Sudden sea level rise — tied to El Niño — is about to hit the California coast

Animation showing how Kelvin waves moved across the Pacific and then up from South America to North America between April 16 and September 10, increasing ocean levels as they went. Red represents higher-than-normal sea surface heights. Some data for September is based on forecasts. Courtesy Dillon Amaya Dillon Amaya

By Andrew Freedman

 

Beachgoers wade in the Pacific Ocean at La Jolla's Windansea Beach at sunset on September 4, 2026 in San Diego, CA. Kevin Carter/Getty Images

 

The sea level along California’s coast will increase by about a foot by mid-October due to the influence of El Niño, which is driving a large volume of water northward from offshore of Mexico and Central America.

This water is coming in the form of a coastal “Kelvin wave,” and it will mark the arrival of one of the first significant impacts of the powerhouse El Niño taking shape in the tropical Pacific. According to Dillon Amaya, an oceanographer at North Carolina State University, the wave is a clear signal that El Niño has arrived in California.

“Typically, we think of El Niño and its impact on precipitation, but some of the first indications that El Niño is really occurring are the arrival of these coastally trapped waves,” he said. 

 

A coastal Kelvin wave is not one that a person typically sees at a beach, breaking and crashing. Instead, it’s barely perceptible to the human eye as it slithers northward from offshore of Mexico’s Baja Peninsula at about six miles per hour. It is detectable, however, using satellites that measure changes in ocean heights.

You can’t surf a Kelvin wave, but it does affect surfing. These waves are important because of their role in raising coastal sea levels, which increases the likelihood of damage from astronomical high tides and winter storms that are also affected by El Niño, scientists say. In essence, one El Niño-related phenomenon — sea level rise — is compounding the damage caused by others.

Kelvin waves in the open ocean are massive, slow-moving and slosh up and down, like water in a bathtub. Once they hit land, Kelvin waves can shift direction, moving north and south, parallel to the coast — raising ocean levels by 6 to 12 inches as they go. 

 The ongoing El Niño, which is characterized by much hotter-than-average sea-surface temperatures in the tropical Pacific, is forecast to be the strongest such event on record since at least 1950. El Niño temporarily increases water levels on top of long-term rising sea levels from human-caused climate change. 

 Water levels along the California coastline have already been increasing in other ways tied to El Niño, Amaya said, including an earlier coastal Kelvin wave that reached California in May and June. The elevated sea levels that will result from the upcoming wave will further raise water levels and put the state at greater risk of coastal flooding, he said.

 

These large, undulating Kelvin waves are actually part of what helps El Niño form, transporting heat from the western Pacific Ocean to its central and eastern regions, near the equator. These waves help push huge quantities of ocean heat under the sea surface, in a process known as downwelling. When they reach the central and eastern tropical Pacific, the undersea ocean heat rises, or upwells, increasing ocean temperatures there.

In about 120 days, a Kelvin wave can travel from the western Pacific to the Pacific Northwest coastline of the US, or even as far as the Gulf of Alaska, raising ocean heights as it goes. 

 

“It’s an epic transit,” Amaya said.

In addition, sea levels are also increasing along the West Coast because the hotter waters associated with El Niño are expanding to take up more space.

“The wave would add to what is already there,” Amaya said. The total sea level height, including this latest wave, is anticipated to be 10-to-14 inches higher than normal along the California coast, he said. 

The sun rises on Hurricane Lowell as it tracks near Hawaii on the morning September 7, 2026. Besides raising sea levels along California's coast, El Niño also increases the likelihood of hurricanes in the Pacific that send their own waves towards California. CIRA/CSU & NOAA

 

Patrick Barnard, research director at the Center for Coastal Climate Resilience at the University of California, Santa Cruz, said the ocean height increase puts many coastal residents at risk of flooding.

“Because so many of our communities are built right at sea level on the West Coast, and our extreme water levels don’t vary widely, every 2 to 4 inches of sea level doubles our flood risk,” Barnard said. 

 

Amaya noted that the background sea level rise since the preindustrial era along parts of the California coast has been about one foot, so these El Niño-related changes will double that century-long trend all at once, albeit temporarily.

“El Niño has arrived. This is some of the first evidence that El Niño is impacting the United States.”

Peter’s farm is on ‘flood country’. As Australia’s sea levels rise, safe land is vanishing and costs are huge

Peter Lake's NSW northern rivers property after a flood in 2022 flood. The cattle farm has flooded five times since 2009. Photograph: Peter Lake

 Climate Council forecasts more than 267,000 coastal properties will be damaged by flooding by 2100, costing hundreds of billions of dollars

by Donna Lu 

 

When grazier Peter Lake moved to the Clarence Valley in the New South Wales northern rivers region in 2007, he knew was “buying in flood country with … eyes open”.

His cattle farm, about halfway between Yamba and Grafton, borders the Coldstream River and has flooded five times since 2009.

“Out of 130 acres … in a major flood we would have maybe 15 acres that were flood-free,” he said. Lake has systems in place to prepare for such events, including moving cattle to the dry paddocks, where they would also store fodder to feed the animals.

But the amount of safe ground is shrinking: in the historically big flood in 2022, “we only had just a few acres of flood-free land”. Because of both drought and frequent floods, “we just haven’t been able to successfully grow a fodder crop for some years”.

“If we’re going to have more frequent and more severe major events … we need to change the way we think about how we manage,” Lake said. “If rising sea levels impact on us, it’ll just make property less and less viable.”

 

Grazier Peter Lake on his Clarence Valley cattle farm

 Agricultural damages are among $855.1bn in economic losses projected Australia-wide by the end of the century due to coastal flooding, according to a Climate Council report released on Thursday.

 

The report forecasts that more than 267,000 coastal properties and 2m hectares (4.9m acres) of Australian land will be damaged by flooding by 2100 as sea levels rise.

Queensland (93,157 properties), NSW (71,210) and Western Australia (51,366) are the three states with the greatest number of homes at risk.

The Gold Coast, Brisbane and Melbourne are the metropolitan areas expected to be worst affected.

Coastal areas around Brisbane and the Gold Coast are at significant risk, the Climate Council says. Illustration: Climate Council

The Gold Coast, the country’s most exposed urban area, faces $84.4bn in projected economic losses, while in Melbourne losses are concentrated in low-lying areas around Port Phillip Bay and the Yarra River.

The Climate Council report is based on mapping coastal flooding by 2100, taking into account both sea level rise and storm surges under the climate scenario known as RCP4.5 – which projects a 2.7C increase in global temperature by the end of the century, similar to expected heating based on current policies worldwide.

Coastal areas around Port Phillip Bay are vulnerable to rising seas. Illustration: Climate Council

It was co-authored by Prof Tom Kompas at the University of Melbourne, whose modelling of the economic impacts was also published in the peer-reviewed journal Scientific Reports and drew upon localised projections at 239 hotspots around Australia.

Kompas said the costs – an estimated $274.3bn in property losses and $580.7bn in land use damages – were a conservative estimate and did not take into account the additional impacts of coastal erosion or significant ice sheet melt.

He said due to the scale of agricultural losses there was a food security issue potentially coming as well: damage is projected to affect 619,713 hectares (1.5m acres) of farming land.

A map showing coastal areas at risk in NSW and the projected economic damage. Illustration: Climate Council

 

Sea levels have risen, on average by more than 22cm globally since 1900, with human-caused global heating the dominant cause of the rise since 1970. An additional 14cm rise is expected in Australia by 2050, increasing the frequency of permanent inundation and tidal flooding.

Kompas said that while reducing greenhouse gas emissions to limit global heating was of paramount importance, “we have to start planning and responding and adapting now”.

“The nice thing about the work is it shows where the hotspots are and what … assets will be impacted. So we can start to plan for how to deal with that.

“The first thing, of course, is not to build on flood plains, which is common still.”

Millions face long-term coastal flooding risk in UK without climate action, scientists warn. A ‘reasonable worst-case scenario’ suggests need for large-scale movement of populations away from reshaped coast

Coastal erosion in Withernsea, East Yorkshire. Lincolnshire and the Humber estuary are the areas most in danger. Photograph: Christopher Furlong/Getty Images

by  Damian Carrington Environment editor

 

Up to 13 million people in the UK face the long-term risk of coastal flooding due to the climate crisis, scientists have warned, with a “reasonable worst-case scenario” suggesting the need for the large-scale movement of populations away from a dramatically reshaped coast.

Even if today’s global pledges to cut carbon pollution are met, about 1.4 million more people will be exposed to coastal floods in 2200 and 1.7 million in 2300 due to the sea level rise driven by melting ice caps and warming oceans.

While this is far in the future, action today to cut emissions and plan future settlements and flood defences could prevent such leaps in flood risk becoming inevitable, the experts said. Keeping within the Paris agreement targets would cut the number of people exposed in 2300 by 1 million, they said.

 Sea level has risen by about 20cm around the UK in the last century and is accelerating. A further 40cm to 60cm by 2100 is already baked in, meaning about half a million more people will be at risk of their homes being flooded, on top of the 2.5 million already in danger near the coasts. Lincolnshire and the Humber estuary are most in danger.

 

However, scientists are concerned that the gradual rise in sea levels seen so far could change rapidly if ice sheets start a runaway collapse into the oceans, instead of just melting slowly in place. In this scenario, the UK could suffer 15 metres of sea level rise by 2300, swamping large parts of London and many other places, the researchers found.

“[Planners] who only consider changes over the coming century may have a false impression of the true risk landscape given the potential for post-2100 acceleration of sea level rise,” the researchers concluded in their study published in the journal Nature Communications. “It is inevitable that a combination of additional or enhanced flood defences and managed retreat will be necessary to mitigate against post-2100 flood risk.”

 

Prof Matt Palmer at the University of Bristol, who led the research, said: “The oceans and ice-covered parts of the world respond very slowly to global warming, which makes sea level rise the ‘sleeping giant’ of climate change. The result is that sea-level rise is locked-in for centuries to come.”

Dr Rob Larter, at the British Antarctic Survey and not involved in the study, said it was a sobering analysis: “It shows how the UK is likely to have to adapt to several metres of sea level rise over coming centuries. The higher impact [scenarios] presented in this study need to be considered as genuine possibilities rather than unlikely scare stories.”

The research is the first to quantify the number of UK people at threat from coastal flooding under long-term sea level rise. It combined sea level rise projections for the UK with a detailed flood model developed by the Bristol company Fathom. Sea level rise is greater in England and Wales than in Scotland and Northern Ireland as the latter countries were pushed down during the last ice age and are still slowly rebounding.

 

The study did not factor in greater surges from storms supercharged by global heating or future changes in population. It also did not consider future changes to flood defences, which are highly uncertain, but instead set out the level of likely threat in different scenarios.

Dr Joanne Williams, at the National Oceanography Centre in Southampton, said: “It is useful to consider [worst-case scenarios], because it shows how expensive and challenging it will be if we do not act on climate, with very large areas at new risk. Upgrading existing flood defence lines to the levels required by these high-end scenarios would be extremely challenging.”

Coastal flooding is just one type of flood risk in the UK. River and flash flooding already affect more people and are worsening as the warming climate leads to more intense rainfall

‘Point of no return’: New Orleans relocation must start now due to sea level, study finds. Louisiana’s cultural hotspot could be surrounded by Gulf of Mexico before end of this century, authors say

 

By Oliver Milman

 

The process of relocating people from New Orleans should start immediately, as the city has reached a “point of no return” that will see it surrounded by the ocean within decades due to the climate crisis, a stark new study has concluded.

Ongoing sea-level rise and the rampant erosion of wetlands in southern Louisiana will swallow up the New Orleans area within a few generations, with the new paper estimating the city “may well be surrounded by the Gulf of Mexico before the end of this century”.

Low-lying southern Louisiana faces multiple threats, with rising sea levels driven by global heating, compounded by strengthening hurricanes, also a feature of the climate crisis, and the gradual subsidence of a coastline that has been carved apart by the oil and gas industry.

 

Southern Louisiana is facing 3-7 metres of sea-level rise and the loss of three-quarters of its remaining coastal wetlands, which will cause the shoreline “to migrate as much as 100km (62 miles) inland”, thereby stranding New Orleans and Baton Rouge, according to the study, which compared today’s rising global temperatures with a period of similar heat 125,000 years ago that caused a rise in sea level.

This scenario makes the region the “most physically vulnerable coastal zone in the world”, the researchers state, and requires immediate action to prepare a smooth transition for people away from New Orleans, which has a population of about 360,000 people, to safer ground.

Louisiana has already experienced population loss in recent years, and this trend will accelerate in a disordered way, the paper warns, should no action be taken to confront the perils faced by its largest city and surrounding communities.

“While climate mitigation should remain the first step to prevent the worst outcomes, coastal Louisiana has evidently already crossed the point of no return,” added the perspectives paper, published in the Nature Sustainability journal. A perspectives paper is a scholarly article that provides an assessment, rather than new data.

Billions of dollars have been spent to fortify New Orleans with a vast network of levees, floodgates and pumps erected after 2005’s catastrophic Hurricane Katrina. But the growing threats to the city mean the levees, which already require hefty upgrades to remain sufficient, will not be able to save the city in the long run, the new paper warns.

 

“In paleo-climate terms, New Orleans is gone; the question is how long it has,” said Jesse Keenan, an expert in climate adaptation at Tulane University and one of the paper’s five co-authors.

 

Keenan said the timeframe available to plan a retreat isn’t certain but “it’s most likely decades rather than centuries”.

“Even if you stopped climate change today, New Orleans’s days are still numbered,” he added. “It will be surrounded by open water, and you can’t keep an island situated below sea level afloat. There’s no amount of money that can do that.”

City, state and federal leaders should begin work to help support people moving away from the New Orleans region in a coordinated way, starting with the most vulnerable communities, such as those in Plaquemines parish who live outside the levee system, Keenan said.

“New Orleans is in a terminal condition, and we need to be clear with the patient that it is terminal,” he said. “There is an opportunity for palliative care, we can transition people and the economy. We can get ahead of this.”

But, he added, “no politician wants to first give this terminal diagnosis. They will speak about it behind closed doors, but never in public.”

New Orleans faces obvious challenges – situated in a bowl-shaped basin below sea level, the city already has 99% of its population at major risk of severe flooding, the worst exposure of any US city according to a separate study released last week.

“Even compared to all other US cities, New Orleans really stands out, which is alarming,” said Wanyun Shao, a co-author of this study and a geographer at the University of Alabama.

“There is no specific timeline to how long New Orleans has left but we know it’s in big trouble. They are facing one of the highest sea level rises in the world and I don’t know how long human effort can fight against that tide. It’s like a timebomb.”

Shao said she concurred that relocation of people would have to take place. “I know it’s a politically and emotionally charged issue, there are people with a deep attachment to New Orleans,” she said. “But managed retreat, no matter how unappealing it may be, is the ultimate solution at some point.”

A major pressure upon this southern cultural hotspot is that its surrounding land is briskly receding. Since the 1930s, Louisiana has lost 2,000 sq miles of land to coastal erosion, equivalent to the size of Delaware, with a further 3,000 sq miles set to vanish over the next 50 years. The rate of land loss is so rapid that a football pitch-sized area is wiped out every 100 minutes.

To help counter this, Louisiana last decade settled upon a new sort of plan that eschewed building yet more flood defenses and instead sought to harness the Mississippi River’s natural ability to rebuild land. Levees and other infrastructure have, until now, straitjacketed the naturally meandering Mississippi and pushed the sediment it carries straight into the Gulf of Mexico, rather than replenish the coastal wetlands.

The so-called Mid-Barataria Sediment Diversion project, which broke ground in 2023, would help restore a more natural flow in the Mississippi Delta and allow sediment to build up in coastal areas where it has been lost. More than 20 sq miles of new land would be created over the next 50 years under the plan, the project estimated.

However, Jeff Landry, Louisiana’s Republican governor, scrapped the project last year, arguing its $3bn cost was too high and that it threatened the state’s fishing industry. “This level of spending is unsustainable,” Landry said at the time, adding that the project imperiled the livelihoods of “people who have sustained our state for generations”.

Proponents of the project, which was funded via a settlement from BP over the Deepwater Horizon disaster in 2010, decried the decision as disastrous for the state, pointing out fishing communities will need to move anyway because of worsening erosion.

Garret Graves, a Republican former congressman who once led the state’s coastal restoration agency, said Landry was guilty of a “boneheaded decision” that would “result in one of the largest setbacks for our coast and the protection of our communities in decades”.

According to the new research paper, the loss of the sediment diversion plan “effectively means giving up on extensive portions of coastal Louisiana, including the New Orleans area”.

A legal effort to force oil and gas companies to pay for damage to Louisiana’s coastline, meanwhile, is also in doubt. This month, the US supreme court allowed the fossil fuel industry to federally contest a state jury decision that Chevron pay $740m to remedy harm caused to wetlands by dredging canals, drilling wells and dumping wastewater.

“The combination of these decisions is driving a scenario where the state has stopped trying to build land,” Keenan said. “That just accelerates the timeline. They could be buying time, but that option is foreclosed now, meaning it’s a certainty the New Orleans levees will fail again multiple times. The flood water will have nowhere else to go.”

While the US has never wholesale moved a major city before, numerous communities have relocated for economic reasons in the past, with some now being shifted due to the climate crisis, too. In Louisiana, the government could start planning and building appropriate infrastructure in safer areas on the other side of Lake Pontchartrain, the large estuary that sits to the north of New Orleans, Keenan said.

“This could be an opportunity for New Orleans to help migrate people further north, invest in long-term infrastructure and make that sustainable,” Keenan said.

“That exodus has already begun, so if nothing is done, people will just trickle out over time and it will be an uncoordinated mess. The market will speak as people won’t be able to get insurance. Louisiana has to stop the bleeding and acknowledge this is happening. But at the moment there is no plan.”

Timothy Dixon, an expert in coastal environments at the University of South Florida who was not involved in the new paper, said the study “does a nice job” of highlighting the challenge Louisiana faces with subsiding land combined with rising sea levels.

“New Orleans is not going to disappear in 10 years or anything like that, but policymakers really should’ve thought about a relocation plan a century ago,” said Dixon, whose own research has recommended a measured retreat from coastal Louisiana.

“Governments may not have the ability to just command people to leave, but people will volunteer to move and we are seeing that already. I’m not optimistic our political system is capable of dealing with this stuff, it will take leadership and unpopular decisions. Also, many people don’t want to move. They love where they are born.”

Landry’s office was contacted for comment but did not respond.

Global sea levels have been underestimated due to poor modelling, research suggests. Analysis shows average levels are 30cm higher than thought, and up to 150cm in south-east Asia and Indo-Pacific

 

The island of Toruar in eastern Papua New Guinea is threatened by rising sea levels. Photograph: Kalolaine Fainu/The Guardian

by  Tara Russell

Sea levels around the world have been underestimated due to inaccurate modelling, with research suggesting ocean levels are far higher than previously understood.

The finding could significantly affect assessments of the future impacts of global heating and the effects on coastal settlements.

Globally, the research found ocean levels are an average of 30cm higher than previously believed, but in some areas of the global south, including south-east Asia and the Indo-Pacific, they may be 100-150cm higher than previously thought.

Rising sea levels are a major threat to coastal communities across the world, and the UN Intergovernmental Panel on Climate Change (IPCC) estimates that by 2100 levels may rise by 28-100cm.

 The latest research, published in Nature, combined the analysis of 385 pieces of peer-reviewed scientific literature released between 2009 and 2025 with calculations of the difference between the commonly assumed and actual measured coastal sea levels.

 

Authors Dr Philip Minderhoud of Wageningen University in the Netherlands and PhD researcher Katharina Seeger discovered that more than 90% of these studies did not use local, direct measurements of sea levels but instead used land elevation measurements referenced against global geoid models.

Geoid models provide an estimate of global sea levels based on the Earth’s gravity and rotation.

As a consequence, sea levels were undervalued by an average of 24-27cm, depending on the geoid model used, with some discrepancies as much as 550-760cm.

Minderhoud said: “In reality, sea level is influenced by additional factors such as winds, ocean currents, seawater temperature and salinity.”

 

The new calculations reveal that following a relative sea level rise of 1 metre, it is estimated that 37% more coastal areas will fall below sea level, affecting up to 132 million individuals.

“If sea level is higher for your particular island or coastal city than was previously assumed, the impacts from sea level rise will happen sooner than projected before,” said Minderhoud.

Describing the discrepancy as an “interdisciplinary blind spot”, the scientists are concerned that a large proportion of the studies analysed in their research, which they believe are inaccurate, are referenced in the most recent climate change reports published by the IPCC.

The study contains ready-to-use coastal elevation data for across the world integrated with the latest sea level measurements and calls for the re-evaluation of existing coastal hazard studies methodology to ensure climate change policies are accurately informed.

Sea level rise will cause ‘catastrophic inland migration’, scientists warn. Rising oceans will force millions away from coasts even if global temperature rise remains below 1.5C, analysis finds

 

The loss of ice from the Greenland and Antarctic ice sheets has quadrupled since the 1990s. Photograph: Bernhard Staehli/Shutterstock

Damian Carrington 

Sea level rise will become unmanageable at just 1.5C of global heating and lead to “catastrophic inland migration”, the scientists behind a new study have warned. This scenario may unfold even if the average level of heating over the last decade of 1.2C continues into the future.

The loss of ice from the giant Greenland and Antarctic ice sheets has quadrupled since the 1990s due to the climate crisis and is now the principal driver of sea level rise.

The international target to keep global temperature rise below 1.5C is already almost out of reach. But the new analysis found that even if fossil fuel emissions were rapidly slashed to meet it, sea levels would be rising by 1cm a year by the end of the century, faster than the speed at which nations could build coastal defences.

The world is on track for 2.5C-2.9C of global heating, which would almost certainly be beyond tipping points for the collapse of the Greenland and west Antarctic ice sheets. The melting of those ice sheets would lead to a “really dire” 12 metres of sea level rise.

Today, about 230 million people live within 1 metre above current sea level, and 1 billion live within 10 metres above sea level. Even just 20cm of sea level rise by 2050 would lead to global flood damages of at least $1tn a year for the world’s 136 largest coastal cities and huge impacts on people’s lives and livelihoods.

However, the scientists emphasised that every fraction of a degree of global heating avoided by climate action still matters, because it slows sea level rise and gives more time to prepare, reducing human suffering.

 

Sea level rise is the biggest long-term impact of the climate crisis, and research in recent years has shown it is occurring far faster than previously estimated. The 1.5C limit was seen as a way to avoid the worst consequences of global heating, but the new research shows this is not the case for sea level rise.

The researchers said the “safe limit” temperature for ice sheets was hard to estimate but was likely to be 1C or lower. Sea level rise of at least 1-2 metres was now inevitable, the scientists said. In the UK, just 1 metre of sea level rise would see large parts of the Fens and Humberside below sea level.

“What we mean by safe limit is one which allows some level of adaptation, rather than catastrophic inland migration and forced migration, and the safe limit is roughly 1cm a year of sea level rise,” said Prof Jonathan Bamber of the University of Bristol in the UK. “If you get to that, then it becomes extremely challenging for any kind of adaptation, and you’re going to see massive land migration on scales that we’ve never witnessed in modern civilisation.” Developing countries such as Bangladesh would fare far worse than rich ones with experience of holding back the waves, such as the Netherlands, he said.

Durham University’s Prof Chris Stokes, lead author of the study, said: “We’re starting to see some of the worst-case scenarios play out almost in front of us. At current warming of 1.2C, sea level rise is accelerating at rates that, if they continue, would become almost unmanageable before the end of this century, [which is] within the lifetime of our young people.”

The average global temperature hit 1.5C for the first time in 2024. But the international target is measured as the average over 20 years, so is not considered to have been broken yet.

 

The new study, published in the journal Communications Earth and Environment, combined data from studies of warm periods up to 3m years ago; observations of ice melting and sea level rise in recent decades; and climate models. It concluded: “Continued mass loss from ice sheets poses an existential threat to the world’s coastal populations.”

Prof Andrea Dutton of the University of Wisconsin-Madison, who was part of the study team, said: “Evidence recovered from past warm periods suggests that several metres of sea level rise – or more – can be expected when global mean temperature reaches 1.5C or higher.”

At the end of the last ice age, about 15,000 years ago, sea level was rising at 10 times the rate today, driven by self-reinforcing feedbacks that may have been triggered by only a small increase in temperature. The last time CO₂ levels in the atmosphere were as high as today, about 3m years ago, sea level rise was 10-20 metres higher.

Even if humanity can bring the planet back to its preindustrial temperature by removing CO₂ from the atmosphere, it will still take hundreds to thousands of years for the ice sheets to recover, the researchers said. That means land lost to sea level rise will remain lost for a long time, perhaps until the Earth enters the next ice age.

Belize moved its capital inland in 1970 after a devastating hurricane, but its largest city is still on the coast and will be inundated with only 1 metre of sea level rise, Carlos Fuller, Belize’s longtime climate negotiator, said: “Findings such as these only sharpen the need to remain within the 1.5C Paris agreement limit, or as close as possible, so we can return to lower temperatures and protect our coastal cities.”

 

Nasa revela aumento 'inesperado' do nível do mar em 2024. Taxa atingiu 0,59 centímetros, índice superior à projeção inicial de 0,43 centímetros anuais.

Segundo a Nasa, o aumento inesperado é atribuído principalmente ao aquecimento dos oceanos. — Foto: Julie G 

A Nasa, a agência espacial norte-americana, revelou nesta quinta-feira (13) que o nível global do mar apresentou uma elevação superior à esperada no ano de 2024, principalmente devido ao aquecimento dos oceanos.

De acordo com a análise conduzida pela agência, a taxa de elevação atingiu 0,59 centímetros, valor consideravelmente superior à projeção inicial de 0,43 centímetros anuais.

 "Os dados que coletamos em 2024 demonstram um aumento além do que nossos modelos previram", explicou Josh Willis, pesquisador especializado em níveis oceânicos do Laboratório de Propulsão a Jato (JPL) da agência. 

 "Embora existam variações anuais, a tendência geral é inequívoca: os oceanos continuam subindo, e a velocidade desse processo está se intensificando progressivamente." 

 

A pesquisa indica uma importante alteração no padrão de contribuição para a elevação do nível do mar.

Tradicionalmente, cerca de dois terços desse aumento eram atribuídos à água proveniente do derretimento de geleiras e camadas de gelo terrestres, enquanto aproximadamente um terço resultava da expansão térmica da água oceânica.

Em 2024, contudo, essa proporção inverteu-se, com dois terços da elevação sendo consequência direta da expansão térmica.

 "O ano de 2024 registrou as temperaturas mais elevadas já documentadas, e os oceanos do planeta respondem diretamente a esse fenômeno, alcançando seus níveis mais altos em três décadas de monitoramento", afirmou Nadya Vinogradova Shiffer, responsável pelos programas de oceanografia física e pelo Observatório Integrado do Sistema Terrestre na sede da Nasa em Washington.

Evolução do nível do mar desde 1993, com projeção de aumento acelerado. — Foto: Nasa 

Série histórica da elevação dos oceanos

Desde 1993, quando os registros por satélite foram iniciados, a taxa anual de elevação do nível do mar mais que dobrou.

No acumulado desse período, o nível global dos oceanos subiu aproximadamente 10 centímetros, conforme demonstram os dados coletados por uma sequência ininterrupta de satélites de observação oceânica.

Atualmente, o monitoramento é realizado pelo satélite Sentinel-6 Michael Freilich, lançado em 2020 como parte de um par idêntico de equipamentos que permitirá a continuidade dessa série histórica de dados para a próxima década.

O futuro satélite Sentinel-6B da agência dará sequência às medições precisas do nível da superfície marinha para aproximadamente 90% dos oceanos mundiais. 

 

Aquecimento e circulação oceânica

A Nasa explica que transferência de calor para os oceanos, responsável pela expansão térmica da água, ocorre através de diversos mecanismos. Em condições normais, a água marinha organiza-se em camadas determinadas por temperatura e densidade, com água mais quente flutuando sobre camadas mais frias e densas.

Na maior parte dos oceanos, o calor superficial percorre essas camadas muito lentamente até alcançar as profundezas.

Porém, em regiões caracterizadas por ventos intensos, as camadas oceânicas podem sofrer agitação suficiente para provocar mistura vertical.

Grandes correntes, como as presentes no Oceano Austral, têm a capacidade de inclinar essas camadas, facilitando o deslocamento das águas superficiais para regiões mais profundas. 

Moradores caminham por área alagada em Jacarta, onde a elevação do nível do mar e o afundamento do solo agravam inundações em novembro de 2024. — Foto: REUTERS/Willy Kurniawan 

O fenômeno El Niño também contribui significativamente para esse processo, uma vez que o deslocamento de grandes massas de água quente, normalmente localizadas na região oeste do Oceano Pacífico, para as regiões central e leste, resulta em movimentos verticais de calor através das camadas oceânicas.

Por isso, o estudo reforça a crescente preocupação da comunidade científica com os impactos das mudanças climáticas, especialmente para comunidades costeiras que já enfrentam episódios mais frequentes de inundações durante marés altas, como é o caso de diversas regiões da Flórida e da Indonésia.

 

 

Global sea ice hit ‘all-time minimum’ in February, scientists say. Scientists called the news ‘particularly worrying’ because ice reflects sunlight and cools the planet

February was the lowest monthly level for sea ice in the Arctic, and the fourth-lowest in the Antarctic. Photograph: Bernhard Staehli/Shutterstock
 

Ajit Niranjan Europe environment correspondent

 

 

Global sea ice fell to a record low in February, scientists have said, a symptom of an atmosphere fouled by planet-heating pollutants.

The combined area of ice around the north and south poles hit a new daily minimum in early February and stayed below the previous record for the rest of the month, the EU’s Copernicus Climate Change Service (C3S) said on Thursday.

“One of the consequences of a warmer world is melting sea ice,” said the C3S deputy director, Samantha Burgess. “The record or near-record low sea ice cover at both poles has pushed global sea ice cover to an all-time minimum.”

The agency found the area of sea ice hit its lowest monthly level for February in the Arctic, at 8% below average, and its fourth-lowest monthly level for February in the Antarctic, at 26% below average. Its satellite observations stretch back to the late 1970s and its historical observations to the middle of the 20th century.

Scientists had already observed an extreme heat anomaly in the north pole at the start of February, which caused temperatures to soar more than 20C above average and cross the threshold for ice to melt. They described the latest broken record as “particularly worrying” because ice reflects sunlight and cools the planet.

“The lack of sea ice means darker ocean surfaces and the ability of the Earth to absorb more sunlight, which accelerates the warming,” said Mika Rantanen, a climate scientist at the Finnish Meteorological Institute.

The strong winter warming event in the Arctic in early February had prevented sea ice from growing normally, he added. “I believe that this meteorological event, combined with the long-term decline of sea ice due to anthropogenic climate change, was the primary cause of the lowest Arctic sea ice extent on record.”

Global sea ice extent varies throughout the year but typically reaches its annual minimum in February, when it is summer in the southern hemisphere

C3S said February 2025 was the third hottest February it had seen. Global temperatures were 1.59C hotter than preindustrial levels, making it the 19th month in the past 20 that was more than 1.5C above preindustrial levels.

Earth observation programmes such as C3S rely on the reanalysis of billions of measurements from satellites, ships, aircraft and weather stations to create snapshots of the state of the climate. The agency cautioned that the margins above 1.5C were small in several months, and could differ slightly in other datasets.

 

The broken sea ice record comes after last year was confirmed as the hottest year on record and a Guardian analysis of C3S data revealed that two-thirds of the world’s surface was seared by record-breaking monthly heat in 2024. The El Niño weather pattern in the first half of the year added to the background heating effect of fossil fuel pollution, which traps sunlight.

El Niño has since subsided and morphed into a weak form of its cooler counterpart, La Niña. The World Meteorological Organization said on Thursday they expected the La Niña that emerged in December to be short-lived.

Richard Allan, a climate scientist at the University of Reading, said the long-term prognosis for Arctic sea ice was grim.

“The region continues to rapidly heat up, and can only be saved with rapid and massive cuts to greenhouse gas emissions,” he said. “That will also limit the growing severity of weather extremes and long-term sea level rise across the world.”

 

‘Ironic’: climate-driven sea level rise will overwhelm major oil ports, study shows. Ports including in Saudi Arabia and the US projected to be seriously damaged by a metre of sea level rise.

Saudi Aramco's Ras Tanura oil refinery and oil terminal. Photograph: Ahmed Jadallah/Reuters

 

 

Rising sea levels driven by the climate crisis will overwhelm many of the world’s biggest oil ports, analysis indicates.

Scientists said the threat was ironic as fossil fuel burning causes global heating. They said reducing emissions by moving to renewable energy would halt global heating and deliver more reliable energy.

Thirteen of the ports with the highest supertanker traffic will be seriously damaged by just 1 metre of sea level rise, the analysis found. The researchers said two low-lying ports in Saudi Arabia – Ras Tanura and Yanbu – were particularly vulnerable. Both are operated by Aramco, the Saudi state oil firm, and 98% of the country’s oil exports leave via these ports.

The oil ports of Houston and Galveston in the US, the world’s biggest oil producer, are also on the list, as are ports in the United Arab Emirates, China, Singapore and the Netherlands.

 

The latest science published by the International Cryosphere Climate Initiative (ICCI) shows 1 metre of sea level rise is now inevitable within a century or so and could come as early as 2070 if ice sheets collapse and emissions are not curbed. An even more catastrophic rise of 3 metres is probably inevitable in the next millennium or two and could arrive as soon as the early 2100s.

Sea level rise is already causing problems around the world even before it overtops coastline developments. The rise to date means storm surges are higher and significantly more likely to cause coastal flooding, while infiltration of saltwater into coastal land can corrode foundations, the researchers note. Cutting emissions sharply would not only slow the rate of sea level rise but also limit the ultimate rise.

 

Pam Pearson, the ICCI director, said: “It’s ironic these oil tanker ports are below 1 metre of sea level rise and need to have their eyes on these potentially higher rates of sea level rise, which themselves come from continued fossil fuel use.”

Sea level rise is the most profound long-term impact of the climate crisis, redrawing the map of the world and affecting many major cities from New York to Shanghai. But Pearson said government and corporate short-term interests meant it was being overlooked. “Basic information [from scientific assessments of sea level rise] don’t seem to have gotten into the consciousness of governments,” she said.

James Kirkham, the chief science adviser at ICCI, said: “Refusing to turn off the oil taps means keeping the taps on for sea level rise. Accelerated ice melt and ocean expansion has already caused the rate of sea level rise to double in the last 30 years. Unless leaders double down on transitioning away from fossil fuels, the terrible impacts of sea level rise will only increase further – affecting every country with a coastline, including those who continue to obstruct increased decarbonisation efforts.”

Aramco declined to comment.

Saudi Arabia has been accused of obstructionism at a series of recent global summits, including “wrecking ball” tactics at the Cop29 climate assembly, and of blocking progress at negotiations on a plastics treaty and on tackling drought and desertification. The latter talks were held in Riyadh and ended without agreement, with the Saudis refusing to include any reference to climate in the agreement.

The new analysis built on work from May in which researchers found that 12 of the 15 oil ports with the biggest oil tanker traffic were vulnerable to sea level rise. Maps of sea level rise from Climate Central and GoogleMaps were used to show that a 1-metre rise would damage jetties, oil storage facilities, refineries and other infrastructure.

The new analysis added the second Saudi port, Yanbu, which is also at high risk with a 1-metre rise. The team used Bloomberg oil export data to estimate the volume and value of the oil being imported and exported from the ports. Together, Ras Tanura and Yanbu exported $214bn (£171bn) worth of oil in 2023. In total, the 13 ports accounted for about 20% of global oil exports in 2023.

Murray Worthy, of Zero Carbon Analytics, who is part of the team, said: “This analysis shows that relying on fossil fuels in a warming world is a path to disaster, not energy security. Countries face a choice: stick with fossil fuels and risk supply disruptions as rising seas flood ports and terminals, or transition to secure, sustainable domestic renewables.”

Efforts could be made to build flood defences, which would be very costly, but Worthy said: “Ultimately it’s a losing battle. You’ve got to keep building those sea walls higher over time.”