Published

1 year ago

February 10, 2025

Alice Rush

“Atmospheric rivers” are bringing rain to the frozen slopes of the West Antarctic ice sheet, hitting the ice shelves that play a major role in holding back rapidly retreating glaciers.

In a new study, my colleagues and I show how rain is occurring in sub-zero temperatures due to these “rivers in the sky” – long, narrow plumes of air which transport heat and moisture from the tropics to the mid-latitudes and poles.

Rain in Antarctica is significant, not only because it is a stark indicator of climate change, but because it remains an under-studied phenomenon which could impact ice shelves.

Ice shelves in Antarctica are important gatekeepers of sea level rise.

They act as a buffer for glaciers that flow off the vast ice sheet, slowing the rate at which ice is released into the ocean.

In the study, we explore the causes of rain falling on ice shelves in the Amundsen Sea embayment region, which stand in front of the critically important Thwaites and Pine Island glaciers.

Researchers have warned the collapse of ice shelves in this region could trigger the loss of the entire West Antarctic ice sheet over several centuries.

Rivers in the sky

Atmospheric rivers are typically associated with bringing extreme rainfall to the mid-latitudes, but, in the frigid Antarctic, they can deliver metres of snow in just a few days.

In West Antarctica, atmospheric rivers deliver a disproportionate quantity of the year’s snowfall. Research shows they account for around 13% of annual snowfall totals, despite occurring on just a few days per year.

But what makes atmospheric rivers in Antarctica so interesting is that snow is only part of the story. In extreme cases, they can also bring rain.

To explore how extreme precipitation affects the Amundsen Sea embayment region, we focused on two events associated with atmospheric rivers in 2020. The summer case took place over a week in February and the winter case over six days in June.

We used three regional climate models to simulate the two extreme weather events around the Thwaites and Pine Island ice shelves, then compared the results with snowfall observations.

During both the winter and summer cases, we find that atmospheric rivers dumped tens of metres of snow over the course of a week or so.

Meanwhile, the quantities of rain driven by these events were not insignificant. We observed up to 30mm of rain on parts of the Thwaites ice shelf in summer and up to 9mm in winter.

Amundsen sea, map. — A map of the Amundsen Sea embayment region in West Antarctica. Source: Produced by the British Antarctic Survey’s Mapping and Geographic Information Centre, 2025.

A mountain to climb

Antarctica’s cold climate and steep, icy topography make it unique. It also makes the region prone to rain in sub-zero temperatures.

The first reason for this is the foehn effect, which is when air forced over a mountain range warms as it descends on the downward slope.

Commonly observed across Antarctica, it is an important cause of melting over ice shelves on the Antarctic peninsula, the northernmost point of the continent.

When air passes over the mountainous terrain of the West Antarctic ice sheet during atmospheric river events, temperatures near the surface of the ice shelves can climb above the melting point of 0C.

This can accentuate the formation of rain and drizzle that stays liquid below 0C – also known as “supercooled drizzle”.

Another factor which leads to liquid drizzle, rather than snow, in sub-zero conditions is a lack of dust and dirt – particles which are usually needed to trigger the formation of ice crystals in clouds.

In the pristine Antarctic, these particles – which act as “ice nuclei” – are few and far between. That means that pure liquid water can exist even when temperatures are below 0C.

The origins of rain over ice shelves

It is easy to assume that rain that reaches the surface in Antarctica is just snow that has melted after falling through a warm layer of air caused by the foehn effect. Indeed, this is what we initially supposed.

But our research shows that more rain reaches the surface of Antarctica when the air near the ground is within a few degrees of freezing.

At times when the foehn effect is strongest, there is often little or no rainfall, because it evaporates before it gets a chance to reach the surface.

However, we saw rain falling well above the warm layer of air near the surface, where temperatures were universally below 0C – and, in some cases, as low as -11C.

Rare rain

Rain in Antarctica is a rare occurrence. The region’s normally frigid temperatures mean that most precipitation over the continent falls as snow.

However, exactly how rare rain is in the region remains relatively unknown, because there are virtually zero measurements of rainfall in Antarctica.

There are a number of reasons for this – rain falls infrequently, and it is very difficult to measure in the hostile Antarctic environment.

Our results show that extreme events such as atmospheric rivers can bring rain. And it is likely that rain will become a more common occurrence in the future as temperatures rise and extreme weather events occur more frequently.

However, until rain starts being measured in Antarctica, scientists will have to rely entirely on models to predict rain, as we did in this research.

It is also not yet known exactly how rain could impact ice in Antarctica.

We do know that rain falling on snow darkens the surface, which can enhance melting, leading to greater ice losses. Meanwhile, rain that refreezes in the snowpack or trickles to the base of the ice can change the way that glaciers flow, impacting the resilience of ice shelves to fracture.

So, if we want to understand the future of the frozen continent, we need to start thinking about rain too. Because while rain may be rare now, it may not be for long.

The post Guest post: How atmospheric rivers are bringing rain to West Antarctica appeared first on Carbon Brief.

Guest post: How atmospheric rivers are bringing rain to West Antarctica

Climate Change

Whale Entanglements in Fishing Gear Surge Off U.S. West Coast During Marine Heatwaves

Published

10 hours ago

February 25, 2026

Alice Rush

New research finds that rising ocean temperatures are shrinking cool-water feeding grounds, pushing humpbacks into gear-heavy waters near shore. Scientists say ocean forecasting tool could help fisheries reduce the risk.

By Teresa Tomassoni

Each spring, humpback whales start to feed off the coast of California and Oregon on dense schools of anchovies, sardines and krill—prey sustained by cool, nutrient-rich water that seasonal winds draw up from the deep ocean.

Whale Entanglements in Fishing Gear Surge Off U.S. West Coast During Marine Heatwaves

Climate Change

Grasslands and Wetlands Are Being Gobbled Up By Agriculture, Mostly Livestock

Published

10 hours ago

February 25, 2026

Alice Rush

A new study takes a first-of-its kind look at how farming converts non-forested areas and major carbon sinks into cropland and pasture.

By Georgina Gustin

Agriculture is widely known to be the biggest driver of forest destruction globally, especially in sprawling, high-profile ecosystems like the Amazon rainforest.

Grasslands and Wetlands Are Being Gobbled Up By Agriculture, Mostly Livestock

Climate Change

Cropped 25 February 2026: Food inflation strikes | El Niño looms | Biodiversity talks stagnate

Published

21 hours ago

February 25, 2026

Alice Rush

We handpick and explain the most important stories at the intersection of climate, land, food and nature over the past fortnight.

This is an online version of Carbon Brief’s fortnightly Cropped email newsletter.
Subscribe for free here.

Key developments

Food inflation on the rise

DELUGE STRIKES FOOD: Extreme rainfall and flooding across the Mediterranean and north Africa has “battered the winter growing regions that feed Europe…threatening food price rises”, reported the Financial Times. Western France has “endured more than 36 days of continuous rain”, while farmers’ associations in Spain’s Andalusia estimate that “20% of all production has been lost”, it added. Policy expert David Barmes told the paper that the “latest storms were part of a wider pattern of climate shocks feeding into food price inflation”.

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NO BEEF: The UK’s beef farmers, meanwhile, “face a double blow” from climate change as “relentless rain forces them to keep cows indoors”, while last summer’s drought hit hay supplies, said another Financial Times article. At the same time, indoor growers in south England described a 60% increase in electricity standing charges as a “ticking timebomb” that could “force them to raise their prices or stop production, which will further fuel food price inflation”, wrote the Guardian.

‘TINDERBOX’ AND TARIFFS: A study, covered by the Guardian, warned that major extreme weather and other “shocks” could “spark social unrest and even food riots in the UK”. Experts cited “chronic” vulnerabilities, including climate change, low incomes, poor farming policy and “fragile” supply chains that have made the UK’s food system a “tinderbox”. A New York Times explainer noted that while trade could once guard against food supply shocks, barriers such as tariffs and export controls – which are being “increasingly” used by politicians – “can shut off that safety valve”.

El Niño looms

NEW ENSO INDEX: Researchers have developed a new index for calculating El Niño, the large-scale climate pattern that influences global weather and causes “billions in damages by bringing floods to some regions and drought to others”, reported CNN. It added that climate change is making it more difficult for scientists to observe El Niño patterns by warming up the entire ocean. The outlet said that with the new metric, “scientists can now see it earlier and our long-range weather forecasts will be improved for it.”

WARMING WARNING: Meanwhile, the US Climate Prediction Center announced that there is a 60% chance of the current La Niña conditions shifting towards a neutral state over the next few months, with an El Niño likely to follow in late spring, according to Reuters. The Vibes, a Malaysian news outlet, quoted a climate scientist saying: “If the El Niño does materialise, it could possibly push 2026 or 2027 as the warmest year on record, replacing 2024.”

CROP IMPACTS: Reuters noted that neutral conditions lead to “more stable weather and potentially better crop yields”. However, the newswire added, an El Niño state would mean “worsening drought conditions and issues for the next growing season” to Australia. El Niño also “typically brings a poor south-west monsoon to India, including droughts”, reported the Hindu’s Business Line. A 2024 guest post for Carbon Brief explained that El Niño is linked to crop failure in south-eastern Africa and south-east Asia.

News and views

DAM-AG-ES: Several South Korean farmers filed a lawsuit against the country’s state-owned utility company, “seek[ing] financial compensation for climate-related agricultural damages”, reported United Press International. Meanwhile, a national climate change assessment for the Philippines found that the country “lost up to $219bn in agricultural damages from typhoons, floods and droughts” over 2000-10, according to Eco-Business.
SCORCHED GRASS: South Africa’s Western Cape province is experiencing “one of the worst droughts in living memory”, which is “scorching grass and killing livestock”, said Reuters. The newswire wrote: “In 2015, a drought almost dried up the taps in the city; farmers say this one has been even more brutal than a decade ago.”
NOUVELLE VEG: New guidelines published under France’s national food, nutrition and climate strategy “urged” citizens to “limit” their meat consumption, reported Euronews. The delayed strategy comes a month after the US government “upended decades of recommendations by touting consumption of red meat and full-fat dairy”, it noted.
COURTING DISASTER: India’s top green court accepted the findings of a committee that “found no flaws” in greenlighting the Great Nicobar project that “will lead to the felling of a million trees” and translocating corals, reported Mongabay. The court found “no good ground to interfere”, despite “threats to a globally unique biodiversity hotspot” and Indigenous tribes at risk of displacement by the project, wrote Frontline.
FISH FALLING: A new study found that fish biomass is “falling by 7.2% from as little as 0.1C of warming per decade”, noted the Guardian. While experts also pointed to the role of overfishing in marine life loss, marine ecologist and study lead author Dr Shahar Chaikin told the outlet: “Our research proves exactly what that biological cost [of warming] looks like underwater.”
TOO HOT FOR COFFEE: According to new analysis by Climate Central, countries where coffee beans are grown “are becoming too hot to cultivate them”, reported the Guardian. The world’s top five coffee-growing countries faced “57 additional days of coffee-harming heat” annually because of climate change, it added.

Spotlight

Nature talks inch forward

This week, Carbon Brief covers the latest round of negotiations under the UN Convention on Biological Diversity (CBD), which occurred in Rome over 16-19 February.

The penultimate set of biodiversity negotiations before October’s Conference of the Parties ended in Rome last week, leaving plenty of unfinished business.

The CBD’s subsidiary body on implementation (SBI) met in the Italian capital for four days to discuss a range of issues, including biodiversity finance and reviewing progress towards the nature targets agreed under the Kunming-Montreal Global Biodiversity Framework (GBF).

However, many of the major sticking points – particularly around finance – will have to wait until later this summer, leaving some observers worried about the capacity for delegates to get through a packed agenda at COP17.

The SBI, along with the subsidiary body on scientific, technical and technological advice (SBSTTA) will both meet in Nairobi, Kenya, later this summer for a final round of talks before COP17 kicks off in Yerevan, Armenia, on 19 October.

Money talks

Finance for nature has long been a sticking point at negotiations under the CBD.

Discussions on a new fund for biodiversity derailed biodiversity talks in Cali, Colombia, in autumn 2024, requiring resumed talks a few months later.

Despite this, finance was barely on the agenda at the SBI meetings in Rome. Delegates discussed three studies on the relationship between debt sustainability and implementation of nature plans, but the more substantive talks are set to take place at the next SBI meeting in Nairobi.

Several parties “highlighted concerns with the imbalance of work” on finance between these SBI talks and the next ones, reported Earth Negotiations Bulletin (ENB).

Lim Li Ching, senior researcher at Third World Network, noted that tensions around finance permeated every aspect of the talks. She told Carbon Brief:

“If you’re talking about the gender plan of action – if there’s little or no financial resources provided to actually put it into practice and implement it, then it’s [just] paper, right? Same with the reporting requirements and obligations.”

Monitoring and reporting

Closely linked to the issue of finance is the obligations of parties to report on their progress towards the goals and targets of the GBF.

Parties do so through the submission of national reports.

Several parties at the talks pointed to a lack of timely funding for driving delays in their reporting, according to ENB.

A note released by the CBD Secretariat in December said that no parties had submitted their national reports yet; by the time of the SBI meetings, only the EU had. It further noted that just 58 parties had submitted their national biodiversity plans, which were initially meant to be published by COP16, in October 2024.

Linda Krueger, director of biodiversity and infrastructure policy at the environmental not-for-profit Nature Conservancy, told Carbon Brief that despite the sparse submissions, parties are “very focused on the national report preparation”. She added:

“Everybody wants to be able to show that we’re on the path and that there still is a pathway to getting to 2030 that’s positive and largely in the right direction.”

Watch, read, listen

NET LOSS: Nigeria’s marine life is being “threatened” by “ghost gear” – nets and other fishing equipment discarded in the ocean – said Dialogue Earth.

COMEBACK CAUSALITY: A Vox long-read looked at whether Costa Rica’s “payments for ecosystem services” programme helped the country turn a corner on deforestation.

HOMEGROWN GOALS: A Straits Times podcast discussed whether import-dependent Singapore can afford to shelve its goal to produce 30% of its food locally by 2030.

‘RUSTING’ RIVERS: The Financial Times took a closer look at a “strange new force blighting the [Arctic] landscape”: rivers turning rust-orange due to global warming.

New science

Lakes in the Congo Basin’s peatlands are releasing carbon that is thousands of years old | Nature Geoscience
Natural non-forest ecosystems – such as grasslands and marshlands – were converted for agriculture at four times the rate of land with tree cover between 2005 and 2020 | Proceedings of the National Academy of Sciences
Around one-quarter of global tree-cover loss over 2001-22 was driven by cropland expansion, pastures and forest plantations for commodity production | Nature Food