When India’s groundwater crisis is discussed, the focus usually stays above ground—on wells that run dry, on farmers drilling ever deeper boreholes, and on states locked into unsustainable irrigation subsidies. What is far less visible, yet far more consequential in the long run, is how changing groundwater levels are altering the very way India’s ecosystems function.
A recent national-scale study published in Ecological Informatics reveals that groundwater depth is not just a hydrological concern but a fundamental ecological control, shaping how efficiently India’s landscapes convert water into biomass and carbon into growth. Titled “Linking groundwater variability to ecosystem carbon and water use efficiencies across India,” the paper is authored by Abhishek Chakraborty, M. Sekhar, Soumendra N. Bhanja, and Lakshminarayana Rao and represents one of the most comprehensive attempts yet to connect groundwater dynamics with ecosystem productivity across the country.
Their conclusion is stark: as India’s water tables change—whether through over-extraction, irrigation, or climate variability—the country’s croplands, forests, and shrublands are being quietly reprogrammed in how they grow, respire, and use water.
Looking beyond yields: Why efficiencies matter
Most agricultural and water policy debates in India revolve around yields—how many tonnes of rice or wheat a hectare produces. The Chakraborty et al. study shifts attention to something subtler but arguably more important: efficiency. The authors focus on two key indicators. Carbon Use Efficiency (CUE) measures the share of carbon fixed by plants through photosynthesis that actually becomes biomass after accounting for respiration losses. Water Use Efficiency (WUE) measures how much carbon plants fix per unit of water lost through evapotranspiration.
These metrics matter because they capture ecosystem health rather than just output. A system can maintain yields for a while through heavy irrigation and fertiliser use, yet become progressively less efficient—losing more carbon to respiration or more water to unproductive evaporation. Such systems are productive but fragile. By analysing CUE and WUE together, the study provides a rare integrated view of how groundwater influences both the carbon cycle and the water cycle across India’s landscapes.