Heatwaves, or hot weather that can last for several days or weeks, can have a significant impact on society, including a rise in heat-related deaths.

While heatwaves don’t get as much attention as other bad-weather phenomena, they can be just as dangerous. More than 166,000 people died from heatwaves within the past ten years.

Heatwaves are increasing due to climate change. Extreme temperatures worldwide are happening more frequently across the globe. These events are lasting longer and with greater intensity than in the past.

The worst places hit are often cities, which experience the urban heat island (UHI) effect. Because city areas are mostly concrete, asphalt, and steel, the cities collect heat more easily and release heat more slowly than the countryside. In other words, cities absorb and trap heat. Add to that all the machinery and cars that create heat, and this can make the city as much as 6°C hotter than the surrounding area.

Heatwaves cause water shortages and power outages. With all the buildings running air conditioners, it strains the cities power grid. Some cities have to do rolling blackouts, that is, where sections of the city don’t have power for a few scheduled hours each day.

When too many people experience heat exhaustion, this can burden health and emergency services. Health-wise, heat exhaustion and dehydration can lead to death.

The body strives to keep a core temperature of about 37.5°C. As the temperature around the body rises the body has to work harder to keep cool.

Heat that is trapped in the body will escape through the skin, causing a person to sweat more. As the sweat evaporates, it cools the skin by releasing the heat.

All that sweating, however, can lead to dehydration, which is the loss of water from the body. Our body is comprised of about 60% water, so when that percentage starts to fall, the body begins to fail.

As well, when it gets too hot, the heart has to work harder to assist in heat release. Overworked hearts can lead to heart attacks. Heat exhaustion is a very dangerous condition, especially because most people don’t even realize it’s happening until it’s too late.

With global warming no longer an imagined phenomena, we can expect more heatwaves in the future. Governments should acknowledge this fact and be better prepared when the next heat wave comes.

The only real preparation against heatwaves is to improve the world’s power grids so that people don’t have to face blackouts. People need to be able to power their air conditioning for relief from the heat, a physical and medical necessity.

As well, individual homes should store a few extra cases of bottled water—just in case.