We all have felt the impact of heat waves this summer, but the costs and stakes are different across communities and neighborhoods in California. While temperatures rise in California, so do extreme heat illnesses and heat mortality. Those most impacted are unlikely to live in cooler coastal communities, or have access to air-conditioned homes.

According to the EPA, which tracks deaths related to extreme heat, between 1979 and 2017, more than 11,000 Americans were killed as a result of extreme heat events, but even this is likely an undercount because, “it has been well documented that many deaths associated with extreme heat are not identified as such by the medical examiner and might not be properly coded on the death certificate.”

Despite this high loss of life, only recently has the federal government responded to the crisis of extreme heat in a coordinated way. In July of 2022, the Biden Administration launched heat.gov, as a central source of information related to extreme heat outcomes, and mitigation through the National Integrated Heat Health Information System.

As vulnerable community members died in extreme heat waiting for the government to respond in a coordinated manner, there have been catastrophic outcomes for those who lack air-conditioned homes, schools, or workplaces.

Residents living in older and substandard structures, including manufactured housing, that have low thermal performance ratings (how well a structure holds or prevents the passage of heat), few energy-efficient installations, or air-conditioning are at elevated risk. On days with extreme temperatures, their homes may be unsafe for human habitation. For those who have issues with mobility (elders, youth, those with disabilities, etc.), traveling to a cooling center may be impossible, essentially trapping vulnerable persons in their extremely hot homes. Out of the 17 million renters in the state of California almost a third of rental units are not equipped with central or single-room air conditioning units.

California’s metro areas have greater temperature disparities between their poorest and wealthiest neighborhoods than any other state in the southwestern U.S., as a result of historic racist redlining and decades of community disinvestment. These, and other studies, have shown that wealthier, whiter neighborhoods often have more street trees, a higher number of parks or open greenspace, and less impermeable black-top than low-income, communities of color – all of which help keep residents cool.

How this climate paradox plays out: wealthier neighborhoods, where homes are more likely to be air-conditioned, experience cooler temperatures than poorer neighborhoods, where many homes lack air-conditioning. And this reality is costing lives.

Read the full article about disparities and extreme heat by  Alan Kwok, Katie Oran, and Sara Schwartz C.R. Kendall at Northern California Grantmakers.