• Energy Research

AbstractVarious transboundary river basins are facing increased pressure on water resources in near future. However, little is known ab out the future drivers globally, namely, changes in natural local runoff and natural inflows from upstream parts of a basin, as well as local and upstream water consumption. Here we use an ensemble of four global hydrological models forced by five global climate models and the latest greenhouse‐gas concentration (RCP) and socioeconomic pathway (SSP) scenarios to assess the impact of these drivers on transboundary water stress in the past and future. Our results show that population under water stress is expected to increase by 50% under a low population growth and emissions scenario (SSP1‐RCP2.6) and double under a high population growth and emission scenario (SSP3‐RCP6.0), compared to the year 2010. As changes in water availability have a smaller effect when water is not yet scarce, changes in water stress globally are dominated by local water consumption—managing local demand is thus necessary in order to avoid future stress. Focusing then on the role of upstream changes, we identified upstream availability (i.e., less natural runoff or increased water consumption) as the dominant driver of changes in net water availability in most downstream areas. Moreover, an increased number of people will be living in areas dependent on upstream originating water in 2050. International water treaties and management will therefore have an increasingly crucial role in these hot spot regions to ensure fair management of transboundary water resources.

This dataset is a supplement to the following publication (please cite that when using the data): Munia et al. 2020. Future transboundary water stress and its drivers under climate change: a global study. Earth’s future. https://doi.org/10.1029/2019EF001321 Water stress category data Dataset presents the water stress category in transboundary basins at sub-basin level for different scenarios (see article for details): stress_category_Historical.gpkg: stress for years 1980 and 2010 stress_category_SSP1‐RCP26.gpkg: stress for year 2050, SSP1‐RCP2.6 scenario stress_category_SSP1‐RCP45.gpkg: stress for year 2050, SSP1‐RCP4.5 scenario stress_category_SSP2‐RCP60.gpkg: stress for year 2050, SSP2‐RCP6.0 scenario stress_category_SSP3‐RCP60.gpkg: stress for year 2050, SSP3‐RCP6.0 scenario Dataset specifications: Type: geopackage (gpkg) Spatial extent: -165, 141.5, -54.5, 70.5 (xmin, xmax, ymin, ymax) Temporal extent: see above Projection: long/lat WGS84 (EPSG:4326) Information: sub-basin name, country, stress level, stress category Unit: - Supplement to https://doi.org/10.1029/2019EF001321

AbstractWater scarcity is a rapidly growing concern around the globe, but little is known about how it has developed over time. This study provides a first assessment of continuous sub-national trajectories of blue water consumption, renewable freshwater availability, and water scarcity for the entire 20th century. Water scarcity is analysed using the fundamental concepts of shortage (impacts due to low availability per capita) and stress (impacts due to high consumption relative to availability) which indicate difficulties in satisfying the needs of a population and overuse of resources respectively. While water consumption increased fourfold within the study period, the population under water scarcity increased from 0.24 billion (14% of global population) in the 1900s to 3.8 billion (58%) in the 2000s. Nearly all sub-national trajectories show an increasing trend in water scarcity. The concept of scarcity trajectory archetypes and shapes is introduced to characterize the historical development of water scarcity and suggest measures for alleviating water scarcity and increasing sustainability. Linking the scarcity trajectories to other datasets may help further deepen understanding of how trajectories relate to historical and future drivers, and hence help tackle these evolving challenges.

AbstractIn environmental management and sustainability there is an increasing interest in measurement and accounting of beneficial impact—as an incentive to action, as a communication tool, and to move toward a positive, constructive approach focused on opportunities rather than problems. One approach uses the metaphor of a “handprint,” complementing the notion of environmental footprints, which have been widely adopted for impact measurement and accounting. We analyze this idea by establishing core principles of handprint thinking: Handprint encourages actions with positive impacts and connects to analyses of footprint reductions but adds value to them and addresses the issue of what action should be taken. We also identify five key questions that need to be addressed and decisions that need to be made in performing a (potentially quantitative) handprint assessment, related to scoping of the improvement to be made, how it is achieved, and how credit is assigned, taking into account constraints on action. A case study of the potential water footprint reduction of an average Finn demonstrates how handprint thinking can be a natural extension of footprint reduction analyses. We find that there is a diversity of possible handprint assessments that have the potential to encourage doing good. Their common foundation is “handprint thinking.”

AbstractThere is a pressing need to improve food security and reduce environmental impacts of agricultural production globally. Two of the proposed measures are diet change from animal‐based to plant‐based foodstuffs and reduction of food losses and waste. These two measures are linked, as diet change affects production and consumption of foodstuffs and consequently loss processes through their different water footprints and loss percentages. This paper takes this link into account for the first time and provides an assessment of the combined potential contribution of diet change and food loss reduction for reducing water footprints and water scarcity. We apply scenarios in which we change diets to follow basic dietary recommendations, limit animal‐based protein intake to 25% of total protein intake, and halve food losses to study single and combined effects of diet change and loss reduction. Dietary recommendations alone would achieve 6% and 7% reductions of blue and green water consumption, respectively, while changing diets to contain less animal products would result in savings of 11% and 18%, respectively. Halving food loss would alone achieve 12% reductions for both blue and green water. Combining the measures would reduce water consumption by 23% and 28%, respectively, lowering water scarcity in areas with a population of over 600 million. At a global scale, effects of diet change and loss reduction were synergistic with loss reductions being more effective under changed diet. This demonstrates the importance of considering the link between diet change and loss reduction in assessments of food security and resource use.