A study released earlier this year found that heat events are rising globally.
In the report Climate Change and the Escalation of Global Extreme Heat: Assessing and Addressing the Risks, researchers studied extreme heat over a 12-month period from May 2024 to May 2025. The purpose was to determine the role that climate change plays in extreme heat and develop strategies that could be deployed to limit the number of lives that extreme heat claims.
historic temperatures) between May 1, 2024, and May 1, 2025. Graph credit: WWA.
The report, released last month, was produced by scientists at World Weather Attribution (WWA), the Red Cross Red Crescent Climate Centre (IFRC), and Climate Central.
The rise in unprecedented new heat records
The report came on the back of a series of new weather records. Most notably, 2024 was the warmest year on record, surpassing 2023, which was the previously warmest year. 2025 has, from the outset, set new records, with January 2025 being the warmest January ever recorded. 2024 was the first year when pre-industrial temperature increases were 1.5°C or more for the whole year.
During that period, the scientists studied 67 extreme heat events, which they deemed notable using WWA criteria. For each heat event, they assessed whether climate change played a role and the length of the heat events.
The 67 events occurred in 232 different countries and territories. Four were studied in depth: the extraordinary heat in Central Asia in March 2025; the extreme heat and its impacts on women and girls in South Sudan in February 2025, the deadly Mediterranean heat wave in July 2024, and the extreme heat in Mexico, the US Southwest, and Central America in June 2024.
Covering all those events, the scientists concluded that human-induced climate change was the key driver of the extreme heat. In many cases, the observed high temperatures would not have been possible without climate change.
Events across the world are made more likely due to climate change
An example is the March 2025 heat wave in Central Asia, up to 10°C warmer than it would have been without human-induced climate change.
The scientists concluded that the event most strongly influenced by climate change occurred across the Pacific Islands from May 1st to 30th, 2024. Human-induced climate change made it 69 times more likely.
The second event with the most substantial climate influence happened in Central America and the northern part of South America between August 30 and September 4, 2024. Due to human-induced climate change, it was made 24 times more likely.
The event with the most substantial climate influence on the African continent occurred from December 14th to 30th, 2024, stretching across central and western Africa, from Senegal to South Sudan and the Central African Republic. It was deemed at least 15 times more likely due to climate change.
The extreme heat stretching across Saudi Arabia, Kuwait, Iraq, and Bahrain between July 11th and 16th, 2024, was the event in Asia with the most substantial climate influence, and it was made 14 times more likely due to human-induced climate change.
From June 5th to 10th, 2024, a major event stretched across three continents: from Greece and Romania in Europe to Egypt in Africa and Asia and the Middle East. This was made 11 times more likely due to human-induced climate change.
Attributing heat events to climate change
Scientific advancements have made such assessments much more frequently possible.
Climate science has made significant progress in understanding how climate change fuels extreme temperatures in the past decade. This is due to developments in attribution science and climate modelling. These developments allow scientists to quantify how much heat climate change has added to an extreme temperature event and to predict how heatwaves will grow more frequent and intense unless emissions are cut drastically. Additionally, research can also show how many people have died because of extreme heat driven by human-induced climate change.
Every country in the world is at least doubling the number of extreme heat days
The scientists could also reveal a damning verdict: During the 12-month period, no region in the world was spared from dangerous extreme heat.
In every country, human-caused climate change has added more extreme heat days.
Globally, four billion people experienced at least one additional month of extreme heat due to human-induced climate change, which is primarily caused by burning fossil fuels.
And as a baseline, the number of extreme heat days has at least doubled across the world’s 195 countries.
Of all countries, Aruba experienced 187 days of extreme heat. Without human-induced climate change, the average person in the Caribbean country, which is part of the Kingdom of the Netherlands, would have experienced the significantly fewer, 45 days.
Underreported heat impacts
The report also noted that extreme heat events and their impacts on human health and wellbeing, as well as on the water and agricultural sectors, are poorly documented, especially in low—and middle-income countries.
This attitude results in the actual impacts not being communicated or publicised correctly. Heat-related deaths are being misattributed to heart conditions in persons, such as cardiovascular disease and pulmonary conditions. This obscures and downplays the health impacts of human-induced climate change.
It cites an example from the 2022 extreme heat events across Europe. The continent saw an estimated 61,672 heat-related fatalities. However, comprehensive mortality data are not available in most regions.
At the time of writing, a series of fatal extreme events are occurring worldwide. This is happening earlier than usual, with the summer in the northern hemisphere barely 1.5 months old.
World Weather Attribution have already started to assess and analyse these events. Early writing on the wall points to a 2025 summer with climate-induced extreme heat impacts. Due to the advances in attributions, we already know how big a role human-induced climate change is playing.
Anders Lorenzen is the founding Editor of A greener life, a greener world.
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