Cities face higher risks of heat and flood

IN just 30 years, cities around the world will face dramatically higher risks from extreme heat, coastal flooding, power blackouts, and food and water shortages unless climate-changing emissions are curbed, urban researchers have warned.

Today, for instance, more than 200 million people in 350 cities face stifling heat where average daily peak temperatures hit 35 degrees Celsius for three months of the year, according to a study released by C40 Cities, a network of major world cities pushing climate action.

But by 2050, more than 1.6 billion people in 970 cities will face those conditions, researchers predicted.

The number of people who are both in poverty and battling brutal heat — usually without air conditioning — will rise tenfold, they said.

“This is a wake-up call,” Kevin Austin, deputy executive director of C40 Cities, said at an international meeting in the South African city of Cape Town on adapting to climate change.

“The magnitude of people affected by heat will be (much) greater than today if we continue to increase greenhouse gases at this rate.”

But cities can take action to directly curb the risks, besides working to cut emissions, he said. In Seoul, for example, a major elevated thoroughfare through the center of the city has been removed, opening up access to the river and lowering urban heat in the area by at least half a degree Celsius, he said.

South Korea’s capital also has planted more than 16 million trees and created shaded cooling centers for those without air conditioning.

“We want to encourage cities to adopt more of these solutions and implement them as quickly as possible. In the worst case scenario, they will need to do them quickly,” Austin said.

The research, carried out by the New York-based Urban Climate Change Research Network, looked at data from more than 2,500 cities and predicted likely conditions if emissions continue to rise at their current rate.

It found that Cape Town’s ongoing battle with drought-driven water shortages could become far more common, with over 650 million people in 500 cities — among them Sao Paulo and Tehran — likely to see their access to water reduced by 2050.

Many thirsty cities are already aiming to set caps on water use per person, with Los Angeles pushing for 200 liters a day, Melbourne for 155 liters and Cape Town a dramatically reduced 50, Austin said.

The US Geological Survey estimates that an average American today uses at least 300 liters of water per day.

Sharing advice on how to make cuts happen, including insights gained in Cape Town which has slashed its water use by half in the face of extreme drought, can save cities time and help them make changes faster, Austin said.

But more cities “need to transition in a planned way, not in response to disaster,” he added.

Cape Town Mayor Patricia de Lille said dealing with a crisis when it arrives leaves little room to maneuver.

“In a crisis like this there is no time to go by trial and error. You unfortunately have to get it right the first time,” she said at the Adaptation Futures conference in Cape Town.

The C40 Cities study also found that by mid-century more than 800 million people will live in 570 coastal cities at risk of flooding from weather extremes and sea level rise. Flooding presents a particular risk to urban power supplies, with many power stations located in flood-prone areas — and everything from transportation to heating and hospitals at risk if power plants flood in cities from London to Rio de Janeiro, the study noted.

Decentralizing power systems, including by getting clean energy from a larger number of smaller power plants, could help cut the risks, researchers said.