How Singapore became obsessed by shade

The sweltering island nation has long prioritised adding greenery and shade at every corner. Could other cities do the same?

by  Sam Bloch

Heat is humanity's most lethal climate threat, taking more lives every year than floods, hurricanes and wildfires combined. And the risk is greatest in cities, which are warming twice as fast as the rest of the planet because of the urban heat island effect.

As dangerous temperatures become more common, the leaders of cities around the globe, from Paris to Phoenix, are strategically planning to throw more shade.

But it's the sweltering island nation of Singapore which may well already have the best shade infrastructure of any city on Earth. People here have long had their own tricks to deal with the torrential rain and sticky heat.

Chief among them might be the covered sidewalks. The origin of this public shade is unclear. Although these "five-foot ways" which tunnel through the ground floors of arcaded shops and houses, resemble the porticoes of Bologna, they may be native to Southeast Asia. Stamford Raffles, the British colonial official considered to have founded Singapore in the early 19th Century, wrote them into the first town plan in 1822.

 

Raffles mandated clear, continuous and covered passages on both sides of every street to ensure efficient transit in inclement weather. Over time, his "verandah-ways" fell out of favour. They were revived in modern form by Lee Kuan Yew, the powerful prime minister who guided Singapore to independence in the 1960s.

Almost half of Singapore is covered in grasses, shrubs and broad-canopied trees, throwing cold water on the idea that cities can't spare room for nature as they grow

 

Singapore's famous Gardens by the Bay combines tropical flora with the iconic 'supertrees': artificial structures providing a vertical garden and shading (Credit: Getty Images)

Lee was something of a micromanager and had a particular interest in climate and comfort. He believed that humidity was stifling the country's economic productivity. Indoors, he transformed Singapore into what journalist Cherian George called the "air-conditioned nation". Outdoors, he was fanatic about shade. Lee was known to lecture subordinates about the poor design of footpaths and promenades, sometimes kneeling on the burning hot ground to prove a point.

In the 1960s and 1970s, as Lee's authoritarian government erected towering public housing estates, architects kept the ground floors of every building open to the air, preserving the areas as communal "void decks" where residents could gather to catch a breeze. In the late 1980s and 1990s, Singapore's housing and transportation agencies directed the construction of freestanding metal canopies over the sidewalks to ensure dry paths to the nearest bus or train.

 

Today, the authorities claim to have erected around 200km (124 miles) of covered walkways. Try to imagine if New York's ubiquitous construction scaffolds were permanent sidewalk architecture and you might have some idea of what the immensely unattractive though functional achievement looks like.

In the US, real estate developers are required to set their buildings back from the street to let in more light, but in Singapore, they must contribute to the shade network by carving 8-12ft (2.4-3.7m) of pedestrian overhangs out of the ground floors of their buildings. Research suggests the canopies have an effect similar to that of a clean and well-designed bus shelter. Just as a shelter can make a wait for the bus go by faster, so too do Singaporeans report that a stroll under the walkways feels 14% shorter than a stroll under the sun.

"You're in a tropical region where it's always super hot, and always very humid," says Yun Hye Hwang, a landscape architect and professor at the National University of Singapore. With daily high temperatures hovering around 31-33C (88-91F) year round, "we always need shade," she adds. 

When it comes to shade, almost everyone would prefer the leaves of a luscious canopy to a clunky aluminium roof, but trees can't always be the answer, says Lea Ruefenacht, a former researcher with Cooling Singapore, a government-affiliated urban heat initiative. But she notes that trees create cooling through shade and by releasing water into the air: in humid Singapore, more moisture can add to the misery. 

For comfort, Ruefenacht recommends a balance of both green and grey shade. In Singapore, the densest grey shade is found in the concrete understory of the skyscraper forest downtown. Real estate developers are required to furnish what the authorities consider "sufficient" shade on outdoor plazas, cooling at least 50% of seating areas between 9:00 and 16:00. The shade can come from any number of sources – trees, umbrellas, awnings – but in their design circulars, the authorities demonstrate that it can also be afforded by a nearby tower's knifing shadow.

A shopping area in a five-foot way in Little India, Singapore. These arcaded tunnel through the ground floors of the city's shops and houses (Credit: Alamy)

 This approach can be contrasted to that of New York City, where building shadows on outdoor spaces are discouraged, and the mere threat of their existence can scuttle a new development. In this cooler climate, developers are instructed to site their plazas on sun-facing south sides, to create winter warmth. (In fact, the plazas are not allowed to face north.)

Singapore has a different priority. Ideally, developers locate plazas on the east side of their buildings, so they can be cooled by afternoon shade. It is the rare place where urban shadows are encouraged as a public benefit.

"In the tropical regions of the world, part of the problem has always been that settlements inherit building codes from the temperate regions, and they don't necessarily have the means to review it and ask, 'does this work for us?'" says Kelvin Ang, the conservation director at Singapore's Urban Redevelopment Authority. "In Singapore, somehow there was a lot of awareness that building codes and planning codes had to encourage shade, because of the intensity of the sun."

 

Planners believe that if a public space is unshaded, no one will use it. Despite the potential effects on humidity, Prime Minister Lee demanded trees everywhere, believing that a "clean and green" Singapore would be attractive to foreign investors. Under his command, a newly formed parks and trees unit spruced up the major boulevards, embowering them under the broad canopies of Angsanas, rain trees, mahoganies and acacias. "Flowers are okay," Lee reportedly told the department head, "but give me shade first". 

In the 1970s, as he implemented congestion pricing and other schemes to push Singaporeans out of their cars and onto public transit, Lee turned his attention to the sidewalks, crosswalks and bus stops where a pounding Sun could have repelled potential new riders.

In Los Angeles, trees are the last piece of the street-design puzzle, blasted into concrete pits and stuffed haphazardly into sidewalks after every vault and metre has been trenched, every curb has been built, every gutter cut, and every driveway poured.

Many of Singapore's plazas and buildings have been designed to cast shadows to help keep pedestrians cooler (Credit: Alamy)

In Singapore, however, Lee ordered his land-use planners to consider them from the beginning. The overhead power lines that disfigure LA's sidewalks and make trees small and shrubby are rare. Most utilities are laid underground in vaults that run alongside the street trees and their roots. The green infrastructure is plotted by urban planners, engineered by public works agencies, and managed by a parks board whose budget increased tenfold under Lee's leadership.

The funding and coordination have proven to be the difference between a thriving urban forest and a bunch of sad city trees. Besides the roads, Lee's urban planners mandated greenery in private developments, regenerating a new garden city to compensate for the natural rainforest that was all but gone.

The Singaporean government had a lot of leverage. Through strong eminent-domain rules, it owned about 90% of the land, and building inspectors wouldn't clear a building for occupancy until they saw trees on the ground. Singapore's extensive public housing estates also came with grassy lawns, leafy courtyards and tree-lined paths that connected to parks and nature reserves. As a result, trees are just about everywhere in Singapore, in rich and poor neighbourhoods alike. 

"We did not differentiate between middle-class and working-class areas," Lee wrote in his memoirs, claiming it would have been "politically disastrous" for the People's Action Party. It makes Singapore distinct from American cities, where shade is a reliable indicator of economic inequality.

Thanks to Lee's smart planning policies, including developing thousands of acres of local parks and hugely ambitious land reclamation efforts, Singapore managed to do something remarkable: it became simultaneously denser and greener. The authorities claim the urban forest grew from 158,600 trees in 1974 to 1.4 million in 2014, even as the city added three million more people. Today, almost half the island is covered in grasses, shrubs and broad-canopied trees, throwing cold water on the idea that cities can't spare room for nature as they grow. 

"It's the biophysical environment that's a differentiating factor," says Daniel Burcham, a former researcher at the parks board, when I ask him to explain Singapore's success. "It's just easy to grow trees when it's summer every single day and you have over 2m [7ft] of rain every year."

 

But without political consensus, he adds, there would not have been room spared for those trees to grow. "This was a goal that they [Lee's government] were going to pursue, and it was a vision that they were all united around achieving."

Burcham now teaches arboriculture – the cultivation of trees and forests – at Colorado State University in Fort Collins, a semi-arid city where political leaders have a few years in office, not decades. "Some would characterise Lee Kuan Yew as a strongman, or semi-authoritarian figure, and to some extent, that's very true," says Burcham. "But this is one good thing that came from that system. He set out this goal and provided material resources and provided political support for people to achieve it."

But while it would require coherence across administrations, there's no reason in principle why democratically elected governments in tropical cities like Miami or Honolulu could not also sustain such a project.

So does all this shade protect Singaporeans? In the afternoon, the streets of Singapore's business district, plunged in the shadows of skyscrapers, are the coolest in the city. The effect ends when the sun goes down, and the buildings release the solar radiation they absorbed. At night, the green grounds of a public housing estate may offer the most relief, as the air is 1-2C (2-4F) cooler than the drafts whistling through a bustling commercial strip.

The well-established epidemiological link between air temperature and heat illness would indicate that these shadiest neighbourhoods are indeed Singapore's safest from heat. Shade infrastructure like trees and buildings won't be enough to overcome all the warming effects of climate change, but it will make a difference.

It's unlikely that local American governments can be as effective as Singapore's, an autocratic nation-state long ruled by a strongman with a personal interest in shade. Nor are most US cities fortunate enough to have Singapore's ideal climate for growing trees.

Nevertheless, Singapore shows what can be done with intentional government planning of shade. A cooler city for everyone is within reach. Let's not pretend it's impossible.

* This article is based on an extract from Sam Bloch's book, Shade: The Promise of a Forgotten Natural Resource, published in July 2025. 

 

 

Syria's worst drought in decades pushes millions to the brink

 

Sheep walk among the dried-out bed of the Orontes River in Jisr al-Shughour, northern Syria

by

Samantha Granville, Beirut

 

 

The wheat fields outside Seqalbia, near the Syrian city of Hama, should be golden and heavy with grain.

Instead, Maher Haddad's 40 dunums (10 acres) are dry and empty, barely yielding a third of their usual harvest.

"This year was disastrous due to drought," said the 46-year-old farmer, reflecting on the land that cost him more to sow than it gave back.

His fields delivered only 190kg (418 lbs) of wheat per dunum - far below the 400-500kg he relies on in a normal year.

"We haven't recovered what we spent on agriculture; we've lost money. I can't finance next year and I can't cover the cost of food and drink," Mr Haddad told the BBC.

With two teenage daughters to feed, he is now borrowing money from relatives to survive.

Mr Haddad's struggle is echoed across Syria, where the worst drought in 36 years has slashed wheat harvests by 40% and is pushing a country - where nearly 90% of the population already lives in poverty - to the brink of a wider food crisis.

A report from the United Nations' Food and Agriculture Organization (FAO) estimates Syria will face a wheat shortfall of 2.73m tonnes this year, the equivalent of annual dietary needs for 16.25 million people.

Farmer Maher Haddad said the drought had been disastrous for his crops

Without more food aid or the ability to import wheat, Syria's hunger crisis is set to worsen dramatically, warned Piro Tomaso Perri, FAO's senior programme officer for Syria.

"Food insecurity could reach unprecedented levels by late 2025 into mid-2026," he said, noting that more than 14 million Syrians - six in 10 people - are already struggling to eat enough. Of those, 9.1 million face acute hunger, including 1.3 million in severe conditions, while 5.5 million risk sliding into crisis without urgent intervention.

The same report showed rainfall has dropped by nearly 70%, crippling 75% of Syria's rain-fed farmland.

"This is the difference between families being able to stay in their communities or being forced to migrate," Mr Perri said. "For urban households, it means rising bread prices. For rural families, it means the collapse of their livelihoods."

Farming families are already selling livestock to supplement lost incomes from wheat, reducing their number of daily meals, and there has been a rise in malnutrition rates among children and pregnant women.

Yet, the implications of the drought stretch far beyond the thousands of kilometres of barren farmlands.

Wheat is a staple crop in Syria. It is the main ingredient for bread and pasta - two food staples that should be low cost foods to families. So with the lack of wheat supply, the cost goes up.

For 39-year-old widow Sanaa Mahamid, affording bread has become a massive struggle.

With six children between the ages of nine and 20, she relies on the wages of two sons, but their salaries are not enough to cover the family's basic expenses.

"Sometimes we borrow money just to buy bread," she said.

Syria is relying more heavily on wheat imports, including shipments from Russia

Last year, a bag of bread cost Sanna 500 Syrian pounds ($4.1; £3; €3.5), but now it is 4,500 Syrian pounds. To feed her family, Sanaa needs two bags a day - an expense of 9,000 pounds, before accounting for any other food.

"This is too much. This is just bread, and we still need other things," she said. "If the price of bread rises again, this will be a big problem. The most important thing is bread."

The crisis is a challenge for interim President Ahmed al-Sharaa, as his administration works to rebuild Syria in the aftermath of the 14-year conflict and the removal of former leader Bashar al-Assad in December 2024.

International agencies, like the UN World Food Programme (WFP), are rushing to step in alongside the government to provide bread subsidies for those at risk of facing severe food insecurity.

But aid officials warn that subsidies are only a temporary fix, and that the long-term stability of Syria depends on whether farmers can stay on their land and sustain production.

"We're trying to keep people in the farming game," Marianne Ward, the WFP's country director for Syria, said. She has worked to give $8m (£6m; €6.9m) in direct payments to small farmers - about 150,000 people - who lost all of their crops.

"If you're not going to make money, you're going to leave the land. And then you're not going to have people who are going to be working in the agriculture sector which is essential for the economy," she said

But after more than a decade of war, Syria's agricultural sector was already battered by economic collapse, destroyed irrigation systems, and mined fields.

Dr Ali Aloush, the agriculture director for the Deir al-Zour region, Syria's breadbasket, said wheat fields needed to be irrigated four to six times per season, but that due to lack of rain, most farmers could not keep up.

"The farmer's primary concern is first securing water and water requires fuel. The fuel price skyrocketed. It reached to 11,000 to 12,000 Syrian pounds per litre," Dr Aloush said.

The high price of fuel and power cuts meant water pumps were out of reach, and many growers were already burdened with debt.

Dr Aloush says a priority for his department and the transitional government in Damascus is putting money into irrigation projects - like solar powered drips - that will make water more accessible to farmers.

But projects like that take time and money - luxuries wheat farmers do not currently have.

So for millions of Syrians across the country, there is only one thing to do in the coming months: pray for rain.

Additional reporting by Lana Antaki in Damascus

An Annual Blast of Pacific Cold Water Did Not Occur, Alarming Scientists. The cold water upwell, which is vital to marine life, did not materialize for the first time on record. Researchers are trying to figure out why.

A fishing vessel off Punta Chame in the Gulf of Panama on the Pacific side of the isthmus.Credit...Oyvind Martinsen, via Alamy

 

By Sachi Kitajima Mulkey

 

Each year between January and April, a blob of cold water rises from the depths of the Gulf of Panama to the surface, playing an essential role in supporting marine life in the region. But this year, it never arrived.

“It came as a surprise,” said Ralf Schiebel, a paleoceanographer at the Max Planck Institute for Chemistry who studies the region. “We’ve never seen something like this before.”

The blob is as much as 10 degrees Celsius colder than the surface water. In Fahrenheit terms, the water would be 18 degrees colder than the surface water. That cold water is also rich in nutrients from decomposing matter that falls to the ocean floor, providing food for local fisheries and wildlife.

Dr. Schiebel was one of the scientists who recently documented the lack of this yearly upwelling in a paper in Proceedings of the National Academy of Sciences and identified a likely culprit: The lack of strong trade winds, which typically blow across Panama and kick off the dry season in January.When the trade winds reach the Gulf of Panama they push hot surface water away from the coast, which makes room for cold water to rise from the deep

 Steven Paton, one of the paper’s co-authors, runs a large environmental monitoring program at the Smithsonian Tropical Research Institute. The record he helps maintain shows the upwelling has taken place annually for at least 40 years. With that data and other long term records, “we can very clearly say something very unusual happened that we need to pay attention to,” he said.

 

It’s unclear whether a warming planet played a role in the disappearance of the cold blob this year. But the researchers have a few theories about what affected the trade winds.

Trade winds, like the ones that drive the cold upwelling in the Gulf of Panama, typically form when air moves from high pressure to low pressure systems. But this year Panama saw only a quarter of the usual dry season trade winds and when they did emerge, it was only for a short period of time.

The Bermuda-Azores High is a high pressure system that moves around the Atlantic Ocean, affecting seasonal weather patterns across Europe, Africa and the Americas. A separate, low pressure system, known as the Intertropical Convergence Zone, wraps around the Equator and moves south of Panama in winter. This southward movement, in combination with the difference in pressure from these two systems, causes the force that drives Panama’s dry season trade winds.

La Niña, the cool phase of an oscillating cycle of water temperatures in the Pacific Ocean, may have shifted the position of the low pressure system. Hot ocean surface temperatures may have also affected the strength of the two atmospheric systems. But the impact of these factors is unclear until more research is done, the researchers said.

 

Andrew Sellers, a marine ecologist at the Smithsonian Tropical Research Institute who coauthored the paper, said the disappearance of the cold water upwelling could cause “major repercussions throughout the food web.”

Nutrient rich waters are important for Panama’s fishing industry, which is concentrated on the Pacific side of the isthmus, rather than in the Caribbean, he said. The upwelling also supports large marine life, like dolphins, rays and migrating whales that pass through the region.

The lower temperatures also provide respite for coral reefs, which are made up of living organisms that can bleach white and die when they get too hot.

Richard Aronson, a professor of marine sciences at the Florida Institute of Technology, has studied this particular patch of ocean off the coast of Panama for decades. The cold blob gives those corals a better chance of surviving marine heat waves than other areas, he said.

Heat stress has plunged the world’s coral reefs into ongoing mass bleaching that began in January 2023. About 85 percent of the world’s coral reef areas have been affected, according to the National Oceanic and Atmospheric Administration.

 

“The climate is warming, that’s putting coral reefs at risk,” said Dr. Aronson, who was not involved with the paper. While corals can adapt to changes in temperature, the climate is changing too quickly for them to keep up in the long run, he said. Sea surface temperatures have risen by more than 1 degree Celsius since humans began burning fossil fuels during the Industrial Revolution, breaking records in 2024 and 2023.

It’s too soon to tell if the blob will return in future years. But if it disappears repeatedly, then “it’s cause for grave concern,” Dr. Aronson said. 

 

There are other cold water blobs across the world, including in the Galápagos and off the coast of Costa Rica, each driven by different air and ocean patterns. As the planet warms, Dr. Schiebel said, other atmospheric pressure systems that drive trade winds may diminish, too.

“Our fear is now that it would also happen to other upwelling systems,” he said.

 

‘China Is the Engine’ Driving Nations Away From Fossil Fuels, Report Says. Its vast investment in solar, wind and batteries is on track to end an era of global growth in the use of coal, oil and gas, the researchers said.

 

Solar panels and wind turbines in Shandong Province, China, in June.Credit...Agence France-Presse — Getty Images

 

 

 

 By Max Bearak

 

 Since the beginning of the industrial age, the global economy has required more and more fossil fuels — coal, oil and gas — to power growth.

It is increasingly clear, however, that China’s aggressive efforts to sell batteries, solar panels and wind turbines to the world is on course to bring that era to an end, a new report says. The Chinese dominance of clean-energy industries is “creating the conditions for a decline in fossil fuel use,” according to a report by Ember, a research group focused on the prospects for clean-energy technologies.

The report includes a sprawling set of data to support its claim.

 The scale of Chinese production since 2010 has driven the price of these technologies down by 60 to 90 percent, the researchers found. And last year, more than 90 percent of wind and solar projects commissioned worldwide produced power more cheaply than the cheapest available fossil-fuel alternative, they said. That cost advantage might have seemed laughable before China began pumping billions of dollars of subsidies into the sector.

 

“China is the engine,” said Richard Black, the report’s editor. “And it is changing the energy landscape not just domestically but in countries across the world.”

If Beijing is trying to wrest the future of energy from anyone, it would be the United States, the world’s biggest oil and gas producer and exporter. The Trump administration has eliminated almost all federal support for renewable energies and has pressured countries to purchase American fossil fuels as part of trade deals.

 

The falling cost of renewable energy, though, means that many countries, particularly poorer ones, have a strong incentive to reduce their reliance on fossil fuels.

According to Ember’s report, the falling costs of energy produced by Chinese-made wind and solar installations have allowed countries like Mexico, Bangladesh and Malaysia to race past the United States in recent years in terms of using renewably produced electricity (rather than fossil fuels) in everyday activities like heating and cooling buildings or powering vehicles.

Across Africa, solar panel imports from China rose 60 percent in the last 12 months, and 20 African countries imported a record amount over that period, Ember said in a separate study recently.

 American companies, who do not make solar panels or wind turbines at anywhere near the scale of Chinese ones, are at a major disadvantage. Chinese companies now supply 80 percent of solar panels and 60 percent of wind turbines worldwide, Ember said.

 

China has pushed for dominance in renewable energy partly for economic reasons and also to protect its national security by limiting its reliance on oil imports. But the implications for the planet’s health could scarcely be greater. Scientific consensus has long been that a sharp decline in fossil fuel use is the surest way to lessen the pace of climate change.

“For too long, emerging economies have faced what seemed like a stark trade-off between growth and sustainability,” said Suwit Khunkitti, Thailand’s former deputy prime minister. The Ember report “challenges that assumption,” he said.

To be sure, some countries would not be keen to rely so heavily on Chinese technology for geopolitical reasons. And few developing countries have the spending capacity to install the kinds of energy transmission and storage capacity that has allowed China to transform its own domestic energy grid so quickly.

 

When the world’s fossil fuel use will peak also comes down to the pace of that change in China itself.

China still burns more coal than the rest of the world combined and emits more climate pollution than the United States and Europe together. The country has not yet seen a decline in coal usage overall, though its total greenhouse gas emissions have reached what looks like a plateau.

But last year, China met 84 percent of its electricity demand growth with solar and wind power, according to the report. That meant it was able to cut fossil fuel use by 2 percent, despite a growing demand for power.

 Mr. Black said that decline in fossil fuel use was largely due to burning less coal to produce electricity. He pointed to a number of recent policy directives that have reallocated subsidies and production incentives away from coal and toward solar and wind.

 

China is still building dozens of new coal-burning power plants, he said, but instead of running constantly like many existing ones, they might be at full capacity only during peaks in energy demand. Meanwhile, the contribution of wind and solar to the grid was quickly growing, he said.

“Coal is increasingly acting like training wheels,” said Yuan Jiahai, a professor at North China Electric Power University. “It provides balance and backup while the clean electricity system gains strength and confidence.”

China’s economy as a whole is increasingly reliant on the clean energy sector.

Investment and production in clean energy last year contributed nearly $2 trillion to China’s economy, a figure which the report said was around one-tenth of the country’s economy as a whole, or comparable to Australia’s entire economy. The clean energy sector grew at a rate three times that of China’s economy overall, according to the report.

Max Bearak is a Times reporter who writes about global energy and climate policies and new approaches to reducing greenhouse gas emissions.

Summer 2025 was hottest on record in UK, says Met Office. Unprecedented average temperature made about 70 times more likely by human-induced climate change, says agency

The water levels at Broomhead reservoir in South Yorkshire have been low this summer. Photograph: Richard McCarthy/PA

by  Damien Gayle

The UK has had its hottest summer on record, the Met Office has said, after the country faced four heatwaves in a single season.

The mean temperature for meteorological summer, which encompasses the months of June, July and August, was 16.1C (60.98F), which is significantly above the current record of 15.76C set in 2018.

All five of the hottest summers on record have now occurred since 2000 – a clear signal of the global heating that scientists say is resulting from increasing concentrations of greenhouse gases in the atmosphere.

The Met Office said it had conducted a rapid analysis that found the record-breaking summer temperatures had been made about 70 times more likely because of human-induced climate change.

 Dr Mark McCarthy, the agency’s head of climate attribution, said: “In a natural climate, we could expect to see a summer like 2025 with an approximate return period of around 340 years, while in the current climate we could expect to see these sorts of summers roughly one in every five years.

“Our analysis suggests that while 2025 has set a new record, we could plausibly experience much hotter summers in our current and near-future climate and shows how what would have been seen as extremes in the past are becoming more common in our changing climate.”

The latest record beats the last by a wide margin. This year’s average temperature was just over a third of a degree hotter than 2018’s previous record, while temperatures for the other four of the five hottest summers on record differed by just hundredths of a degree. Overall the mean temperature was 1.51C above the long-term meteorological average.

June and July had hot weather, with four heatwaves including days above 30C. There has been very little rain across much of the country, with England experiencing what the government has called “nationally significant” water shortfalls. Much of England is under a hosepipe ban as reservoirs, rivers and groundwater run dry.

Although the summer has been consistently warm, there has not been extreme heat. The highest temperature recorded to date for 2025 was 35.8C in Faversham, Kent, on 1 July, well short of the UK’s all-time high of 40.3C, set in July 2022.

But in June alone there were two heatwaves, making it the hottest June on record for England and the second hottest for the UK overall. A third heatwave in July and a fourth in August pushed the overall average temperature for the summer into record-breaking territory.

 

Towards the end of June, scientists calculated that the heat endured by people in the south-east of England had been made 100 times more likely by the climate crisis.

Meteorologists have said this year’s consistent warmth was driven by dry ground from spring, high-pressure systems, and unusually warm seas around the UK, and minimum temperatures had been exceptionally above average.

The Met Office scientist Dr Emily Carlisle said: “These conditions have created an environment where heat builds quickly and lingers, with both maximum and minimum temperatures considerably above average,.”

Collapse of critical Atlantic current is no longer low-likelihood, study finds. Scientists say ‘shocking’ discovery shows rapid cuts in carbon emissions are needed to avoid catastrophic fallout

New modelling suggests the tipping point that makes an Amoc shutdown inevitable is likely to be passed within a few decades. Photograph: Henrik Egede-Lassen/Zoomedia/PA

 
by Damian Carrington Environment editor

 

The collapse of a critical Atlantic current can no longer be considered a low-likelihood event, a study has concluded, making deep cuts to fossil fuel emissions even more urgent to avoid the catastrophic impact.

The Atlantic meridional overturning circulation (Amoc) is a major part of the global climate system. It brings sun-warmed tropical water to Europe and the Arctic, where it cools and sinks to form a deep return current. The Amoc was already known to be at its weakest in 1,600 years as a result of the climate crisis.

Climate models recently indicated that a collapse before 2100 was unlikely but the new analysis examined models that were run for longer, to 2300 and 2500. These show the tipping point that makes an Amoc shutdown inevitable is likely to be passed within a few decades, but that the collapse itself may not happen until 50 to 100 years later.

 

The research found that if carbon emissions continued to rise, 70% of the model runs led to collapse, while an intermediate level of emissions resulted in collapse in 37% of the models. Even in the case of low future emissions, an Amoc shutdown happened in 25% of the models.

Scientists have warned previously that Amoc collapse must be avoided “at all costs”. It would shift the tropical rainfall belt on which many millions of people rely to grow their food, plunge western Europe into extreme cold winters and summer droughts, and add 50cm to already rising sea levels.

 

The new results are “quite shocking, because I used to say that the chance of Amoc collapsing as a result of global warming was less than 10%”, said Prof Stefan Rahmstorf, at the Potsdam Institute for Climate Impact Research in Germany, who was part of the study team. “Now even in a low-emission scenario, sticking to the Paris agreement, it looks like it may be more like 25%.

“These numbers are not very certain, but we are talking about a matter of risk assessment where even a 10% chance of an Amoc collapse would be far too high. We found that the tipping point where the shutdown becomes inevitable is probably in the next 10 to 20 years or so. That is quite a shocking finding as well and why we have to act really fast in cutting down emissions.”

Scientists spotted warning signs of a tipping point in 2021 and know that the Amoc has collapsed in the Earth’s past. “Observations in the deep [far North Atlantic] already show a downward trend over the past five to 10 years, consistent with the models’ projections,” said Prof Sybren Drijfhout, at the Royal Netherlands Meteorological Institute, who was also part of the team.

“Even in some intermediate and low-emission scenarios, the Amoc slows drastically by 2100 and completely shuts off thereafter. That shows the shutdown risk is more serious than many people realise.”

The study, published in the journal Environmental Research Letters, analysed the standard models used by the Intergovernmental Panel on Climate Change (IPCC). The scientists were particularly concerned to find that in many models the tipping point is reached in the next decade or two, after which the shutdown of the Amoc becomes inevitable owing to a self-amplifying feedback.

Air temperatures are rising rapidly in the Arctic because of the climate crisis, meaning the ocean cools more slowly there. Warmer water is less dense and therefore sinks into the depths more slowly. This slowing allows more rainfall to accumulate in the salty surface waters, also making it less dense, and further slowing the sinking, forming the feedback loop. Another new study, using a different approach, also found the tipping point is probably going to be reached around the middle of this century.

 

Only some of the IPCC models have been run beyond 2100, so the researchers also looked to see which of those running to the end of this century showed Amoc was already in terminal decline. This produced the 70%, 37% and 25% figures. The scientists concluded: “Such numbers no longer comply with the low-likelihood-high-impact event that is used to discuss an abrupt Amoc collapse in [the IPCC’s last report].”

Rahmstorf said the true figures could be even worse, because the models did not include the torrent of meltwater from the Greenland ice cap that is also freshening the ocean waters.

Dr Aixue Hu at the Global Climate Dynamics Laboratory in Colorado, US, who was not part of the study team, said the results were important. “But it is still very uncertain when Amoc collapse will happen or when the Amoc tipping point is going to crossed because of the lack of direct observations [of the ocean] and the varying results from the models.”

The study that found that a total collapse of the Amoc was unlikely this century was led by Dr Jonathan Baker at the Met Office Hadley Centre in the UK. “This new study highlights that the risk rises after 2100,” he said. “[But] these percentages should be treated with caution – the sample size is small, so more simulations [beyond 2100] are needed to better quantify the risk.”

Nonetheless, Baker said, “the ocean is already changing, and projected shifts in North Atlantic convection are a real concern. Even if a collapse is unlikely, a major weakening is expected, and that alone could have serious impacts on Europe’s climate in the decades to come. But the future of the Atlantic circulation is still in our hands.”

Dramatic slowdown in melting of Arctic sea ice surprises scientists. Natural climate variation is most likely reason as global heating due to fossil fuel burning has continued

Melting is likely to start again at about double the long-term rate in the next five to 10 years, the scientists said. Photograph: Keren Su/China Span/Alamy

 

The melting of sea ice in the Arctic has slowed dramatically in the past 20 years, scientists have reported, with no statistically significant decline in its extent since 2005.

The finding is surprising, the researchers say, given that carbon emissions from fossil fuel burning have continued to rise and trap ever more heat over that time.

They said natural variations in ocean currents that limit ice melting had probably balanced out the continuing rise in global temperatures. However, they said this was only a temporary reprieve and melting was highly likely to start again at about double the long-term rate at some point in the next five to 10 years.

The findings do not mean Arctic sea ice is rebounding. Sea ice area in September, when it reaches its annual minimum, has halved since 1979, when satellite measurements began. The climate crisis remains “unequivocally real”, the scientists said, and the need for urgent action to avoid the worst impacts remains unchanged.

 The natural variation causing the slowdown is probably the multi-decadal fluctuations in currents in the Atlantic and Pacific oceans, which change the amount of warmed water flowing into the Arctic. The Arctic is still expected to see ice-free conditions later in the century, harming people and wildlife in the region and boosting global heating by exposing the dark, heat-absorbing ocean.

 

Dr Mark England, who led the study while at the University of Exeter, said: “It is surprising, when there is a current debate about whether global warming is accelerating, that we’re talking about a slowdown.

“The good news is that 10 to 15 years ago when sea ice loss was accelerating, some people were talking about an ice-free Arctic before 2020. But now the [natural] variability has switched to largely cancelling out sea ice loss. It has bought us a bit more time but it is a temporary reprieve – when it ends, it isn’t good news.”

The research, published in the journal Geophysical Research Letters, used two different datasets of Arctic sea ice levels from 1979 to the present day. The scientists analysed the sea ice area for every month of the year and the slowdown was seen in all cases.

To see if such a slowdown could be a result of natural variation, they examined the results of thousands of climate model runs. “This is not an extremely rare event – over a century, it should happen a couple of times,” said England, now at the University of California, Irvine. Furthermore, all the simulations showed sea ice loss accelerating again after the slowdown.

Prof Julienne Stroeve, of University College London, said: “We know climate records, be it in global temperatures or sea ice, can remain the same for several years in a row as a result of internal climate variability.”

Stroeve’s analysis of the long-term trend from 1979 to 2024 shows that about 2.5 sq metres of September ice is lost for every tonne of CO₂ emitted.

 

Prof Andrew Shepherd, of Northumbria University, said: “We know that the Arctic sea ice pack is also thinning, and so even if the area was not reducing, the volume still is. Our data show that since 2010 the average October thickness has fallen by 0.6cm per year.”

The rate of the rise in global surface temperature has also slowed down in the past, before resuming a rapid rise. A major El Niño event in 1998 was followed by a decade or so of similar global temperatures, which was nicknamed “the pause”. However, the planet continued to accumulate heat throughout and global temperatures have since risen rapidly.

England rejected any suggestion the sea ice slowdown suggested climate change was not real. “Climate change is unequivocally real, human-driven, and continues to pose serious threats. The fundamental science and urgency for climate action remain unchanged,” he said.

“It is good to explain to people that [the slowdown] is happening, else they are going to hear it from someone who is trying to use it in bad faith as a way to undermine our very solid understanding of what’s happening with climate change.”