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22 June 2017

Climate Change is Causing Increasingly Deadly Heatwaves Worldwide


Despite how bad the weather can seem at times, we’ve not been short of hot summer days lately. In places like the UK where rain is a more prominent feature than sunshine, this heat is seen as a relief by those who would normally escape to somewhere like the Mediterranean to top up their tan.

However, this increase in hot weather is not something to be grateful about.

A new research study in Nature Climate Change has found that almost one third of the world’s population is at risk from heat-related deaths due to climate change creating deadly heatwaves. According to the authors of the study, this percentage of people spend at least twenty days every year being exposed to extreme heat which poses a threat to their lives. What’s more, this exposure could increase to as high as three quarters of the population by 2100 if there’s no change to the production of greenhouse gases, and 48% if these emissions are reduced. That’s almost half of the world at risk even if we start to turn things around.

The problem with extreme heat is that it pushes our bodies to the limit until they can no longer cope. Respiration becomes difficult because the haemoglobin that transports oxygen through our blood struggles to do so when temperatures rise, meaning every time we breathe our bodies are gaining less oxygen. As for sweat, the body’s natural response to keep us cool in higher temperatures, the presence of thick humidity in the air prevents it from evaporating, thereby leaving us to overheat.

Camilo Mora, lead author of the study, explained that this was due to heat toxicity, where “blood rushes to the skin to cool you down so there’s less blood going to the organs. A common killer is when the lining of your gut breaks down and leaks toxins into the rest of your body.” He quite rightly described dying in a heatwave as pure torture – “it’s like being slowly cooked”.

The risks that extreme heat has for our bodies are exacerbated by the pollutants in the air that caused global warming in the first place. The mixture of heat, pollutants and sunlight creates ground level ozone, and this can lead to chest pain, coughing and throat irritation, as well as worsening asthma, bronchitis and emphysema. If there isn’t much done to improve the quality of the air, the problem could potentially snowball out of control until there’s nothing that can be done about it.


The authors of this new study are hopeful that their work will help incite change in the public and make everyone aware of the issue at hand, although some people have doubts over the results. Daniel Mitchell, an atmospheric scientist at Oxford University, has stated that while the paper does make a step in the right direction, he has concerns over the nature of the study. In his words:

“It’s a bit of an ambitious study, they’re trying to answer a really important question, but I don’t necessarily think they’re going about it in the right way. There are lots of things that can lead to mortality that have nothing to do with the climate.”

Mitchell’s belief is that research for something as big as this should be conducted with actual science as opposed to compiling data from previous work on the topic. The study itself consisted of the authors analysing 911 peer reviewed papers which included information from over 1900 case studies where deaths were associated with high temperatures. The problem is that some of these case studies don’t reliably show an impact of their respective heatwaves due to certain other circumstances. Mitchell cited the 2015 Egyptian heatwave as one such example.

“A large number of people died, but they all died in places like prisons and psychiatric hospitals, and the reason was because the timing of the heatwave was such that they didn’t have people around to take care of them,” he explained.

Mora himself identified that there was an issue with defining what a heatwave is because so many definitions exist, and that a range of factors come into play that result in death. Temperatures as low as 23°C have proved to be life-threatening in the past, because of the level of humidity in the area, and vice-versa.

Understanding heatwaves and when they pose a severe risk to life is still not entirely known, but this new study has definitely highlighted that a problem exists in the here and now, rather than in the future. Although things may have to get worse before they get better, there’s still potential to turn things around in the long-run. We just have to start taking action.


James Darvill

James is a passionate scriptwriter and reluctant poet with a talent for the dystopian. When he’s not staying up late watching the Simpsons he’s beating the world at Mario Kart, always with a glass of wine in hand.