 Climate change is projected to cause significant changes in river flow regimes around the world. These changes could have serious implications for freshwater ecosystems, which depend heavily on regular and predictable patterns of flow. According to this research, climate change is expected to cause greater alterations in river flow regimes than existing human activities such as dams and water withdrawals. This suggests that climate change could have a more severe impact on freshwater ecosystems than previously thought. This article was authored by P. Dahl and J. Zhang.