Heat: A Silent Enemy
Heat is often underestimated as a natural disaster, but it is responsible for more deaths in the US than any other type of weather disaster. According to a recent report, extreme heat kills one person every minute worldwide, a rate that has increased by 23% since the 1990s.
Heat-related deaths are also chronically underreported, both in the US and worldwide. Outdoor workers are particularly vulnerable, as are the elderly, children, and people with chronic health conditions. However, heat can affect anyone, and our own biases about what constitutes good weather (sunny summer days are glorious) often minimize its risks.
Why Heat is so Deadly
Heat is a growing threat. No single heat event can be attributed solely to climate change, but there is no doubt that heatwaves are occurring more frequently and reaching higher temperatures as a result of climate change. In fact, the scientific consensus now is that climate change has played a role in making nearly all heatwaves more likely or more severe.
Other factors can amplify the warming effects of climate change, such as the natural weather pattern of El Niño. In an El Niño year, global heat is typically exacerbated by high ocean temperatures in the Pacific. The hottest years on record tend to occur during El Niño.
The Science Behind Heat
The term heatwave generally describes any period of abnormally hot weather. However, some of the most dangerous heatwaves are caused by something known as a heat dome. In a heat dome, a high-pressure system traps hot air in a region, feeding on itself to increase the heat and humidity as it remains stagnant in one place.
Humidity makes heat even more dangerous. Any kind of heat can be dangerous when the body can't sweat fast enough to stay cool. However, heat and humidity work together to affect the body's cooling ability. Higher humidity makes it harder for sweat to evaporate, reducing the body's ability to cool itself naturally.
Health Consequences of Heat
Exposure to high temperatures has immediate effects on health. Extreme heat forces the heart to pump two to four times more blood per minute to cool the body. This can lead to dehydration, which makes the blood thicker and harder to circulate, and worsens to heat exhaustion or heatstroke, or leads to heart failure. On particularly hot days, burns from scorching surfaces, including pavement, are an additional risk.
Each year, hundreds of thousands of people in the US end up in the emergency room due to heat-related illnesses and cardiovascular, respiratory, and kidney problems.
Preparation and Prevention
Your home makes a big difference. If a heatwave is on the way, dehumidify your home to reduce indoor humidity. Close openings around windows and doors to prevent hot air from entering. Cover windows to prevent the sun from heating up the interior — blinds, curtains, or even DIY solutions work.
In a low-humidity environment, you can even create your own air conditioning.
Keep water, electrolytes, and ice on hand, at home and at work, and identify cool places to go, such as a public library. This is not just useful for relieving boredom — heat can put extra pressure on the power grid, as everyone runs their air conditioners, sometimes resulting in power outages.
Conclusions and Next Steps
Heat is a silent enemy that can have devastating consequences for health and safety. It is essential to understand the risks associated with heat and take measures to protect oneself and others. By preparing and preventing, we can reduce the impact of heat and create safer and more resilient communities.
Source / Reference
This story was originally published by Grist with the title 'Why heat is so deadly and how to stay safe' on July 9, 2026.