Global heatwaves an 'alarm system to climate change'

Severe heatwaves and record temperatures are being recorded in countries around the world in recent days.

Canada broke its temperature record for the third day in a row on Tuesday, with 49.6C recorded in Lytton, British Columbia, while Moscow saw its hottest day in 142 years just over a week earlier, with 31.9C recorded.

Experts at the University of Reading have explained the reasons for this, and why the record temperatures are a taste of what is likely to come in the future.

Chloe Brimicombe, a PhD heatwaves researcher at the University of Reading, said:

“Climate Change raises the likelihood of these heatwaves happening because a hotter climate provides a higher baseline from which heatwaves can develop. This means most spells of weather in the future that are even a little warmer than average are likely to be far hotter than we usually see today. For this reason, we know that heatwaves are increasing in area, intensity, frequency, and duration.

“The heatwaves are being caused by something called the silk road teleconnections, which is a series of high and low pressure patterns, including high pressure over the northern US and Canada and Eastern Europe, which traps hot air over these regions. This is also the reason it is currently raining in the UK. The fading effects of La Nina are also a factor.

“Some 473 million vulnerable people were affected by heatwaves in the last year. They raise excess mortality rates and can cause a rise in air pollution levels, increasing admissions to hospital for those with lung diseases. They cause a rise in hospital admissions generally, which is being seen in America. They also affect wellbeing and productivity, such as being linked to a rise in stillbirths and miscarriages, and kidney diseases in outdoor workers because of dehydration.

“Heatwaves melt roads, cause power outages, signal and wire failures for power and trainlines, reduce crop yields, and kill livestock, as well as more humans globally than many realise.

“Heatwaves are a risk now and are only growing. They are our alarm system to climate change. The more of them that occur, the more of an emergency we are experiencing. Mitigating is key to stopping a rise in heatwaves. But we need proper heat adaptation now. If we adapt now, we can beat the heat.”

Professor Richard Allan, professor of climate science at the University of Reading, said:

“Weather patterns that produce persistent high pressure, cloud-free conditions and dry continental winds can generate heatwaves.

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

“Heatwaves have clear implications for human health as well as for plants and animals while conditions are often exacerbated by increased risk of fires, droughts and poor air quality as stagnant, sun-baked air traps pollutants.”

Professor Hannah Cloke, a natural hazards researcher at the University of Reading, said: “

“The deaths from extreme heat in Canada is both a tragedy and a warning to the world.

“The tragedy is that deaths from heatwaves are avoidable, but we will need better early warning systems and adaptations to our homes and lifestyles to avoid similar tragedies in the future.

“The warning is that these extreme weather events are just a precursor of what is still yet to come. Extreme heat is just one of the many impacts of a warming climate that will make the world more dangerous for people.

“We must recognise that heat, like disease, affects the most vulnerable people first. Those who cannot afford to adapt their homes or move to safety in a heatwave will be among the first to die.

“While temperatures of nearly 50 degrees in Canada are extraordinary, we will have to get used to the fact that an increasing number of regions across the world, particularly in Africa, will become almost uninhabitable due to heat in the future. This emphasises the need for action to curb climate change as a key part of global equity.”

Professor Andrew Charlton-Perez, Head of the Department of Meteorology at the University of Reading, said:

“Heatwaves have obvious impacts on human health. Even quite moderate temperatures, 20 degrees and above, are associated with increases in death rates and hospital admissions.

“Mostly these increases are driven by changes in respiratory and cardiovascular conditions. At the very high temperatures seen, for example, in the US and Canada recently other more severe conditions where human thermoregulation starts to fail can occur.

“Heatwaves can also have far reaching effects on society in other ways, including on productivity and on infrastructure. It will be necessary for society to continue to adapt to more frequent and extreme temperatures as climate warms.

“As noted by the recent Committee on Climate Change report, progress on adapting buildings and cities more generally to heatwave conditions has been slow in the UK. Recent heatwaves around the world should remind us that this is challenge we need to act on quickly.”