Large-scale interventions to water resources, such as irrigation, dams and reservoirs, and water withdrawals, have been essential to human development. But interventions tend to solve water scarcity problems at a local level, while aggravating water scarcity downstream. In a new study published in the journal Nature Communications, researchers have now assessed the impacts of human interventions on water scarcity at a global scale.
Large-scale interventions to water resources, such as irrigation, dams and reservoirs, and water withdrawals, have been essential to human development. But interventions tend to solve water scarcity problems at a local level, while aggravating water scarcity downstream. In a new study published in the journal Nature Communications, researchers have now assessed the impacts of human interventions on water scarcity at a global scale.
“It’s common sense that taking water out of a river will leave less for those people downstream. But it’s not so straightforward,” says Ted Veldkamp, researcher at Vrije Universiteit Amsterdam and guest researcher at IIASA, who led the study. Seasonal changes in precipitation and water storage make it difficult for modelers to estimate water availability and impacts of interventions, and the effects of climate change can be difficult to tease out from other impacts like human activities.
The new study is one of the first to provide a global accounting of regional and local water impacts, taking into account seasonal changes and different types of intervention, including water withdrawals, reservoir regulation, land-use change, and irrigation. Using an ensemble of five global hydrological models, the researchers examined the evolution of water availability, demand, and scarcity globally from 1971 to 2010. They also highlighted the separate impact of climate change and human interventions.
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