From 2008 to 2020, the National Library of Medicine reported an increase in heat-related emergency room visits — in every single region of the US.
As the world keeps getting hotter, necessity breeds invention, especially in cities that serve as “urban heat islands:” areas that experience blazing temperatures in relation to outlying regions.
In Tel Aviv, solar-paneled streetlights provide shade on hot days, and new Canadian cooling pavilions provide air conditioning to the pedestrians standing beneath them — by drawing power from their body heat.
But for years, Los Angeles has been adopting an approach that relies on two more simplistic measures: painting rooftops and streets with white, reflective paint and planting more trees and vegetation.
Together, the city’s paint job — and “plant” job — could save lives.
A recent study, published in the International Journal of Biometeorology, estimated that these efforts could significantly reduce ER visits by up to 50% during heatwaves.
“Cooling urban neighborhoods by planting trees and vegetation and increasing the albedo of roofs, pavements, and walls can mitigate urban heat,” wrote Scott Sheridan, Edith B. de Guzman, and their team of researchers.
“Albedo” is the percentage of light reflected by a surface. White paint has a high rate of albedo, which reduces the amount of heat that accumulates in urban areas.
In 2021, street teams in Los Angeles sprayed white “cooling” paint on pavement in ten neighborhoods throughout West Hollywood and South L.A. and the effect was immediate — painted locations were two degrees cooler than their corresponding neighborhoods.
In the years since, L.A. slowly began rolling out more expansive painting projects, as street services coated roofs, walls, and entire blocks of pavement with high-albedo paint.
L.A. has also launched multiple tree-planting initiatives in the last decade. In 2021, University of Southern California scientists developed a tree-planting blueprint that would double shade in L.A.’s Eastside by 2028.
And last year, TreePeople — an environmental justice group based in L.A. — received $8 million in federal funding to funnel toward tree-planting and maintenance projects.
“What we proposed was to be able to plant trees where they’re needed the most, and that was from the northeast Valley all the way to the Inland Empire,” Marcos Trinidad, senior director of forestry with TreePeople, told the LA Times.
“So we’ve expanded our reach, just in being able to identify the areas that need trees the most, but also the communities that are suffering the impacts,” Trinidad continued. “Not just from global warming, but everything that goes into creating a healthy community.”
L.A. is not alone. Cities across America have been adopting similar approaches to beat the heat.
Chicago planted 75,000 trees to create green canopies in urban areas. Cities in Camden, Newark, and Baltimore followed suit with their own tree-planting projects. Tucson even made a pledge to plant 1 million trees to combat climate change and keep temperatures from climbing.
And all of the cities above have prioritized underserved communities on their maps — because heat-related deaths disproportionately impact BIPOC communities living in low-income areas.
“It's not that the heat is seeking out low-income populations,” John Dialesandro, a Ph.D. candidate studying urban climatology at the University of California, Davis, told Environmental Health News. “It’s a lack of greenspace.”
This latest study published in the International Journal of Biometeorology backs up Dialesandro’s assertion.
“Strategic changes in the land cover of urban areas can have significant and measurable positive benefits for public health, particularly for lower-income communities and people of color who suffer disproportionately from heat,” wrote Sheridan, Guzman, et al in their report.
So although futuristic methods are emerging to cool down cities, this latest research posits that most U.S. cities already have the infrastructure at their disposal to combat extreme heat.
“This is a key point,” the research team concluded. “Present strategies exist to greatly improve public health during heat events.”
