Changing vegetation-carbon-climate relationships in India during recent decades

India is the second largest contributor to the global greening, which is situated in the higher carbon uptake tropical region. We find that India has been greening with a marked enhancement in Normalised Difference Vegetation Index (NDVI, 10%), Leaf Area Index (LAI, 11%) and Solar Induced Fluorescence (SIF, 13%) in recent decade (2010 to 2019) as compared to previous decade (2000 to 2009). This greening is largely cropland-based where croplands exhibit twice the greening magnitude of forests. Cropland greening driven by improved irrigation facilities, better farm mechanisation, enhanced land management and use of nitrogen fertilisers contributes 86.5% to India’s net greening. To comprehend the translation of this greening into ecosystem health and functionality, we assess the Carbon Use Efficiency (CUE), and Water Use Efficiency (WUE). Soil moisture (SM) exhibits direct causal relationships with CUE and its determinants, with SM being the primary driver of both CUE and WUE. The coupling of the carbon and water cycles in India has intensified in recent decades, particularly in croplands. We find hindered ability of Indian forests to translate the structure (greenness) into functioning (carbon uptake) recent decades. To further decipher this, we for the first time estimated the Ecosystem Photosynthetic Efficiency (EPE) for Indian forests. Our recent study explicitly highlights the weakening of Indian forests as carbon stocks in the recent decade (2010–2019) from the previous decade (2000–2009) due to reduction in the translation factor i.e., EPE. This decline in EPE is predominant in the pristine forests of eastern Himalaya and Western Ghats due to enhanced moisture stress, rising aridity and increased wildfires, in the warming climate. We find just 16% of the Indian forests maintain high ecological integrity or intactness.