The recovery of European freshwater biodiversity has come to a halt.

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss1. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity2. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity.

Oceanic climate changes threaten the sustainability of Asia's water tower.

Water resources sustainability in High Mountain Asia (HMA) surrounding the Tibetan Plateau (TP)-known as Asia's water tower-has triggered widespread concerns because HMA protects millions of people against water stress1,2. However, the mechanisms behind the heterogeneous trends observed in terrestrial water storage (TWS) over the TP remain poorly understood. Here we use a Lagrangian particle dispersion model and satellite observations to attribute about 1 Gt of monthly TWS decline in the southern TP during 2003-2016 to westerlies-carried deficit in precipitation minus evaporation (PME) from the southeast North Atlantic. We further show that HMA blocks the propagation of PME deficit into the central TP, causing a monthly TWS increase by about 0.5 Gt. Furthermore, warming-induced snow and glacial melt as well as drying-induced TWS depletion in HMA weaken the blocking of HMA's mountains, causing persistent northward expansion of the TP's TWS deficit since 2009. Future projections under two emissions scenarios verified by satellite observations during 2020-2021 indicate that, by the end of the twenty-first century, up to 84% (for scenario SSP245) and 97% (for scenario SSP585) of the TP could be afflicted by TWS deficits. Our findings indicate a trajectory towards unsustainable water systems in HMA that could exacerbate downstream water stress.

Evaluating Losses from Water Scarcity and Benefits of Water Conservation Measures to Intercity Supply Chains in China.

The severe water scarcity in China poses significant economic risks to its agriculture, energy, and manufacturing sectors, which can have a cascading effect through the supply chains. Current research has assessed water scarcity losses for global countries and Chinese provinces by using the water scarcity risk (WSR) method. However, this method involves subjective functions and parameter settings, and it fails to capture the adaptive behaviors of economies to water scarcity, compromising the reliability of quantified water scarcity loss. There is a pressing need for a new method to assess losses related to water scarcity. Here, we develop an agent-based complex network model to estimate the inter-regional and intersectoral impacts of water scarcity on both cities and basins. Subsequently, we evaluate the supply chain-wide economic benefits of four different water conservation measures as stipulated by the 14th Five-Year Plan for the Construction of a Water-Saving Society. These measures include increasing the utilization rate of recycled water in water-scarce cities, reducing the national water consumption per industrial value-added, and implementing agricultural and residential water conservation measures. Results show that direct losses constitute only 9% of the total losses from water scarcity. Approximately 37% of the losses can be attributed to interregional impacts. Among the water-scarce cities, Qingdao, Lanzhou, Jinan, and Zhengzhou pose a significant threat to China's supply chains. Agricultural water conservation yields the highest amount of water savings and economic benefits, while residential water conservation provides the highest economic benefit per unit of water saved. The results provide insights into managing water scarcity, promoting cross-regional cooperation, and mitigating economic impacts.