Large-scale water scarcity assessment under global changes: insights from a hydroeconomic framework

Abstract

Abstract.Global changes are expected to exacerbate water scarcity issues in the Mediterranean region in the next decades. In this work, we investigate the impacts of reservoirs operation rules based on an economic criterion. We examine whether can they help reduce the costs of water scarcity, and whether they become more relevant under future climatic and socioeconomic conditions.We develop an original hydroeconomic model able to compare water supply and demand on a large scale, while representing 5 river basin heterogeneity.On the supply side, we evaluate the impacts of climate change on water inflows to the reservoirs. On the demand side, we focus on the two main sectors of water use: irrigation and domestic sectors. Demands are projected in terms of both quantity and economic value. Coordinated operating rules of the reservoirs are set up, considering spatial and temporal trade-offs. The objective is the maximisation of water benefits. 10The methodology is applied to Algeria at the 2050 horizon. Our results show that the supply-demand imbalance and its costs will increase in most Algerian basins under future climatic and socioeconomic conditions. Our results suggest that the benefits of operating rules based on economic criteria are not unequivocally increased with global changes. In some basins the positive impact of economic prioritisation is higher in future conditions, but in other basins it is higher in historical conditions. Given its generic nature and low data requirements, the developed framework could be implemented in other regions con-15 cerned with water scarcity, or extended to a global coverage.

Tropical Indo-Pacific SST influences on vegetation variability in eastern Africa

“…The 2-year-long vegetation decline in Tanzania during an ENSO cycle can be explained as a double-integration of the local rainfall anomalies, which originate from the seasonally-modulated ENSO Pacific-SST forcing (Combination mode). In the presence of interannual TIO SST forcing, the southeast African precipitation and vegetation responses to ENSO are muted due to Indian Ocean warming and the resulting anomalous upward motion in the atmosphere.Natural fluctuations in Africa's vegetation are affected by rainfall variability [1][2][3][4][5][6][7] . Especially the Sahel, eastern Africa, and southern Africa show large interannual variations in terrestrial productivity, which can be attributed to year-to-year changes in water stress 8 .…”

A Global Analysis of Future Water Deficit Based On Different Allocation Mechanisms

“…In this version of the model, local water scarcity does not dynamically influence water efficiency factors in electricity, industry, and municipal sectors. Future model improvements could include these dynamic effects, so that water‐scarce grid cells implement efficiency improvements faster than water‐abundant cells, which would also make the regional average efficiency improvements endogenous instead of exogenous (see also Neverre et al, ).…”

Representing Human Water Management in a Land Surface Model Using a Supply/Demand Approach

“…This formulation ensures the unicity of the adduction path to a given river as U is a monotonic function along the graph. The value used here is the same as the one recommended by Neverre et al (2016) (k = 10,000).…”