London faces the “incredibly worrying” prospect of enduring days that hit 45C (113F) due to the worsening climate crisis, its mayor, Sadiq Khan, told the Guardian at a climate summit in New York where governments have gathered to discuss how to best cope with searing temperatures. Khan said an interim independent climate resilience report for London had found the capital could experience multiple 45C days “in the foreseeable future”, potentially buckling various basic functions of the city. “It means the Underground is not fit for purpose, some of the homes are too hot in the daytime, care homes and schools too,” Khan said. “It means we have to adapt for those temperatures now. It’s now time for those who are delaying action to wake up and smell the coffee because this is happening now. It’s now and it’s happening to us.” The London mayor said he had ensured the planting of more shading trees and the installation of air conditioning on buses but that more government support was needed to help cities adapt to the climate crisis, criticising the UK’s Conservative government for not providing a green stimulus akin to the US’s Inflation Reduction Act to help retrofit buildings and spur jobs in renewable energy. “We are learning expertise from other cities but we can’t pretend we aren’t behind because the UK has been slow catching up,” Khan said from New York, ahead of the annual UN general assembly and a special climate summit this week. “We have to throw everything at this. We’ve had very little support from the government. The fact the prime minister [Rishi Sunak] isn’t coming to the UN general assembly and may not go to Cop28 speaks volumes.” London’s climate review was launched in June, nearly a year after the UK capital experienced an extraordinary, record-breaking heatwave. Temperatures breached 40C (104F) in London for the first time on record in July last year, causing schools to close, hospital operations to be cancelled and for the London fire brigade to have its busiest day since the second world war as it fought numerous blazes, including wildfires at the city’s outskirts. Temperatures of 40C were previously almost unthinkable for the temperate climes of the UK, with Professor Hannah Cloke, at the University of Reading, saying at the time of the heatwave: “The all-time temperature record for the UK has not just been broken, it has been absolutely obliterated. Even as a climate scientist who studies this stuff, this is scary.” But the reality of the worsening climate crisis will heighten the risk of even hotter temperatures in the future. London faces the distinct possibility of enduring withering temperatures of 45C, along with other hazards such as flooding, as the world continues to heat up, according to Emma Howard Boyd, the chair of the climate review and former chair of the UK Environment Agency. “Forty-five degrees celsius is something we could see in the coming years,” Howard Boyd, who will release a full set of recommendations at the end of the review in December, told the Guardian. “Not many people really thought we’d experience 40C until we did last year, so we need this review to understand how we keep the city thriving in terms of people’s health and working environment even under these higher temperatures. Everything we’re hearing from scientists is that Europe is heating up quicker than anywhere else.” Khan is in New York at the start of a week-long Climate Week summit involving numerous businesses, governments and environmental groups that runs alongside the UN general assembly which will, on Wednesday, include a gathering of more than 100 national governments aimed at heightening global ambition to cut emissions. The UN has warned the world is well off track to meet goals that would avert disastrous climate change. Meanwhile, New York City itself is bringing in the first congestion charge for cars in any US city next year, a move that proponents say will help cut emissions, help tackle deadly air pollution and reduce the severe traffic jams that cost New Yorkers 117 hours of their time, on average, each year. The new congestion pricing scheme will apply to cars in Manhattan below 60th street and could cost anything up to $23 a trip, with funding going towards New York’s beleaguered Metropolitan Transportation Authority (MTA) to help upgrade its heavily used but fraying network of subway trains and buses. Technology to scan cars as they enter the zone is already being put in place. The plan was approved by the federal government in June but has faced staunch opposition from some politicians, Uber drivers and business owners who claim it is unfair on those who commute by car. “We have to put our foot down to protect New Jerseyans,” Phil Murphy, the governor of the neighbouring state of New Jersey, which is suing to stop the plan, said in July. “We’re not going to allow this poorly designed proposal to be fast-tracked.” The controversy has some echoes for Khan, who presides over a city that has had congestion pricing since 2003 and recently provoked ire among some residents by expanding its Ultra Low Emission Zone (or Ulez) to the whole of Greater London, forcing people to pay a daily fee if they drive a car that doesn’t comply with pollution standards. The backlash to the Ulez expansion has been widely blamed for Labour failing to take Boris Johnson’s former seat of Uxbridge in July, placing pressure on Khan to scale back the scheme. “It’s simply not sustainable for in London 10 million people to drive around in cars [or] in New York for 9 million people to drive around in cars,” Khan said. “You’ve got to listen to genuine concerns people have and try to address them, at the same time be cognisant that there’s a vocal minority backed by vested interests that are opposing stuff. “Cities have got to incentivise policies that encourage people to use alternatives to the car. I understand the reasons New York wants to do this, what they will need to do is make sure they have alternatives in place.” The MTA, which is overseeing congestion pricing in New York, has said it looked to London, as well as other cities that charge drivers in urban cores such as Stockholm and Milan, in the design of its own congestion price. “Congestion is bad and it’s got a lot worse in the last 10 to 15 years,” said Juliette Michaelson, a special adviser to the MTA. “We know the best way to manage congestion is through pricing, the effect is immediate and sustained over time.” Despite the opposition to the initiative, public transport advocates believe New York is finally about to fulfil the demands of activists who have, for decades, pushed for congestion pricing. “It’s been a long time coming,” said Philip Miatkowski, senior director of research and policy at Transportation Alternatives. “This is a once-in-a-generation opportunity to make New York City better. We really want this to be a success, like in London, so it can be copied in other cities in the US.”