Heatwaves ‘more frequent, longer and hotter’ due to climate change

Sunset in hot weather (Peter Byrne/PA)

Dr Friederike Otto, a senior lecturer at the Grantham Institute for Climate Change at Imperial College London, said the soaring temperatures facing the UK would not have been as high without global warming.

“Every heatwave we are experiencing now has been made more frequent, longer and hotter because of climate change,” she told the PA news agency.

“Of course, every extreme weather event has also an element of just the chaotic natural variability of the weather system.

Heatwaves are extremely deadly, much more so than floods or storms

( Dr Friederike Otto, Imperial College London )

 “There would have been high temperatures without climate change, but they would not have been as high as what we will see – no matter what exactly we will see, we know for sure it would have been cooler without climate change.”

Dr Otto, one of the scientists behind pioneering studies that attribute the role of climate change in extreme weather events, warned that heatwaves kill.

And she said very hot spells have a greater potential impact than other climate extremes such as flooding in the UK, as their frequency is increasing at a faster rate, and, while floods have a high cost impact on infrastructure, more people die in heatwaves.

“Heat kills. Heatwaves are extremely deadly, much more so than floods or storms,” she said, warning that people tend to die in their homes, with extreme heat affecting those with existing medical problems and linked to inequality.

But she said the “good news” is that efforts to tackle climate change, such as insulating homes, and redesigning cities to make more room for green space, could also help the UK adapt to more heatwaves.

We urgently need to improve our existing housing stock to better insulate against both hot and cold weather

( Nigel Arnell, University of Reading )

Heatwaves are made more intense and frequent mainly because overall temperatures are higher due to global warming, and so, when weather systems such as summer high pressure occur, the heat they bring is amplified.

Richard Allan, professor of climate science at the University of Reading, said: “Heatwaves are caused by weather patterns that produce persistent high-pressure, cloud-free conditions and dry continental winds during summer.

“Climate change is intensifying these heatwaves as greenhouse gas increases raise temperatures and a warmer, more thirsty atmosphere dries out the soil so that more of the sun’s energy is available to heat the ground rather than evaporating water.”

Professor Nigel Arnell, from the Department of Meteorology at the University of Reading, said the current heatwave is not the first of the year, and probably will not be the last.

We urgently need to improve our existing housing stock to better insulate against both hot and cold weather – and that will help reduce our exposure to rising energy bills too

( Professor Nigel Arnell, University of Reading )

“And we’ll get more next year, and the year after, and so on. Our analysis shows that we are highly likely to get more and longer heatwaves in the future due to climate change, for the numbers of heat-health alerts, heat-stress days – days when it is too hot to work – and damaging heat extremes to increase.”

He warned that the UK is “not really geared up to deal with more frequent heatwaves”, apart from enacting emergency plans, and the country cannot run in crisis mode each summer.

“We urgently need to improve our existing housing stock to better insulate against both hot and cold weather – and that will help reduce our exposure to rising energy bills too,” he said.