Who Feels the Effects of Climate Change Most in American Cities?

Alida Soileau

If you had to guess which regions are feeling the effects of climate change the most, you would be correct to guess low-lying islands and coastal areas. But within urban areas of the United States, certain parts of cities are feeling the effects of climate change more than others, specifically a rise in temperatures. The neighborhoods most affected are majority low to moderate income and non-white. This is significant because increases in temperature correspond to increases in mortality rates.

What is redlining?

The areas of cities experiencing greater temperature increases correspond to the areas of cities that were “redlined.” Redlining refers to the practice of federal agencies and monetary lenders designating some parts of cities as undesirable. This designation indicated to lenders that the U.S. federal government, specifically the Home Owners’ Loan Corporation (created by President Roosevelt in 1933), deemed these areas risky for investment and would decline to back private loans for development there. On a city map, these areas were literally colored-coded red. In practice, creating single-family housing in redlined areas became impossible.

Redlined areas were non-white neighborhoods composed of Black, Hispanic, immigrant, and other minority residents. If a neighborhood was middle class, but a single African-American family lived there, it was designated as red. “The maps became self-fulfilling prophesies, as ‘hazardous’ neighborhoods—‘redlined’ ones—were starved of investment and deteriorated further in ways that most likely also fed white flight and rising racial segregation.” Because non-white families did not have equal access to federal loans and assistance, it was nearly impossible to build wealth to pass to future generations. As a result, these previously redlined neighborhoods are predominantly low to moderate income and non-white today. In contrast, the “better” (whiter) the neighborhood, the safer the federal government deemed it for investment. In these “better” neighborhoods, the federal government backed private loans and provided other forms of financial assistance. Thus, white families in non-redlined areas were able to build wealth and pass that wealth on to future generations.

Why does redlining matter now with regard to climate change?

Previously redlined areas are more vulnerable to rising temperatures than non-redlined areas. Generally, increasing the amount of green vegetation in a space decreases its temperature. Formerly redlined areas, “consistently have far fewer trees and parks that help cool the air . . . [and] more paved surfaces, such as asphalt lots or nearby highways, that absorb and radiate heat.” Temperatures can vary by up to 20 degrees in different parts of the same city. For example, a study conducted in Baltimore found a temperature of approximately 103 degrees in the downtown area on a particular day. Downtown Baltimore has a sizeable Black population, 32.3 percent, and is characterized by “large brick buildings, parking lots and few trees.” That same day, the study found “a conspicuous belt of high heat east of downtown across residential neighborhoods made up of dense row houses, typically with no yards and little tree cover.” Average temperatures in this area, which is majority Black and largely lower-income, hovered between 98 and 99 degrees, with hot spots reaching as high as 102 degrees. At the same time, average temperatures in the more affluent, tree-lined residential areas in the city’s north stayed in the low 90s—a difference of over 10 degrees on the same day. These northern areas are majority white; the Roland Park neighborhood has a white population of 82.6 percent and a Black population of only 6.9 percent.

This heat disparity exists, at least in part, for the following reasons:

”[n]eighborhoods with white homeowners had more clout to lobby city governments for tree-lined sidewalks and parks. In Black neighborhoods, homeownership declined, and landlords rarely invested in green space. City planners also targeted redlined areas as cheap land for new industries, highways, warehouses and public housing, built with lots of heat-absorbing asphalt and little cooling vegetation.”

Effectively, the same federal policies that established and enforced neighborhood segregation also successfully diverted resources away from non-white areas, leading to disparities in urban climates today.

Why are heat disparities a problem?

Increases in temperature correspond to increases in mortality rates. A 2010 study by two Yale scientists found that for every 1 degree Fahrenheit increase in temperature, heat wave mortality increased by 2.49 percent. Further, in the past decade heat exposure has caused the premature deaths of up to 12,000 Americans annually. On a biological level, “[e]xposure to heat can compromise the body's ability to regulate its internal temperature, potentially resulting in heat exhaustion, hyperthermia, worsening of chronic conditions, and heatstroke, leading to temperature‐related deaths . . . small temperature changes at mild or moderate temperatures can have larger health impacts than changes at extreme levels . . .”

A 2019 study of 108 U.S. cities found “[t]he consistency of greater temperature in formerly redlined areas across the vast majority (94 percent) of the cities included in this study indicates that current maps of intra-urban heat echo the legacy of past planning policies.” The individuals who live in hotter neighborhoods are, more often than not, low to moderate income and therefore may not be able to keep cool or access medical care if heat-related illness does occur. Individuals who live in formerly redlined areas, the majority of whom are moderate to low income people of color, are experiencing the effects of climate change–in the form of increased temperatures–more so than others as a direct result of federal policy.

What next?

The Intergovernmental Panel on Climate Change (IPCC), composed of over 1,300 scientists from around the world, predicts a temperature rise of 2.5 degrees to 10 degrees Fahrenheit over the next 100 years. Additionally, the IPCC predicts future heatwaves will occur more frequently and last longer than they have in the past. The good news is mitigating the human impacts of these anticipated temperature increases is possible. Cities are planting more trees, converting vacant lots into green spaces, and opening cooling centers so those without air conditioning can escape the heat. These changes are productive, but ultimately, large-scale legislative change will likely be requisite to remedy the decades of harm inflicted by discriminatory government policy.

*In Denver, historically redlined areas included the heart of Aurora, parts of Englewood, the Lincoln Park neighborhood, and parts of Cherry Creek.