The Undeniable Link Between Redlining and Extreme Heat in American Cities

"In cities like Baltimore, Dallas, Denver, Miami, Portland and New York, neighborhoods that are poorer and have more residents of color can be 5 to 20 degrees Fahrenheit hotter in summer than wealthier, whiter parts of the same city," report Brad Plumer and Nadja Popovich.

The links between these disparities in urban temperatures and the history of redlining are becoming more apparent. Redlined neighborhoods, which tend to be lower-income communities of color, also have fewer trees, less green space, and more concrete and asphalt.

Digitized redlining maps clearly show the overlap with hotter weather and the legacy of racial inequality that continues to the present day. Plumer and Popovich say the pattern of extreme heat in formerly redlined areas is consistent in cities across the country but each urban area has its own story to tell:

In Denver, formerly redlined neighborhoods tend to have more Hispanic than Black residents today, but they remain hotter: parks were intentionally placed in whiter, wealthier neighborhoods that then blocked construction of affordable housing nearby even after racial segregation was banned. In Baltimore, polluting industries were more likely to be located near communities of color. In Portland, zoning rules allowed multifamily apartment buildings to cover the entire lot and be built without any green space, a practice the city only recently changed.

As cities recognize the relationship between heat and racial equity, many are taking steps to broaden their climate and master plans. Increasing tree canopies, expanding green space, and improving flood protection in these communities are examples of goals and initiatives cities are planning to start addressing these long-standing inequalities.