temperature also increases the rate of evapotranspiration, which leads to a reduction in the actual amount of groundwater available for human use. India extracts 1000 km3 of groundwater annually, which is 25% of groundwater at a global level (Mukherji 2019).
Climate change affects Indian water resources through warming of the atmosphere, alterations in the hydrologic cycle, melting of glaciers, rising sea levels, and changes in precipitation patterns (amount, timing, and intensity). The alteration of monsoon patterns decreases rainy days but increases the amount of rainfall. Himalayan glaciers are receding faster than any other part of the world. Further, the combined impacts of changes in precipitation patterns, glaciers melting, and sea‐level rise has caused flood‐like situations in different parts of the country. One noticeable thing, if the conditions continue, glaciers will melt quicker and no glaciers will be left to supply water for the entire year, then rivers like Brahmaputra and Ganges will become seasonal rivers.
1.5 Impact of Climate Change on the Quality of Water Resources
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.
1.6 The Health Perspective in Association with Water Security and Climate Change
As per the WHO (2018), in the period between 2030 and 2050, climate change could be the reason for approximately 250 000 additional deaths per year by malnutrition, malaria, diarrhea, and heat stress. The additional health costs by 2030 are estimated to project USD 2–4 billion/year. Climate change affects health through polluted air, unsafe drinking water, insufficient food, and shelter safety. Extreme high air temperatures directly affect cardiovascular and respiratory systems, particularly to older adults. In Europe, more than 70 000 deaths were recorded under the influence of a summer heatwave during 2003 (Robine et al. 2008). High temperature also increases ozone levels and other pollutants in the air, leading to cardiovascular and respiratory diseases. The levels of pollen and other aerial allergens are high in extreme temperature/heat. This can trigger asthma, which affects nearly 300 million people in the world (WHO 2018). Apart from this, climate change has a high impact on water‐related diseases. The nonuniform rainfall patterns are likely to affect freshwater and make it unsafe for humans. This water can compromise hygiene and increase the risk of diarrheal disease, which kills over 500 000 children aged under five years, every year (IPCC 2014).
India is one of the major countries that suffers from water‐related diseases. The security of drinking water ensures the prevention and control of water‐borne diseases. As per the WHO assessment, around 37.7 million people in India are affected by water‐borne diseases every year, and among them, 75% are children (Khurana and Sen 2009). The World Bank has also estimated that 21% of communicable diseases in India are related to unsafe water. The impact of climate change increases the risks of water‐borne diseases like cholera, malaria, and dengue by warming of the climate and intense rainfall. A UN report stated that more than one lakh people die annually from water‐borne diseases and 73 working days are lost due to water‐borne diseases. Another report stated that 1.5 million children die annually from diarrhea (Khurana and Sen 2009). Apart from water‐borne diseases, cancer, cardiovascular diseases, mental disorders, and other diseases are reported due to probable contaminants found in water (Kaur et al. 2019). A resulting economic burden of $600 million has been estimated per year due to water‐borne diseases. Further, climate change makes the situation more critical. Rising temperatures often bring negative impacts to human health and life. The incidences of water‐borne diseases like cholera, diarrhea, and so on,. become more prevalent in warmer climates (Figure 1.4). Vector‐borne diseases like malaria can thrive when the temperature increases as a result of global warming. It is also estimated that up to 2050, the malaria vector will shift away from central regions towards southwestern and northern states due to the variation of rainfall (Kiszewski et al. 2004). Malaria kills over 400 000 people every year on the global level.
Vector‐borne diseases like dengue also increase in warm and rainy climate due to the increasing mosquito population. The Aedes mosquito vector of dengue is also highly sensitive to climate conditions, and studies suggest that climate change is likely to increase exposure to dengue. Apart from the risks caused by increased temperature, intense rainfall could result in floods and waterlogging in several places. Waterlogged areas will then become the potential grounds for mosquitoes breeding. In India, especially in the Ganges basin, poor habitats have no choice for drinking and cooking other than using the polluted water of rivers. This results in numerous diseases. Among these diseases, stomach infections like diarrhea and dysentery are common. People living in rural areas and urban slums will be more vulnerable to diseases and infections because they do not have access to piped water and cannot afford to buy clean water. Water shortages have an enormously devastating impact on human health, including malnutrition, pathogen or chemical loading, and infectious diseases from water contamination. In the future, this cycle of diseases will place an enormous burden on the government, who will have to scramble to provide health care for all those affected and have to take preventive measures to control the situation from worsening.
Climate change affects health through polluted air, unsafe drinking water, insufficient food, and shelter safety. The nonuniform rainfall patterns are likely to affect freshwater in India and make it unsafe for humans. This water can compromise hygiene and increase the risk of diarrheal disease, in these cases, children are the main sufferers. Further, the impact of climate change also increases the risks of water and vector‐borne
