by Peter Franklin
Friday, 2
July 2021

Canada’s heatwave is a vision of our future

In decades to come swathes of the world will resemble British Columbia today
by Peter Franklin
He might get a tan, but it won’t be worth it in the long-term. (Photo by Scott Barbour/Getty Images)

We don’t usually associate the Great White North with blistering heat, but on Tuesday a new record was set for Canada — 49.6°C in Lytton, British Columbia. 

Of course, heatwaves happen; and Canada isn’t immune. Nevertheless what’s happened this week is extraordinary. The country’s temperature record wasn’t just broken, it was smashed — by nearly five degrees centigrade. 

We can’t be absolutely sure that this is directly related to climate change — or that anything as bad (or worse) will happen again soon. However, we can be certain that the planet is warming up and that all that extra energy won’t be distributing itself evenly. 

On a geological timescale, what we’re doing to the climate is happening very fast. But what about the human timescale? We’ve still got years — indeed, decades — to adapt, haven’t we?

Well, yes, as a species, we have. But as individuals, there’s literally a point at which we can’t cope with extreme heat. 

You may have heard a few mentions this week — e.g. here and here — of something called ‘wet-bulb temperature’. This takes a bit of explaining, but bear with me because your life might just depend it.

It’s got nothing to do with planting tulips, but rather refers to the bulb of a thermometer. If you cover the bulb in a wet cloth then, because of the cooling effect of evaporation, a lower temperature is recorded than if the bulb is left dry. 

The purpose of the exercise is to simulate what human bodies do to stay cool, i.e. perspire. When the moisture on our skin evaporates, the cooling effect allows us to tolerate higher ambient  temperatures than if we didn’t sweat like pigs.

However, there are limits. At a wet-bulb temperature of around 35°C, human bodies gain more heat than they lose, no matter how much they sweat. It’s at this point that people start dying.

Though many parts of the world regularly experience temperatures above 35°C, these are ambient or ‘dry-bulb’ temperatures that don’t take into account the cooling effect of evaporation. Currently, wet-bulb temperatures very rarely reach this danger level (except in very local environments like a stifling apartment or a locked car). However, if we continue to push global temperatures upwards at the current rate, whole parts of world will slip into the danger zone. 

Outside of artificially-cooled spaces, these areas would become uninhabitable — which is obviously a very bad thing, even if, at first, it only happens occasionally.

Environmental campaigners are missing a trick by not doing more to highlight this issue. While global warming has all sorts of nasty consequences well before we hit the wet-bulb danger zone, it strikes me that a hard limit on human survival is a great way of concentrating minds. 

Join the discussion

  • There was also a very nasty cold spell in Texas this year. Please don’t say this was just a freak weather incident. I recently read that the current Heat Dome in British Columbia is comparable to heatwaves during La Niña, which, according to the climate scientists, had nothing to do with Global Warming.
    I really would like UnHerd to publish one of many scientists, who have other scientific explanations of natural occurring Warming, than the usual suspects who are just part of the Herd of Main Stream thinking.

  • Once upon a time climate scientists told us to expect a global freezing, that a new ice age was imminent, then there was the hole in the ozone layer melting the ice caps, then it was global warming. Now its climate change, I guess they gave up on predicting if its getting warmer or colder. How does this climate science have any credibility.
    Boss: are we making or losing money?
    George: All I can tell you is that the money we have will be different from yesterday.
    Boss: you’re fired.

  • Science keeps saying this Pacific NW heat event is a 1 in 1000 year ‘Heat Dome’, a very rare climatic event.
    Yes. It’s easy to google the heatwave in the pacific northwest and learn about the rare conjunction of factors that caused the heat dome. As the author of this article rightly notes at the beginning, there’s no evidence to link climate change to this anomalous event (although I think it should be conceded there might be a link to some extent). I’m not sure why the author chose to concede the current heatwave can’t definitely be linked to climate change and then use it as an example of what will happen to all of us if we don’t change our CO2-producing ways.
    The more interesting question for me is what if the changes we now see in the climate are, for the most part, not caused by human activity? What if they’re part of a natural cycle of climate change? We can’t control that; all we can do is adapt and learn to live with it.

  • To get involved in the discussion and stay up to date, become a registered user.

    It's simple, quick and free.

    Sign me up