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James Smith

@shelfyice

Marine geologist/glacial sedimentologist at the British Antarctic Survey interested in ice shelf/sheet history. Views my own

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Latest posts by James Smith @shelfyice

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Warm ocean water, not air temperature, drove massive Antarctic ice retreat after the last ice age  - British Antarctic Survey A new study concludes that warm ocean water was the primary driver of major West Antarctic Ice Sheet retreat since the end of the last ice age 18,000 years ago.

Congratulations to our colleagues @erinmcclimate.bsky.social and Charlotte Spencer-Jones on the publication of their co-authored article in Nature Communications ‘Ocean heat forced West Antarctic Ice Sheet retreat after the Last Glacial Maximum’: www.bas.ac.uk/news/warm-oc...

03.03.2026 09:48 👍 8 🔁 2 💬 0 📌 0

Furthermore, the time required to fully replace water properties following a regime shift, is a few years for small shelf seas like the Amundsen Sea (Nakayama et al. doi.org/10.1002/2014...) and up to a few decades for larger ones such as the Weddell (Naughten et al. www.nature.com/articles/s41...)

03.03.2026 12:36 👍 2 🔁 0 💬 0 📌 0

This was justifiably questioned during the review process, but I think we addressed it well. Ultimately any single location in the Amundsen Sea – below a certain water depth - is likely to be representative (in the broadest terms) of the entire shelf 🧵⬇️

03.03.2026 12:36 👍 2 🔁 0 💬 1 📌 0

Even when we found cores that contained enough of these tiny fossils, the temporal resolution was patchy or sometimes incomplete = 😭. This was painstaking and laborious and huge kudos to @emawbey.bsky.social for hanging on in there. However, because of this we used a multi-core approach 🧵⬇️

03.03.2026 12:36 👍 2 🔁 0 💬 1 📌 0

Second, this type of work is really hard, just ask @emawbey.bsky.social who spent years (literally) sifting through sand grains looking for forams! Along with colleagues from @awi.de and the US, we’ve collected >400 cores from the Amundsen Sea and only a handful contained enough forams for Mg/Ca 🧵⬇️

03.03.2026 12:36 👍 2 🔁 0 💬 1 📌 0

A couple of take home messages. First, and perhaps uncontroversially (!?), is that ice in the Amundsen Sea retreats when warm water is circulating on the shelf and stops retreating when heat is reduced. Probably not as simple as turning CDW on/off and might relate to the depth of the thermocline 🧵⬇️

03.03.2026 12:36 👍 2 🔁 0 💬 1 📌 0
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Ocean heat forced West Antarctic Ice Sheet retreat after the Last Glacial Maximum - Nature Communications Amundsen Sea records show warm Circumpolar Deep Water drove major West Antarctic Ice Sheet retreat from 18,000–10,000 years ago. Subsequent cooling stabilized the grounding line, indicating ocean heat...

Pleased to see this finally out, involving a brilliant team @emawbey.bsky.social, @erinmcclimate.bsky.social, @krhendry.bsky.social, @polarrobs.bsky.social, @wellner.bsky.social, supported by @bas.ac.uk, @awi.de , @geogdurham.bsky.social and #Thwaites🧵⤵️

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

03.03.2026 12:36 👍 16 🔁 5 💬 2 📌 1
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Imperial researchers help unlock Antarctica’s deep past with record-breaking drill into the ice An international team co-led by Imperial College London has obtained the longest ever sediment core from beneath the Antarctic ice – a multimil...

Brilliant effort 🤌 www.imperial.ac.uk/news/article...

17.02.2026 19:37 👍 4 🔁 0 💬 0 📌 0
addison-wheeler-fellowship - Durham University

🚨job opportunity🚨

Durham is advertising 3-year fellowships (any field). We are very keen to hear from Antarctic/Cryo people who might be interested in joining a great group. The positions come with some travel & research funds. See here for details or get in touch www.durham.ac.uk/research/ins...

05.02.2026 12:08 👍 3 🔁 8 💬 0 📌 0
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We’ve wrapped up drilling at Crary Ice Rise with 228m of sediment core. This is an unprecedented record of the history of the West Antarctic Ice Sheet stretching back millions of years. Initial observations indicate the core includes periods of environmental change during past times of warming.

09.01.2026 07:48 👍 53 🔁 19 💬 0 📌 1
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We have successfully drilled 200 metres of sediment core from beneath the ice sheet at Crary Ice Rise! The pipe is still spinning - with a bit of time up our sleeve, we’re not stopping drilling yet, as we continue to drill back through the geological archive hidden beneath the ice. 📷 Ana Tovey

06.01.2026 01:20 👍 39 🔁 14 💬 2 📌 1
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We’ve got our eyes on the prize 24/7, through blowing snow, lashing winds and sunshine. With more than 100 metres of sediment core retrieved, we’re more than halfway towards our target of 200 metres. Co-Chief Huw Horgan shares this expedition update from our deep-field camp at Crary Ice Rise.

04.01.2026 03:56 👍 18 🔁 7 💬 0 📌 2
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@swais2c.bsky.social drilling project (Antarctica): First core on deck🚨 10 m of core material on deck at end of shift 1 of bedrock drilling. Congratulations🥳
More project info ℹ️ tinyurl.com/489td3z3
SWAIS2C ℹ️ www.swais2c.aq
🎥Ana Tovey-SWAIS2C

29.12.2025 12:35 👍 13 🔁 4 💬 0 📌 1
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Ocean driven retreat of the Northeast Greenland Ice Stream following the Last Glacial Maximum Nature Communications - Warm Atlantic Water was a major driver of both initial NEGIS retreat from 21.6 ka BP and the collapse of its ice shelf ~15.2 ka BP. This study demonstrates the key role of...

Brilliant to see this paper rdcu.be/eUWMI by @NEGIS_Durham team & led by @louisecallard.bsky.social Work offshore with partners @awi.de revealing how ocean warming triggered ice shelf collapse @geogdurham.bsky.social @ncl-geography.bsky.social

17.12.2025 12:19 👍 12 🔁 7 💬 0 📌 0
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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...

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

24.04.2025 09:06 👍 86 🔁 30 💬 2 📌 7
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🎉 Latest paper from the NERC-funded Northeast Greenland Ice Stream project. Offshore geophysical and sedimentological evidence shows the ice stream extended to the shelf edge at the Last Glacial Maximum.

@shelfyice.bsky.social

www.sciencedirect.com/science/arti...

22.04.2025 12:04 👍 7 🔁 1 💬 0 📌 0
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Finally published @science.org:
Can AI help yield new insights from vast amounts of Earth data?
We use large-scale data and neural nets to find the constitutive laws of glacial ice, which differ from commonly assumed forms in conventional models. #ScienceResearch
www.science.org/doi/10.1126/...

14.03.2025 15:55 👍 44 🔁 16 💬 4 📌 2

Please feel free to get in contact if you've got any questions! (n.gandy@shu.ac.uk)

05.03.2025 16:12 👍 0 🔁 1 💬 0 📌 0
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Scientific history, sampling approach, and physical characterization of the Camp Century subglacial material, a rare archive from beneath the Greenland Ice Sheet Abstract. Basal materials in ice cores hold information about paleoclimate conditions, glacial processes, and the timing of past ice-free intervals, all of which aid understanding of ice sheet stabili...

doi.org/10.5194/tc-1...
Recent paper from our international team. 3 million years of ice sheet and climate history from below Greenland's ice in a core from 1966. Free to read. US NSF supported research. 🧪❄️💙📚

24.02.2025 12:48 👍 30 🔁 8 💬 2 📌 1
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We have an exciting opportunity for postdoc to join our group at @bas.ac.uk and take part in two big ice core projects: www.beyondepica.eu and @fetch4.bsky.social.

Package includes: mugs, stickers, maps, trips to Copenhagen, Grenoble and (maybe) Greenland.

bas.ciphr-irecruit.com/applicants/v...

24.02.2025 13:11 👍 30 🔁 18 💬 1 📌 3
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The Ronne Ice Shelf survived the last interglacial - Nature Sea salt data from an ice core record show that Antarctica’s Ronne Ice Shelf survived the last interglacial, the last period of enhanced and sustained global warmth about 125,000 years ago.

Important paper in Nature today about collapse of the West Antarctic Ice Sheet. There is a positive isotope anomaly at Skytrain Ice Rise during the last interglacial, consistent with what we found in our high-resolution water-isotope simulations when WAIS collapses.

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

29.01.2025 16:56 👍 19 🔁 6 💬 0 📌 1
Four people in bright down jackets pose together on a bright, empty ice shelf. They are holding a long ice core cylinder, which is taller than all of them. Photo: Emma Pearce

Four people in bright down jackets pose together on a bright, empty ice shelf. They are holding a long ice core cylinder, which is taller than all of them. Photo: Emma Pearce

Hello from the Brunt Ice Shelf! ⚡🧪

The RIFT-TIP team are using ice cores and seismology to model how huge fractures travel across ice shelves.

With just a few weeks left, they've been putting in a real shift:
🧊 4 ice cores drilled
🔍 60km of radar transects taken
⚡ 64 surface seismometers set up

16.01.2025 16:55 👍 109 🔁 9 💬 7 📌 0
Expedition Update: Season sign off
Expedition Update: Season sign off YouTube video by SWAIS2C

It’s been a huge season for our on-ice team KIS3 - our Co-Chief @vandeflierdt.bsky.social sums it up in this end of season wrap. We’re now focussed on our next season at Crary Ice Rise, where we will attempt to obtain a long sediment core youtube.com/shorts/NM5pe...

08.01.2025 04:53 👍 8 🔁 4 💬 0 📌 1
Two maps - the first shows the Amundsen Sea Embayment, West Antarctica, and major glaciers that flow into it (most notably Pine Island and Thwaites glaciers). The second map shows the Hudson Mountains, a series of volcanoes adjacent to Pine Island Glacier and dissected by Larter and Lucchita glaciers.

Two maps - the first shows the Amundsen Sea Embayment, West Antarctica, and major glaciers that flow into it (most notably Pine Island and Thwaites glaciers). The second map shows the Hudson Mountains, a series of volcanoes adjacent to Pine Island Glacier and dissected by Larter and Lucchita glaciers.

Three plots showing the surface profile (elevation) of Pine Island, Larter, and a Lucchitta glaciers against distance from ice shelf front or grounding line (km). Grey boxes above the surface profiles show the extent of exposed rock at each nunatak (a volcano in each case here). Different symbols in/on the grey boxes show the location and elevation of erratic cobbles collected or observed at each nunatak. There is a pie chart above each nunatak showing the different erratic lithologies observed.

Three plots showing the surface profile (elevation) of Pine Island, Larter, and a Lucchitta glaciers against distance from ice shelf front or grounding line (km). Grey boxes above the surface profiles show the extent of exposed rock at each nunatak (a volcano in each case here). Different symbols in/on the grey boxes show the location and elevation of erratic cobbles collected or observed at each nunatak. There is a pie chart above each nunatak showing the different erratic lithologies observed.

Chuffed to have contributed to this new QSR paper led by @geologicaljo.bsky.social! Check it out of you fancy learning about glacial deposits in the Hudson Mountains, West Antarctica, and what they tell us about past ice thicknesses, thermal regimes, and ice flow directions 🧊🇦🇶🏔️ tinyurl.com/yh9je8sf

08.01.2025 07:32 👍 24 🔁 7 💬 3 📌 1
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Inspiring Girls Expeditions Inspiring Girls* Expeditions

Applications are OPEN for our tuition-FREE, multi-day expeditions blending science, art, and backcountry travel! Open to high school girls* (ages 16-18 on June 1, 2025). Visit inspiringgirls.org for more details. Share to help spread the word - we can't wait to adventure! ♥️ #InspiringGirls

07.01.2025 05:04 👍 15 🔁 10 💬 1 📌 2
Assistant Research Professor The University of Maine is a community of more than 11,900 undergraduate and graduate students, and 2,500 employees located on the Orono campus, the regional campus in Machias, and throughout the stat...

Hi friends & colleagues! We have an exciting new position as an Assistant Research Professor at @umaine.bsky.social working with our team on snow, water, and landscape evolution research! Please share this far & wide! fa-ewca-saasfaprod1.fa.ocs.oraclecloud.com/hcmUI/Candid... 🧪

07.01.2025 18:19 👍 7 🔁 6 💬 0 📌 0
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Congratulations to Rod Arnold, MBE! 🥇

As Head of the Air Unit at British Antarctic Survey, Rod was awarded his MBE in the New Years Honours list for services to Polar Science and Aviation in British Antarctic Territory

Find out more about his achievements 👇
www.bas.ac.uk/media-post/n...

03.01.2025 18:09 👍 39 🔁 4 💬 3 📌 2
Helen A. Fricker (2024) | IGS

To round of the year my wonderful friend @helen-amanda.bsky.social has been awarded the prestigious Seligmann Crystal by the International Glaciology Society !!!!

What fabulous news !!!

🤩🎊🎉🥂🥳🛰❄️🧊🧪🍾🎆🌍

www.igsoc.org/about/awards...

21.12.2024 16:48 👍 33 🔁 4 💬 2 📌 1