State of Global Water Resources 2021

As a first edition of the annual State of Global Water Resources, this report shows how maps and a graphical summary of streamflow and terrestrial water storage (TWS) in river basins worldwide could look in regular reports on global water resources. These maps are based on modelled data (and validated with observed data to the extent possible) and remotely sensed information from the NASA GRACE mission for TWS. Modelled data was used to achieve maximum geographical coverage. The 2021 report also includes chapters on major hydrological events in 2021 and a brief overview of cryosphere changes as they related to water resources.

The report shows how large areas of the globe recorded drier than normal conditions in 2021 - a year in which precipitation patterns were influenced by climate change and a La Niña event. The area with below-average streamflow was approximately two times larger than the above-average area, in comparison to the 30-year hydrological average. Significant flood events with numerous casualties were reported, among others, from China (Henan province), northern India, western Europe, and countries impacted by tropical cyclones, such as Mozambique, the Philippines and Indonesia. Ethiopia, Kenya and Somalia have faced several consecutive years with below-average rainfall causing a regional drought.