In 2024, global warming added 41 extra days of extreme heat compared to pre-industrial levels, posing severe risks to health and mortality. Learn how climate change reshaped global heat patterns.
This year, humanity experienced six additional weeks of extreme heat compared to a world without global warming. Researchers estimate that the planet’s average temperature, now 1.3°C higher than pre-industrial levels (1850–1900), has resulted in 41 extra days of dangerous heat—a month and a half above historical norms.
The findings come from the World Weather Attribution (WWA) initiative and Climate Central, which released their first annual report analyzing the relationship between climate change and extreme weather events.
How Extreme Heat Changed in 2024
2024 is on track to become the hottest year on record since systematic measurements began. Estimates from Copernicus suggest that for the first time, the year could close with an average global temperature anomaly exceeding 1.5°C, potentially reaching 1.6°C.
However, rising temperatures are not the only concern. Another alarming trend is the increase in extreme heat days, which disproportionately affect vulnerable populations and lead to heightened mortality rates.
According to ISGlobal in Barcelona, extreme heat during the summer of 2022 caused 13,000 deaths in Italy alone. Globally, heat-related deaths account for 1% of all fatalities, while in Europe, that figure rises to 1.96%. Italy’s rate is even higher at 2.47%, according to recent research by Monash University.
Europe alone bears the brunt of extreme heat-related mortality, representing 36% of global deaths from high temperatures. The World Health Organization (WHO) estimates that extreme heat claims 175,000 lives annually in Europe.
Calculating the Days of Extreme Heat
The WWA and Climate Central used a robust methodology to calculate the number of “dangerously hot days” in 2024. They compared daily temperatures to the 90th percentile threshold (top 10% of the hottest days) for the baseline period of 1991–2020. This metric is closely linked to heat-related mortality.
Researchers then estimated the number of days exceeding this threshold in 2024 and compared it to a hypothetical world without climate change. Their conclusion? Global warming directly contributed to 41 additional extreme heat days this year, compared to a 1.3°C cooler planet.
A Global Issue with Local Extrem
While 41 days is the global average, the impact is far more severe for some regions. Small island nations face the most dire consequences, with up to 130 additional days of extreme heat annually—more than four extra months of dangerously high temperatures.
The Human Toll of Extreme Heat
The link between rising temperatures and mortality is stark. As extreme heat events become more frequent, so do their devastating health impacts, particularly on vulnerable populations. This year’s data underscores the urgent need for robust climate action to mitigate global warming and its profound effects on human life.
