The now-familiar scenes of a city inundated by floods unfolded in London over the weekend, when heavy rains submerged parts of the UK capital.
When two London hospitals turned away elective patients after being inundated over the weekend, it was a stark reminder that even some of the world’s wealthiest cities are dangerously unprepared for the kind of extreme weather conditions that are becoming more and more common and severe due to the climate. change.
Climate and infrastructure experts have been warning for years that London, like many other major cities, is not ready for climate change, with large parts of the city built on a floodplain and a Victorian drainage system unable to withstand this kind of heavy rain.
“It is deeply concerning to see hospital emergency departments shut down due to flooding, something must certainly be done to ensure that critical infrastructure is not at risk,” said Liz Stephens, associate professor in the department. of geography and environment. sciences at the University of Reading.
The city has built a giant flood defense system on the River Thames to protect against tidal flooding, but barriers are of little help when it comes to flash floods caused by sudden heavy rainfall – the kind that is becoming more and more common due to rising temperatures.
Images from Sunday showed Londoners taken by surprise, wandering through flooded streets. Some are even trying to pull away through the rising waters, which officials warn against due to the high likelihood of automobiles being swept away or drivers being trapped.
London firefighters said on Monday they had taken more than 1,000 emergency flood-related calls with crews rescuing people from cars and helping them flee their homes.
While these images of people not taking the risk seriously are concerning, Stephens said individuals were hardly to blame here.
“Our ability to map the risk of surface water flooding is not particularly good,” Stephens said. He noted that UK surface water flood risk maps have not improved significantly since 2013, although more precise technology is available and despite the fact that numerous reports have been published. that focus on increasing risk.
On top of that, the way flood risk is monitored and managed in the UK is extremely complicated, with different agencies responsible for different parts of the effort and no single agency in charge.
The Met Office, the UK’s national weather service, issued weather warnings for heavy rain and thunderstorms on Sunday, but Stephens said these might not be immediately understood by people.
“I think there was an orange warning telling you there could be some serious impacts, but the orange warning was covering a very large part of south-east England,” Stephens said. “So, as an individual, what would you do with this kind of information. If you don’t know your property is at risk of flooding and you have a very large scale flood warning, or even no flood warning, a heavy rainfall warning, then I don’t think so. we might be surprised if people are not prepared for this, ”she said.
A report on the impacts of climate change on the UK released last month by the government’s independent climate advisory group, the Climate Change Committee, warned the country was not ready, saying ” adaptation measures have not kept pace with risk. “
“The risk is always greater in an urban setting because we have concrete surfaces, but we also rely on old drainage infrastructure in London, we are talking about Victorian drains,” Stephens said.
Images like those coming from London on Sunday are becoming more and more familiar.
Just two weeks ago, devastating floods caused by heavy rains swept across much of western Europe, leaving more than 200 dead and thousands homeless. Across the world, much of central China’s Henan Province was devastated after record rains last week, killing at least 58, cutting electricity and forcing the displacement of more than one million. of people.
And although it is not possible to attribute a single event to climate change, heavy rains and flooding are increasingly common. As the Earth’s atmosphere warms, it can hold more moisture, which can lead to unprecedented precipitation. The total average precipitation in an area may not change, but the extremes are magnified, which can mean longer dry spells or more intense storms. When heavy rains strike after a prolonged drought, soils are less able to absorb water and rain is more likely to cause flooding.
Urban areas are more at risk of flash floods because the surfaces are covered with concrete, which means the ground cannot absorb water. According to the European Environment Agency, Paris, Thessaloniki, Bucharest and Barcelona are among the cities with more than three quarters of their surface area “sealed”, which means that they are more exposed to surface flooding.
In addition, many European cities depend on very old infrastructure and sewage systems cannot cope with heavier rainfall.
“Summer thunderstorms are not a new phenomenon, but it is becoming increasingly clear that worsening flood impacts from heavy rains are having devastating effects here in the UK and across Europe,” said Jess Neumann, hydrologist at the University of Reading. a commentary at the Science Media Center. “The severity and frequency of flooding is a stark warning that we are not prepared for climate change. “