There are a lot of humans. Teeming is perhaps an unkind word, but when 8 billion people cram themselves on to a planet that, three centuries before, held less than a tenth of that number, it seems apt. Eight billion hot-breathed individuals, downloading apps and piling into buses and shoving their plasticky waste into bins – it is a stupefying and occasionally sickening thought.

And yet, humans are not Earth’s chief occupants. Trees are. There are three trillion of them, with a collective biomass thousands of times that of humanity. But although they are the preponderant beings on Earth – outnumbering us by nearly 400 to one – they’re easy to miss. Show someone a photograph of a forest with a doe peeking out from behind a maple and ask what they see. “A deer,” they’ll triumphantly exclaim, as if the green matter occupying most of the frame were mere scenery. “Plant blindness” is the name for this. It describes the many who can confidently distinguish hybrid dog breeds – chiweenies, cavapoos, pomskies – yet cannot identify an apple tree.

Admittedly, trees do not draw our attention. Apart from plopping the occasional fruit upon the head of a pondering physicist, they achieve little that is of narrative interest. They are “sessile” – the botanist’s term meaning incapable of locomotion. Books about trees often have a sessile quality, too; they are informative yet aimless affairs, heavy on serenity, light on plot.

Or, at least, they were until recently. The German forester Peter Wohlleben’s surprise bestseller, The Hidden Life of Trees (published in English in 2016), has inaugurated a new tree discourse, which sees them not as inert objects but intelligent subjects. Trees have thoughts and desires, Wohlleben writes, and they converse via fungi that connect their roots “like fibre-optic internet cables”. The same idea pervades The Overstory, Richard Powers’ celebrated 2018 novel, in which a forest scientist upends her field by demonstrating that fungal connections “link trees into gigantic, smart communities”.

Both books share an unlikely source. In 1997, a young Canadian forest ecologist named Suzanne Simard (the model for Powers’ character) published with five co-authors a study in Nature describing resources passing between trees, apparently via fungi. Trees don’t just supply sugars to each other, Simard has further argued; they can also transmit distress signals, and they shunt resources to neighbours in need. “We used to believe that trees competed with each other,” explains a football coach on the US hit television show Ted Lasso. But thanks to “Suzanne Simard’s fieldwork”, he continues, “we now realise that the forest is a socialist community”.

The idea of trees as intelligent and cooperative has moved swiftly from research articles to “did you know?” cocktail chatter to children’s book fare. There is more botanical revisionism to come. “We are standing at the precipice of a new understanding of plant life,” the journalist Zoë Schlanger writes. Her captivating new book, The Light Eaters, describes a set of researchers studying plant sensing and behaviour, who have come to regard their subjects as conscious. Just as artificial intelligence champions note that neural networks, despite lacking actual neurons, can nevertheless perform strikingly brain-like functions, some botanists conjure notions of vegetal intelligence.

This is an age of many minds, it would seem. Oddly, it took grappling with new technology – the internet, artificial intelligence – for us to see intellectual capacities in our oldest companions, trees. In this new light, they appear much more like us, or perhaps us as we would wish to be. There is a form of redemption on offer: having for centuries treated trees as timber, we are now invited to embrace them as kin.

But before enfolding their rough barks in our soft arms, it may do to pause a beat. Whereas researchers must usually toil in respectable obscurity for decades before their ideas attract notice, the intelligent-plant notion is moving at top speed. Public demand, as much as peer review, is driving the train, with popular books reporting excitedly on studies that scientists are still debating – sometimes outracing the science entirely. It’s worth asking what makes us so eager to ascribe human qualities to the arboreal world. Might we be missing something important when we gaze into the wooden mirror and see only ourselves?

The title of Simard’s 1997 Nature article was almost impeccably dry – Net transfer of carbon between ectomycorrhizal tree species in the field – and a casual observer might have missed the study’s significance. Botanists have long understood that fungi called mycorrhizae formed symbiotic relationships with trees, exchanging water and nutrients for photosynthesised sugars. What Simard and her co-authors showed is that the sugars made their way not just to the fungi but to other trees in the forest, seemingly travelling through the fungi. The journal’s editors sensed promise. They made it Nature’s cover story, commissioned a foreword by a leading botanist, and affixed an indelible pun: this was the “wood-wide web”.

It wasn’t Simard’s metaphor, but she has pounced on it. The forest, she has written, is “like the internet”: a system of “centres and satellites, where the old trees were the biggest communication hubs and the smaller ones the less busy nodes, with messages transmitting back and forth through the fungal links”. Rather than rivals scrabbling over resources, connected trees are what Simard calls “supercooperators”.

Simard’s fellow foresters were initially unmoved by her idea of the harmonious forest. Simard describes, after publishing, having her government research budget threatened and her findings mocked. “No other animal closes ranks faster than Homo sapiens,” Powers wrote in his fictionalised account of the episode. But the problem wasn’t the whole species so much as its male members, in Simard’s telling. “Miss Birch” is what the men called her within earshot – just a Scrabble tile away from what they called her outside it.

Much-needed support came from women. Simard has singled out the mycorrhiza expert Melanie Jones, who sat on Simard’s doctoral committee and co-authored the Nature article, and several female companions who accompanied her on her research. All this suggested another metaphor to Simard: maternity. Although the conifers she studied had both male and female organs, the way mature trees aided seedlings via fungal networks “felt like mothering to me”. She imagined “the flow of energy from the Mother Trees as powerful as the ocean tide, as strong as the sun’s rays, as irrepressible as the wind in the mountains, as unstoppable as a mother protecting her child”.

There has been, indeed, something unstoppable about the idea of networked mother trees. In her memoir, Finding the Mother Tree, Simard writes that her ideas inspired James Cameron’s 2009 film Avatar, in which all forest life connects via a biological network to large trees (the film also features an ecologically sensitive female scientist). It is unclear how much Cameron, who was already at work on Avatar before the “wood-wide web” paper appeared, knew of Simard’s research. Still, the resemblance between her theory and Cameron’s fantasy – in what somehow remains the highest-grossing film in history – attests to the idea’s exquisite zeitgeistiness.

The idea became even more zeitgeisty in 2016, the year of the Brexit vote and Donald Trump’s election. That was when Simard gave her much-watched Ted Talk, How Trees Talk to Each Other (approaching 8m views), and appeared with Wohlleben in the documentary Intelligent Trees. It was also when Wohlleben’s phenomenally popular Hidden Life of Trees was published in English, with an appreciative afterword by Simard. Wohlleben, who cannot pass by a tree without attributing human qualities to it, described trees as learning, disciplining their offspring and forming powerful friendships. Simard’s research, he explained, revealed their “maternal instincts … You might even say they are nursing their babies.”

Wohlleben’s book has sold more than 3m copies in more than 35 editions. Powers’ The Overstory, featuring its Simardian character, won the 2019 Pulitzer prize for fiction. This year, Time magazine named Simard one of the world’s 100 most influential people. Amy Adams’ and Jake Gyllenhaal’s production companies have bought the film rights to Simard’s Finding the Mother Tree, with the intention that Adams would play Simard.

It is rare for academic ideas to reach the Amy Adams stage without drawing scholarly fire. Since 2023, three articles have appeared in scientific journals, with 45 authors in all, arguing that the claims made on behalf of the wood-wide web have far outstripped the evidence. The objections are numerous. Many studies of inter-tree transfers have found only minuscule amounts of sugars shuttling between the trees – “statistically significant” but not necessarily “biologically significant”, one group of authors says – and most don’t rule out the possibility that the resources travelled through the air or soil rather than fungally. Despite Wohlleben’s insistence in Hidden Life that in a mycorrhizally conjoined forest “it is not possible for trees to grow too close to each other”, studies have not generally shown that seedlings ensconced in fungal networks do better when close to older trees (they often do worse). And although many trees are colonised by mycorrhizae, there is debate about whether those mycorrhizae actually form a durable network through which nutrients and signals could pass.

Nature, the original venue for Simard’s research, recently ran an explosive news feature by Aisling Irwin on the “groundswell of unease” among ecologists with public discussions of mycorrhizal networks. Irwin reports on the scientists’ general scepticism and on a particular episode that has raised concerns. In her memoirs, Simard makes much of the idea that “mother trees” favour their kin. She describes in detail field research by her graduate student showing that seedlings placed in a fungal network “survived better and were noticeably bigger” if they were genetically related to nearby older trees. But that field study, the critics have noted, actually showed the opposite: the related seedlings were likelier to die, though the trend was not statistically significant. (Simard says that other studies by the student, from the laboratory, support her claims and she’d merely made a narrative choice to describe the results as emanating from the forest. “I do not, and would never, imply anything misleading when presenting research,” she told Irwin.)

What makes the recent criticisms of Simard’s work so striking is that some come from her former colleagues and admirers. The first critical review of evidence was by three scientists – Justine Karst, Melanie Jones and Jason Hoeksema – who had all co-authored papers with Simard. The lead author, Karst, has discussed how she was inspired by Simard’s research to become a mycorrhizal ecologist. The second, Melanie Jones, appears in Simard’s memoirs as a hero who supported Simard when few others would. Jones co-authored the 1997 “wood-wide web” article, though she no longer stands fully by it. It was the cultural obsession with intelligent trees, from television shows to airport books, that impelled Karst, Jones and Hoeksema to reconsider their own earlier work.

Simard, who is preparing detailed replies, regards these in-the-weeds debates as distracting from the urgent task of protecting forests. She has described the attention that Karst, Jones and Hoeksema’s criticisms have received as “an injustice to the whole world”. Perhaps, but it is exceedingly hard to read the recent reviews of evidence and retain faith in the wood-wide web as settled scientific fact.

“Why do we so badly want this to be true?” Karst has asked. Maybe the unrelenting news of global warming and its attendant catastrophes – wildfires, hurricanes – has driven readers for respite toward calmer environmental stories. Or perhaps recent political cruelties have led us to seek reassurance that, in nature, beings are thoughtful and kind. The connective aspect seems important, too, as if trees’ fungal friendships could release us from our phone-checking isolation. Fairly or not, we’ve loaded our aspirations on to the forest: be the tree you want to see in the world.

The literary scholar Rob Nixon sees the wood-wide web as an economic parable. Most often, he notes, popular understandings of nature connect to politics, as people look to the natural order to legitimate the social one. In the 1970s, when free markets were gaining support, books like Richard Dawkins’s The Selfish Gene (1976) highlighting capitalist dynamics in nature won large audiences. If you see society as fundamentally competitive, you’re primed to see biology that way, too. But since the 2007-8 financial crash, Nixon explains, prevailing economic instincts have tilted in the other direction. It’s satisfying, for the leftishly inclined, to imagine connected forests as what Wohlleben calls “gigantic redistribution mechanisms”.

The wood-wide web narrative, Nixon believes, transcends science. Beyond the peer-reviewed research, there is something about the concept that, to many, just feels instinctively right. It gives us the trees for our times: anti-capitalist, feminist and extremely online.

The Hidden Life of Trees is the title of Peter Wohlleben’s book. This must not be confused with The Secret Life of Trees, by Colin Tudge, which also tells the mycorrhizal story. Nor should either be confused with The Secret Forest, the book that the Suzanne Simard character writes in The Overstory.

Such titles are just one or two words away from the title of the most notorious botany book ever written: The Secret Life of Plants, a 1973 bestseller by Peter Tompkins and Christopher Bird. That book, like Wohlleben’s, rejected the idea of plants as “senseless automata” and sought to portray them as perceptive, energetic and intelligent. Plants, like animals, transmit electrical pulses through their bodies. Such pulses, Tompkins and Bird believed, could reveal plants’ thoughts.

A series of wild experiments ensued, which can serve as a reminder both of the importance of peer review and of how fun the 1970s were. If people had sex on holiday, would their plants back at home know? All it took to find out was a begonia, electrodes and a lakeside cottage. “Chapter 1: Plants and ESP,” was the book’s auspicious beginning, and from there matters moved swiftly on to energy fields, faster-than-light communication and aliens.

The book inaugurated an odd era of people talking to their houseplants and playing them classical music. The CIA and US army funded research into vegetal perception (plants could be deployed in airports to detect the “turbulent emotions” of would-be hijackers, Tompkins and Bird suggested). Stevie Wonder, fresh off an extraordinary streak of innovative hit albums, infuriated his label by releasing a double LP titled Stevie Wonder’s Journey Through the Secret Life of Plants. “Most felt it was mad to conceive,” he sang, “that plants thought, felt and moved quite like we.”

It was not Wonder’s finest lyric, and, in hindsight, the whole episode seems fairly preposterous – the intellectual counterpart to the age’s waterbeds and extra-wide neckties. After the plant-talking fad receded, Tompkins moved on to his next enthusiasm: finding the lost land of Atlantis. But The Secret Life of Plants hung heavily over botany for decades as an admonition against excess. Research on plant sensation and reaction was hindered. “The twin gatekeepers of science funding boards and peer review boards – always conservative institutions – closed the doors,” Zoë Schlanger writes.

This was unfortunate, Schlanger feels, because plants really are capable of remarkable things. Alongside the wood-wide web idea has come a surge of new plant writing, including Monica Gagliano’s Thus Spoke the Plant (foreword by Suzanne Simard), Paco Calvo and Natalie Lawrence’s Planta Sapiens, Daniel Chamovitz’s What a Plant Knows and Stefano Mancuso’s The Revolutionary Genius of Plants, all chronicling uncanny plant behaviour. Maybe The Secret Life of Plants, absurd in its particulars, nevertheless got the general idea right.

Schlanger describes today’s plant scientists as walking a fine line. They want to tout their findings but understandably fear overdoing it. For many, to speak of “plant sensing” is all right, but “plant behaviour” is iffy, “plant intelligence” is treacherous and “plant consciousness” is the sky falling. The anthropologist Natasha Myers has reported a “wavering between enchantment and disenchantment” among botanists. Among themselves, they speak animatedly of plants’ desires, but when they publish they “remove all reference to the plants as active agents”.

And yet they move. Most plants do so slowly in the expected ways – leaves reaching for light, roots for moisture – but some, like climbing vines, move with unexpected agility. Viewed in real time, vines are innocently immobile. Sped up via time-lapse photography, they become tiny, nefarious krakens, their tendrils methodically probing for targets to latch on to.

The most intriguing research concerns dodder vines, which cannot photosynthesise and thus must quickly find other plants to parasitise. Researchers have found that they can detect qualities of potential hosts – species, distance, even health – before making contact, and they aim toward the best prey, such as tomato plants. They can pick up chemical trails in the air, and they will even grow more toward LED lights that are arranged in the shape of suitable hosts, suggesting that the vines’ light-sensing abilities may amount to a rudimentary form of sight.

With time-lapse videos, we can see vines sensing and reacting. Most other plants’ behaviour is invisible. Vines aside, plants are pitiful athletes, but they are often quite gifted chemists, exhaling and secreting sophisticated compounds to entice, repel or poison their neighbours. Trees excel here. The woodsy sweetness of balsam trees, the tang of pines: these are not perfumes but chemical weapons deployed in an interspecies war. They are insecticides, and there is something softly psychotic in how much we delight in their smells.

Interestingly, trees can smell themselves, or at least detect their own airborne chemical compounds. A leaf, being eaten, can emit gases that prompt other branches – and other nearby trees – to defensively fill their own leaves with toxins. It is well known that acacias secrete sugars and proteins to recruit ants as foot soldiers in their campaign against vines and caterpillars. If trees do communicate underground, I like to think of them swearing like sailors while, rooted in place, they fend off waves of piratical attackers.

Proponents of plant sentience have a favourite plant, the boquila vine, which grows in Chilean and Argentine rainforests. In 2013, the ecologist Ernesto Gianoli realised that the boquila could convincingly imitate other plant species. It hides from its harassers, such as snails and beetles, by matching the shape, size and colour of its leaves to those of its neighbours. Gianoli notes that it can mimic plants that haven’t formed part of its evolutionary history, which would seem to indicate it somehow senses their forms in real time. The boquila is hard to grow outside its native environment, so research is slow. Still, boquila enthusiasts (including Wohlleben, in an over-oxygenated sequel to Hidden Life) have made much of a man in Utah who appears to have induced one to imitate a plastic plant on his windowsill.

For bolder botanists, such findings reopen the old question of whether plants can think. Plants lack brains – traditionally felt to be a prerequisite for intelligence – but, then again, so do computers. With chatbots showing what can be achieved by neural networks, it might be time to reconsider plants. Perhaps they also have what Stefano Mancuso calls “distributed intelligence”, with the root system acting as “a sort of collective brain”.

The ethical implications are exhausting. Taking plants’ moral standing seriously throws even veganism into disarray. “If plants also have sentience,” the philosopher Philip Goff asks, “what is there left to eat?” Still, the argument for plant consciousness is straightforward and emphatic: just look what they can do. Surely, by the time a vine is strategically transforming its body to mimic a plastic houseplant’s, it crossed the consciousness threshold long ago.

There is, however, a counterargument: the spinal cord of a rat. Sever a rat’s spinal cord from its brain (pausing to contemplate the chain of choices that brought you to this act), and you will find that the isolated spinal cord can still direct affairs with surprising competence. It can retract the legs when they receive electric shocks. It can, more impressively, learn to anticipate shocks and direct the legs to avoid them. It is capable of more sophisticated forms of learning than any plant has been shown to be. But is a rat’s spinal cord conscious?

Consciousness is frustratingly hard to define. Perhaps it inheres in many things, even parts of things. Or perhaps evolutionary forces can programme sophisticated behaviours – flexible and sensitive to environmental cues – that nonetheless operate without the special spark that signifies intelligent life. Reasonable, well-informed people disagree wildly about where to draw the line, from the panpsychists who regard atoms as conscious (in a limited way) to the conservatives who have questions about chimpanzees.

The only beings whose consciousness we agree on are humans. Beyond them, we judge candidates on whether they seem to have subjectivities like ours. In other words, the question of consciousness is fundamentally narcissistic; things merit esteem to the degree that they remind us of ourselves. This is the implicit premise of many plant and tree books, with their chorus line of mother trees, socialist fungi and cunning vines performing high kicks for human approval. But is it the best way to think about nature? As Justine Karst put it to me, “Do we not have the capacity to love and care for things that are not like us?”

Trees are, ultimately, not like us. They have torsos, limbs and crowns, and we often personify them as benevolent helpers. But stray from the forest path or let the sun go down, and their weird, sinister qualities soon emerge. It is the dark woods – “savage, rough and stern” – that lead to the underworld in Dante’s Inferno. The same dark woods, per peasant lore, teem with witches, wolves and unsupervised German children. The numerous tales about perilous forests appeal to a deep-seated sense that there is something unsettling about trees. They are a familiar sight but an alien presence.

One source of their strangeness is their size. As saplings they match our height and meet our gaze, but they continue to grow, some higher than humans can comfortably apprehend. The ecologist Meg Lowman describes the treetops as a still-unexplored “eighth continent”. The tallest trees, the redwoods of northern California, contain whole environments in their canopies. There are grasses, ferns, aquatic crustaceans and, indeed, other trees up there, unsullied by the earth, inhabiting the redwoods’ sky worlds.

The California redwoods are the tallest life forms on Earth. The biggest exceeds 115 metres: essentially the length of a large football pitch, but straight up. They are “so huge that they shut you up”, writes Anne Lamott. The redwoods famously appear in Alfred Hitchcock’s masterpiece Vertigo. But they appear there only in part. It was virtually impossible for Hitchcock to fully capture both his actors and the trees in the same shot without making the actors appear ludicrously small, so he cropped out all but the bases of the massive trees.

The philosopher George Santayana, born in Madrid, visited those redwoods in 1911. He found northern California “intellectually emptier than the Sahara” but was awed by its “virgin and prodigious” landscape. The place was a standing chastisement to European philosophy, Santayana felt. It taught “the vanity and superficiality of all logic, the needlessness of argument”. In such an environment, he reflected, you can no longer feel that nature is yours to command: “You must feel, rather, that you are an offshoot of her life; one brave little force among her immense forces.”

Trees attain more-than-human scales not only in metres, but in years. They are the only organisms in view that conspicuously outlive us, and some do so by multiple orders of magnitude. We usually last for decades; trees can last millennia. Such trees are not timeless but “timeful”, the historian Jared Farmer writes in his poignant book Elderflora: A Modern History of Ancient Trees. They contribute “chronodiversity” to a biological world otherwise measured in days, years and decades.

Old trees, like roots bulging through the pavement, unbalance our sense of time. In Manhattan’s Washington Square Park, surrounded by New York University’s buildings, the Hangman’s Elm protrudes as an eerie relic from the 17th century and a stern warning to the undergraduates. As long-lived trees go, that elm is not especially impressive. The UK has yews that are, literally, ancient, in that they date to antiquity and are thousands of years old. The oldest known tree, a bristlecone pine in California, is about five millennia old, meaning that it was a sapling in the bronze age. (There is a tree in Chile that might be older. And a few trees can create physically connected, genetically identical copies of themselves; these clonal trees “live,” in the sense of carrying on in replica form, even longer.) Caring for the environment, Farmer believes, will require learning to “think in the fullness of tree time”.

Tree time, however, appears to be running out. In 2005, scientists set out to examine the largest African baobabs: massively thick trees that don’t have just one stem, like most trees, but multiple, fused together. The most famous, Chapman’s Baobab in Botswana, has six stems that range from about 500 to 1,400 years old. Or, it had six stems. On 7 January 2016, the whole thing tumbled over. Two years later, the researchers announced that nine of the 13 oldest baobabs, or at least their largest or oldest stems, had collapsed since the study started.

Other long-lived trees – the cedars of Lebanon, the California redwood – are also perishing. The culprit is probably the obvious suspect: climate change. Trees equipped to survive in a place do poorly when the qualities of that place, such as temperature, water supply and length of seasons, change drastically. With time, tree species could adapt or find new habitats. The problem is just that arboreal evolution and migration are painfully slow, and global heating is painfully fast.

A tree, Farmer writes, is “a radically nonhuman thing”, and a large, old tree is especially one. If trees have conceptual value, it is not because their similarity to us elicits our sympathy, but because their difference from us enlarges our horizons. They are the most visible markers on the evolutionary road not taken. Trees stand in for all the photosynthesising, carbon-dioxide breathing, fixed-in-place species that share our world yet have fundamentally different ways of living in it.

Contemplating trees should be, above all, an exercise in humility. The mountains and woods, Santayana told his California audience, allow you to “take yourselves simply, humbly, for what you are, and to salute the wild, indifferent, non-censorious infinity of nature”. Perhaps the presence of beings older, larger and more numerous than we are – whether or not they resemble internet users or our mothers – can be a reminder that we are not everything, and that everything is not us. “Let us therefore be frankly human,” Santayana enjoined. And let the trees be trees.

Electric and plug-in hybrid car sales will jump to a new global record in 2024 despite slowing growth in some markets, according to forecasts from the influential International Energy Agency (IEA).

The Paris-based forecaster said that 17m battery electric vehicles and plug-in hybrid electric vehicles will be sold in 2024, up more than 20% compared with 2023.

The IEA also said most electric cars will cost the same as petrol equivalents by 2030 as prices drop. Tesla lowered prices over the weekend as it fights to retain its market share amid fierce competition from Chinese rivals such as BYD, its closest contender as the world’s largest producer of battery electric cars.

Carmakers have complained that growth in demand for electric cars is slowing, forcing them to offer discounts to compete. While this could damage some carmakers, lower prices are also likely to accelerate the transition, the IEA said.

Fatih Birol, the energy economist who heads the IEA, acknowledged that sales are stronger in some countries than others, but added that there was clear momentum for the transition.

“Rather than tapering off, the global EV revolution appears to be gearing up for a new phase of growth,” he said.

“The wave of investment in battery manufacturing suggests the EV supply chain is advancing to meet automakers’ ambitious plans for expansion. As a result, the share of EVs on the roads is expected to continue to climb rapidly.”

In the first quarter of 2024 there were more sales of electric and plug-in hybrids (which combine a petrol engine with a battery) than in the whole of 2020, the IEA said.

Hybrids still emit large amounts of CO₂ when in use, although some in the car industry argue that – if used correctly – they are a necessary step to lower emissions until public charging infrastructure improves.

Some countries have concentrated on encouraging electric vehicle adoption: four-fifths of all cars sold in Norway in 2023 were electric. However, policies vary widely, with China and richer European countries generally ahead of the rest of the world, including the US.

The UK was Europe’s biggest electric car market over the first three months of 2023 for the first time, according to Matthias Schmidt, an independent analyst.

The timing of the adoption of electric cars in Europe is heavily influenced by the regulations, as carmakers try to eke out profits from their petrol and diesel models while avoiding fines for failing to sell enough electric cars.

Schmidt said he expected UK electric sales in 2024 to remain equal to or slightly higher than Germany, which has a bigger population. Schmidt said German sales were suffering due to subsidy cuts, and because manufacturers are deliberately holding back sales until 2025, when tougher rules on average CO₂ emissions come in.

“That delay will give Chinese manufacturers a small window to manipulate, because from 2025 the traditional manufacturers will really begin their electric vehicle push in earnest,” Schmidt said.

In the UK the government removed subsidies from privately bought electric cars in 2022.

The Society of Motor Manufacturers and Traders on Tuesday raised concerns about the separate grants for zero-emissions lorries. The lobby group said the grants were not being used because it takes too long to certify that trucks produce zero emissions.

Mexico has been undergoing its first heatwave of the season. The heatwave started on Sunday 14 April, when Mexico City recorded a new date record with a high of 32.9C, surpassing the previous record of 32C from 1998.

Anticyclonic conditions over the region have been responsible for this heatwave by inhibiting cloud formation, allowing temperatures to rise significantly. These conditions persisted through much of last week, allowing temperatures to reach 35-45C across much of the country.

However, on Sunday night and into Monday, a cold front moved southwardsallowing temperatures to fall considerably below average at the start of this week and bringing wet and windy weather to the country.

The prefrontal trough that is expected to develop ahead of this cold front will lead to heavy rain and thunderstorms across the south-eastern parts of the country on Monday. These will include lightning, hailstorms, and possibly allow some tornadoes and whirlwinds to develop too.

Additionally, across north-eastern parts of the country, this frontal boundary will introduce some strong winds and high wave heights. As a consequence, there is a risk of seeing some localised flooding in places, as well as an increased risk of landslides.

Meanwhile, parts of southern China have been experiencing torrential rain. Convective activity over the past few days has led to a significant flooding risk across Guangdong province in southern China, with fears of seeing a one-in-50-year flood there.

Saturday had the heaviest downpours, with 12 consecutive hours of rainfall, prompting the Chinese government to issue flood warnings across the Beijiang basin. By Sunday morning, aerial footage showed many low-lying towns and buildings were already underwater, and telecommunication channels and power supplies have been damaged across the province. The fear of flooding continues this week as further heavy rain is forecast.

In Europe, temperatures are set to fall considerably below the seasonal norm this week. Parts of Germany, Italy, France as well as the Baltic states will have temperatures about 7-10C below average. However, by the end of the week and into the weekend, temperatures are expected to return to around or just above average across Europe.

The concept of “net zero” has become a political slogan used to start a “dangerous” culture war over the climate, and may be better dropped, the outgoing head of the UK’s climate watchdog has warned.

Chris Stark, the chief executive of the Climate Change Committee (CCC), said sensible improvements to the economy and people’s lives were being blocked by a populist response to the net zero label, and he would be “intensely relaxed” about losing the term.

“Net zero has definitely become a slogan that I feel occasionally is now unhelpful, because it’s so associated with the campaigns against it,” he said. “That wasn’t something I expected.”

Politicians on all sides are now wary of associating themselves with the term, he said, which was inhibiting progress. Rishi Sunak, the prime minister, made several policy U-turns last year, including delaying the changeover to electric vehicles, while the Labour leader, Keir Starmer, watered down a promise to invest £28bn a year in a green economy.

“It’s the culture warriors who have really taken against it,” said Stark. “A small group of politicians or political voices has moved in to say that net zero is something that you can’t afford, net zero is something that you should be afraid of … But we’ve still got to reduce emissions. In the end, that’s all that matters.”

The real fight was to make the UK’s economy competitive with other countries that were investing heavily in renewable energy, electric vehicles and other green technologies that were the focus of innovation and investment around the world, he said.

“If it [net zero] is only a slogan, if it is seen as a sort of holding pen for a whole host of cultural issues, then I’m intensely relaxed about dropping it,” he said. “We keep it as a scientific target, but we don’t need to use it as a badge that we keep on every programme.”

Stark gave the example of heat pumps, which have been demonised in some quarters despite offering a low-carbon and potentially low-cost alternative to gas boilers.

“It’s very strange that some see heat pumps as an enemy of the people,” he said, in an interview with the Guardian before leaving his post this Friday. “This is a remarkably sensible technology that we’ve known about for a long time, a straightforward technology to put in your house to keep it warm, or to keep it cool in the summer. But in this country, they’ve taken on a totally different totemic role, as a technology that is being somehow forced upon the populace. I think that’s very dangerous.”

Policymakers should focus instead on what lies behind net zero – investment in the UK’s economy, in ways that would not only reduce greenhouse gas emissions but cut energy use, improve national security, clean up the air and protect nature and the countryside, he added.

“We are talking about cleaning up the economy and making it more productive – you can call that anything you like,” Stark said.

He has been chief executive of the CCC, the statutory body that advises government under the 2008 Climate Change Act, since 2018, under the chair John Gummer (Lord Deben), the former Conservative environment minister. Stark, who will move to the Carbon Trust, a consultancy set up by the government to help businesses cut emissions, leaves at a time when the organisation is without a permanent chair, as Deben left last year and the devolved governments have rejected the Tories’ choice as the new chair.

Tackling the climate crisis has been presented as a massive change, but Stark was at pains to point out that it would not be. “The world that we’ll have in 2050 is extremely similar to the one we have now. We will still be flying, we’ll still be eating meat, we will still be warming our homes, just heating them differently,” he said. “The lifestyle change that goes with this is not enormous at all.”

But it was not just those who were against climate action who were causing the problem, according to Stark. Climate activists were also alarming people, he warned, and creating “quite a serious barrier to large parts of the political spectrum to support climate action” by forceful protests, and presenting environmental policies as radical.

“It would be more helpful if they were less divisive,” he said. “I don’t think it is radical. It’s really important that we stop using words like that, as it is understandably frightening.”

Politicians could design measures so the costs were borne by those best able to shoulder them and people on lower incomes were also able to take advantage of home insulation, heat pumps and other ways of reducing energy bills. “We do need a policy package that is fair,” he said.

Stark pointed to China, the US and the EU, which are all investing heavily in low-carbon technologies that are cheaper or becoming cheaper than fossil fuels. People should not listen to trying to delay the transition, he said. “We will regret going slow in this transition, because we’ll be missing out on the economic benefits of it.”

Ministers are under growing pressure to firm up plans for a green levy on imports to the UK before the general election campaign.

The government is consulting on plans to introduce a carbon border adjustment mechanism (CBAM) from 2027. Under the system, overseas companies wishing to export key goods to the UK would have to show they were paying for their carbon emissions, or face a levy equivalent to the price paid for carbon by UK manufacturers.

This would ensure British manufacturers obliged to reduce their greenhouse gas emissions under the net zero target were not undercut by products from countries with lighter climate rules.

The CBAM is likely to affect imports of carbon-intensive goods, such as steel, cement, glass and ceramics, but the details of the scheme have yet to be set out.

Many Conservative MPs, Labour and the Liberal Democrats, and many businesses and economists, have said they support the plans in principle. However, some on the right of the Tory party, including arch free marketeers who object to such “red tape” interventions, and figures such as David Frost who are sceptical of the net zero goal, are opposed.

There are concerns this opposition will slow progress on the plans, and could mean the CBAM is in effect shelved before the general election, which must be held before the end of January.

The Conservative Environment Network, which comprises more than 100 backbench Tory MPs, urged ministers to press ahead. Tim Loughton, the MP for East Worthing and Shoreham, said: “We should be proud of the Conservative government’s successes in decarbonising our economy. But not every country has followed our lead. If we want to support British industry, we must ensure a level playing field for them to compete with cheaper carbon-intensive imports. These include those produced in China with its coal-dominated power grid.”

John Penrose, the Tory MP for Weston-super-Mare, said a CBAM for the UK would benefit all nations. “Once those countries realise that polluting doesn’t pay, because there’s no competitive advantage in it for them, they will have an incentive to become greener themselves,” he said. “As Conservatives, promoting free markets and handing on a healthy planet for future generations is part of our DNA. A CBAM provides a free-market way to tackle climate change.”

CBAMs have been discussed for decades, but have taken on new urgency in recent years as efforts to reach net zero greenhouse gas emissions have increased in developed countries. Last October, the EU introduced a trial CBAM, requiring manufacturers to show data on the emissions involved in the manufacture of certain goods, chiefly cement, iron, steel, aluminium and fertilisers.

From 2026, when the EU begins to impose levies for imports where the carbon price is lower than its own, UK manufacturers could potentially face charges totalling hundreds of millions of pounds a year unless they can show regulators they are paying an equivalent carbon price in the UK.

Jo Gideon, the Tory MP for Stoke-on-Trent Central, said UK companies would be at a severe disadvantage unless the government acted quickly. “When the EU implements its CBAM, high-carbon goods will no longer be able to enter the EU tariff-free. The manufacturers of these goods will instead turn to us, flooding our market with these cheaper goods and undercutting our British industries who have done the right thing and started to decarbonise,” she said.

“While there are still important questions about the design and scope of the UK’s CBAM, I hope that we can introduce this mechanism quickly to prevent this dumping of higher carbon goods.”

Labour is understood to support the principle of the CBAM, but is awaiting detail on the proposals. Wera Hobhouse, the Liberal Democrat spokesperson for energy and climate change, said: “Introducing a CBAM for high-emission products is a vital step in tackling the climate emergency and protecting UK businesses from unfair competition. With the government’s consultation set to conclude in just a few months, ministers must press ahead with these plans without delay. This mustn’t turn into another Conservative setback in our country’s efforts to fight climate change.”

Laith Whitwham, a senior policy adviser at the E3G thinktank, said: “The government has committed to introducing a CBAM in 2027 – a year behind the EU – but it could go much faster, particularly as the UK does not need to reach agreement across 27 member states. Dithering and delay at this point weakens the competitiveness of UK industry and threatens to slow the pace of global decarbonisation through the risk of carbon leakage.”

The Guardian has revealed that India is seeking exemptions from the UK’s CBAM as part of a potential trade deal. Whitwham said that would “be a disaster for the UK’s consumption emissions and for its steel sector. The UK government has just agreed to provide £500m to Indian steel giant Tata Steel to replace its UK blast furnace in Port Talbot with a cleaner electric arc furnace. Exempting India from the UK CBAM now would allow Tata to import steel from its higher carbon blast furnaces in India, without paying a carbon price – which UK producers must do. The UK would in effect be closing its own blast furnaces only to import more steel from blast furnaces abroad.”

A Treasury spokesperson said: “We are currently consulting on delivering a UK CBAM to ensure highly traded, carbon-intensive products from overseas face a comparable carbon price to that paid if the good were produced in the UK. This should give UK industry the confidence to invest knowing that their efforts won’t be undermined by carbon leakage.”