NBC blares that “Extreme heat in cities a growing problem as climate warms, study finds/ People flocking to cities in rapidly urbanizing areas such as southern Asia and sub-Saharan Africa are increasingly vulnerable to soaring temperatures and high humidity.” So apparently people are dolts who ignore journalists’ warnings. Which in this case continue, “The risk of extreme heat is a rising threat to fast-growing cities around the world, according to a new study published this month in the Proceedings of the National Academy of Sciences. As more people move to cities and the climate warms, extreme heat could harm and kill more people.” But then the story pins the blame on “population growth, climate change and the fact that city infrastructure absorbs more heat.” OK. But just because you list climate change before the Urban Heat Island (UHI) effect doesn’t mean it’s the main factor.
The story adds that “The analysis reveals that many people flocking to cities in rapidly urbanizing areas such as southern Asia and sub-Saharan Africa are coming to places that are increasingly vulnerable to soaring temperatures and high humidity.” So again people are too dumb, or charitably too desperate to notice or care, that they’re moving into an oven while the Western press shouts no stop you fools.
The story is also accompanied by a cow skeleton in dust next to “the town of Kargi, Kenya” which suggests that the place they were moving from wasn’t exactly cool and verdant either. But on it goes, kitchen sink after kitchen sink: “The report also says climate change is increasing conditions suitable for infectious disease pathogens, reversing global progress in providing food and water security and increasing exposure to wildfires.” And while the piece notes that mere temperature is not the only issue, that a crucial factor is humidity, you know what’s coming. “The authors estimate that the global population experienced a total of about 40 billion days when wet-bulb temperatures hit at least 86 degrees in 1983. In 2016, that number had nearly tripled to 119 billion, the paper says.” But the reason is a bit of a surprise: “Two-thirds of the change was due to population growth. The rest of the increase was due to climate change and additional heat due to urbanization.” So the first bit actually reduces the share attributable to climate change to one-third, minus the part due to the UHI.
Now go read the headline again: “Extreme heat in cities a growing problem as climate warms, study finds”. Of course this story is in their “Climate in crisis” section which suggests a prior ideological commitment. And the author holds a “Bachelor of Journalism, Magazine Journalism” with “Minors in Film and Creative Writing” so possibly his statistical training was not rigorous. And while he didn’t write the headline, it looks as if someone else with a creative writing background might have. The fine print says a lot of things are at play. But the big type screams climate as usual.
When it comes to Ottawa temperatures, and there is nothing exceptional about Ottawa, a concern that certainly ought to exist is the UHI. Not to mention the Airport Runway and Jet Engine Effect, if you are so unwise as to measure temperatures in such an artificial environment. A term that applies especially to a tarmac but also to a city more generally. In fact the City of Ottawa did just release a map of the situation during the local July 2019 heatwave and it reveals more than was intended. Specifically, as the CBC noted, “the colour-coded map shows a wide range in surface temperatures recorded that day, from 15 C along portions of the Ottawa River to between 36 and 38 C in certain small pockets of the city where both water and vegetation are in short supply.” What’s more, an alert reader points out, a second city-generated map of the whole area within the local “Greenbelt” reveals that if you have any interest in accurate comparisons between temperatures today and those a century ago you definitely should stay out of the orange built-up stuff and instead put your thermometer in a field.
The purpose of these maps appears to have been to warn that global warming is ultra-terrible and will kill you if you work somewhere asphalty without air conditioning or are homeless or something. “With temperatures expected to rise by 3.2 degrees Celsius by the 2050s and the number of days above 30 degrees Celsius expected to rise fourfold to 43 days, heat islands worsen the impact of extreme heat events.” Uh, 3.2 degrees by the 2050s means 1 degree C per decade or 10 degrees C per century. Who is claiming warming on that scale?
We already know that over the 100 years from 1919 to 2019 the change in Ottawa weather was hardly noticeable. Never mind, it’s all downhill from here, or up thermometer. “Extreme heat affects everyone,” the CBC continues, “but certain people are more vulnerable to heat stress, including the very young and old, people who are pregnant, people with existing health conditions, people who work outside, athletes, people who are homeless or precariously housed, and those that don’t have good access to air conditioning.” But another possibility is that even a very hot day is no different now than it was way back when… except where humans have built heat traps into which they then crammed themselves.
For instance, the second map in question has text that includes saying July 18, 2019 was “a hot day, a day where temperatures reached 27.3 degrees Celsius”. So? Ottawa temperatures on July 18 1919 reached 32.8 degrees Celsius, and averaged 28.8 degrees for the month as a whole. And the story also said, “The annual mean air temperature of a city with one million people or more can be one to three degrees Celsius warmer than its surroundings during the day.” So take 3 degrees off the 2019 number and temperatures only reached about 24.3.
Positively chilly compared to a century earlier.