Last week’s heatwave left many UK city dwellers struggling to sleep. These conditions also increasingly threaten lives because such high night temperatures can make it impossible for the body to cool down.
Air conditioning solves individual problems but, apart from the cost of electricity, it worsens the climate crisis and makes future heatwaves even worse.
Researchers studying the Paris region, where the problem is already acute, compared various methods of cooling the city and combined them with minimal air conditioning to see how much they could reduce dangerous night temperatures.
They tested their ideas against the real heatwave of 2003, when thousands died in France. After nine days of intense heat, the temperature at 4am in Paris had been lethal for many older people.
The results of the research are impressive. A combination of urban greening – replacing as much tarmac and concrete with as many trees, shrubs and grass as possible – thermal insulation of buildings to keep the heat out, and reflective walls and roofs, made a big difference.
Reflective exteriors, at their simplest, use white paint instead of dark colours. Heat reflective paints in many shades are also coming on the market. These measures, combined with using moderate air conditioning, reduced inside temperatures by as much as 4.2C – enough to ensure comfort and save many lives.
