The research network World Weather Attribution (WWA) has, together with Climate Central and Red Cross Climate Centre, analyzed the past year. The researchers have analyzed data from extreme heatwaves and compared it with other data on weather at the location and also run it through climate models, so-called attribution studies. Since the researchers know that the average temperature on Earth has risen, they can compare scenarios with and without that rise.
Their conclusions are that between May 2024 and May 2025, around half of the world's population has experienced 30 extra days with extreme heat, defined as temperatures higher than 90 percent of historical observations at the location.
In many countries and regions, climate change has at least doubled the number of days with extreme heat compared to a world without climate change. The 67 largest global extreme weather events likely occurred due to climate change, according to the researchers.
"These recurring intense heatwaves are linked to consequences such as disease, death, strain on healthcare systems, crop loss, lower production, and transport disruptions," says Roop Singh, from Red Cross Climate Centre, in a press release.
2025 began with the warmest January month ever recorded and the lowest level of Arctic sea ice. The researchers urge all countries to prepare for rising temperatures to reduce the risk of fatalities and damage.
