As Vancouver cruises into its summer crescendo, the warm breeze that makes the perfect beach day can also ratchet the city into a public health emergency.
While this summer has not yet seen the extreme temperatures of the deadly heat dome in 2021, May still brought record high temperatures — a risk correlated with the climate crisis. Heat waves are also sweeping Europe and the Southern US.
What does heat do to our bodies and communities, and how can Vancouver adapt?
You're getting warmer
Dr. Sarah Henderson, an assistant professor at UBC as well as a senior scientist in environmental health services with the BC Centre for Disease Control, specialises in the public health impacts of extreme heat events. According to Henderson, heat starts causing problems when it causes the body to stray from a fairly rigid healthy internal temperature.
“Your body wants to maintain a body temperature of 36.6 C, and there’s not a lot of leeway there,” said Henderson. “So if you start reaching an internal body temperature of 39 or 40, you will get heatstroke.”
The body has a variety of ways to cool off, from facial flushing to sweat.
“The body will apply different measures to try to stay cool, and usually that happens quite effectively,” said Dr. Michael Schwandt, a professor at the UBC School of Population and Public Health, “[But] if we become [too] dehydrated, from sweating and loss of fluids in the heat, we can actually have a shock to the circulatory system so not getting enough blood back to the heart, not getting enough blood to the brain, to the kidneys, and other organs.”
This is, of course, assuming a perfectly healthy body in an unpolluted environment. In reality, we live in a world with increasing risk of exposure to air contaminants, such as wildfire smoke.
Henderson explained how the immune system responds to particulate pollutants like smoke by causing inflammation, which stresses the body further. The combination of inflammation and heat stress produces a “multiplicative effect.”
“The combined exposure of heat and smoke is worse than the sum of its parts,” said Henderson.
Henderson also highlighted how human physiology is also often well-adapted to regional climates.
“We're all adapted to our baseline climate, and the baseline climate in this region is temperate ... And so we're really used to 20 to 22 degrees at our maximum temperatures in the summer.”
Heat waves cause inequitable harm
Just like many of its residents, Vancouver is not built for heat.
“We've really focused on building houses that are energy efficient for retaining the heat. We want to spend as little energy as possible to heat the indoor space, but when we do that, we build buildings that retain heat really well," said Schwandt.
Demographic factors also play a big role.
“Our mechanisms for cooling off just become less effective with age in general,” said Schwandt. During the 2021 heat dome in the Pacific Northwest, over 90 per cent of all heat-related deaths were individuals over the age of 60, with no deaths reported in those under 30. Other compounding factors include pre-existing conditions, as well as ongoing alcohol and substance use.
Both Henderson and Schwandt were quick to point out that socio-economic conditions are very influential in determining risk from extreme heat.
According to Henderson, many heatstroke victims get it indoors as opposed to outdoors, and low-income housing often lacks cooling infrastructure. The BC Coroner’s review of the 2021 heat dome found that 10 per cent of the 619 deceased lived in social housing, SROs and supportive housing, and that high-indoor temperatures were the leading cause of death
“Many of the people living in those conditions aren't going to be able to afford air conditioning [units] or the energy costs associated with air conditioning.”
Studies have repeatedly shown that areas with lower-income residents and renters often have lower availability of shade and green spaces compared to more affluent neighbourhoods. Vancouver, per a UBC study, showed the strongest correlation between average neighbourhood income and availability of green space compared to other metro areas in the country.
“Both the physical environment having less vegetation, more paved areas, and so forth, contribute to urban heat islands where we can have temperatures that are actually substantially hotter,” said Schwandt.
So, what can we do?
“I think that at the individual level, I think one of the things that many of us can do is to be aware of those around us in our communities who might be at higher risk and to support them,” said Schwandt. He emphasised looking out for those living in isolation, the elderly and those with disabilities.
Henderson gave a few tips on managing our personal spaces. She recommended closing the windows and blinds during the hottest of hours, and reopening them once the weather is cooler to help bring in colder air (preferably with the aid of a fan).
“If you're being careful about keeping sun off the windows and managing the indoor temperatures as best as possible, you can make a two to four degree difference indoors and that can be the difference between life and death for people.”