Spatio-temporal variability in evapotranspiration and moisture availability for crops under future climate change scenarios in north-west India

Assessment of the impact of climate variability on evapotranspiration and moisture availability is crucial for planning of water resources and achieving food security in north-west India. Therefore, spatio-temporal variability in annual and seasonal climatic variables [maximum temperature (Tmax), minimum temperature (Tmin) and rainfall), reference evapotranspiration (ETo), moisture index (MI) and aridity index (AI)] were assessed for three regions (north-east, central and south-west) of Indian Punjab during baseline period (1971–2018), mid-century (2040–2060) and end century (2080–2095). The long-term data of Tmax, Tmin and rainfall during baseline period was collected from difference sources, and the MarkSim data of Representative Concentration Pathway 4.5 during mid-century (2040–2060) and end century (2080–2095) was used. The ETo, AI and MI were calculated from Tmax, Tmin and rainfall during different time periods, and the temporal variations in these parameters during baseline period, mid-century and end century were studied using Mann–Kendall test. In addition, spatial variability in these parameters was studied using inverse distance weighted method. The maximum and minimum temperatures are likely to increase by 1.1 to 4.8 °C in different regions of Punjab, and the variable pattern of rainfall is expected by mid-century and end century. Annual and Kharif (June–October) season rainfall is likely to increase by 18.2 to 42.9%, but it is expected to decrease by − 7.6 to − 62.3% (− 27.0 to − 7.6% for north-east, − 23.5 to − 17.6% for central and − 42.8 to − 62.3% for south-west region) during Rabi season (October–April). As a result of increase in temperature and erratic rainfall pattern, ETo is likely to increase by 7.4 to 13.2% in the three regions of the state. The analysis of MI and AI indicated better moisture availability conditions in the north-east followed by central and lowest in the south-west region. Analysis for mid-century (2040–2060) and end century (2080–2095) indicated that the annual MI is predicted to be slightly dry in north-east (− 32.2 and − 26.7) and central (− 54.4 and − 53.7) regions, but semi-dry in the south-west region (− 68.4 and − 68.9). Similarly, annual aridity index is predicted to be humid in north-east and semi-arid in central and south-west region. During the baseline period, wheat and rice yields were observed to be positively correlated with ETo in all the regions. However, aridity index, moisture index and rainfall were observed to be negatively correlated with wheat yield and positive with rice yield. The results of this study suggested that climatic variations by mid-century and end century can have significant implications on crop and water productivity along with severe pressure on water resources in the region. As the climatic conditions are likely to become more uncertain in future with large fluctuations, hence research is required to precisely explain the moisture extraction patterns of crops and their productivity under future climatic scenarios.