Impact attribution: exploring the contribution of climate change to recent trends in hydrological processes—an editorial introduction

The world is already in the midst of climate change and, in addition to preventing further climate change, it is of fundamental interest to analyse the existing impacts and implement appropriate adaptation measures. To this end, it is important to distinguish the influences of human management and land use change from the pure effects of climate change. However, the attribution of climate change effects in hydrology is still in its infancy, and the aim of this collection with its in total 9 articles is to contribute to a better understanding of the underlying methods on the one hand, and to quantify the recent consequences of climate change for hydrological processes on the other. The attribution of recent trends in mean annual discharge to climate change was possible in 42% of the 97 selected river basins from three continents investigated, mostly pointing on positive trends in streamflow: in Norway, northern Russia, northern Kazakhstan, western China and in the Lake Victoria basin. Negative trends in streamflow attributable to climate change were detected in the Blue Nile and Main Nile, in three basins of Central and South Asia and in the Selenga river.