Why the weirdest sea level changes on Earth are happening off the coast of Japan

Fishing boats sail toward a kelp harvest area in the Northern Territories, 3.7 kilometers off Nemuro, Hokkaido, Japan on June 2, 2018. Fish and kombu seaweed harvested in this region are crucial to Japan's food culture, but recent changes in a warm ocean current called the Kuroshio have damaged these fisheries.

The Asahi Shimbun/Getty Images

 

 By Chris Mooney, Yumi Asada

 

 

Bathtubs and pools mislead us about the ocean: Its surface is anything but flat.

Seas pile up in some spots, pushed by trade winds or pulled by gravity toward big things like ice sheets. Amid it all, at the western end of large ocean basins, the fastest surface currents — veins of warm water — race toward the poles, causing additional slopes at the surface.

The ocean is uneven to begin with, and its unevenness is also changing. Maps of recent changes show intricate patterns of watery hills and valleys, but also call attention to one extraordinary location. Off the coast of Japan, one region of the ocean has been rising by nearly an inch every year, right next to another where it has been falling even faster.

It’s the fingerprint of one of those surface currents changing its location, an event that has had dramatic repercussions. The Kuroshio, or “Black Current,” is one of the largest streams of water anywhere in the world, and its recent movement has triggered record-warm ocean temperatures and upended fisheries, an indelible staple of Japanese culture. Scientists say the warm waters have even amplified heatwaves on land and driven extreme rainfall. 

 

And while there are signs some of the changes are now waning, fishing communities say they aren’t yet back to normal. Meanwhile, scientists worry it could be a sign of more volatility to come.

The position of the current could keep fluctuating, said Bo Qiu, a leading Kuroshio expert at the University of Hawaiʻi at Mānoa. “It’s hard to predict the future, but given the data we have so far, I can only see the intensity becoming larger and larger,” he said. 

The Boso Peninsula forms the eastern edge of Tokyo Bay. Normally, the Kuroshio Extension banks away from Japan and heads into the Pacific near this spot. But in recent years, it's continued northward, bringing unprecedented warm water with it.

John S Lander/LightRocket/Getty Images

 

 

A river in the ocean

The deep, warm Kuroshio transports more than 200 times as much water as the Amazon River, traveling north from the equator and normally banking east around Japan’s Boso peninsula, near Tokyo. Here, it becomes known as the Kuroshio Extension as it heads into the open Pacific. 

 

But in recent years, the current has been behaving in anything but the usual way, and the Extension, in particular, made a major divergence along Japan’s coast. Its northern edge shifted as much as 300 miles farther poleward, leading to unprecedented warm waters in the surrounding region.

“I was so surprised I don’t even know if ‘surprised’ is the right word,” said Shusaku Sugimoto, an associate professor at Tohoku University in Sendai, Japan, a northern coastal city. 

 

When a major ocean current changed course, sea levels changed with it

Recent changes in a warm current called the Kuroshio have created some of the fastest rising seas on the planet — right next to seas that are falling even faster. 

Sugimoto led a study analyzing ocean temperatures off the coast in locations the Extension didn’t historically reach, but has in recent years. “The fact that the temperature rose 6 degrees (Celsius) off the Sanriku coast, and the elevated temperature persisted for two years, represents a level of water temperature rise we’ve never seen before,” he said. 

It’s not the only change.

In August of 2017, the Kuroshio current south of Japan settled into a “large meander” pattern, leaving the coastline and looping southward, taking its warm waters with it. This big shift in water temperatures south of Japan changes the distributions of fish species offshore.

Large meanders themselves are a well-known recurring feature of the current, explained Shinichiro Kida, an oceanographer at Kyushu University. Records of these events date back to the 1960s. During a lengthy meander event from 1975 to 1980, scientists saw a severe decline in anchovy in the Enshunada Sea, a major fishing region to the south of Japan’s main island of Honshu. The anchovy were replaced by sardines, which favor the warmer water the current brought to the region.

But no Kuroshio large meander that we know of has lasted as long as this one. In August, the Japan Meteorological Agency finally declared that it had ended after nearly eight years. But overall both changes have had a big effect on this country that is home to more than 100 million. 

 

The meander and the Extension shift are connected, Qiu said. He co-authored a new paper in the Journal of Climate arguing as much, and calling the configuration a “new dynamic regime.”

“I’ve been working on the Kuroshio Extension for more than three decades,” Qiu said. “I never expected this.”

As the Kuroshio powers along, it not only brings warmer water but also, depending on its location, higher sea level. There can be a several-foot difference between ocean heights on different sides of the current, thanks to its warmth and speed .

But because of these factors, any new movement of the current can have dramatic effects. 

 

The large meander, for example, triggered a sea level fall in one region and pronounced sea level rise — by as much as half a foot — along the coast of the island of Honshu south of Tokyo. In October of 2017, when Typhoon Lan struck the Shizuoka Prefecture along this coastline, the higher sea level amplified the damage, according to the Japan Meteorological Agency.

It is not only the height of the sea: As the Kuroshio is a warm current, and one traveling northward into cooler waters, its arrival in a new location has enormous effects on ocean temperatures.

The big question is how much the recent phenomena are part of a natural cycle, and how much it’s influenced by something else, like climate change. (And how much it’s both, combined.)

The impact of climate change on the large meander is unclear, because of its long history. But as far as the Extension shift goes, there are mounting reasons to implicate greenhouse gases and a changing climate.

When the tropics travel to you

To understand the recent changes in the Kuroshio is to understand how water moves through the world’s oceans, especially the large rotating “gyres” found in the world’s major ocean basins. 

 Five of these basins — North and South Pacific, North and South Atlantic, and Indian — feature a similar pattern. Warm water travels west along the equator, then turns toward the poles. The currents carrying the warm water north or south on poleward transits are called “western boundary currents,” and they include the Kuroshio and its four famed cousins: the Gulf Stream, the Brazil, the East Australian, and the Agulhas.

 

Japan has seen some of the world's most extreme ocean changes

In recent years, waters off Japan’s Pacific Coast have experienced some of the world’s highest rates of ocean warming, as well as extreme changes in sea level.

 

Scientists are now seeing most of these currents changing in a similar way — getting warmer and pushing even farther poleward.

This change is rooted in a phenomenon known as the Hadley Cell, a global zone of warm, rising air across the tropics. It’s now expanding due to climate change. 

 

“This expansion shifts not just rainfall patterns but also the zones of sinking air that anchor high-pressure systems, such as the Pacific High,” explains Brown University climate scientist Emanuele Di Lorenzo.

In the middle latitudes, these massive high-pressure systems are the driving force behind currents like the Kuroshio. So, when the winds move, the currents do too.

Both models and data suggest the Kuroshio Extension, in particular, has been moving north partly because of the atmospheric shift, Di Lorenzo explained.

Between 1993 and 2021, driven by wind changes, the northern edge of the Kuroshio Extension shifted north by about 130 miles, a recent study found. This was before an even larger shift in 2023 and 2024. 

 

The Kuroshio Extension’s leap in 2023 and 2024 was an extreme event. The northern edge reached nearly to the northern tip of Honshu, Japan’s largest island. In a different study, Sugimoto and colleagues with the Japan Meteorological Agency and the Meteorological Research Institute took oceanographic measurements in the Extension’s new location. They found water as much as 18 degrees Fahrenheit warmer than usual, extending to a depth of around 400 meters, or 1,300 feet.

The authors note that for an entire year and a half between April 2023 and August 2024, the region saw “intense marine heatwave conditions almost every day.”

And it was not just in the water: the Japan Meteorological Agency also found that the extreme ocean conditions contributed to record summer heat over land in northern Japan in 2023. Another group of scientists, meanwhile, linked the warm offshore current to extreme rainfall over Japan’s Chiba Prefecture, near Tokyo, in September of 2023. 

The first saury catch of the season is landed at a port in Nemuro on Japan's northernmost main island of Hokkaido on Aug. 15, 2025. This species has been particularly affected by changes in the Kuroshio.

Kyodo News/Getty Images

 

An uncertain future for fisheries

These ocean changes have altered the distributions of fish populations along Japan’s Pacific Coast, creating extreme impacts on Japan’s iconic fisheries. 

 

In central Japan, for instance, a major mackerel fishery was upended, and fishers say that even though the large meander has now ended, that doesn’t mean things can instantly go back to the way they were.

“Immediate recovery is not a reality, and while conditions may gradually improve, at present, there has been no recovery in catches,” said Osamu Nagai, executive director of the Mie Gaiwan (Outer Bay) Fisheries Cooperative Association.

“The catch has fallen to less than half of what it was 10 years ago — we’re now only catching about 20 to 30 percent of the mackerel. This is a major blow,” Nagai said.

Northeastern Japan’s Sanriku coast, known for its rich fisheries, is a different story, but still a bad one. Here, the southward flowing Oyashio current traditionally brings down cool waters and supports rich fisheries. But when the Kuroshio Extension moved northward into this region, it displaced the Oyashio, bringing on a stark change in ocean temperature. 

 

And it is not just fish species, like Pacific salmon and saury, that became harder to catch.

“What matters most is the foundation of Japan’s most important food culture, which is the flavor made out of Kombu seaweed — it can only be harvested in Hokkaido, near Japan,” said Yoshihiro Tachibana, a professor who specializes in climate dynamics at Mie University. 

 

Kombu kelp is laid in the sun to dry Wakkanai, Hokkaido, on July 15, 2012. This seaweed is a vital part of Japan's food culture and economy. But it's becoming harder to harvest.

Hiroaki Murata/The Yomiuri Shimbun/AP

 

 

“Kombu stocks are declining dramatically. Dashi (the fundamental Japanese soup stock) culture might collapse. It’s declining. We can’t get any at all. So I believe this has a tremendous impact on our food culture as well,” he said.

Recently, the northern edge of the Kuroshio extension has retreated a bit. It has moved back to around 37 degrees North Latitude, according to Qiu. That’s still a high location historically, but hardly as extreme as before. 

 

But the questions remain: what do these extreme ocean events mean, how they are linked to climate change? For at least one researcher, they’re an early sign of things to come.

“It’s a great opportunity to learn what the oceans will be like 100 years from now,” said Sugimoto, of Tohoku University in the northeastern region of Honshu, Japan’s largest island.

“An unprecedented ocean phenomenon is now occurring by chance in Tohoku,” he continued. “Understanding how this has altered the seas of Tohoku offers a chance to understand how the world’s oceans will change in the future.”

Elisabeth Doty contributed to this report.

Hidrelétricas da Amazônia podem perder até 40% de força de geração nos próximos anos

 

Trecho de vazão reduzida do rio Xingu sofre com redução de água devido à barragem de Belo Monte, no Pará - Lalo de Almeida 20.set.22/Folhapress 

 

by  André Borges

 

 

 

Brasília

O protagonismo da geração hidrelétrica está em xeque. Grande parte das usinas da Amazônia poderá sofrer reduções drásticas em seu potencial de geração de energia elétrica, com perdas projetadas entre 30% e 40% nas próximas décadas, devido aos impactos das mudanças climáticas.

A conclusão faz parte de um novo estudo da ANA (Agência Nacional de Águas e Saneamento Básico) sobre as projeções climáticas para o regime de chuvas, vazões de rios e a segurança hídrica no Brasil nas próximas décadas. A redução projetada considera um horizonte de quatro décadas, até 2065.

Caso os investimentos em novos projetos continuem baseados apenas em dados históricos, especialistas alertam que o país pode ver uma onda de usinas incapazes de produzir a energia esperada, resultando em aumento de custo para o consumidor e dependência de termelétricas fósseis.

 

Segundo o relatório "Impacto da Mudança Climática nos Recursos Hídricos do Brasil", a queda na produção seria uma consequência de mudanças que podem ocorrer no padrão de fluxo natural das águas por causa do aquecimento global.

Ao observar o comportamento já verificado das vazões médias dos rios no período de 1950 a 2014, o documento projeta o desempenho no futuro próximo, até 2065, e para tempos mais distantes, num horizonte até 2100. O resultado aponta que a região Norte é a com maior risco de ser afetada.

Enquanto Sul, Sudeste e Centro-Oeste tendem a registrar diminuições de até 10% na geração hidrelétrica, a Amazônia pode enfrentar perdas maiores devido à redução de vazões, afetando usinas de grande porte já instaladas e os empreendimentos planejados para os próximos anos.

"Considerando que a geração de energia seja diretamente relacionada à vazão média afluente, as regiões Sul, Sudeste e Centro-Oeste mostram reduções de 0(zero)-10%, enquanto a região Norte apresenta as projeções mais pessimistas, com alterações de 30-40%", afirma o estudo.

 

"Dentre os empreendimentos existentes, os maiores impactos se concentram nas usinas com maior potência instalada, a maioria delas localizada na bacia Amazônica", continua o documento.

O estudo da Agência Nacional de Águas aponta que, se nada for ajustado, a expansão hidrelétrica brasileira corre o risco de ser planejada com base em um cenário climático que não existirá mais.

Nas últimas duas décadas, o país apostou na Amazônia como a última grande fronteira hídrica para ampliar sua capacidade hidrelétrica, com a construção de usinas como Belo Monte, no rio Xingu, e Santo Antônio e Jirau, no rio Madeira.

Ocorre que, segundo o documento, essas usinas foram projetadas levando em conta séries históricas de vazões que já não representam mais o padrão futuro dos rios. Com o prolongamento das estações secas e a antecipação da perda de umidade no solo, fenômenos já observados anualmente no Xingu e no sul do Amazonas, o ciclo de água na região está vivendo uma fase de mudança estrutural.

 

No rio Amazonas, houve um aumento na ocorrência de cheias e secas extremas nas últimas décadas. Se considerado o período dos últimos 125 anos, nota-se que, entre as dez maiores cheias ocorridas na região, sete se deram nos últimos 16 anos, a partir de 2009.

No caso das secas, entre os 10 menores níveis observados, 5 ocorreram nos últimos 28 anos. Em 2023 e 2024 a região registrou duas secas seguidas sem precedentes, com níveis de água muito abaixo do que já havia sido observado no passado.

A ANA sustenta que incorporar cenários climáticos futuros ao planejamento de longo prazo não é apenas uma recomendação técnica, mas uma necessidade para evitar perdas financeiras e insegurança energética.

O Brasil possui hoje 216 gigawatts de potência de energia elétrica, com mais de 24 mil usinas em operação comercial, segundo a Aneel (Agência Nacional de Energia Elétrica). Metade dessa geração vem da força dos rios, com 50,5% atrelada a usinas hidrelétricas de todos os portes.

O estudo reforça que os efeitos não se limitam à geração elétrica. A redução de vazões também vai afetar a irrigação, o abastecimento urbano e a biodiversidade, caso o planejamento dessas áreas não passe a incorporar as projeções climáticas.

 

Os resultados indicam que as mudanças climáticas na hidrologia deverão mexer com a segurança hídrica em boa parte do Brasil, enquanto outras regiões devem sofrer com o aumento de enxurradas e alagamentos urbanos, como se viu no Rio Grande do Sul em 2024.

Do lado do poder público, a falta de recursos financeiros tem comprometido o enfrentamento do problema, afirma a ANA. "A sustentabilidade política das políticas hídricas e climáticas segue ameaçada por cortes orçamentários, descontinuidade institucional e ausência de uma política de Estado que una água e clima de forma duradoura", diz a agência no documento.

A ANA afirma que uma eventual mudança de postura "exige blindagem orçamentária, maior participação social e inovação normativa, de modo a reconhecer a incerteza como ponto de partida para garantir segurança hídrica em cenários climáticos cada vez mais instáveis".

‘Ghost resorts’: as hundreds of ski slopes lie abandoned, will nature reclaim the Alps? With the snow line edging higher, 186 French ski resorts have shut, while global heating threatens dozens more.

 

The skeletal remains of a once-busy ski lift in Céüze 2000, in France’s Hautes-Alpes department. The resort, which had welcomed skiers for 85 years, never reopened after March 2018 as smaller snowfalls in successive seasons made it unviable. Photograph: Thomas Valentin/The Guardian

 by Phoebe Weston in Céüze

When Céüze 2000 ski resort closed at the end of the season in 2018, the workers assumed they would be back the following winter. Maps of the pistes were left stacked beside a stapler; the staff rota pinned to the wall.

Six years on, a yellowing newspaper dated 8 March 2018 sits folded on its side, as if someone has just flicked through it during a quiet spell. A half-drunk bottle of water remains on the table.

The Céüze 2000 resort when snow was plentiful.

 

 

The Céüze resort in the southern French Alps had been open for 85 years and was one of the oldest in the country. Today, it is one of scores of ski resorts abandoned across France – part of a new landscape of “ghost stations”.

More than 186 have been permanently closed already, raising questions about how we leave mountains – among the last wild spaces in Europe – once the lifts stop running.

 

As global heating pushes the snow line higher across the Alps, thousands of structures are being left to rot – some of them breaking down and contaminating the surrounding earth, driving debate about what should happen to the remnants of old ways of life – and whether to let nature reclaim the mountains.

Snowfall at Céüze started becoming unreliable in the 1990s. To be financially viable, the resort needed to be open for at least three months. In that last winter, it only managed a month and a half. For the two years before that it had not been able to operate at all.

Opening the resort each season cost the local authority as much as €450,000 (£390,000). As the season got shorter, the numbers no longer added up. To avoid a spiral of debt, the decision was made to close.

The resort closed permanently during the 2020 winter due to a lack of snow. Photograph: Thomas Valentin/The Guardian

“It was costing us more to keep it open than to keep it closed for the season,” says Michel Ricou-Charles, president of the local Buëch‑Dévoluy community council, which oversees the site. Even under the most optimistic projections, the future looked bleak. “We looked into using artificial snow, but realised that would delay the inevitable,” he says.

It was seven years before the trucks and helicopters came in to begin removing the pylons. Still, the local community grieved for the small, family-oriented resort, which was host to generations of memories. As demolitions began, they came to take nuts, bolts and washers as mementoes of what they had lost.

Degrading wild terrain

In France, there are today 113 ski lifts totalling nearly 40 miles (63km) in length that have been abandoned, nearly three-quarters of them in protected areas. It is not just ski infrastructure. The Mountain Wilderness association estimates that there are more than 3,000 abandoned structures dotted around French mountains, slowly degrading Europe’s richest wild terrain. This includes military, industrial and forestry waste, such as old cables, bits of barbed wire, fencing and old machinery.

There are 113 abandoned ski lifts in France, nearly three-quarters of which are in protected areas. Photograph: Thomas Valentin/The Guardian

Céüze ski resort is fast becoming one of these pollutants. The little wooden cabin at the bottom of the first button lift is shedding insulation. Ropes once used to mark out the piste hang in tatters and bits of plastic are falling off a pylon. The old sheds at each end of the ski lifts often still contain transformers, asbestos, motor oils and greases. Over time, these substances seep into the soil and water.

Corrosion and rust from metal structures left over from the second world war, such as anti-tank rails and metal spikes, have led to changes in plant species in the surrounding area, potentially offering a vision of what could happen if pylons are left to rust over the coming decades.

 

“In Latin, we say memento mori – remember that you are mortal. Don’t think that you are making eternal things; they will end up becoming obsolete,” says Nicolas Masson, from Mountain Wilderness, which is campaigning for old ski infrastructure to be dismantled to make space for nature. “When you make them, ask yourself the question: what will remain?”

Some believe the resorts should remain memorialised landscapes, honouring generations of people who lived and skied here; others believe they should be returned to wild landscapes with their disintegrating machinery removed.

Ecologist Nicolas Masson is part of a campaign to dismantle old ski infrastructure. Photograph: Thomas Valentin/The Guardian

 

  

Nature’s recovery

Céüze’s deconstruction started on 4 November 2025, a month before the ski season would once have kicked off. The resort’s ski lifts were airlifted out using a helicopter to minimise environmental disturbance and compression of the earth.

French law requires ski lifts to be removed and dismantled if they are no longer in use. The law only applies to ski lifts built after 2017, however. Most last for 30 years, so no lifts would be considered obsolete until at least 2047. The process is also expensive: dismantling Céüze will cost €123,000. This means most abandoned ski infrastructure is left to disintegrate in situ. What is happening in Céüze is rare.

With pylons cleared and the resort already closed for seven years, early signs of ecological recovery are already visible. A red haze floats over the white snow: winter berries of the dog rose are sprouting where the piste is no longer mown.

Berries can be see on dog rose shrubs which are starting to flourish now the piste is no longer cleared for skiers. Photograph: Thomas Valentin/The Guardian

 

The berries are important winter food for birds such as the rare red-billed chough, and their thorny stems are used for nest-building come spring. In the summer, orchids and yellow gentians bloom over these hillsides. The hills surrounding the site are classed as Natura 2000, meaning they are home to Europe’s rarest and most protected wildlife.

The trees are coming back too. “I don’t know if it would take 10, 20 or 50 years, but this is becoming a forest,” says Masson.

 

Wild boar and roe deer living in these forests will benefit from quieter winters. Birds such as grouse shelter from severe cold in winter by digging into the snow, and prefer deep powdery snow – just like skiers. The species is endangered in all the mountain ranges of France.

The dismantling of Céüze comes at a time when many spaces for nature are shrinking. Pierre-Alexandre Métral, a geographer at the University of Grenoble Alpes, who studies abandoned ski resorts, says: “There is a lot of debate about the nature of this dismantling – is it just removing mechanical stuff, or are we attempting to put mountains back into a kind of original state?”

Ecological recovery can be filled with surprises, he says, noting that the maintenance of pistes can be beneficial to some alpine flowers. “If we let nature come back spontaneously – in a wild, uncontrolled way – there are also risks that some invasive species that tend to be stronger could colonise faster,” says Métral.

The hills around the former resort are home to some of Europe’s rarest and most protected wildlife. Photograph: Thomas Valentin/The Guardian

There is scant research in this area, but studies from the Valcotos ski resort closure in Madrid’s Sierra de Guadarrama in 1999 show it led to significant recovery of native vegetation and cleaner waterways, while reducing soil erosion.

“These are laboratories of what the mountain could be like in the future with new closures,” says Métral.

On the brink

The question of what to do with these places will play out across Europe’s mountains, and around the world. Skiing is disappearing from many alpine landscapes. “Many lower ones are already closed,” says Masson. “A fraction of a degree changes everything in the mountain environment. It’s the difference between having snow and no snow.”

 

Research suggests that with 2C (3.6F) of global heating, more than half of existing resorts risk having too little snow. Higher altitude resorts are vulnerable to the loss of permafrost, threatening pylons that have been drilled into it. Some resorts, such as St-Honoré 1500, were abandoned before construction was even completed. Even bigger resorts, which typically have funds to invest in new pistes and artificial snow, are struggling to survive.

For some, the loss of Céüze feels premature. Richard Klein,who lives in Roche des Arnauds, near Céüze, feels the ski resort could – and should – have been saved. “It’s a wonderful place to learn to ski – it’s the best. I think it’s really stupid they closed it,” he says. “There were always loads of people.” Klein believes the local authority should have begun using artificial snow, adding: “Now it’s too late.”

 

Yet life has not disappeared from Céüze. In October 2025, the resort’s Hotel Galliard is being sold to a developer looking to open it for events, according to Ricou-Charles. A property developer has bought the children’s holiday residence, and a carpenter has moved into the building where the old ticket office was. The rooms used as a holiday camp for children have cracks appearing down the side, but might open again in the future.

“Céüze will continue to live, despite the loss of the resort,” says Ricou-Charles. “We are not mourning Céüze because it is not dead.”

On winter weekends dozens of cars still gather in the car park, with people enjoying quieter activities on the hillside, such as walking, snow-shoeing, cross-country skiing and sledging.

A poster from the resort’s 80th anniversary celebrations. Photograph: Thomas Valentin/The Guardian

Masson does not like the term “ghost resort” because it suggests total abandonment when what is happening in his area is more complicated. “People continue to come,” he says. “We don’t need large machines to make mountains attractive.”

What happens at Céüze is a glimpse into a future that faces dozens of other small resorts, and mountain landscapes, across Europe. “What is our heritage that we will want to keep,” asks Masson. “And what is just a ruin we want to dismantle? That is a question we have to ask every time, and it requires some reflection.”

‘Massive disruption’: UK’s worst-case climate crisis scenarios revealed by scientists. Scientists say government must prepare for unlikely but ‘plausible’ 4C rise in temperature and a 2-metre rise in sea levels

Flooding in Wraysbury, England, last year. Photograph: Daniel Leal/AFP/Getty Images

by  Damian Carrington 

 

The worst-case impacts of the climate crisis for the UK have been laid bare by scientists, ranging from a scorching 4C rise in temperatures to a 2-metre rise in sea level. Another scenario sees a plunge of 6C in temperature after the collapse of key Atlantic Ocean currents, massively disrupting farming and energy needs.

The impacts, some of which are linked to climate tipping points, are seen as low probability but plausible. The researchers said the scenarios filled a gap in forecasting that had left the UK unprepared for extreme outcomes.

A second set of worst-case scenarios sets out the potential extent of extreme weather between now and the end of the century. These indicate that temperatures could soar in some months by up to 6C above average, while rainfall could be triple normal levels.

 

“The climate extremes we have mapped aren’t predictions, but they are plausible,” said Nigel Arnell, a University of Reading professor who led the study. “The UK has been planning without the tools to test against worst-case scenarios. We’ve now given decision-makers what they need to prepare for climate outcomes they hope never happen, but can’t afford to ignore.”

The probability of the extreme scenarios happening could not be calculated because of uncertainty about what action will be taken to tackle global heating and how the climate system will respond. Arnell said this made the analysis similar to national security risk assessments or the Bank of England’s stress tests for the financial system.

“You couldn’t have known what the probability of Russia invading Ukraine was, but you could have said this is what the consequences might be,” he added.

The worst-case scenarios could be used to inform the building of long-term infrastructure, such as new towns, nuclear power stations and urban drainage systems, Arnell said, adding that awareness of climate risks could speed the drive to cut fossil fuel emissions.

Published in the journal Earth’s Future, the analysis developed the worst-case scenarios using a combination of observed and historical experience, computer simulations and theory.

Global temperatures rising well above 4C by 2100 could happen if climate action collapses or if there are strong feedback loops such as the Amazon rainforest dying and releasing its enormous store of carbon. This would result in extreme and prolonged heatwaves and droughts hitting the UK in summer. Thousands of early deaths have already occurred in England in heatwaves with just a 1.3C increase in global temperatures.

Temperatures could also be driven up by about 0.75C if pollution from industry is sharply cut, the scientists said. This is because aerosol particles from burning coal and heavy fuels block sunlight from reaching the ground.

A major ocean current, the Atlantic meridional overturning circulation (Amoc) is weakening and losing stability because of global heating. It is one of the tipping points that most concerns scientists. A collapse beginning in 2030 would lead to 6C cooling in the UK.

“Agriculture would struggle enormously and water resources would be completely altered,” said Arnell. “Our heat and energy system would be completely caught out by changing winter energy demand. It wouldn’t happen overnight, but it would be massively disruptive.”

A collapse of even one part of Amoc, the sub-polar gyre, would reduce UK temperatures by 2.5C, the scientists said.

Glaciers to reach peak rate of extinction in the Alps in eight years

Alpinists train on the Mer de Glace in France. Like nearly all of Europe's glaciers, it is melting fast. Photograph: Sean Gallup/Getty Images

by  Damian Carrington Environment editor

 Climate crisis forecast to wipe out thousands of glaciers a year globally, threatening water supplies and cultural heritage

 Glaciers in the European Alps are likely to reach their peak rate of extinction in only eight years, according to a study, with more than 100 due to melt away permanently by 2033. Glaciers in the western US and Canada are forecast to reach their peak year of loss less than a decade later, with more than 800 disappearing each year by then.

 

The melting of glaciers driven by human-caused global heating is one of the clearest signs of the climate crisis. Communities around the world have already held funeral ceremonies for lost glaciers, and a Global Glacier Casualty List records the names and histories of those that have vanished.

About 200,000 glaciers remain worldwide, with about 750 disappearing each year. However, the research indicates this pace will accelerate rapidly as emissions from burning fossil fuels continue to be released into the atmosphere.

Current climate action plans from governments are forecast to push global temperatures to about 2.7C above preindustrial levels, supercharging extreme weather. Under this scenario, glacier losses would peak at about 3,000 a year in 2040 and plateau at that rate until 2060. By the end of the century, 80% of today’s glaciers will have gone.

By contrast, rapid cuts to carbon emissions to keep global temperature rise to 1.5C would cap annual losses at about 2,000 a year in 2040, after which the rate would decline.

 

Glacier collapses, burying evacuated Swiss village in mud and rocks – video

 Previous studies have focused on the volume of ice lost, given its contribution to rising sea levels that threaten coastal towns and cities. Individual glaciers, however, are also important as water sources and tourist attractions for many communities, and often have spiritual significance for local people. This prompted the researchers to analyse the number of glaciers disappearing.

 

Matthias Huss, a senior scientist at ETH Zurich in Switzerland and a member of the study team, said: “As glaciologists, we do not only model the disappearance of glaciers globally, but we are very directly concerned with this loss of glaciers in our daily work.”

As the director of the Swiss glacier monitoring network, Huss recently declared four extinct, the latest in an estimated 1,000 lost in the country over the past three decades.

Huss also spoke at a funeral ceremony for the Pizol glacier in 2019. “More than 250 people climbed up to this glacier to say goodbye. It was very impressive.”

Such funerals have also taken place in Iceland, Nepal and elsewhere. “People climb up to these vanishing glaciers to say goodbye for themselves, but also to send out a strong signal to the public to tell them it matters to us.”

The Kā Roimata o Hine Hukatere in New Zealand is experiencing substantial ice loss. Photograph: Jon Bower New Zealand/Alamy

Many glaciers hold spiritual significance, for example Māori culture regard them as ancestors. The Māori political leader Nā Lisa Tumahai visited the melting Kā Roimata o Hine Hukatere in 2022 and told the Global Glacier Casualty List: “This mighty glacier, a presence once so physically commanding, is shrinking into oblivion. [It] has been subdued, humiliated by the actions of humans.

“To see this retreating giant is to understand impermanence, to understand the real and terrible results of industrialisation, of climate change.”

The new study, published in Nature Climate Change, analysed more than 200,000 glaciers from a database of outlines derived from satellite images. The researchers used three global glacier models to assess their fate under different heating scenarios.

Arctic endured year of record heat as climate scientists warn of ‘winter being redefined’. Region known as ‘world’s refrigerator’ is heating up as much as four times as quickly as global average, Noaa experts say

 

This aerial view shows icebergs and ice sheets floating in the water off Nuuk, Greenland, on 07 March 2025. Photograph: Odd Andersen/AFP/Getty Images

by Oliver Milman

The Arctic endured a year of record heat and shrunken sea ice as the world’s northern latitudes continue a rapid shift to becoming rainier and less ice-bound due to the climate crisis, scientists have reported.

From October 2024 to September 2025, temperatures across the entire Arctic region were the hottest in 125 years of modern record keeping, the US National Oceanic and Atmospheric Administration (Noaa) said, with the last 10 years being the 10 warmest on record in the Arctic.

The Arctic is heating up as much as four times as quickly as the global average, due to the burning of fossil fuels, and this extra heat is warping the world’s refrigerator – a region that acts as a key climate regulator for the rest of the planet.

 

The maximum extent of sea ice in 2025 was the lowest in the 47-year satellite record, Noaa reported on in its annual Arctic report card. This is the latest landmark in a longer trend, with the region’s oldest, thickest ice declining by more than 95% since the 1980s as the Arctic becomes hotter and rainier.

This year was a record for precipitation in the Arctic. Much of this is not settling as snow – the June snow cover extent over the Arctic today is half of what it was six decades ago.

 “This year was the warmest on record and had the most precipitation on record – to see both of those things happen in one year is remarkable,” said Matthew Langdon Druckenmiller, an Arctic scientist with the National Snow and Ice Data Center at the University of Colorado and an editor of the Arctic report card. “This year has really underscored what is to come.”

 

Scientists have been struck by how exceptional warmth in other seasons, particularly summer, is now becoming evident in winter too, affecting the annual growth of sea ice across the Arctic in its coldest months. In the past month or so, sea ice extent has been the lowest on record, potentially heralding another reduced maximum for sea ice next year.

“There’s been a steady decline in sea ice and unfortunately we are seeing rain now even in winter,” said Druckenmiller. “We are seeing changes in the heart of winter, when we expect the Arctic to be cold. The whole concept of winter is being redefined in the Arctic.”

These changes are acutely felt by people and wildlife in the Arctic – rain falling on to snow can freeze into a barrier that makes it harder for animals to forage for food, while also making for more slippery, hazardous conditions for people traveling by road. The retreat of glaciers can also cause potentially dangerous flooding, as seen in Juneau, Alaska, this year.

The loss of sea ice is opening up vast areas of dark ocean, which is absorbing, rather than reflecting, more of the heat that is raising global temperatures. While the melting sea ice isn’t itself causing the seas to rise, the loss of land-based glaciers is, with Noaa reporting that the huge Greenland ice sheet lost 129bn tons of ice in 2025. This will add to sea level rise that will menace coastal cities for generations to come.

“We are seeing cascading impacts from a warming Arctic,” said Zack Labe, a climate scientist at Climate Central. “Coastal cities aren’t ready for the rising sea levels, we have completely changed the fisheries in the Arctic which leads to rising food bills for sea food. We can point to the Arctic as a far away place but the changes there affect the rest of the world.”