Environ. Res. Lett. 15, 014007 (2020)

The altered precipitation and temperature patterns that come with climate change are expected to affect water availability across the globe. In addition to this, human systems have an impact on water resources, for example through increasing water demand by growing populations or investment in technologies that limit water use. The impact of climate and human systems is simultaneous; however, their relative roles in determining water availability, as well as how this may change in the future, are unclear.

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To address this question, Neal Graham from the Joint Global Change Research Institute and colleagues quantify the contribution of both systems as drivers of future water availability under the Shared Socioeconomic Pathways–Representative Concentration Pathways framework. They find that humans drive water availability under all scenarios, but whether its scarcity increases or decreases depends on the socioeconomic pathway, as well as geographical area. In some cases, humans could reduce water scarcity in nearly half of the world by 2100. The results show the importance of technological development in managing water resources under climate change.