Over the past century, substantial growth in population, industrial and agricultural activities, and living standards have exacerbated water stress in many parts of the world, especially in semi-arid and arid regions. Climate change, however, will regionally exacerbate or offset the effects of population pressure for the next decades. It is projected to reduce renewable surface water and groundwater resources significantly in most dry subtropical regions. In contrast, water resources are projected to increase at high latitudes. Proportional changes are typically one to three times greater for runoff than for precipitation. Furthermore, Climate change is projected to reduce raw water quality, posing risks to drinking water quality even with conventional treatment (IPCC Fifth Assessment, 2014).

This section provides insights into projected climate change impacts on various hydrological indicators.