Clair R. Barnes

Abstract Event attribution studies assess whether and to what extent human-induced climate change has altered the likelihood or severity of extreme weather events. In recent years, studies have become routine, particularly for heatwaves in many regions, and for heavy rainfall in parts of Asia and Europe. As this body of research grows, a key question emerges: when does a new attribution study add scientific or societal value?

Extreme rainfall events in 2025 were globally associated with exceptional short-duration intensities consistent with hydrological intensification in a warming climate. A total of 46 events were considered, including 18 tropical cyclones and 10 convective storms, producing widespread flooding, economic losses and substantial societal impacts. Key points Extreme rainfall in 2025 was globally widespread, often exceeding historical records for sub-daily and multi-day rainfall totals.