In cities across the United States, people of color endure warmer summer temperatures than their white counterparts, new research shows. This is another sign that the consequences of rising temperatures will hit vulnerable communities harder than others.

A person of color, on average, lives in a census tract that is more than a degree Celsius (nearly 2 degrees Fahrenheit) warmer in the summer than their non-Hispanic white counterparts, according to a study published today in the journal . Nature communications. This included everyone who made do not identify as “white single,” as well as anyone who identifies as Hispanic. The temperature difference was even slightly larger for black residents.

Cities are generally several degrees warmer than rural areas, and areas inside cities without much green space are even warmer. Asphalt, cement and dark roofs absorb heat, while exhaust from tailpipes and industry warms neighborhoods even further. This is a phenomenon called the “urban heat island effect”.

Extreme heat is already the deadliest weather disaster in the United States. The urban heat island effect and climate change make soaring temperatures even more risky for people who live in cities. The risks are even greater for certain groups, such as black Americans, who face a long history of housing discrimination and divestment. Even a few degrees increase poses serious threats, warns the study’s lead author. The one-degree Celsius average temperature difference experienced by people of color in America masks more extreme disparities – perhaps up to 10 degrees Celsius – that some communities face.

“It’s a lot when you translate that into real impacts and how it feels on a summer day,” says Angel Hsu, lead author of the study and assistant professor of public policy and environment, ecology and development. energy at the University of the North. Carolina-Chapel Hill.

Some neighborhoods in Hsu’s hometown of Greenville, South Carolina may see temperatures six to eight degrees Celsius warmer than other parts of the city. They tended to be neighborhoods with higher proportions of black residents. Other communities in Baltimore, Maryland are eight to ten degrees Celsius warmer than their neighbors.

Research has also shown that households below the poverty line, across all racial and ethnic groups, face more searing temperatures than better-off households. But the average person of color always faced warmer temperatures than their white counterparts, regardless of their income.

It’s proof that something fishy is going on regarding the breed in particular, Hsu says. Other studies have suggested the same: Blacks, Asians, and Latinos are more likely to live in urban heat islands.

There is also a long and terrible history of segregation in the United States that has pushed black Americans and other marginalized groups into specific neighborhoods. Since the 1930s, financial institutions have systematically refused home loans and insurance to black Americans. The result was “red” neighborhoods, where the majority of residents were black. City planners have built more roads and large housing developments in and around redline neighborhoods – and all that asphalt and concrete has turned them into heat traps. Black Americans are also more likely to live near polluting industries, which can also make neighborhoods warmer. Today, these neighborhoods are up to 7 degrees Celsius warmer than other neighborhoods, according to another study published last year.

All of these disparities come at a deadly cost. In New York City, between 2000 and 2012, African Americans made up about a quarter of the city’s population, but almost half of its heat-related deaths.

The new study released today gives one of the most comprehensive views to date on the extent of injustice. The researchers compared 2017 census data to high-resolution satellite temperature data for 497 urban areas in the United States. They used satellite remote sensing to take stock of differences in surface temperatures between urban landscapes and more rural areas. They used this data to understand how surfaces like asphalt made a place warmer compared to a more rural baseline. Ultimately, they found that in 169 of the 175 largest urban areas in the continental United States, the average person of color lives with warmer summer surface temperatures during the day than a non-white person. Hispanic.

“What was really surprising was how systemic this problem is. We’re not talking about one or two cities or a few big cities like Chicago or San Francisco. We are talking about [this trend] in every city, ”Hsu says.

The next step, she says, is to look at a time series to determine whether the temperature differences between Americans of different races have improved or worsened over the years. She hopes that this work can identify what still causes these disparities and shed light on solutions to cool these neighborhoods.

Looking ahead, average temperatures are increasing around the world due to climate change. But some places may feel the heat even more if they continue to lose trees and green space to industrial development and urban sprawl.