Unbearably hot temperatures are already testing the limits of human survival and will continue to rise, challenging our bodies’ ability to cope and making parts of the world increasingly uninhabitable.
Scientists say urgent action is needed for humans to adapt to extreme heat, including rethinking the way we live, work and blow alternating current.
“Extreme heat is going to become more of a problem in the future, period,” said Professor Blair Feltmate, director of the Intact Center on Climate Adaptation at the University of Waterloo in Ontario.
India and Pakistan have recently seen temperatures soar to 50 C, killing at least 90 people and devastating agricultural crops. South Asia, as well as Africa, Australia and the US Gulf states, are now facing potentially deadly combinations of heat and humidity — conditions that scientists had not anticipated until the end of this century.
Canada is also feeling the effects of extreme heat: in British Columbia last summer, 595 people died from the heat. The village of Lytton, British Columbia, set a new Canadian record for heat (49.6°C) on June 29, before being engulfed by fire the following day. The same “heat dome” dried out the ground, contributing to catastrophic flooding in British Columbia months later.
Feltmate is one of the authors of recent report warns of ‘potentially deadly future’ for Canadians in terms of heat, especially those living in the southern interior of British Columbia, along the US border in the Prairies, and in southern Ontario and Quebec.
“We’re going to see extreme heat spells that will make what we saw in British Columbia last year during the heat dome relatively mild,” Feltmate said.
How heat affects our body
When you’re exposed to prolonged heat, you may feel sluggish because your organs are working harder to keep you cool and alive.
Your heart beats harder to push blood to your skin, where it can cool down. Sweating is also essential for cooling your body, but it becomes more difficult as the humidity rises.
In extreme cases of heatstroke, your body essentially begins to cook, breaking down cells and causing organ damage.
“It’s a bit like frying an egg,” said Professor Stephen Cheung, an environmental stress expert on human physiology at Brock University in St. Catharines, Ont.
“The reason it goes from a liquid to a solid white mass is that the proteins have changed… If your body continues to heat up and is not able to control its temperature, your proteins will eventually do the same in your cells.
Sitting in the shade and drinking water is not enough when you are already suffering from heatstroke. “It is essential to cool [an overheating person] as quickly as possible, ideally by immersing them in as cold water as possible,” Cheung said.
Being too hot at bedtime also prevents us from sleeping, which can lead to poor decisions and injuries, and have a detrimental impact on people’s mental health, says Michael Brauer, a professor at the University of British Columbia. and public health.
“Night temperatures matter a lot. It’s really about trying to get your bedroom cool enough, get your body cool enough to be able to sleep.”
beat the heat
For anyone who assumes he can train his body to handle the increasing heat, Cheung – who helped Canadian athletes prepare for the heat and humidity at the Tokyo Olympics last year – says it’s possible to some extent. Our body’s core temperature can adapt to higher heat over a period of about two weeks of continuous, gradual exposure.
But “in terms of global warming, it’s a band-aid solution.”
“The biggest advantage, in a sense, that humans have over other animals is our behavior — that we can develop things like housing, air conditioning, better clothes, etc.,” Cheung said. “But it comes at a cost, whether it’s keeping us indoors or increasing the energy consumption of the air conditioning.”
Many people are unable to stay indoors and stay cool, including those whose jobs involve physical exertion outdoors, such as farmers and manual workers.
Going forward, Feltmate says, the working day will need to change so that these workers can avoid the hottest part of the day – for example, starting work at 5:30 a.m. and finishing at 1 p.m.
Cities themselves need to be cooled, which means designing and retrofitting buildings with heat in mind, planting more trees and painting roofs white to reflect light instead of absorbing it, explains Feltmate.
He also says that it is essential that residential buildings have a backup power supply to ensure that air conditioning and fans continue to operate in the event of a heat-induced power failure.
A lack of urgency
Simple as these measures may seem, Feltmate says Canadian cities and governments are not acting fast enough, despite warnings about the potential for devastating loss of life from extreme heat.
“What’s missing from the equation, more than anything, is a lack of sense of the need to act urgently to put adaptation measures in place.”
Adapting also means making a plan for when places actually get too hot for human habitabilityas it should be in parts of the Persian Gulf, South Asia, Central America and West Africa before the end of the century.
“There are real thresholds that our bodies can cross even when you’re acclimatized, and the Gulf region is starting to cross those thresholds more regularly,” said Cascade Tuholske, a researcher at the Center for International Earth Science Information Network at the University of Columbia, of which research focuses on exposure to deadly urban heat.
Poorer countries where people depend on subsistence farming could see mass migration to cities, which are themselves ill-equipped to deal with the rising heat.
This is why global solutions to climate change are so important, Tuholske said.
“I really question the quality of life in many of the most populated places on the planet due to extreme heat without adaptation. The future really depends on the present and how much we mitigate the heat now.”