Most affected by the heat

Study shows differences in mortality across the US

A new study examines how extreme temperatures in the United States affect mortality among different ethnic groups. It comes to the conclusion that both cold and hot days increase mortality. Non-Hispanic Blacks in particular had higher excess mortality on hot days than white people. The findings highlight the importance of adaptation measures, particularly for ethnic minorities, and call for urgent action and targeted strategies to reduce health risks from extreme temperatures resulting from climate change.

Every year, climate change pushes summer temperatures to new extremes, with one heat record following the next. In a new study, scientists at the Max Planck Institute for Demographic Research (MPIDR) examined how extreme temperatures in the United States affect mortality among people from different ethnic groups. Risto Conte Keivabu, Ugofilippo Basellini and Emilio Zagheni (director of the MPIDR) analyzed data from 1993 to 2005 and examined differences between ethnic groups in temperature-related deaths. The study found that both extreme cold (temperatures in the coldest five percent of all temperatures) and extreme heat (temperatures in the warmest five percent of all temperatures) increase mortality rates, with heat disproportionately affecting ethnic minorities.

For their study, researchers analyzed death registry data in more than 3,000 US counties and found strong evidence that hot days in particular have a disproportionate impact on ethnic minorities. Based on these results, the researchers expanded their analysis to predict trends from 2006 to 2023, as data was not available for this period. Their calculations suggest that recent temperature increases have increased racial disparities in heat-related deaths.

Minorities bear the brunt

These differences are particularly pronounced when looking at 2022, one of the hottest summers since weather records began. For this period, the researchers calculated that the mortality rate for non-Hispanic blacks was about 26 per 100,000, while for white people it was about 15 per 100,000. The study also showed large geographic differences in these estimates, further highlighting the unequal burden of extreme heat.

“Our study provides important insights, but also has some limitations. Data only goes back to 2005, so the impact of recent temperature increases may not have been fully reflected in our calculations. We also lacked individual socioeconomic data that may be important for understanding the effects of temperature on mortality. Finally, our counterfactual analysis assumes that the relationship between heat and mortality remains even after the study period,” explains Risto Conte Keivabu.

Despite these limitations, the study provides compelling arguments for immediate action. “Our results underscore the urgency of adaptation measures to protect vulnerable populations from the increasing dangers of extreme temperatures,” said the researcher.