Heat kills. Cold kills more.
If any city in America knows how to handle itself in snow and freezing weather it is Buffalo, N.Y., which is notorious for its brutal winters and massive, lake-effect blizzards. Yet the city took a blow to the solar plexus from the Christmas weekend storm that struck much of the United States. Dozens of people were killed in the Buffalo area — at least 38 so far, with more deaths expected to be uncovered as National Guard teams and emergency crews go door-to-door to check on residents and search for victims. And while Buffalo bore the brunt of the blizzard, there were dozens of additional fatalities across the country.
Some of those who died were caught outdoors and froze to death. Several had heart attacks while shoveling snow. Some died in homes that had no heat. Others faced medical emergencies that turned lethal when impassable roads kept ambulances from reaching them. The circumstances varied, but the underlying killer was the cold winter weather.
And deaths from cold, even if many people don’t realize it, are far more numerous than deaths from heat.
“Data from the Centers for Disease Control and Prevention has consistently shown that excessive cold presents a greater threat to life than excessive heat,” reported The Washington Post in 2016. During one five-year period analyzed by the CDC’s National Center for Health Statistics, about 31 percent of weather-related deaths in the United States were attributed to “excessive natural heat, heat stroke, [or] sun stroke” but more than twice as many — 63 percent — were attributed to exposure to “excessive natural cold [or] hypothermia.”
What is true for the United States — hypothermia ends more lives than hyperthermia — is no less true worldwide. According to one study published last year in The Lancet, the British medical journal, cold weather killed more people than hot weather “in all countries for which data were available.” In South Africa, for example, there were 453 deaths from excessive heat in 2019 vs. 8,372 deaths from excessive cold. In New Zealand, there were just two heat-connected deaths but 1,191 deaths related to cold. The number of heat deaths in China was an appalling 46,224. But that amounted to only onetenth of China’s death toll from cold: 455,735.
Deaths caused by blizzards and cold snaps generally draw less attention because they are less sudden, suggests the Danish scholar Bjorn Lomborg, who notes that too much heat is apt to kill within a few days, whereas cold is more likely to kill over weeks. The physiological processes that lead to death from heat and cold are not mirror images of each other. During brutal heat waves, which have grown more frequent as the global climate shifts, people die when their body temperature gets too high, triggering a quick collapse of the internal regulating system that keeps heart and brain functional. Death from cold is a slower process. During cold weather, the body restricts blood flow to the skin, boosting blood pressure, steadily lowering resistance to disease, and inviting respiratory infection.
There is a reason why far more people prefer to live in warmer places than colder ones.
Doubtless climate change will affect these patterns to some extent. As the planet warms, heat deaths are likely to increase. But that cloud has a significant silver lining: Deaths from cold — a much greater threat to human life — will decrease.
There is a temptation in many quarters these days to treat climate change as a morality tale of good against evil. But the evidence doesn’t fit such a simplistic pattern. If global warming continues as expected, weather during the summer months will become hotter and more humid, while winter weather will gradually grow less frigid and dry. On balance, and even considering other effects of climate change, that suggests fatalities from temperature extremes will fall.
Fans of “The Twilight Zone” may remember a 1961 episode set in New York City amid seemingly unstoppable worldwide warming. The Earth’s orbit has shifted somehow, and the planet is moving inexorably toward the sun. The story centers on several desperate residents struggling to survive the murderous heat. As the temperature climbs, social order crumbles. Finally Norma, the main character, screams and passes out. Then comes the Rod Serling twist: Norma wakes up and it’s snowing outside. She had been having a nightmare. The Earth isn’t plunging toward the sun — it is hurtling away from it. The threat to humankind isn’t remorseless heat, but a deathly deep freeze. Fade to credits.
In real life, climate doesn’t operate like a “Twilight Zone” episode. Our world isn’t ending in fire or in ice. Changes in global temperatures will bring changes in the number of weather-related deaths, but we can assume that the total of those deaths will be lower. After all, over the past 50 years, the number of deaths tied to weather and climate disasters has dropped by twothirds. There is no reason they can’t go lower still.
Jeff Jacoby can be reached at jeff.jacoby@globe.com. Follow him on Twitter @jeff_jacoby. To subscribe to his weekly newsletter, visit bit.ly/ArguableNewsletter.