Groundwater is the source of almost 85% of freshwater requirement in rural India and 50% in urban India. Bihar is particularly reliant on groundwater, as it has the lowest supply of piped drinking water among Indian states. We examine the exposure of this resource to stress due to climate change, specifically, we estimate the influence of climate parameters on availability of groundwater in Bihar in about 10 years (2021) and 40 years (2051) from the most recent reference-point of 2011 for which data are available. Considering the estimated increase in temperature in Bihar of 0.32°C and 1.28°C from the reference period under high-end scenario, annual replenishable groundwater would decrease by 4.6 and 17.8%, respectively, for 2021 and 2051. An estimated increase in annual average precipitation by 1.6 and 6.4% from the reference period under low-end scenario would increase estimated recharge levels by only 0.6 and 2.4%, respectively, in 2021 and 2051. The combined impact of estimated change in climate parameters (temperature and precipitation) would bring groundwater availability from 24 litres per capita per day (lpcd) now to 23lpcd by 2021 and 20lpcd by 2051 under worst-climate scenario (high-end temperature and low-end precipitation). Projections of population growth for the years examined compared to the Indian population in 2011 revealed the reduction in water availability further to an estimated 20lpcd by 2021 and to 13lpcd by 2051 under 'pessimistic scenario' (worst-climate and high-end population). Planned artificial replenishment can fill the gap neither in the shorter nor in the longer term. We therefore conclude that due to the cumulative effects of climate and population, groundwater scarcity in Bihar could reach a level well below the minimum lpcd set by the Government of India and by WHO, unless effective corrective interventions will occur.

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International Journal of Climatology
Erasmus School of Health Policy & Management (ESHPM)

Sharma, B, Jangle, N, Bhatt, N, & Dror, D.M. (2015). Can climate change cause groundwater scarcity? An estimate for Bihar. International Journal of Climatology, 35(14), 4066–4078. doi:10.1002/joc.4266