Supporting sustainable water policy

The pressure on water resources has been mounting worldwide, with water scarcity becoming a widespread problem in most arid and semiarid regions around the world. Global water extractions have increased more than six fold in the last century, which is more than twice the rate of human population growth [1]. However, the impact of growing water scarcity on long-term sustainable development has not been adequately addressed by the integrated assessment research community.

Specifically, the allocation of water resources across regions and sectors at the global level remains largely unaccounted for in long-term modeling. To reconcile potential inconsistencies introduced by constraints on future water availability, IIASA researchers are developing the Global Hydro-economic Model, which will integrate spatially distributed water resource systems, infrastructure, management options, and economic values. In addition, it will be possible to link it with other IIASA integrated assessment models: the Community Water Model; the Model for Energy Supply Strategy Alternatives and their General Environmental Impact; and the Global Biosphere Management Model.

The Global Hydro-economic Model uses optimization to balance global water demand and supply at the level of large-scale river basins. The technique allows the model to minimize the total costs of meeting the water demands from the agricultural, industrial (energy and manufacturing), and domestic sectors, while also taking into account various resource, institutional, and environmental constraints, such as retaining enough water for healthy aquatic ecosystems.