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The impact of climate change on water quality has not gained much concern as an emerging topic in water research to date. However, possible effects are discussed with the association of health as depicted in Figure 1.4. Floods and droughts also affect the surface water qualitatively (in terms of pollutant concentration) and quantitatively. Whenever drought condition persists, the groundwater resources are depleted and the concentration of the pollutants are elevated in the residual water (IPCC 2007). Changes in precipitation or hydrological pattern and increased run‐off can result in the rise of pathogens and contaminants in water bodies. Increased frequency and intensity of rainfall may cause more water pollution due to run‐off water. The decrease in dissolved oxygen in water due to the increase in the temperature of the water is the direct consequence of climate change on water quality. Further, the concentration of dissolved carbon, phosphates, nitrates, and micropollutants are also directly altered as a consequence of climate change and they produce an adverse impact on health (Delpla et al. 2009).

Climate change is not only expected to influence the quantity of groundwater but also to influence the quality of groundwater (Dragoni and Sukhija 2008). Water recharges during an arid period contain a high concentration of salts and increases total dissolved solids (TDS). However, in a wet period, the reverse phenomena can occur. Climate change increases sea surface temperatures and results in rising sea levels. Further, rising sea levels may lead to saltwater intrusion into coastal aquifers, which influences groundwater quality and contaminates drinking water sources whenever salty water percolates into the freshwater system. It is very difficult to reverse the process. Climate change influences the amount or pattern of precipitation, resulting in a flood‐like situation and affects groundwater quality through the release of agrochemicals/industrial wastes from soil to groundwater.

Figure 1.4 Impact of climate change on water quality and its association with health.

Climate change affects water quality through the decrease of dissolved oxygen due to the rise of temperature, while alternations to the hydrological cycle increase pathogens and contaminants in surface water. Groundwater quality has been indirectly affected by climate change due to increases in TDS, salts, and other contaminants. Further, rising sea levels may lead to saltwater percolation in coastal aquifers, which influences groundwater quality.