Deadly urban heat is increasing

A recent study by Tuholske et al (2021) found that rising temperatures and growing urban populations have resulted in triple the number of person-days, a measure of the number of people affected, when people are exposed to extreme heat and humidity compared to the 1980s. As the authors state, this can increase mobidity, mortality, and ability to work which in turn reduces economic output.

Living in a winter city and studying and teaching about climate change I have often heard that “global warming doesn’t sound too bad.” A few less -30°C and a few more +30°C days can seem pretty appealing when you’re waiting for the bus, scraping your windshield, or taking the dog out to pee. This summer, Edmonton broke the previous record for number of days over +30°C. I personally found it challenging. I had to get up almost before the sun, another challenge for a northern city in summer, in order to do anything active and I moved my computer downstairs so the dog didn’t spend the whole day panting. But I have the privilege to have a downstairs and to work in a job that exposes me to minimal extra heat. When I bus into work, I can dress for -30°C, see afore mentioned privilege, but at +30°C there’s not much a person can do.

It’s cooler in rural areas, but more people are moving to urban spaces. This increase in urban populations accounts for two-thirds of the increase in the person-days. Climate change accounts for the other third. Basically, there are more people living in urban spaces so there are more people exposed to higher urban temperatures; but there are also more days with hotter temperatures because of climate change.

Here’s the thing, we can’t control the weather and I personally have never lived or visited a location where people don’t complain about the weather at least a little. But, the idea that people are dying because it is getting hotter means that it is unethical for us not to act. But it also doesn’t make sense for us not to act from an economic standpoint. Hotter temperatures lead to lower productivity.