Rising Temperatures Will Mean More Fatal Injuries in the U.S., Says Study

A new study says higher temperatures may mean more people killed by accidents and violence. (Image: Amy Wolfe)

Thousands more people could die from injuries each year as rising temperatures in the United States affect people’s behavior, says a new study. Most of the additional deaths would be caused by transport accidents, drownings, suicides, and assaults; young men would be the main victims, say the authors. The study appears this week in the journal Nature Medicine.

Lead author Robbie Parks, a postdoctoral researcher at Columbia University’s Earth Institute, said, “Our work highlights how deaths [already] rise with warm temperature, and could also worsen by rising temperatures resulting from climate change.” Parks carried out the research with colleagues while working on his PhD at Imperial College London.

The researchers started by studying the number of fatal injuries each year in every county in the mainland United States (Hawaii and Alaska were excluded) between 1980 and 2017. They classed injuries as unintentional, which included vehicle accidents, falls and drowning, and intentional, which included assaults and suicides. Data from the National Center for Health Statistics showed that 4.1 million boys and men and 1.8 million girls and women died from injuries during the 38-year period.

The scientists then tracked temperatures in every month, and, using a statistical model, calculated the number of additional deaths from injuries associated with unusual temperatures. The biggest effects came from drowning and transport accidents. The researchers say this was probably because people tend to drive and go swimming more when temperatures are higher; they also tend to consume more alcohol. There were also rises in suicides and fatal assaults, though not as large. Possibly accounting for the violence, people tend to become more agitated and spend more time outdoors in hot weather, increasing chances of physical confrontations, say the researchers. In terms of suicides, previous research has suggested high temperatures are associated with higher levels of mental distress, especially in young people.

The researchers then used a model to predict the number of additional deaths if human-induced climate change were to increase average temperatures either 1.5 or 2 degrees Celsius (2.7 or 3.6 degrees Fahrenheit). They came up with an additional yearly 1,600 deaths for a 1.5-degree rise and 2,100 for a 2-degree rise. Most of the deaths would be among males between the ages of 15 to 34. Slightly offsetting the additional deaths, warmer winter months would be associated with a reduction in deaths from falls among older men and women.

While the study considered only the continental United States, it would be reasonable to think that similar increases in fatal injuries would occur in much of the rest of the world, said Parks, leading to hundreds of thousands of deaths.

The study’s senior author, Majid Ezzati of the Abdul Latif Jameel Institute for Disease and Emergency Analytics at Imperial College, said,  “These new results show how much climate change can affect young people. We need to respond to this threat with better preparedness in terms of emergency services, social support and health warnings.”

The other authors of the study are James Bennett, Helen Tamura-Wicks, Vasilis Kontis and Ralf Toumi, all of Imperial College, and Goodarz Daniel of the Harvard T.H. Chan School of Public Health. The research was funded by the U.S. Environmental Protection Agency and the Wellcome Trust.

Earth Institute. Adapted from a press release by Imperial College London.

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