No contest on this one. Cold weather leads directly or indirectly to 17 times as many excess human deaths as hot weather.
What’s surprising is that even the New York Times reported this, and prominently. In the December 19, 2016, issue, Jane Brody wrote:
Most of the Northern Hemisphere is now in the throes of the deadliest time of the year. Cold kills, and I don’t mean just extreme cold and crippling blizzards. I mean ordinary winter cold, like that typically experienced, chronically or episodically, by people in every state but Hawaii from late fall through early spring.
While casualties resulting from heat waves receive wide publicity, deaths from bouts of extreme cold rarely do, and those resulting from ordinary winter weather warrant virtually no attention. Yet an international study covering 384 locations in 13 countries, including the United States, found that cold weather is responsible, directly or indirectly, for 17 times as many deaths as hot weather.
Over time, as global temperatures rise, milder winter temperatures are likely to result in fewer cold-related deaths, a benefit that could outweigh a smaller rise in heat-caused mortality. In winter in the United States, mortality is generally 10 percent to 15 percent higher than on typical summer days.
Brody cites a major study in The Lancet.
One might think people who love people would welcome some greenhouse gas-induced global warming, which, according to prevailing theory, would raise temperatures more in winter than in summer, more nearer to the poles than to the equator, and more at night than in the daytime. That means it would raise temperatures in the coldest times and places far more than in the warmest times and places.
The predictable result? A reduction in the number of premature deaths.
Some evangelical environmentalists would, if they were honest and objective, celebrate manmade global warming therefore as “pro-life,” as they do policies to mitigate global warming for the (much smaller) reduction in mortality they might drive, despite the fact that doing so would obscure the meaning of “pro-life” (a term historically coined to designate opposition to abortion). We won’t do that. But we will say that if you want to reduce premature deaths due to temperature, you should welcome some global warming.