Fig. 5: Evolution of flood volume under different warming levels and their contributing factors.

a–c, g–i Median flood volumes and their contributions from rainfall (blue box) and snowmelt (yellow box) under varying warming levels for Europe and all subregions. Purple lines represent the combined volume of rainfall and snowmelt contributing to median floods, while gray lines indicate the total generated runoff volume, considered as flood volume. Lines show the median values among model simulations, with shading indicating the interquartile range. Blue and yellow boxes represent the absolute volumes of contributing rainfall and snowmelt. Boxplots indicate the interquartile range, with whiskers extending to 1.5× the interquartile range across model simulations. d–f, j–l Relative changes of flood volume (gray lines), rainfall contribution (blue lines), snowmelt contribution (yellow lines) and the combined volume of rainfall and snowmelt (purple lines) under the 3 °C warming level compared to the baseline period, for different percentiles (Methods). Lines represent the median values across model simulations. Dashed gray lines denote the historical distribution of flood volumes over the baseline period.