On July 19, a record-breaking heatwave consumed the UK.
The sweltering temperatures – as high as 40.3°C at Coningsby, Lincolnshire – pushed the Met Office to issue their first ever Red Extreme heat warnings for parts of England.
It was an unprecedented, headline-making couple of days – but this isn’t a freak event.
Temperatures as high as 40°C, previously unheard of, are likely to hit the UK more frequently.
Why? Our climate is warming, mostly due to the burning of fossil fuels such as oil, gas, and coal. These fossil fuels release carbon dioxide into the air, causing the planet to heat up.
Met Office climate attribution scientist Nikos Christidis said in a press release that 40°C days in the UK are now as much as 10 times more likely than they would be ‘under a natural climate unaffected by human influence.
Professor Stephen Belcher, Met Office Chief Scientist, adds: ‘Under a very high emissions scenario we could see temperatures exceeding 40 degrees as frequently as every three years by the end of the century in the UK.
‘Reducing carbon emissions will help to reduce the frequency, but we will still continue to see some occurrences of temperatures exceeding 40°C and the UK will need to adapt to these extreme events.’
The UK isn’t built for this increasingly hot, volatile weather, and as global temperatures rise, infrastructure will suffer.
Case in point: roads, runways, traffic lights and road signs literally melted in the sun , while roadside heaths and houses went up in flames during this July heatwave.
Birds fell out of the sky, RSCPA received a huge increase in calls for heat-exhausted animals and nature reserves burned.
Kiran Tota-Maharaj, reader in Civil and Environmental Engineering at Aston University London wrote in The Conversation that ‘UK infrastructure has typically been designed to retain heat during the winter, but it must become effective at keeping the heat out in the summer’.
As things stand, he says, roughly 20% of existing UK infrastructure is at risk of overheating – and this threat is projected to rise as average temperatures climb.
Then there’s the steel that makes up the thousands of miles of UK railway tracks and is likely to buckle during the heatwave.
It puts strain on power cables too, making power cuts more likely.
This, obviously, is not ideal. So what can we do about it? We spoke to urban climate experts to find out how we can radical reimagine our cities for future heatwaves.
Making our homes eco-friendly
In the UK, most houses aren’t well insulated. They are cold in the winter and warm in the summer.
Smith Mordak, Director of Sustainability and Physics at Buro Happold, says: ‘Britain’s old homes simply weren’t built to cope with such extremes of heat.’
This isn’t great news, given that one in six house in the UK were built before 1900, and almost half (46%) between 1930 and 1982.
In contrast, the average age of an American home is only around 40 years old.
Air conditioning only became a standard in the late 1960s – hence this cooling method isn’t built into our older homes.
Smith argues that air con isn’t the answer, anyway.
‘To tackle more extreme hot temperatures, we need area-wide measures that benefit us all, not just plugging in a personal quick fix such as an air conditioning unit,’ they say.
‘Not only does air con use lots of energy so contribute to global heating, it often puts heat out into the street and increases the “heat island” effect in towns and cities.’
Instead, Smith says the government need to be retrofitting current houses, which means improving a building to make it more energy efficient.
This is much more cost-efficient than knocking everything down and starting again. This would look like solar panels and better insulation to cut soaring bills and help the planet out.
Smith adds: ‘In 2050, 80% of the buildings we’ll be using already exist today.
‘So we need to adapt what we have by retrofitting our buildings with shutters and awnings, as well as insulation that will keep us more comfortable in both summer and winter.’
Who will fund this? Smith suggests public funding through the government.
‘It’s really important that healthy spaces that keep us cool in the summer and warm in the winter are not just for those that can afford them,’ they say.
‘We need policies, tax incentives, and grants to enable all homeowners and landlords to retrofit their buildings so everyone can benefit.’
Trees, glorious trees
So better insulated, more energy efficient homes can help keep them cool, but what about outside?
Nature has already provided one gloriously effective urban cooler: trees.
Smith explains: ‘Trees are magic, and nature’s own air conditioning units – one of the best things we can do is plant lots more trees in our town and cities.
‘Not only do they provide shade in summer, they actually cool the air around them through a process called ‘evapotranspiration’, using the heat energy in the air to evaporate the water in their leaves.’
Chris Bennett, the CEO of EVORA Global, says that the biggest part of adapting infrastructure to cope with heatwaves is ‘to build with nature in mind rather than seeking to dominate it’. This approach would lead to urban spaces better for both people, the environment and our wildlife, who were baking and dehydrated under the intense heat.
He adds: ‘Incorporating trees and plants reduces the reflective nature of the streetscape, provides habitats for wildlife, and offers shelter from harsh UV radiation and solar heat during summer.
If we want to reduce the frequency and intensity of future London heatwaves, this is what our streets need to look like. https://t.co/qM5mcJ6Xnp
‘In London, we are blessed with many urban parks and squares that the Georgians and Victorians created. But many of the city’s trees have been lost in order to provide car parking spaces.
‘Planting street trees will increase protection from the climate by reducing heat stress and reduce the degradation of the urban construction materials, making buildings last longer.’
The cooling effect of trees can’t be overstated: As climate expert Jon Burke wrote for The Big Issue: ‘Street trees in particular have the potential to deliver an enormous amount of cooling through shading – one Manchester study, for example, found that shade from street trees reduced surface temperatures by an average of 12C – and via the transpiration and evaporation of water through leaves.
‘To illustrate just how pronounced this cooling effect can be, researchers in the US have discovered that a single, young, healthy street tree produces the same atmospheric cooling effect as five room-sized air conditioning units operating 20 hours a day.’
As well as cooling the city, trees suck Co2 out of the atmosphere and help our mental health too.
Cooling the hot city
Our cities are built from materials that trap and magnify heat: concrete, steel, glass, and tarmac.
These types of surfaces ‘soak up and hold the heat, making the area around them as much as 10c hotter’, Smith says. Tarmac starts to soften at around 50°C (which it can reach under the direct sun when the air temperature is just 25 degrees), and stores this heat until nighttime, when the heat is slowly released, elevating temperatures by up to 25%.
Reducing the amount of exposed paving, tarmac and masonry surfaces can really help make our urban environments more livable, Smith says.
Removing these can be impractical, though: Instead, we need to provide shady areas using trees.
Also, Chris argues: ‘reducing hard reflective surfaces such as road pavements would help to lower temperatures’.
He adds: ‘Our urban environments are dominated by densely grouped buildings made of reflective materials creating “heat island effect”, This is why it’s often hotter in cities than in rural areas.
What would this look like in practice? It’s not necessary to replace all hard surfaces, Chris says, but to ‘rebalance the ratio of hard paved areas with soft landscaping.’
He envisions pavements made from porous concrete blocks instead of tarmac, so water can flow through when it’s raining heavily or if it floods – which will happen more as part of the extreme weather events.
Then, Chris explains, when the weather is hot and dry, these pavers will hold onto water to ‘gently evaporate, just as a natural soil surface would do, thereby providing a degree of evaporative cooling effect’. This will help with droughts – that are warned to be coming in August – too, as natural ground holds on to water.
We can help in our gardens by bucking the trend of paving and astroturf (over seven illion front gardens have been paved over, according to The Royal Horticultural Society) and choosing natural grass and soil.
Finally, Chris notes, that changing the colour of the pavements can help reduce their reflectiveness, which makes them cooler too.
Heat proofing water pipes
During the summer, people need more water to hydrate and keep cool. However, when temperatures soar, water pipes are more likely to burst. That’s not a good combination.
Dr Timothy Farewell, Head of Science for Dye & Durham and Director of MapleSky, has been researching the impact of climate change on the UK’s water networks.
He says that as our summers become even hotter and drier, we will see a great increase in the number of bursts from PVC pipes, asbestos cement pipes, and iron pipes, especially where these pipes lie within clay and peat-rich soils, which are quite common in the South East of England.
‘We need to make investments now to set us up so we are not in a horrible position in a few decades,’ Dr Tim says, adding that even with 3-degree warming (an eventuality if nothing changes) there will be an increase in year-round bursts, thanks to the shrinking and swelling of soil.
In addition, data analysis from Dye & Durham’s National Ground Risk Model has identified that more than 7.65 million properties in Great Britain could be exposed to ‘medium or high risk of soil subsidence by the 2080s’ as a result of climate change.
Subsidence is when the ground beneath a house sinks, pulling the house’s foundations with it. It happens when the ground it parched during long droughts.
The climate crisis is here, and it’s only going to get worse. The heatwave may be a novelty for some now, but it is a result of our overheated planet.
If we want to keep living comfortably in cities, we need to make them green, invest in infrastructure and build energy-efficient homes.
There’s plenty you can do, from lobbying your MPs, to joining green groups. Why not start small, and bring some nature back to your garden?
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