Rapid melting of Antarctic sea ice largely driven by ocean warming

University of Gothenburg

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Southern Elephant seal with a CTD-SRDL tag.

view more 

Credit: Photo: Dan Costa (UCSC)

Sea ice around Antarctica expanded for several decades until a dramatic decline in 2015. The reasons behind this are revealed by research from the University of Gothenburg.

Antarctic sea ice plays a crucial role in the ecosystem and physical environment of Antarctica and the Southern Ocean. Since the ice reflects the sun's rays and blocks heat exchange between the ocean and the atmosphere, it is critical to our weather and climate. Therefore, we need to understand what affects its extent to improve future climate models and prediction.

While Arctic sea ice has been steadily declining since satellite measurements of sea ice began, Antarctic sea ice has exhibited a completely different behaviour. After expanding slowly for several decades, Antarctic sea ice declined rapidly in late 2015 and has since experienced large year-to-year fluctuations in extent. Research on this change, led by the University of Gothenburg, is now published in Nature Climate Change.

Protective layer

“There was a protective layer of cold water beneath the sea ice in Antarctica that prevented warmer deep water from rising and melting the ice from below. But during the winter of 2015, storms in the Southern Ocean were unusually strong, reducing the cold-water protective layer effect and resulting in the sustained sea ice loss around Antarctica,” says Theo Spira, former doctoral student in oceanography at the University of Gothenburg and first author to the study.

Water masses with large differences in salinity and/or temperature do not mix easily and settle in layers on top of each other. This is called stratification. The cold Winter Water layer that protects the sea ice becomes increasingly fresh as the ice grows from more sea ice melt, and this increases stratification in relation to the warm and salty water layer below.

Storms stirred things up

This natural protection contributed to long-term growth in Antarctic Sea ice until 2015. However, under the ice the Winter Water layer slowly got thinner as the deep water got warmer, weakening the ocean’s protective cool layer.

“With the help of almost two decades of observations, I can see that the Winter Water layer has thinned over large parts of the Southern Ocean, allowing the deep, warm water to approach the surface. The storms in 2015 stirred up the sea and warmer water mixed with the cold-water layer, the protection disappeared and the ice melted at record speed,” says Theo Spira.

Elephant seals help scientists

The Southern Ocean is a remote environment for research, far from inhabited areas. Theo Spira used autonomous marine robots to measure temperature and salinity in the ocean water but also enlisted the help of elephant seals living in the area. Sensors were attached to their bodies, which accompanied them on their long dives hundreds of metres down into the ocean. After 10 months, the sensor detaches from the elephant seal.

“This is valuable because elephant seals live within and at the edge of the sea ice in Antarctica and can provide data on the stratification of the water there. Winter Water acts as a gatekeeper for heat exchange between the deep ocean and the surface, and by quantifying its role, my research identifies processes that are missing or poorly represented in today's climate models,” says Theo Spira.

The Antarctic sea ice is getting thinner in recent years.

Credit

Theo Spira

Journal

Nature Climate Change

DOI

10.1038/s41558-026-02601-4 

Method of Research

Observational study

Subject of Research

Not applicable

Article Title

Wind-triggered Antarctic sea ice decline preconditioned by thinning Winter Water

Article Publication Date

18-Mar-2026

 

Beavers can convert stream corridors to persistent carbon sinks

Playing a significant role in Europe’s climate mitigation efforts, beavers are transforming suitable river corridors into long‑term carbon stores.

University of Birmingham

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

Beavers could engineer riverbeds into promising carbon dioxide sinks, according to a new international study led by researchers at the University of Birmingham.

The new paper, published in Communications Earth & Environment today, has for the first time calculated the carbon dioxide (CO2) emitted and sequestered due to engineering work done by beavers in suitable wetland areas. The research was led by the University of Birmingham, Wageningen University, the University of Bern, and numerous international partners and the study was conducted in a stream corridor in northern Switzerland which has seen more than a decade of beaver activity.

The researchers’ findings demonstrate that these beaver-engineered wetlands can store carbon at rates up to ten times higher than similar systems without beaver activity. Over a 13‑year period, the wetland accumulated an estimated 1,194 tonnes of carbon, equivalent to 10.1 tonnes of CO2 per hectare per year.

Dr Joshua Larsen, from the University of Birmingham and lead senior author of the study, said: “Our findings show that beavers don’t just change landscapes: they fundamentally shift how CO2 moves through them. By slowing water, trapping sediments, and expanding wetlands, they turn streams into powerful carbon sinks. This first-of-its-kind study represents an important opportunity and breakthrough for future nature‑based climate solutions across Europe.”

Beavers are increasingly returning to rivers and other natural landscapes across Europe, following decades of collaborative conservation efforts. The team have found that beavers dramatically reshape how CO2 is stored, cycled, and retained in headwater stream systems, which are the small, upstream beginnings of rivers.

By building dams, beavers flood stream margins, create wetlands, alter groundwater pathways, and trap large amounts of organic and inorganic material, including CO2.

This study suggests that efforts to further rewild beaver populations in suitable wetland areas could have a major benefit, with large amounts of carbon able to be captured, stored, and prevented from re‑entering the atmosphere.

Beavers working as ecosystem engineers

The research team combined high‑resolution hydrological data, chemical analysis, sediment sampling, greenhouse gas (GHG) monitoring, and long‑term modelling to construct the most comprehensive carbon budget ever produced for a beaver landscape in Europe.

Due to the beaver activity within the area, the wetland acted as a net annual carbon sink of 98.3 ± 33.4 tonnes of carbon per year, driven primarily by the removal and retention of dissolved inorganic carbon through subsurface pathways.

However, the beaver-engineered system also showed clear seasonal patterns. During the summer, when water levels receded and exposed sediment surfaces increased, carbon dioxide (CO₂) emissions temporarily exceeded retention - making the system a short‑term carbon source.

Over full annual cycles, the beaver‑driven accumulation of sediments, vegetation, and deadwood resulted in substantial net carbon storage. Notably, methane (CH₄) emissions - which are often a major concern in wetland systems - were found to be negligible, making up less than 0.1% of the carbon budget.

Dr Lukas Hallberg from the University of Birmingham and corresponding author of the study, said: “Within just over a decade, the system we studied had already transformed into a long‑term carbon sink, far exceeding what we would expect from an unmanaged stream corridor. This highlights the enormous potential of beaver-led restorations and offers valuable insights into potential land‑use planning, rewilding strategies, and climate policy.”

Implications for future climate management

Over time, carbon is locked away as sediments accumulate and deadwood builds in beaver-built wetlands. Researchers found that this sediment contained up to 14 times more inorganic carbon and eight times more organic carbon than surrounding forest soils. Meanwhile, deadwood from forested areas growing along riverbanks, streams, or wetlands (known as riparian forests) accounted for nearly half of all long‑term stored carbon.

These stores could persist over decades, suggesting that beaver‑modified wetlands act as reliable, long‑duration carbon sinks – so as long as their dams stayed intact.

Dr Annegret Larsen, Assistant Professor in the Soil Geography and Landscape Group at Wageningen University, said: “Our research shows that beavers are powerful agents of carbon capture and adsorption. By reshaping waterways and creating rich wetland habitats, beavers physically change how carbon is stored across landscapes.”

When scaled across all floodplain areas suitable for beaver recolonisation in Switzerland, researchers estimate that beaver wetlands could offset 1.2–1.8% of the nation’s annual carbon emissions: delivering climate benefits without active human intervention or financial cost.

Led by the University of Birmingham, Wageningen University, the University of Bern, and numerous international partners, the study was conducted in a stream corridor in northern Switzerland which has had over a decade of beaver-activity within it.

As beaver populations continue to expand, further research into understanding their role in shaping future ecosystems, and future carbon budgets, will be crucial.

ENDS

Notes to Editor:

For media enquiries and more information please contact Holly Young, Press Office, University of Birmingham, tel: +44 (0)7815 607 157.

‘Beavers can convert stream corridors to persistent carbon sinks’ - Lukas Hallberg, Annegret Larsen, Joshua R. Larsen et al is published in Communications Earth & Environment

About the University of Birmingham

The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, educators and more than 40,000 students from over 150 countries.

England’s first civic university, the University of Birmingham is proud to be rooted in of one of the most dynamic and diverse cities in the country. A member of the Russell Group and a founding member of the Universitas 21 global network of research universities, the University of Birmingham has been changing the way the world works for more than a century.

About Wageningen University

The mission of Wageningen University & Research is “To explore the potential of nature to improve the quality of life”. Under the banner Wageningen University & Research, Wageningen University and the specialised research institutes of the Wageningen Research Foundation have joined forces in contributing to finding solutions to important questions in the domain of healthy food and living environment.

With its roughly 30 branches, 7,700 employees (7,000 fte), 2,500 PhD and EngD candidates, 13,100 students and over 150,000 participants to WUR’s Life Long Learning, Wageningen University & Research is one of the leading organisations in its domain. The unique Wageningen approach lies in its integrated approach to issues and the collaboration between different disciplines.

---

Journal

Communications Earth & Environment

DOI

10.1038/s43247-026-03283-8. 

Method of Research

Commentary/editorial

Subject of Research

Animals

Article Title

Beavers can convert stream corridors to persistent carbon sinks

Article Publication Date

18-Mar-2026

SCIENCE THORS DAY

 

 

University of Manchester scientists play key role in discovery of new heavy-proton particle at CERN

University of Manchester

FacebookXLinkedInWeChatBlueskyMessageWhatsAppEmail

 

image: 

Artist’s illustration of this heavy proton-like particle.

view more 

Credit: Chris Parkes

Scientists from the University of Manchester have played a leading role in the discovery of a new subatomic particle at CERN’s Large Hadron Collider (LHC). The particle, known as the Ξcc⁺ (Xi‑cc‑plus), is a new type of heavy proton-like particle containing two charm quarks and one down quark.

The result is the first particle discovery made using the upgraded LHCb detector, a major international project involving more than 1,000 scientists across 20 countries. The UK made the largest national contribution to the upgrade, with significant leadership from Manchester.

The newly observed Ξcc⁺ is a heavier relative of the proton, which was famously discovered in Manchester by Ernest Rutherford and colleagues in 1917-1919. The proton contains two up quarks and a down quark. The new discovery replaces the up quarks with their heavier relatives the charm quarks. It also extends a legacy begun in the 1950s, when Manchester physicists were the first to identify a member of the Ξ (Xi) particle family.

Professor Chris Parkes, head of the University’s Department of Physics and Astronomy, led the international collaboration during the installation and first operation of the LHCb Upgrade detector. He also led the UK contribution to the project for over a decade, from approval through to delivery.

The Manchester LHCb group designed and built key components of the upgraded tracking system, the silicon pixel detector modules assembled in the University’s Schuster Building. These detectors are central to precisely reconstructing the particle decays in which the Ξcc⁺ signal was observed.

Professor Parkes, said: “Rutherford’s gold‑foil experiment in a Manchester basement transformed our understanding of matter, and today’s discovery builds on that legacy using state‑of‑the‑art technology at CERN. Both milestones demonstrate just how far curiosity driven research can take us. This discovery showcases the extraordinary capability of the upgraded LHCb detector and the strength of UK and Manchester contributions to the experiment.”

Dr Stefano De Capua, from The University of Manchester, who led the silicon detector module production, added: “The detector is a form of ‘camera’ that images the particles produced at the LHC and takes photographs 40 million times per second. It utilises a custom designed silicon chip that also has a variant for use in medical imaging applications.”

The Ξcc⁺ particle was identified through its decay into three lighter particles (Λc⁺ K⁻ π⁺), recorded in proton‑proton collisions at the LHC in 2024, the first year of full operation of the LHCb Upgrade experiment. A clear peak of around 915 events was observed at a mass of 3619.97 MeV/c², consistent with expectations based on a previously discovered partner particle, the Ξcc⁺⁺.

This observation resolves a question that had remained open for more than two decades since an unconfirmed claim of the observation of this particle was made. The particle has now been discovered by LHCb at a mass incompatible with this earlier claim and a mass that is compatible with the theoretical expectations based on the partner particle.

In the next phase of the LHC programme, The University of Manchester is playing a leading role in LHCb Upgrade 2, which is planned to take advantage of the High-Luminosity LHC accelerator. 

Details of the Ξcc⁺ discovery are presented at the Rencontres de Moriond Electroweak conference.

-ends-

Dr Stefano de Capua testing the LHCb silicon detector modules in the Schuster Laboratory clean-rooms at the University of Manchester.  https://cds.cern.ch/record/2814453

credit: Amy O’Connor/STFC UKRI