So-called urban heat islands expose black Americans in US cities to twice as much additional warming during the summer as whites, a gap with potentially serious health implications, researchers said Tuesday.
From June to August, in 175 cities representing 65% of the U.S. population, districts inhabited primarily by white residents experienced, on average, an additional 1.5 degrees Celsius (2.7 degrees Fahrenheit) warming due to concrete trapping heat, dark tarmac and air conditioning exhaust, they reported in Nature Communications.
Black residents, on the other hand, endured temperatures exceeding 3 ° C above surrounding non-urban areas.
“We find that people of color in the United States live in neighborhoods with higher urban heat island intensity than non-Hispanic whites in 97% of those cities during summer days,” coauthor Tirthankar Chakraborty, a researcher at the Yale University School of the Environment, told AFP.
U.S. government statistics on heat-related deaths in the United States from 2004 to 2018 show an approximately 50% higher death rate among non-Hispanic blacks than non-Hispanic whites, suggesting that a additional exposure can result in disastrous health consequences.
The heat gap between rich and poor city dwellers was not as large: people living below the poverty line resided in areas warmer by 2.5 ° C on average, while those with incomes at least two times above the poverty line only saw an increase of 1.8 ° C.
Significantly, race and income level do not overlap much, according to the study, which matched satellite temperature data with 2017 census data: only 10% of people of color live below the cut-off point. poverty, but in half of the American cities, they are exposed to summer heat higher than the average of the poor.
“This suggests that generalized inequalities in heat exposure by race and ethnicity cannot be well explained by differences in income alone,” Chakraborty said.
– ‘Green corridors’ –
With just 1 ° C of global warming to date, exposure to high temperatures was responsible for 2,400 deaths in the United States in 2019, according to a study by the Institute for Health Metrics and Evaluation (IHME) published on last fall in The Lancet.
Globally, the high heat claimed the lives of more than 300,000 people that year, according to the IHME.
In 2003, a fierce heat wave across Western Europe caused some 70,000 more deaths in a handful of countries this summer.
Even in optimistic scenarios in which global warming does not exceed pre-industrial levels by 2 ° C, heat waves are expected to become both more intense and more frequent, especially in the tropics.
# photo1 ″ At 2 ° C of warming, Karachi and Kolkata could experience conditions equivalent to their deadly 2015 heat waves on an annual basis, ”the UN’s science advisory group, IPCC, said in a landmark report from 2018.
More than 2,000 people died from heat prostration in each city in 2015.
In the United States, politicians and city planners should heed the new findings “to identify best practices and strategies to mitigate overall exposure to urban heat islands, as well as inequalities in its distribution,” the authors concluded.
They also mentioned planting trees and other forms of urban vegetation in low income and minority areas as a heat reduction strategy.
The city of Medellin’s “Green Corridors” initiative – a network of trees, plants and shrubs planted near the streams that crisscross the city – has lowered summer temperatures by as much as two degrees Celsius, as reported by showed previous research.
© 2021 AFP