Climate Extremes Result in Over 69,000 U.S. Deaths in 25 Years

Researchers from Mass General Brigham have revealed alarming statistics regarding climate-related fatalities in the United States. A study published in the Annals of Internal Medicine indicates that over the past 25 years, extreme temperatures have contributed to more than 69,000 deaths, with certain populations affected disproportionately.

The study, led by Shady Abohashem, MD, MPH, who is an investigator at the Cardiovascular Imaging Research Center of Massachusetts General Hospital, provides a comprehensive look into the impacts of both heat and cold on mortality rates. Abohashem, who also serves as an instructor at Harvard Medical School, emphasized that past research primarily focused on heat-related or cold-related deaths separately. This study presents a contemporary assessment of how non-optimal temperatures affect various demographic groups across the nation.

Utilizing data from the Centers for Disease Control and Prevention’s WONDER platform, the research team analyzed death certificates between 1999 and 2024. Of the total 69,713,971 deaths recorded in that period, 69,256 (approximately 1 in 1,000) listed extreme temperature exposure as a contributing factor. Among these, 35% were attributed to heat exposure, while 65% were due to cold exposure. The data suggests that mortality rates related to temperature extremes have been rising in recent years.

“Our findings show that both heat and cold exposure continue to claim thousands of lives every year in the United States—deaths that are largely preventable,” stated Abohashem. He warned that while cold-related deaths currently dominate, heat-related fatalities are expected to increase as climate change progresses.

The study highlights demographic disparities in temperature-related mortality. Older adults aged 65 and above, as well as males, faced higher mortality rates compared to their younger and female counterparts. When examining race and ethnicity, the data revealed that Black individuals had the highest adjusted mortality rates for heat exposure, more than double that of white individuals. Similarly, the cold-related mortality rates were highest among Black individuals, followed by white and Hispanic populations.

Climate change poses a growing threat, amplifying the risks associated with severe weather events. Abohashem called for targeted adaptation strategies to mitigate these risks, advocating for improvements in housing quality and enhanced access to heating and cooling systems. He also stressed the importance of early-warning systems to protect vulnerable communities as climate extremes become more frequent and intense.

The findings of this study serve as a crucial reminder of the urgent need for public health strategies that address the specific needs of those most affected by temperature extremes. As the climate continues to change, understanding which populations are disproportionately impacted will be key in developing effective prevention measures.

The full study is available in the Annals of Internal Medicine under the title “Temperature-related deaths in the US, 1999 – 2024” by Hassan, I., et al. DOI:10.7326/ANNALS-25-01006.