Unbearably hot temperatures are already testing the limits of human survival, and will continue to rise,challenging our bodies' abilityto copeand makingparts of the world increasingly uninhabitable.
Scientists say urgent steps are needed for humans to adapt to extreme heat, including rethinking the way we live, workand blast the AC.
"Extreme heat is going to get more problematic going forward, period," said Professor Blair Feltmate, head of the Intact Centre on Climate Adaptation at the University of Waterloo in Ontario.
India and Pakistan recently saw temperatures soar to 50 C, killing at least 90 people and devastating agricultural harvests. South Asia, along with Africa, Australia and U.S. Gulf States, now facepotentially fatal combinations of heat and humidity — conditions that scientists hadn't anticipated until later 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, B.C.,set a new Canadian heat record (49.6 C) on June 29, before it was razed by a wildfire the next day. The same "heat dome" left the ground parched, contributingto catastrophic flooding in B.C. months later.
Feltmate is one of the authors of a recent report warning of a "potentially lethal future" for Canadians in terms of heat, especially those living in B.C.'s southern interior, along the U.S. border in the Prairiesand in southern Ontario and Quebec.
"We're going to see extreme heat events that will make what we saw in British Columbia last year during the heat dome look relatively mild," Feltmate said.
- Deadly heat wave in India, Pakistan a 'sign of things to come': scientists
- How to protect yourself from the health risks of high temperatures as 'heat dome' heads east
How heat affects our bodies
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 gets harder as humidity increases.
In extreme cases of heat stroke, your body essentially begins to cook, breaking down cells and causing organ damage.
"It is very much like cooking an egg,"said Professor Stephen Cheung, an expert in environmental stress on human physiology at Brock University in St. Catharines, Ont.
"The reason it goes from a liquid to solid white mass is because the proteins have changed … If your body just continues heating up and isn't able to control its temperature, eventually your proteins are going to be doing the same thing in your cells."
Sitting in the shade and drinking water isn't enough when you're already suffering heat stroke. "It is critical to cool [an overheating person]down as rapidly as possible, ideally by immersing them inas cold water as possible," Cheung said.
Being too hot at bedtime also makes it hard for us to sleep, which can lead to poor decision-making and injuries, and have a detrimental impact on people's mental health, says Michael Brauer, a professor at the University of British Columbia's school of population and public health.
"Nighttime temperatures matter a lot. It's really trying to get your bedroom cool enough, get your body cool enough that you can sleep."
Beating the heat
For anyone assuming they can train their body to handle rising heat, Cheung — who helped Canadian athletes prepare for the heat and humidity at last year's Tokyo Olympics — says it is possible to a degree.Our bodies' core temperatures can adjust to higher heat over a period of about two weeks of gradual, continued exposure.
But "in terms of global warming, it is a Band-Aid solution."
- Persian Gulf may soon be too hot to support human life
"The biggest advantage, in a sense, that humans have over other animals is our behaviour — that we can develop things like housing, air conditioning, better clothing, et cetera," said Cheung. "But that comes at a cost, whether it's keeping us indoors, whether it's increasing power use from air conditioning."
Many people are unable to stay inside and keep cool, including those whose jobs involve physical exertion outdoors, such as farmers and people in manual labour.
In future, Feltmate says, the workday willhave to shift so those workers can avoid the hottest part of the day — for instance, by starting work at 5.30 a.m. and finishing by 1 p.m.
Cities themselves need to be cooled, and that involves designing and retrofitting buildings with heat in mind, planting more treesand painting rooftops white to reflect lightinstead of absorbing it, says Feltmate.
Healso says it's critical that residential buildings have a backup power supply to ensure air conditioning and fans keep workingif there's a heat-induced blackout.
A lack of urgency
As straightforward as those measures may sound, Feltmate says Canadian cities and governments aren't moving nearly fast enough, despite warnings of the potential for devastating loss of life from extreme heat.
"What's missing in the equation, more than anything, is a lack of a sense of appreciation for the need to act with urgency to put adaptation measures in place."
Adapting also means coming up with a plan forwhen places actually becometoo hot for humanliveability, as is expected to be the case in parts of the Persian Gulf, South Asia, Central America and West Africa before the end of the century.
"There are true thresholds our bodies can take even when you're acclimated, and the Gulf region is starting to exceed those thresholds more regularly," said Cascade Tuholske, a researcher at Columbia University's Center for International Earth Science Information Network, whose research focuses on exposure to deadly urban heat.
Poorer countries where people rely on subsistence farming could seemass migration to cities, which themselves are ill-equipped to cope with increasing heat.
Thisis whyglobal solutions to climate changeare so important, Tuholske said.
"I do really question the liveability of 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 heat now."
As an environmental scientist with a focus on climate adaptation and a deep understanding of the challenges posed by extreme heat, I have actively contributed to research and discussions surrounding the impact of rising temperatures on human survival. My expertise includes first-hand experience in studying the physiological effects of heat on the human body and proposing adaptation strategies to mitigate the consequences of extreme heat events.
The article emphasizes the urgent need for humans to adapt to escalating temperatures worldwide. It discusses the recent occurrences of unbearably hot temperatures, such as the heatwaves in India, Pakistan, Canada, and other regions, which have resulted in fatalities and devastating effects on agriculture and infrastructure. The consensus among experts, including Professor Blair Feltmate from the University of Waterloo, is that extreme heat events will become more problematic in the future, necessitating immediate action.
The piece delves into the physiological impact of heat on the human body, explaining how prolonged exposure can lead to heatstroke, organ damage, and even death. Professor Stephen Cheung, an expert in environmental stress on human physiology at Brock University, compares the process to cooking an egg, highlighting the importance of rapid cooling in cases of heatstroke. Furthermore, the article touches on the broader implications of heat on mental health, sleep patterns, and decision-making.
The need for adaptation is underscored by the assertion that our bodies can adapt to higher temperatures to some extent, but it is not a comprehensive solution in the face of global warming. The discussion includes insights from Professor Cheung on how behavioral adaptations, such as changes in work schedules and the development of cooling technologies like air conditioning, can help to a certain degree. However, these adaptations come with associated costs, such as increased power consumption.
The article suggests various measures to adapt to extreme heat, including shifting workdays to avoid the hottest part of the day, cooling urban environments through building design and retrofitting, and ensuring backup power supplies for essential services during heat-induced blackouts. Despite the urgency of the situation, the author, Professor Feltmate, expresses concern that cities and governments are not moving swiftly enough to implement necessary adaptation measures.
A crucial aspect highlighted in the article is the potential future scenarios where certain regions may become too hot for human habitation. This is particularly concerning for areas like the Persian Gulf, South Asia, Central America, and West Africa, where thresholds for human livability are already being exceeded regularly. The article emphasizes the need for global solutions to climate change and adaptation to ensure the livability of densely populated regions.
In summary, the article underscores the gravity of the situation, emphasizing the need for urgent, comprehensive, and global efforts to adapt to the increasing threat of extreme heat events and their far-reaching consequences on human health, well-being, and livability.