A new study from Science finds that climate change is altering the timing of river flooding in Europe. In some regions, like southern England, floods are occurring 15 days earlier than they did 50 years ago. Conversely, around the North Sea, in the Netherlands, Denmark and Scotland, floods are occurring later.

Floods from rivers impact more people than any other natural hazard, which holds serious implications for the many towns and cities in Europe built on rivers’ edge. Flood risk has been managed by measuring the timing and extent of past floods; however, changes induced by climate change may make future flooding harder to predict.