A new study finds the number of deaths caused by high temperatures increased by 74% globally between 1980 and 2016. Deaths related to extreme cold increased 31% since 1990, a new report, the first of its kind, finds.
Human-caused climate change -- generated by carbon, methane and other greenhouse gas emissions from industry, transportation, and agriculture -- has led to a "new normal" with more days of extreme temperatures than in recorded history.
"The papers we publish today provide a strong scientific argument that the health dimensions of heat can no longer be overlooked," the Lancet, which published the twin studies, said in an editorial.
Heat-related deaths and illnesses are preventable, according to the US Centers for Disease Control and Prevention, and yet more than 600 people in the US alone are killed by extreme heat every year. This year has already seen hundreds of deaths related to an historic heat wave in the US West. By the end of the century, more than half of the global population is projected to be exposed to weeks of dangerous heat every year.
For this new study, the University of Washington researchers examined 64.9 million death records from nine different countries and determined that at least 1.69 million of those deaths could be attributed to extreme temperatures in 2019 alone. About 356,000 were linked to extreme heat and 1.3 million were related to extreme cold temperatures.
These are conservative estimates, they reported in the Lancet, and those numbers will continue to grow as the world experienced more extreme temperatures.
These extreme temperatures can linked to at least 17 causes of death, most related to heart trouble and breathing issues, but these excess temperature related deaths also include suicide, drowning and homicides.
Earlier studies have shown that exposure to extreme heat can also cause mental health issues, problems for pregnant women and poor birth outcomes. The elderly, people with chronic health conditions and children are at the highest risk for heat-related illnesses.
"Our analysis finds that the harmful effects of extreme heat can far exceed those caused by cold in places where it is already hot, such as Southern Asia, the Middle East and many parts of Africa," said study co-author Dr. Katrin Burkhart, with the Institute of Health Metrics and Evaluation at the University of Washington. "This is very concerning, particularly given that the risk of exposure to high temperatures appears to have been increasing steadily for decades."
Environmental epidemiologist Tarik Benmarhnia of the University of California, San Diego, said the CDC death numbers only reflect when a death certificate is explicit about heat being a cause of death. He said the new study accounts for the indirect deaths. "What a lot of people don't get, and what explains why the burden is huge is because heat becomes the, as you say in English, 'the straw that broke the camel's back,'" Benmarhnia, who was not involved in the research, told CNN.
"What is most problematic about heat is that this is a sneaky climate issue, because it kills many people, but it is not impressive like a hurricane or something. It's just happening all the time, so it is sneaky."
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