Australian Antarctic Program Partnership

ON THIN ICE A science briefing about changes in Antarctic sea ice

3️⃣ The ocean’s structure sets how far north sea ice can reach, influenced by several factors: how warm the ocean is after summer, how much the atmosphere cools the ocean, and how much heat is carried upward from deeper ocean layers.

Sea-ice briefing ▶️ aapp.shorthandstories.com/on-thin-ice/...

2️⃣ A new study led by @icecoldwill.bsky.social in @jgroceans.bsky.social looks at the ocean's role in limiting winter sea-ice growth. A metric called “Stability at Freezing Temperature” estimates how much heat the ocean must lose to the atmosphere for ice to form.

▶️ doi.org/10.1029/2025...

1️⃣ Antarctic sea ice during winter didn’t use to change very much from year to year. But in recent winters, the extent of ice has crashed to unusually low levels. Which begs the question: what controls how much sea ice can form in winter?

🌊 plot by @edoddridge.bsky.social

Globally, no single day in 2025 was cooler than its 1991-2020 average.
climate.copernicus.eu/global-clima...

Global trends in ocean fronts and impacts on the air–sea CO2 flux and chlorophyll concentrations Nature Climate Change - Changes in ocean fronts could impact biological productivity and carbon exchange. By analysing satellite and reanalysis data, the authors identify areas with active frontal...

Researchers tracked where ocean fronts occur globally and how they're changing.

"We can now directly link changes in frontal activity to changes in both phytoplankton biomass and ocean carbon dioxide uptake" — Dr Amelie Meyer @imas-utas.bsky.social

@nature.com ▶️ rdcu.be/e0RHf

🌊 Ocean fronts are boundaries where different water masses collide. They cover about 1/3 of the global ocean but account for nearly 3/4 of total ocean CO2 uptake, absorbing about 1.8 billion tonnes of carbon each year.

Research led @utas.edu.au ▶️ tinyurl.com/jtxddyt9

Anim: Kuroshio current by NASA

How to drill an ice shelf — and why A mission to reach the ocean under the Shackleton Ice Shelf in East Antarctica

Hats off to the New Zealand team behind this research in @jgroceans.bsky.social. Drilling through ice shelves is no easy feat.

▶️ aapp.shorthandstories.com/how-to-drill...

@aucklanduni.bsky.social
@universityofotago.bsky.social

(a) An ice thickness map of Ross Ice Shelf using the Bedmap-2 data set (Fretwell et al., 2013). Contours represent ice thickness at 100 m intervals. The orange dot represents the HWD2 borehole. (b) HWD2 mooring schematic showing instrument deployment pressures. Nortek Aquadopp current meters are shown in red and Seabird SBE 37 CTD are shown in blue. All numbers are in dbar. The ice shelf thickness and seafloor depth at the HWD2 site were 321 and 741 m, respectively.

"In this study, we describe results from a 4.5-year record of ocean measurements beneath the central Ross Ice Shelf ... our analysis of the data suggests the ice shelf melting is linked to changes in how much sea ice forms each winter in a nearby area of open water."

▶️ doi.org/10.1029/2025...

Beneath Antarctica’s largest ice shelf, a hidden ocean is revealing its secrets A four-year record from the heart of the Ross Ice Shelf shows how subtle changes could shape future sea level rise, ocean ecosystems – and even our weather.

🌊 "Ice shelves act as buttresses for Antarctica’s 30 million cubic kilometres of ice ... The Ross Ice Shelf is the largest, among the coldest and most southerly, and perhaps the most sheltered from a warming ocean."
—@aunz.theconversation.com

▶️ theconversation.com/beneath-anta...

🚨 WORK WITH US at @imas-utas.bsky.social!

🧊 Research Associate – Sea-Level Analyst

🌊 Evaluate sea level risks for Australia and Pacific Island nations using #Antarctic Ice Sheet projections under @ipcc.bsky.social #climate scenarios

✍️ Apply by 22 Feb 2026

▶️ aappartnership.org.au/vacancies/

Nominations for the @soosocean.bsky.social Weddell Sea and Dronning Maud Land Regional Working Group close on 30 Jan.

Applications for ECR representatives will open soon.

🐧 soos.aq/opportunitie...

New sanctuary preserves ice cores from melting glaciers | CBC News Scientists on Wednesday inaugurated the first global repository of mountain ice cores, preserving the history of the Earth's atmosphere in an Antarctic vault for future generations to study as global ...

"The Ice Memory Foundation ensures that future generations of researchers will be able to study past climate conditions using technologies that may not yet exist" — Prof Carlo Barbante, Ca' Foscari University of Venice

▶️ www.cbc.ca/news/science...

LISTEN IN: Prof Tas van Ommen describes the Ice Memory Sanctuary in #Antarctica on ABC Radio National

🎧 www.abc.net.au/listen/progr...

@tasvo.bsky.social @utas.edu.au @cnrs.fr @ugrenoblealpes.bsky.social @ird-fr.bsky.social

Infographic: @en.afp.com

Scientists map key oceanic unknowns in climate interventions | Cornell Chronicle Researchers review climate intervention strategies to cut emissions and improve oceanic health.

“Our oceans are already feeling the massive impacts of climate change. They will also be on the front lines of any climate intervention, yet we still lack a clear picture of how these approaches could impact marine life.” — Kelsey Roberts, Cornell University

news.cornell.edu/stories/2026...

Potential Impacts of Climate Interventions on Marine Ecosystems Climate intervention research is expanding as current mitigation efforts to limit warming below crucial targets are falling short Substantial knowledge gaps exist on the potential impacts of clim...

@agu.org Reviews of Geophysics: "The identified overlap between high-impact processes and poor model representation provides a roadmap for determining which technologies have the most high-risk uncertainty and which research directions are most urgent."

▶️ doi.org/10.1029/2024...

Climate engineering would alter the oceans, reshaping marine life – our new study examines each method’s risks Some methods being tried to counter climate change shift the ocean’s biology or chemistry. Others would deflect solar radiation. All have consequences for marine life.

"It is possible that no climate intervention will ever be safe enough to implement on a large scale. But we believe that decision should be guided by evidence – not market pressure, fear or ideology."
— @tyler-rohr.bsky.social et al in @theconversation.com

▶️ theconversation.com/climate-engi...

4️⃣ "Marine science voyages like MISO are absolutely critical for observing long-term changes in the ocean and climate system. Without MISO and the highly calibrated oxygen sensors we were able to use, we would not have known that the Dibble Polynya was exporting Antarctic Bottom Water" —Annie Foppert

3️⃣ The discovery, made on the 2024 Multidisciplinary Investigations of the Southern Ocean ( #MISO ) voyage with @utas.edu.au, @imas-utas.bsky.social, @antarcticsciaus.bsky.social and CSIRO, highlights how climate-driven changes in Antarctica’s icescape can drastically reshape deep-ocean circulation.

2️⃣ A new study by Australian and Japanese researchers led by @kaihezak.bsky.social in @commsearth.nature.com shows the Dibble Polynya in East #Antarctica is a surprising source of deep-ocean ventilation—with important implications for global #ocean currents and #climate systems.

▶️ rdcu.be/eYMct

East Antarctic ‘sea ice factory’ revealed as unexpected global current driver - AAPP A surprising source of deep-ocean ventilation in East Antarctica, with implications for global ocean currents and climate systems

1️⃣🌊 Coastal polynyas (semi-permanent areas of ice-free ocean) are known as ‘sea ice factories’ because they produce vast amounts of new ice. This process drives the global current system which redistributes heat and #carbon around the world.

▶️ aappartnership.org.au/east-antarct...

📸 @esa.int

Happy new year!

🌊 Our December issue of 'Southern Signals' is out today.

Read it at createsend.com/t/j-B0184840...

And please sign up at aappartnership.org.au/contact-us/ to receive your own quarterly #Antarctic #science bulletin by email.

Our best wishes to you and yours for a safe and peaceful holiday season.

3/ "What Controls the Formation of Antarctic Bottom Water at Cape Darnley, East Antarctica?" published in Geophysical Resarch Letters

➡️ doi.org/10.1029/2025...

with AAPP @utas.edu.au, @antarcticsciaus.bsky.social, @imas-utas.bsky.social, Uni of Qld, Australian Antarctic Division

A delicate Antarctic balance crucial to global climate New findings about ocean processes in the Antarctic show melting ice shelves and changes to sea ice could have catastrophic implications for the global climate.

2/ New simulations led by @davegwyther.bsky.social show the sensitivity of dense water formation to meltwater from ice shelves and changes to sea ice – “a delicate #Antarctic balance crucial to global #climate.”

▶️ news.uq.edu.au/2025-12-deli...

1/ The coldest densest water on the planet – Antarctic Bottom Water formed in just 4 places around Antarctica – drives global currents which influence Earth's climate. One of these areas is Cape Darnley. This animation shows melting beneath Amery Ice shelf and ocean temperatures around Cape Darnley.

Ocean warming threatens the viability of 60% of Antarctic ice shelves Nature - The viability of Antarctic ice shelves under low rates and high rates of global warming is modelled to estimate when it will become unfeasible for the ice shelves to maintain their...

🌊 Most of 64 floating Antarctic ice shelves are set to disappear if high emissions and ocean warming continue. Their disappearance would strongly accelerate sea level rise, as the grounded #Antarctic ice sheet would be less restrained from flowing into the ocean.

In @nature.com ▶️ rdcu.be/eULQI

13/ A slowdown in the overturning circulation ♻️
➡️ pump breaks down
➡️ deep ocean stagnates
➡️ ocean carbon uptake reduced
➡️less upwelling of nutrients to life at the surface

Take a deeper dive with this explainer by @antarcticsciaus.bsky.social
▶️ antarctic.org.au/wp-content/u...

12/ “Observed trends (that is, contraction of AABW, slowing of the deep overturning circulation, and rapid deep warming) will continue and accelerate in the future.”

11/ Their computer modelling projects other changes in AABW such as meltwater, salinity and temperature by 2050 – “essentially an intensification of the patterns of change observed since the 1990s”, the review says.

Antarctic deep ocean currents have slowed in the past three decades - AAPP Researchers have found that the deep ocean circulation around parts of Antarctica has slowed by 30 per cent since the 1990s, reducing oxygen levels across the world’s deep seas.

10/ 𝗔𝗔𝗕𝗪 𝗶𝘀 𝗳𝗿𝗲𝘀𝗵𝗲𝗻𝗶𝗻𝗴. Melting ice shelves make the waters fresher and more buoyant. Another study by some of the same authors simulated the future response of the ocean to meltwater input, projecting a slowdown of the Antarctic overturning by 40% by 2050.

▶️ aappartnership.org.au/antarctic-de...