Assessing Climate Change Impacts on Water Availability Accounting for Human-Induced Water Stress

Abstract:

The water cycle is closely coupled with the dynamics of the human interactions (e.g., increased water demand, man-made infrastructure, and hydrologic alterations). Studies of climatic impact on water and environment primarily focus on large scale atmospheric conditions under anthropogenic emission scenarios, but ignore the local human component. Here we outline a methodological framework for assessing water availability in a changing climate, considering anthropogenic water demand and man-made infrastructure, designed to cope with climatic extremes. The framework is used to assess future water stress in southeastern Australia considering projected human demand scenarios, storage reservoirs, desalination infrastructure, and climatic change. Results show that in some combinations of the climatic change and water demand scenarios, the region would experience water stress that has not been observed in the baseline which includes the epic Millennium Drought. A question that is often ignored in the climate community is that to what extend uncontrolled growth with concomitant increase in water demand will exacerbate the future water stress. We argue that anthropogenic water demand should be an integral component of water stress assessment in the future climate, and the presented methodology offers a unique avenue for linking climatic and hydrologic processes to human interactions.