Impacts of Climate Change on Hydrologic Resilience to Shifting Water-Energy Balance Based on Budyko Framework Across Western Arid Regions of India

Abstract

Changing climate has been methodically shifting the equilibrium between energy and water-based parameters of all earthly systems as variations in warming and precipitation lead to a shift in evaporative demand. The trend has been expected to increase warming along with fluctuations in precipitation in the future. In this study, we demonstrate that as climate changes the equilibrium between water supply and demand, buffer to plant water stress has been provided by the groundwater, mainly in regions where the groundwater is at shallow depth. Persistent warming and changing monsoon patterns in India lead to the development of stress on groundwater storage, especially in areas within the vicinity of arid and semi-arid regions, which results in affecting groundwater connections. The aridity index map demonstrates the equilibrium between water demand (described as potential evapotranspiration, PET) and water supply (as precipitation, P). The Aridity index (AI, described as ratio of PET/P) was used to denote the water and energy drivers of the terrestrial and hydrologic systems across India. Two global datasets were used for this study, namely, Climate Hazards Ground Infra-Red Precipitation (CHIRPS), MOD16A2 data product for PET based on the widely used Penman-Monteith equation, which takes inputs of the meteorological reanalysis data. Analysis was carried out on the cloud-computing-based Google Earth Engine (GEE). To demonstrate the variations in annual PET, three warming cases of 1.5 °C, 2 °C, and 4 °C were chosen, with a focus on the semi-arid regions of Western Rajasthan, India. The Budyko framework-based observations clearly highlight the transition zones of water to energy-limited systems in northwest and peninsular India for the year 2020. Results demonstrate that continuous warming has a direct impact on the rise in evapotranspiration rates leading to higher stress on available groundwater resources.