The heat is on

We increasingly need to learn how to cope with extreme heat, beyond the trite representation in the media of heatwaves as an opportunity for a trip to the beach.

A combination of climate change and an impending monster El Niño, which is expected to intensify over the course of the year, means we need to consider how we might adapt to the various dangers that lie ahead in the years to come.

Heat stress remains the deadliest weather-related threat globally, causing more fatalities than floods, storms, or other extreme weather events. Heatwaves have wide-ranging impacts on public health, society, the economy, and critical infrastructure.

Exhaustion

During periods of extreme heat, the body is forced to work harder to maintain a stable core temperature, placing significant strain on the cardiovascular, digestive, and respiratory systems.

Those most at risk include older adults, infants, pregnant women, and individuals with pre-existing health conditions, including diabetes, kidney disease, and Parkinson’s disease.

The stress on those with these ailments is exacerbated by the fact that some drugs become less effective at high temperatures, particularly for people taking multiple medicines.

These conditions inevitably lead to substantial increases in excess mortality. There were an estimated 2,803 to 3,271 excess deaths across England and Wales during the record-breaking summer of 2022, when temperatures in the UK exceeded 40°C.

At the same time, healthcare services face mounting pressure as cases of heat exhaustion, dehydration, and other heat-related emergencies increase, resulting in higher rates of hospital admission.

Violence

In the longer term, climate change may also contribute to the northward spread of disease vectors, increasing the potential for tropical diseases such as malaria, Zika virus, and dengue fever to emerge in regions where they have historically been absent. 

We also need to consider the implications of wet-bulb temperatures – conditions in which temperatures become so high and humidity so intense that sweating can no longer cool the body effectively. Under such circumstances, death can occur rapidly.

Beyond physical health, extreme heat also affects mental well-being and behaviour.

Elevated temperatures can disrupt sleep patterns, leading to irritability, heightened anxiety, reduced emotional resilience, and an overall decline in mental health. Research has also linked hotter weather to increases in aggressive behaviour and violent crime.

Analysis of Metropolitan Police data, for example, suggests that incidents of violence tend to increase significantly when temperatures exceed as little as 18°C.

Economics

The economic consequences of heatwaves are equally significant. High temperatures reduce labour productivity, particularly in physically demanding sectors such as construction and agriculture, where workers face greater risks of heat stress and exhaustion. 

Workplace performance also tends to decline as employees struggle with reduced concentration and increased fatigue.

There is no legal minimum or maximum working temperature in Britain. However, the Workplace (Health, Safety and Welfare) Regulations require employers to provide a “reasonable” working environment.

Educational institutions are also affected, as excessive classroom temperatures can impair concentration and learning outcomes and, in some cases, force schools to close.

As with the workplace, schools are not subject to legal maximum temperature requirements. However, unions advise that when classroom temperatures exceed 30°C to 32°C, conditions become unsuitable for prolonged work and learning.

Infrastructure

Heatwaves also place considerable strain on infrastructure. Increased demand for cooling systems can overload electricity grids, raising the risk of power outages that further exacerbate health risks by disabling air conditioning and other essential cooling technologies.

In urban areas, the ‘urban heat island effect’ intensifies these challenges, as densely built environments absorb and retain heat, making cities considerably warmer than surrounding rural regions.

Transport networks are also vulnerable, with extreme temperatures capable of causing railway tracks to buckle and road surfaces to soften, leading to travel disruption, delays, and impacts on supply chains.

Strategies

We should learn from our European neighbours, who have more experience in dealing with heatwaves.

Open windows only at night or early in the morning when the outside air is cooler than the air inside your home, and keep windows closed during the day to prevent warm air from entering. 

Electric fans can be helpful, but if temperatures exceed 35°C, they may simply circulate hot air and contribute to dehydration. One way to mitigate this is to place a bowl of ice or a frozen bottle of water in front of the fan.

To get the best from workforces, employers should consider reconfiguring the working day to include a Spanish-style midday siesta when the sun is at its hottest, confining working hours to early morning and late evening.

Drink plenty of water throughout the day, before you feel thirsty, and avoid excessive caffeine and alcohol, as both act as diuretics.

Misting

Consume cold food and drinks, take cool showers, and wear damp clothing where appropriate.

In the longer term we need to urge local councils to revive public drinking fountains and, of course, plant more trees, create additional green spaces, and rewild previously manicured parkland.

Community support groups – which proved so effective during the COVID-19 pandemic – will be imperative. These groups could establish community ‘cool hubs’, along the lines of the warm hubs created during the energy crisis, potentially located in cellars, church crypts, public airconditioned facilities, and other naturally cool spaces.

In the longer term, adaptation strategies might include painting roofs white to reflect solar heat. As for a potential insect invasion, screened doors and windows may become essential.

And with the threat of lethal wet-bulb temperatures spreading northward, we might take a lead from Parisians, who during their own extended heatwaves set up outdoor misting systems and traffic-reduction schemes.

Net-zero

It is sobering to think that there is now no way back for our children. Even if we stopped emitting CO₂ today, the climate would continue to heat until the atmosphere purges itself of excess greenhouse gases – long beyond our lifetimes and those of our children.

If we cross critical climate tipping points, warming will accelerate dramatically and become increasingly difficult to control. At that point, our options would be limited to slowing the process and adapting to its consequences.

For this reason, adaptation must go hand in hand with continued efforts to reduce emissions and hold the government to its net-zero commitments.

This Author

Tom Hardy has over 40 years’ experience in education as an editor, writer, and consultant. He has written for the Times Educational Supplement and the International Journal of Art and Design Education and advised the Department for Education. He now works with Media Revolution.