17 hours ago
Why is the UK experiencing a heatwave and what can people do in response?
Temperatures are set to climb to as high as 35C in the latest heatwave to hit parts of the UK.
So what is causing it and what are the impacts?
– What is causing the heatwave?
The UK is on the edge of a 'heat dome' currently sitting over continental Europe which has pushed temperatures to extreme highs in places such as Spain, Italy and Greece.
Dr Akshay Deoras, from the University of Reading, says the heat dome, an area of high pressure currently centred on Denmark, with the UK on its western edge, is 'bringing stable, mostly cloudless weather and drawing in hot, dry air from the south'.
Dr Michael Byrne, reader in climate science at the University of St Andrews, said heat domes, which occur when high pressure weather systems that normally last a few days get stuck in place for a week or more, are 'nothing new'.
But they and other scientists are clear that climate change – caused by human activity such as burning fossil fuels – is making heatwaves more frequent and intense.
– So what is the role of climate change in heatwaves?
Put simply, the Earth has warmed significantly since pre-industrial times due to humans putting more greenhouse gases into the atmosphere which trap more heat.
When hot conditions occur on top of that background warming, for example during a heat dome situation, they are hotter than they would be without it, while it also means heatwaves occur more frequently.
So while Dr Byrne says there is nothing new about heat domes, 'what is new are the temperatures heat domes deliver: Europe is more than 2C warmer than in pre-industrial times, so when a heat dome occurs it drives a hotter heatwave', he says.
Dr Ben Clarke, research associate in extreme weather and climate change at the Centre for Environmental Policy at Imperial College London, says that without climate change, the UK would still experience periods of fine, warm weather in June – but the hotter atmosphere means that 'fine' weather is now very hot.
'In short, climate change is making 'nice' weather more dangerous, and already dangerous weather more deadly,' he warned.
– How do we know climate change is making heatwaves hotter and more frequent?
Scientists have conducted numerous 'attribution' studies to assess the role of climate change in extreme weather such as heatwaves, comparing the current conditions with what would have happened in a world without global warming.
For example in the summer of 2022, when temperatures smashed through the 40C mark for the first time on record in the UK, scientists found it would have been 'almost impossible' without global warming.
Most recently, the same World Weather Attribution group of scientists found the heatwave earlier this month was made about 100 times more likely, or around 2-4C hotter due to global warming.
And Met Office analysis has found the kind of 40C temperatures seen in 2022 have a 50:50 chance of happening again in the next 12 years as the risk of extreme heat rises with climate change – with temperatures of 45C now possible in the UK.
– What are the impacts of heatwaves?
Scientists such as Dr Fredi Otto, from the Centre for Environmental Policy at Imperial and one of the scientists leading the World Weather Attribution work, label heatwaves as 'silent killers'.
'Every year thousands of people in Europe die due to extreme heat, particularly those that live in poorly insulated homes, on busy, polluted roads, and that have already health problems,' she said.
Particularly at risk are those who are older, or have pre-existing health conditions: more than 1,000 excess deaths among older people were recorded around the four-day peak of the July 2022 heatwave, with more than 3,000 heat-related deaths in England over that summer.
Heatwaves also lead to increased calls to ambulance and emergency services, affect the functioning of hospitals, care homes and schools, hit outdoor workers and damage agriculture, cause transport disruption, raise the risk of wildfires and put water supplies under pressure.
Experts also warn extreme heat is linked to worsening symptoms of depression, anxiety and stress, and to increased violence.
– So what can people do to protect themselves?
Experts suggest a number of practical steps people can take to protect themselves and others against this week's extreme heat.
These include trying to keep homes cool by closing windows and curtains during the day to keep out the heat, and opening them at night when it is cooler, drinking plenty of non-alcoholic cold drinks, staying out of the sun, avoiding exercise and checking on elderly people.
Measures are also needed to protect communities, including green spaces, better quality housing, temporary cooling centres, and even rescheduling large-scale outdoor events outside the summer months, according to Dr Malcolm Mistry, from the London School of Hygiene and Tropical Medicine.
Ultimately though, the risk of extreme heat is only going to worsen with continued climate change, with scientists warning the only way to curb global warming is to cut greenhouse gas emissions to net zero worldwide.
As Professor James Dyke, assistant director of the Global Systems Institute at the University of Exeter, puts it: 'These latest European heatwaves are the result of record-breaking greenhouse gas emissions.
'Europe is the fastest-warming continent as a result of human-caused climate change.
'The only way to avoid even more extreme heat is to rapidly phase out fossil fuels.'
