How to Survive The Hottest Summers in Human History

Practical advice

Photo by fabian jones on Unsplash

The entire world is already dealing with killer heat waves.

Alaska just issued its first heat advisory in history. Iceland and Greenland have both experienced record heat this year. Arizona is seeing its first triple-digit days of the summer. In India, temperatures have already hit 47.3C degrees (117F). The last two years have been the hottest in recorded history, with temperatures reaching 52C degrees (126F) in parts of China. More and more, temperatures across the world in major cities are breaking into the 110s and 120s. In fact, the last ten years have been the hottest ten years on record. Heat deaths are rising, while governments and corporations respond by cutting water breaks and raising prices on essential goods like water—because they can.

A 2023 study predicted that a heatwave accompanied by a blackout in major cities like Phoenix would send half the population to the ER. According to a separate analysis covered in The New York Times, two-thirds of North America already face “shortfalls in the electrical grid, particularly during periods of extreme heat when demand for air conditioning spikes, straining resources.”

Odds are, you or someone in your family will be living through something like this in the foreseeable future—an intense heatwave accompanied by a blackout, or at least a grid flickering as it buckles under energy demand.

How are you going to survive?

I looked into it.

Yes, you can survive

Melissa Norris and her family survived several days at 120F degrees without air conditioning. Their indoor air temperature topped out at 88F degrees. It wasn’t comfortable, but they made it. They explain what they did in this video, and it covers a range of simple strategies like blinds and blackout curtains, limiting stove use, and strategic use of fans at night to promote air exchange.

Frozen towels and sheets do the job

Melissa Norris is spot on with the advice about frozen towels. If you’ve heard this before, there’s a fancier term for it in emergency medicine. It’s called ice sheet cooling (ISC), and the military considers it a standard intervention in field medicine to treat heat-related illnesses and injury.

A 2023 study in The Journal of Emergency Medicine found ice sheets effective in treating heat stroke and preventing mortality, and it’s a good alternative to the “gold standard” of cold water immersion. If they’re reasonably effective in treating someone already suffering from heat stroke, then it stands to reason they’re even better at keeping you cool to prevent it in the first place.

A 2022 study in Military Medicine reached a similar conclusion. In this study, participants exercised in a heated chamber until they underwent “exertional hyperthermia,” and then they were treated with “bed sheets soaked in ice water… at the neck, chest, and groin with another sheet covering the body.”

So, get soaking.

They’re a good alternative to AC

It’s worth keeping this method in your playbook, because brownouts and grid failures will increasingly accompany heat waves as cities that aren’t prepared for the climate crisis struggle with thousands of residents blasting their AC all day. Air conditioners are a modern luxury that we probably can’t count on for the indefinite future, especially as grids start to flicker and fail. Even before grid failures become the norm, power bills will soar and price a lot of us out.

It’s incredibly difficult to keep an air conditioner running with solar power. I’ve done the math. A really good portable battery setup with solar panels can produce 750-1000 watts per hour. A window unit or portable AC would consume most of that, and probably all of it, depending on the size and the circumstances. Even a fully-fledged rooftop solar system would struggle to power a central AC unit during a heatwave. It’s just not a very good use of resources.

But…

You can power a freezer with a few solar panels. Your average chest freezer uses half the electricity of a window unit, at 80-200 watts per hour. Depending on size, a freezer can even use a third or even less electricity.

Freezers are far more energy efficient because they cool air and then keep it insulated. So, freeze something and then put it next to your body’s hot spots to cool you down, around your neck or under your arms.

You can still try to run a portable AC with solar panels, but you can leverage an energy-efficient freezer as a backup.

It could save lives.

Take a bath

Just like ice, liquid water cools you down.

According to science, it takes 3200 times as much energy to heat water to the same temperature as air. It also transfers heat away from your body at a high rate. Water’s density also makes your body work harder to heat it up. This piece in The Conversation recommends water at 26 or 27C degrees (80F) for someone suffering heatstroke (to avoid cold shock), but you can go lower if you’re not having an emergency. Generally, your tap water comes out at 10-20C degrees (50-70F). So, just taking a cool bath or shower could save your life.

If you can’t take a bath or shower, you can just submerge your hands or feet in a tub of water or wrap them in sheets. You can also use a mister.

They all work.

Turn off the lights and appliances

During a heatwave, you want to add to the problem as little as possible. According to HVAC experts, people don’t think about the significant amounts of heat they’re adding to their homes throughout the day with lights, electronics, and appliances, especially ones like dryers and stoves. Even a high-performance PC in a closed room can feel like you’ve got a heater running. This article also explains the way overlooked appliances and lightbulbs add heat to your home.

So in our dystopian, low-energy future, it’s going to make sense to use less electricity so you don’t cook yourself in your own home.

Not fun news, I know.

Use fans strategically

Fans can help with air flow, but they work better if you understand the basic principles of positive and negative air pressure. Simply parking yourself in front of one can actually speed up dehydration and heat illness. Above 35C degrees (95F), they start to pose more of a liability than anything.

It’s a little counterintuitive…

Just putting a fan in the window often doesn’t do enough. This article from Instructables explains how to create pressure systems to manage the air in your home depending on the time of day.

So, use fans to exchange air in your home.

For example:

If you want to cool one room, like a bedroom, then open a window at the other end of your home. Seal the other rooms.

Put a fan near but not in the far window opening to create a vortex, then open the bedroom window. That creates a windstream that replaces warm, stuffy air with fresh, cool air. Do this at night, and then keep your place sealed during the day to keep that cooler air inside, and the hotter air outside.

Invest in good curtains

Sunlight heats rooms. It’s called heat gain. The more you can do to block out sunlight during a heatwave, the better. Even basic curtains can reduce heat gain by 33 percent. Window quilts do an even better job.

Make a zeer

Cultures around the world have been keeping goods cool with zeer pots, or pots within pots, for thousands of years. You can cool food, or you can cool water, and cool water can help you stay alive during a heat wave.

Drinking cool water lowers your core temperature.

This guy shows you how to make one.

So does this article.

The inside temperature of a zeer pot can be 20-30F degrees lower than the outside temperature, especially in drier climates. They can chill down to 40F degrees (4C), even during the summer. They still work in more humid environments, just not quite as well. So, that’s a powerful tool.

They’re simple and robust.

Make a terracotta cooler

According to a 2024 study in the Journal of Engineering Sciences, terracotta has resurfaced as a material for cooling as the world cooks. Research has found that terracotta coolers can lower indoor temperatures “up to 6-10C in arid and semi-arid regions,” or up to 18F degrees. They work best in areas with low humidity. Some companies like Team Solstice have even designed air conditioners with terracotta that use much less energy while lowering room temperatures to 22-27C (mid-upper 70s in farenheight). Other companies like CoolAnt have designed terracotta beehive structures to cool the air up to 15C (27F).

This video shows you how to make a “mud pot air cooler” that can cool air from 40C down to 15C and distribute the air with a simple DC fan.

Here’s an alternate design. Some versions use a water pump, but it’s not essential. You basically mount two small fans on a clay pot, fill it with water, and take advantage of terracotta’s natural cooling properties.

The terracotta option is going to work better under certain conditions than others, but it’s a good option to know about.

You can also scale it up.

Other long term options

Go downstairs, or into a basement if you have access to one. For the long term, it’s not a bad idea to find a home with some kind of underground level. It’s always going to be cooler. You can also grow a vine trellis outside your home to provide shade. Vines do a great job of blocking heat, and growing them on a trellis means you don’t have to worry about them damaging your home itself. Studies have shown that vines on a building can reduce inside temperatures by 3-4C degrees (6F) or more, when you cover 40-70 percent of the walls.

According to an article in Interesting Engineering, earth-sheltered homes offer a wide range of advantages for our dystopian future, especially when it comes to disasters and heat waves. Native Americans built quite a lot of these structures across the plains, further demonstrating how much better they understood this continent and how poorly adapted our lifestyles remain.

Also, improve your insulation.

Seal any windows you don’t plan on opening up. If you can afford it, upgrade them to reduce heat gain. Look at the R value (5-7 ideal). Also inspect your walls for gaps around power outlets or other areas where your living space could be bleeding cool air to the outside. The more seals, the better.

So, that’s what I’ve got.

To survive the heatwaves and grid failures of the future, the kind that’ll send half the populations of major cities to the ER, I would start implementing these strategies and helping other people do it. If you’re building community, share this information and help your friends ruggedize their homes. Think about setting up some cooling centers, even underground ones.

What are your heatwave survival strategies?

Let me know.