Up to half a million people globally succumb to the effects of extreme heat each year, according to recent scientific research, exceeding the combined impact of floods, earthquakes and hurricanes. This places the observable increase of extreme heat events among the most important emerging risks, according to Swiss Re's 2025 SONAR report.

Swiss Re noted in its report that there is clear evidence that extreme heat events are happening with greater severity, frequency and duration. July 2024 saw the hottest three days ever recorded on earth. Extreme heat events can have a large impact on human health. Recent data show that around 480 000 deaths per year can be attributed to extreme heat events. Heat stress can lead to exhaustion, heatstroke and organ failure, while exacerbating cardiovascular and respiratory diseases. People at an advanced age and pregnant women are especially vulnerable.

"Extreme heat used to be considered the 'invisible peril' because the impacts are not as obvious as of other natural perils", said Jérôme Haegeli, Swiss Re's Group Chief Economist. "With a clear trend to longer, hotter heatwaves, it is important we shine a light on the true cost to human life, our economy, infrastructure, agriculture and healthcare system", Swiss Re's Group Chief Economist added.

"Amid an increasingly interconnected risk environment, insurers are having to continuously adjust the scope of their risk horizon. Between the growing risk of extreme heat events, emerging liability risks or the changing scope of AI-related risks, it's clear the conversation must evolve beyond individual topics to examine how large macro trends are now reshaping today’s risk landscape", commented Patrick Raaflaub, Swiss Re's Group Chief Risk Officer.

Swiss Re's latest SONAR report examines emerging structural risks, among them a rising number of artificial intelligence (AI) incidents and decreasing trust in institutions.

The full report can be found here.