The Guardian: How US cities are scrambling to protect people from extreme heat

August 20, 2019

With cities facing both rapid growth and radical, permanent climate change, urban authorities are faced with an increasingly vulnerable population.

Washington DC has been given a recent glimpse into its future – a 92F (33C) burst of heat last May saw the city break a 105-year-old record for high temperatures. Sitting on the banks of two tidal rivers – the Potomac and the Anacostia – Washington DC is also essentially a delta city at growing risk of flooding as bursts of rainfall become more intense.

City leaders have attempted to identify the threat and counter it. A climate resilience plan, released in April, states that DC’s temperature has already risen by 2F (1.1C) over the past 50 years, with a further 4.5F (2.5C) increase to come within 30 years.

The number of “heat emergency days” in DC, where the heat index tops 95F (35C), is expected to occur on more than 50 days a year as the century draws to a close. “That means that, in 2080, our summer will be one long heat emergency,” the DC resilience document warns.

This scorching new climate is set to heavily burden DC’s growing population, many of them low-income and struggling with housing affordability. Vulnerable people will likely suffer dehydration or heatstroke, with increasing use of air conditioning placing a strain on the electrical grid.

Power outages will probably start to spike.

“It will affect how people live, work and get around in the city,” said Jessica Grannis, adaptation program manager at the Georgetown Climate Center. “It won’t just be uncomfortable, it will be a life or death challenge for many people. Once it starts getting very hot at night, people without air conditioning are going to be at serious risk if they can’t cool down properly.”

Kevin Bush, DC’s chief resilience officer, has pledged to “make the city’s immune system stronger” to cope with this threat, comparing it to how cities in California prepare for the ructions of an earthquake.

Under the resilience plan, all DC buildings must be retrofitted to cope with rising heat and flooding threats by 2050, with all new buildings adhering to stricter codes within 13 years. The most at-risk buildings may even be removed.

There’s a plan to add more greenery to DC by planting more trees, which will provide shade, and other vegetation that will help soak up stormwater from heavy downpours. The curbsides of several major streets are already getting a makeover, with new plants being bedded in to help cool down the city.

“If walk along the streets in DC at the moment you’ll see a lot of pavements being taken out in favour of plantings,” Grannis said. DC is, she added, “one of the most climate prepared cities in the US. Unfortunately it’s not quite the same everywhere.”

Read the full article by Oliver Milman, Emily Holden, and Tom Dart in The Guardian