By Bjørn Lomborg
Whenever there’s a heatwave—whether at home or abroad—the media loves to splash it. Politicians and campaigners then jump in to warn that climate change is at fault, and urge us to cut carbon emissions. But they are only telling us one-tenth of the story and giving terrible advice.
Global warming indeed causes more heat waves, and these raise the risk that more people die because of heat. That much is true. But higher temperatures also cause a reduction in cold temperatures, reducing the risk that people die from the cold. Almost everywhere in the world—not just Canada—cold kills 5-15 times more people than heat.
Heat gets a lot of attention both because of its obvious link to climate change and because it is immediately visible—meaning it is photogenic for the media. Heat kills within a few days of temperatures getting too high, because it alters the fluid and electrolytic balance in weaker, often older people.
Cold, on the other hand, slowly kills over months. At low temperatures, the body constricts outer blood vessels to conserve heat, driving up blood pressure. High blood pressure is the world’s leading killer, causing 19 per cent of all deaths.
Depending on where we live, taking into account infrastructure like heating and cooling, along with vehicles and clothes to keep us comfortable, there is a temperature at which deaths will be at a minimum. If it gets warmer or colder, more people will die.
A recent Lancet study shows that if we count all the additional deaths from too-hot temperatures globally, heat kills nearly half a million people each year. But too-cold temperatures are more than nine-times deadlier, killing over 4.5 million people.
In Canada, unsurprisingly, cold is even deadlier, killing more than 12 times more than heat. Each year, about 1,400 Canadians die from heat, but more than 17,000 die because of the cold.
Every time there is a heatwave, climate activists will tell you that global warming is an existential problem and we need to switch to renewables. And yes, the terrible heat dome in BC in June 2021 tragically killed 450-600 people and was likely made worse by global warming. But in that same year, the cold in BC killed 2,500 people, yet these deaths made few headlines.
Moreover, the advice from climate activists—that we should hasten the switch away from fossil fuels—is deeply problematic. Switching to renewables drives up energy prices. How do people better survive heat? With air conditioning. Over the last century, despite the temperature increasing, the US saw a remarkable drop in heat deaths because of more air conditioning. Making electricity for air conditioning more expensive means especially poorer people cannot afford to stay cool, and more people die.
Likewise, access to more heating has made our homes less deadly in winter, driving down cold mortality over the 20th century. One study shows that cheap gas heating in the late 2000s saved 12,500 Americans from dying of cold each year. Making heating more expensive will consign at least 12,500 people to die each year because they can no longer afford to keep warm.
One thing climate campaigners never admit is that current temperature rises actually make fewer people die overall from heat and cold. While rising temperatures drive more heat deaths, they also reduce the number of cold deaths — and because cold deaths are much more prevalent, this reduces total deaths significantly.
The only global estimate shows that in the last two decades, rising temperatures have increased heat deaths by 0.21 percentage points but reduced cold deaths by 0.51 percentage points. Rising temperatures have reduced net global death by 0.3 per cent, meaning some 166,000 deaths have been avoided. The researchers haven’t done the numbers for Canada alone, but combined with the US, increased temperatures have caused an extra 5,000 heat deaths annually, but reduced the number of cold deaths by 14,000.
If temperatures keep rising, cold deaths can only be reduced so much. Eventually, of course, total deaths will increase again. But a new near-global Nature study shows that, looking only at the impact of climate change, the number of total dead from heat and cold will stay lower than today almost up to a 3oC temperature increase, which is more than currently expected by the end of the century.
People claim that we will soon be in a world that is literally too hot and humid to live in, using something called the “wet bulb” temperature. But under realistic assumptions, the actual number of people who by century’s end will live in unlivable circumstances is still zero.
The incessant focus on tens or hundreds of people dying in for instance Indian heatwaves makes us forget that even in India, cold is a much bigger challenge. While heat kills 89,000 people each year, cold kills seven times more at 632,000 every year. Yet, you would never know with the current climate information we get.
Hearing only the alarmist side of heat and cold deaths not only scares people—especially younger generations—but points us toward ineffective policies that drive up energy costs and let more people die from lack of adequate protection against both heat and cold.

Bjørn Lomborg
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