London must drop its “keep calm and carry on approach” to extreme weather, a climate expert has warned.
Bevan Jones, a sustainability consultant at Greengage Environmental, said heatwaves can increase violence, put strain on the NHS, and dent the economy.
Speaking at the London Assembly, Mr Jones said hot weather should now be treated with the same seriousness as snow or extreme storms.
The climate expert said governments must work to prevent a “monumentally catastrophic” 4C to 6C shift in world temperatures.
But he said we should expect an increase of at least 3.1C, even if international targets are met.
The last decade was the hottest in a century for the UK, according to the Met Office.
And London’s micro-climate – known as the urban heat island – means it can be as much as 10C warmer than neighbouring rural areas.
This is because sunlight is absorbed by hard surfaces like concrete and asphalt, rather than earth and vegetation.
Mr Jones said climate change means extreme weather is happening more often, giving the capital less time to prepare.
Last year, 41 people died in the city’s summer heatwave – meaning London was the only UK region with a statistically significant increase in deaths.
Mr Jones also warned that violent crime typically increases in the hot summer months.
And the climate expert said that every 1C temperature rise above 20C meant 1% more ambulance call outs.
He said: “With a health service that’s already stretched and normally uses April to September as its recovery period, we’re now seeing the NHS having to deal with a year-round A&E emergency.”
And Mr Jones said other services – such as railways – are often unprepared for rising temperatures. Heatwaves could cost the London economy £35million, according to a report by Lloyds of London.
The study said related risks such as droughts and floods – a growing threat as ice caps melt and sea levels rise – could cost £363million and over £1.2billion respectively.
Alex Nickson, water resources lead at Thameswater, said climate change would mean “more frequent and intenser droughts” in the city.
He said less rainfall combined with damage to pipes as London’s clay soil dries – causing more frequent leaks – would reduce water supply.
It could mean extra hosepipe bans or “more serious action”, he warned.
Mr Jones said London must now completely change its approach and stop viewing extreme weather defences as the “poor relation” of climate action.
He said: “What we are going to have to see is more Paris-style emergency management where schools will be closed, where people are encouraged not to commute to work, and where we are going to start treating heat like snowfall or storminess.
“I think employers and employees are going to have to change their mindset around ‘keep calm and carry on’.
“It’s going to have to be much more managed and much more rational.”