With heatwaves becoming more regular, it is important to know the risks that come with them and the underestimated consequences of climate change. Often referred to as “silent killers,” these prolonged periods of extreme heat are responsible for around half a million deaths each year globally. The threat goes beyond heatstroke—high temperatures worsen existing health conditions like heart, lung, and kidney diseases. Heatwaves also place enormous strain on infrastructure, leading to power outages, transport issues, and even deadly wildfires, all of which compound their deadly impact.

Certain groups face far greater risk during heatwaves: outdoor workers, elderly people, those with chronic illnesses and more. Cities, in particular, are hotter due to the “urban heat island” effect, which traps heat in built-up areas. Humidity can make things worse, preventing the body from cooling down properly, especially during nights when temperatures stay dangerously high.

As global temperatures continue to rise—already up by around 1.3°C since pre-industrial times—heatwaves are becoming more frequent, longer, and more intense. Without significant climate action, experts predict a sharp increase in heat-related deaths in the coming decades. While reducing greenhouse gas emissions is essential, adaptation is also key. Greener cities, better building design, heat alerts, and community support systems can help save lives. On an individual level, staying hydrated, avoiding the midday sun, using fans or ventilation, and checking on vulnerable neighbours can make a critical difference.

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