How can civil engineers keep us cool during heatwaves?

As temperatures in the UK soar, civil engineers need to use their skills, knowledge, expertise and empathy to protect communities.

Heatwaves lead to less sleep and time spent outdoors, which can affect our mental and physical health.

Vulnerable members of society, the elderly in particular, are usually less able to adapt to abrupt changes in temperature.

This leads to them having an increased chance of developing chronic medical conditions, which can change their body’s normal response to higher temperatures.

These are one of the many critical impacts of us being in a climate and nature emergency.

Impact of heatwaves

The Lancet Countdown on Health and Climate Change stated that in 2023, "people were exposed, on average, to an unprecedented 50 more days of health-threatening heat than expected without climate change".

This has resulted in 167% more annual deaths of people aged over 65 than in the 1990s.

Older people generally live in less expensive accommodation, which has a higher exposure to heat stress, as well as fewer resources to mitigate against it.

Habitants in cities are also exposed to other heat-related death risks, such as high-density housing, shortage of green spaces, and increased temperatures.

It’s been shown that high rise buildings, with an increased density, and housing with a lack of ventilation and insulation increase the risk of morbidity in the elderly.

It’s also vital that the right type of wall and roof insulation is used.

Too high levels of insulation and airtightness are some of the major causes of overheating, due to trapped heat and lack of cross ventilation.

Green spaces provide a refuge

Urban UK environments are on average 1-2°C higher in comparison to rural areas, due to the urban heat island effect.

This is because the surface materials in urban areas absorb more of the energy of the sun compared to vegetation.

Nature-based solutions, such as the increase of green spaces, can be used as places of refuge during these high temperatures.

They can offer many benefits, such as:

• Trees and other vegetation provide shading and reduce the temperature through evapotranspiration (the process where the energy from the sun moves water from the plant’s leaves to the surrounding atmosphere).
• Water bodies with wildlife provide opportunities for less intensive recreational activities and can encourage people to use these spaces.
• Drinking fountains actively promote hydration.

Another factor that often causes chronic medical conditions in the elderly during heatwaves is the inadequately insulated apartments that many of them live in.

As mobility decreases with age, if green spaces are too far and difficult for the elderly to get to, they will have to stay in their poorly insulated apartments, increasing the risk of them developing medical conditions.

This can also lead to more isolation and poor mental health.

As we develop more green spaces, it’s vital that we change people’s perception that staying indoors in poorly ventilated and insulated apartments will keep you cooler than visiting green spaces.

Creating accessible green spaces in cities

In urban environments where there’s often a shortage of space, alternatives can be used, such as green roofs.

The advantages of creating green roofs are that they’re more accessible to the elderly and can also be used as community gardens to grow their own food, which helps to combat loneliness.

A good example of green roofs are council houses in Hammersmith and Fulham in London.

It’s also vital that the design of the access routes to green spaces are mindful of the elderly, so they feel comfortable and safe travelling to these areas.

For example, by ensuring that there are adequate benches placed along the route to provide resting places, and by increasing vegetation along the routes to provide natural shading.

It’s not only about ensuring that any journey is inclusive, but that they feel that the neighbourhood is safe, which was one of the biggest reasons why the elderly stayed inside during the 1995 heatwave in Chicago, USA.

As neighbours meet more frequently in green spaces, relationships are built and the sense of community increases.

Beyond heatwaves

Green spaces not only provide benefits to communities during heatwaves, but throughout all seasons, improving human health and wellbeing.

At present, over 70% of Europeans live in urban environments exposed to high air pollution. Green spaces can help to improve air quality by storing carbon.

These spaces also decrease flooding risks by absorbing excess surface water.

They also encourage an increase in physical fitness, which can improve mental health and reduce depression.

These green spaces not only benefit humans but also create much-needed habitats for wildlife.

Read more: 6 types of nature-based solutions to consider for your next project

Now is the time for civil engineers to act

As the ageing population and urbanisation increases, it’s vital that civil engineers do all they can to ensure our cities are designed to help protect their communities.

In 2014, approximately 54% of the earth’s population lived in towns and cities, and this number is set to increase to almost 70% by 2050.

To accommodate this, nearly two-thirds of our towns and cities that will be required by 2030 have yet to be constructed.

Therefore, now is the time to act to ensure that, as civil engineers, we are creating more sustainable, resilient and inclusive urban areas.

The answer lies in nature-based solutions which provide multiple benefits and give much-needed respite to our elderly.