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Chris Wright

Chris Wright

Managing Director

In the Summer of 2003, over 70,000 people died across Europe. Most of them were old, alone and at home

This week has seen incredible reports of heatwaves claiming more than 100 lives across Canada and Japan as temperatures have continued to hit record levels.

Japan suffered one of its hottest ever months, that has already led to over 40 deaths and 10,000 hospitalisations. This week, the country has seen its highest ever temperature (41°C), and on Saturday, the Tokyo Fire Department had to send more than 3000 ambulances across city to help deal with heat stress.

Earlier in the month, a similar scene was unfolding across Quebec, Canada, with up to 70 heat-related deaths in the first week of July. It got so bad, not even the morgue could cope with the bodies.

These events raise the important question of how exactly do heat waves cause such havoc, and how can you avoid them?

The basic science of heatwaves isn’t too dissimilar from when your mum used to check your temperature if you had a cold. Our bodies are pretty amazing at staying cool. This is thanks largely to our ability to sweat. In fact, some Harvard scientists have been arguing that when you look at the animal kingdom, its not our brains but our sweat glands that are the truly “human” superpower.

But when our bodies get pushed beyond that 36.5–37.5 °C range, they start to freak out. Your body initially goes into  sweat overload to try to cool you down as soon as possible. If that doesn’t work, your internal systems start breaking down, and you might faint, or vomit.

How Your Body Breaks Down

At this stage, you should be fine as long as you can cool down, and hopefully drink some water.

If you don’t, and your body stays hot, it kicks into Plan B. Sweat stops. You’re now dehydrated. It needs that water for vital organs, and your blood. It dilates your blood vessels in your skin and stops the flow into your gut. If this doesn’t work, and you stay hot, your gut will begin releasing toxins, you’ll get delirious and your internal organs will begin to break down.

This process is a much greater threat to very young and very old people. Newborns are very susceptible to extreme heat, but usually have family around to help them. Old people however, are often isolated, at increased risk of dehydration, and when people die, its usually them.

When Heatwaves Get Scary

In the Summer of 2003, over 70,000 people died across Europe. Most of them were old, alone and at home, as their families were scattered across the continent on holiday. Over 14,000 people died in apartments without air conditioning or elevators across Paris that Summer.

In 2015, Over 1000 people died in Karachi in 2 weeks of heat. This year, the heat soared during Ramadan. Only 65 reported deaths took place. The response was much better. So was the power.

When the heat surges, people turn up their fans, air-con, and energy systems can break down. This impacts poorer, less mobile communities the worst. Karachi learned a harsh lesson in 2015.

What makes a Heatwave Deadly?

However, determining whether a heatwave will be deadly or not isn’t as simple as you might think, there are 3 other critical factors you might not have thought about:

  • Hot days aren’t usually deadly on their own.  Breaking heat records gets headlines, but doesn’t necessarily kill people. Minimum temperatures are just as important, especially for old people. As long as you can cool down, you’re fine. But if you can’t get cool, and it doesn’t cool down at night you’re in trouble. If you’re isolated for a few days, the prolonged heat exposure means a lot of people die not in the middle of the day, but the middle of the night.
  • It’s not just about the heat, but the humidity. When the air is sticky and humid it traps in heat for longer, especially at night. It also stops your sweat from cooling you down
  • It’s not about the Absolute temperature, it’s about what you’re used to. Many of the deadliest heatwaves happen not in the “hottest” places, but in places where people aren’t used to that level of heat, or aren’t expecting it at that time. One of the biggest differences in Karachi between 2015 and 2018 wasn’t the temperature, but people were more prepared.

What You Can Do?

When a heatwave hits you, there’s a lot you can do. The New York Times recommends putting your sheets in the freezer. Here in Malaysia, its humid A-F, and many people would head to a Mall. Science agrees, when the aircon is pumping out like a sub-zero party it dries the air, and you can sweat like normal again. If you got some spare $$, buy some aircon – and hope there isn’t a power cut.

However, if you’re not interested in frozen sheets and aircon sweats, here’s 3 easy ways to avoid the heat, get healthy and be a an awesome human:

  • Drink 1L of water when you wake up. It’ll be great for your body as it wakes up, help with the Insta healthy-living goals, and help your body store up some future-sweat. Take the water bottle with you, and repeat.
  • Say hello to your neighbours and have a picnic. This might sound funny, but if they’re old, you could save their life. In a 1995 study of the heatwave in Chicago, groups who met in public places were at less risk than those who remained indoors. Saying hello over the fence, or knocking on someone’s apartment door to check in on them could save their life, and you could scam their aircon.
Chris Wright

About Chris Wright

Co-founder and Director of Climate Tracker. We’ve inspired 8000+ journalists to report on Climate Change. Based in Borneo. Trail Running convert. Learning Python.