Modelling of Climate-Induced Groundwater Recharge for Assessing Carbon Emission from Groundwater Irrigation

In this study impact of climate change on groundwater recharge is investigated and the carbon emission from groundwater irrigation is assessed under projected climate change scenarios for Karnal district of Haryana state in India. HYDRUS-1D and MODFLOW models were used to simulate the climate change impacts on groundwater recharge for different projected climate change scenarios. Simulation results showed that groundwater recharge would increase marginally by 2030 over the baseline year of 2008 under the scenario based on ARIMA predictions, which considered the effect of all climate parameters. However, under the scenarios, which considered only rise in temperature, groundwater recharge would decrease by 0.07–0.22 m. Rise in temperature by 3.5°C and 4.3°C along with 9% and 16% increase in rainfall over the base year would increase the recharge by 0.09 m and 0.14 m respectively. The study also revealed that the effect of climate change on cumulative recharge would be more in sugarcane fields than in rice fields. Carbon emission of groundwater irrigation under the scenarios based on rise in temperature only would increase by a minimum of 12 kg CO₂/ha in pearl millet crop by the year 2030 to a maximum of 3250 kg CO₂/ha for sugarcane crop by the end of this century. Estimated total carbon emission in 2030 would be 345,857 metric tonne from groundwater irrigation in Karnal district which is 87,474 metric tonne more than the baseline emission.