Counting the health costs of warmer weather

Aside from the visual and physical impact of these conditions, extreme heat can be hugely detrimental to our health.

A recent study by Barcelona Institute for Global Health revealed that searing heat killed more than 60,000 people in Europe last year.

Using epidemiological models, researchers were able to work out how many deaths could be traced back to the temperature. They found 61,672 people died of heat-related causes in Europe between 30 May and 4 September 2022. The mortality rate was highest in Italy, Greece, Spain, and Portugal.

The study found that, in every week of summer 2022, average temperatures in Europe “uninterruptedly” exceeded the baseline values of the previous three decades. The most intense heat hit from 18 to 24 July, when it killed 11,637 people.

A report published last year in the American Journal of Kidney Disease found that emergency hospital visits for the condition rose between 1.7 per cent and 3.1 per cent on ultra-hot days.

The harder organs need to work, the more stress they are under – causing potential deaths when coupled with other typical heatwave side-effects, such as dehydration and hyperthermia (when the body’s regulatory mechanisms fail to contend with its raised internal temperature, and fatigue sets in).

Hot weather can also have a significant effect on air quality, reducing lung function: long-term exposure to ozone pollution, which is exacerbated by heat, is linked to 1 million premature deaths every year.

While heatwaves are believed to be most dangerous for elderly people (the highest number of deaths during the 2022 heatwave in Europe occurred among over-80s), pregnant women and people with cardiovascular disease, chronic obstructive pulmonary disease, types of respiratory disease and diabetes, may also be at greater risk.

Warmer weather is also increasing the spread – and potency – of infectious diseases. Changes in temperature, humidity and rainfall are proving fertile ground for the transmission of conditions such as dengue fever, malaria, Zika virus, chikungunya, and cholera in areas where they were previously unknown.

In 2022, an EEA report warned that Europeans would be at elevated risk of infectious diseases if global heating was not addressed; a paper published in Nature Climate Change months earlier noted that 58 per cent of infectious diseases had been exacerbated by climate change.

Studies have also shown a significant impact on mental, as well as physical, health in the face of extreme heat, with several recording increased risk of suicide, and a surge in emergency department visits for mental health conditions on very hot days.

Academics are concerned that, with unprecedented temperatures expected to continue to occur, vulnerable groups may be left to bear the brunt.

Solutions are being sought but many are convinced that long-term education and awareness about the dangers of climate change and the need to reverse it should be at the heart of all future initiatives.

Related: Light and noise pollution ‘neglected’ health hazards