turning to slush puppie.

💥 Boom! And it's just happened. The huge volumes of meltwater that had collected on the surface of iceberg A23a have triggered a massive and catastrophic hydrofracture event. Much of the berg has turned to mush. Three major segments remain, the largest about 500 sq km.

Want to see an iceberg turn to mush? What remains of iceberg A23a (<1,000 sq km) is about to experience death by hydrofracture. Look at all the meltwater sitting atop the berg. The whole thing could just fall apart any day now.

I haven't heard about the disagreements. The ice was sitting on an ice plain - a very flat bed with low basal drag. These are present beneath the downstream parts of many Antarctic glaciers where the sediment they transport has built a depositional body known as a grounding zone wedge.

A fascinating paper in @NatureGeosci that has already sparked considerable debate in the ice community. It's the super-fast withdrawal of Hektoria Glacier on the eastern side of the Antarctic Peninsula in 2022/23. Words by me in @newscientist.com www.newscientist.com/article/2502...

Speed reading "Science under Siege" - ahead of next week's recording of BBC Science in Action, where co-author @michaelemann.bsky.social joins a panel on the front line of the current assault on science, to answer what can be done. An appropriate topic for the last edition of the 60yr old series.

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.

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.

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.

🚨🚨🚨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

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.

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.

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.

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.

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?

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

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.

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...

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

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.

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.

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? ⬇️

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

It's crazy to think the UK once had its own colossal icebergs. @jdkirkham.bsky.social et al have found the preserved scour marks the megabergs made when their undersides ploughed through the muddy bottom of the North Sea some 20k-18k years ago. 🧵

US National Ice Center formally catalogues A23c, the big off-cut from grounded behemoth A23a. Daughter berg is ~130km² - or 2x Manhattan Island. A23a (~3,100km²) only needs to lose another ~30km² to hand "World's Biggest Iceberg" title to D15a (~3,070km²) in Amery Sea.

A big chunk has broken away from iceberg A23a, currently grounded at South Georgia. I calculate ~110 sq km. Looks to have fractured sometime on 11/12 April. It will get a US National Ice Center designation. It should be A23c, unless I'm mistaken.

🎉 Imagery from the newly launched Sentinel-1C Copernicus satellite is now accessible via Polar View www.polarview.aq and the Ice Logistics Portal www.icelogistics.info/antarctic?ce...! This addition significantly increases the repeatability of SAR observations in the Polar Regions 🛰️

The UK and Ireland nearly cloud free on April 2nd. Amazing colours over land and sea. Thanks to Sentinel satellites.

"Almost every building we saw had cracks running through at least one of its walls, unsafe to step into. At the main city hospital they're having to treat patients outdoors." BBC's Yogita Limaye reports from Mandalay www.bbc.co.uk/news/article...

You don't need to be a seismologist to look at this figure and understand the huge forces that ripped through Myanmar on March 28. The M7.7 quake ruptured fully 500km of the Sagaing Fault, moving its western flank north, with >3m of slip at the surface. Data from EU Sentinel satellites.

"Poor infrastructure and a patchwork of civil conflicts are severely hampering the relief effort in Myanmar". The USGS Pager assessment immediately following the quake estimated a >50% probability that the eventual death toll would rise above 10,000. www.bbc.co.uk/news/article...

Mars update: We've had the formal announcement of work that has been ongoing since late 2022 to develop a new landing mechanism for ESA's Rosalind Franklin rover. Covered by a £150m contract for Airbus UK that also includes modifications to the rover itself.

The Rainfall Rescue project was a stunning achievement. Announced at the beginning of lockdown, it caught a wave. The glamorous Lady Bayning, who fastidiously collected rain gauge data from 1835 to 1887, would have been thrilled.

15 years ago I was in the Airbus UK cleanroom and captured this picture. What was it? It was the electrical and service module for what would eventually become ESA's Gaia satellite - the discovery machine that mapped some two billion stars and other objects on the night sky. Adieu 👋

Iceberg A23a pictured from the ISS. The space station is almost as far south as it can reach here (51.5° S, 49.0° W - altitude of 422km). Picture taken on 14 March, so the berg had been grounded at South Georgia for a fortnight by this time.

#SouthGeorgia island and giant iceberg #A23a in this image taken by astronaut Nick Hague looking east from space station #ISS on 13 March 2025. The iceberg has apparently run aground and is not moving anymore. Original eol.jsc.nasa.gov/SearchPhotos... @daveatcogs.bsky.social

What happens when giant #icebergs start to fall apart! #biopole2 #antarctica #southgeorgia #ice #A23a @bas.ac.uk @biopole.bsky.social

Hello A23a! The world’s biggest iceberg! Stretching as far as we can see! #biopole2 @biopole.bsky.social @bas.ac.uk

Stupendous views yesterday of our friend A23a. The berg is listed with an official (usicecenter.gov) area of 1,010.13 sq nautical miles. It only needs to lose 118 sqNM to hand the title of the "World's biggest Iceberg" to D15a, which remains grounded off Princess Elizabeth Land.

Great report from Sky’s Tom Clark, who flew over iceberg A23a, now grounded at South Georgia. Clear imagery of the “footloose” terracing that’s driven by wave and warm surface water erosion. The terraces are ultimately ripped away by buoyant forces.

Ever wondered where the thickest ice is in Antarctica? It's here - in un-named canyon at 76.052°S, 118.378°E in Wilkes Land. A whopping 4,757 metres thick, or more than 15 times the height of the Shard, the UK's tallest skyscraper.

No doubt about it. Iceberg A23a is now grounded on the edge of South Georgia's continental shelf. It became wedged in the sediments on Saturday and hasn't moved since. Will it free itself? Perhaps this is where we see the megaberg break apart?

🚨 Unless my eyes deceive me, iceberg A23a has indeed grounded on the continental shelf at South Georgia. No movement between Saturday and Sunday. @bas.ac.uk

NASA/USGS Landsat-9 took this very pretty picture yesterday of Iceberg A23a on approach to South Georgia. The 3,200 sq km berg looks like it's going to try to squeeze past the northwestern tip of the British Overseas Territory, but it risks grounding in the shallows.