This study conducts the first comprehensive analysis of ecological droughts, defined as prolonged moisture stress causing severe ecological disruptions in India during the Indian Summer Monsoon (ISM) from 2000 to 2019, using remote sensing data and machine learning. Ecological droughts are found to be increasing in ecologically fragile regions, including the Himalayas, Northeast India, eastern Indo-Gangetic Plain (IGP), and southern India, driving vegetation browning in pristine forests and intensive croplands. A Random Forest model identifies meteorological aridity (23.9%) and ocean warming (18.2%) as the dominant drivers, with causal analysis revealing ocean warming indirectly exacerbates droughts by altering moisture availability and atmospheric aridity. Human interventions, such as forest degradation and land-use changes, further amplify vulnerability. The findings highlight the urgent need to integrate ecological droughts into climate policies and adopt nature-based solutions, as rising droughts threaten India’s sustainability, food security, and climate change mitigation efforts, with implications for similar bioclimatic regions globally.
Droughts are among the most devastating natural hazards, but conventional definitions overlook their long-term ecological impacts, an oversight addressed by this study focusing on ecological droughts in India, a country heavily dependent on monsoon rainfall for agriculture and forest ecosystems. Using remote sensing indices (Vegetation Health Index, VHI; Vegetation Condition Index, VCI; Temperature Condition Index, TCI) and advanced analytical tools (Random Forest, causal discovery, rotated principal component analysis), the research investigates spatio-temporal patterns, drivers, and implications of ecological droughts during 2000–2019. Key findings reveal that ecological droughts are concentrated in ecologically vulnerable zones: the western Himalayas (cold-induced stress), southern India (moisture scarcity), and the eastern IGP (cropland moisture stress). Decadal comparisons show a notable rise in droughts in the 2010–2019 period, linked to enhanced meteorological (Palmer Drought Severity Index), atmospheric (Vapour Pressure Deficit), and land evaporative (Evapotranspiration Ratio) aridity. The Random Forest model quantifies drivers: meteorological aridity (23.9%) and ocean warming (18.2%) are primary, followed by land evaporative aridity (14%) and atmospheric aridity (12.4%). Causal analysis confirms ocean warming acts indirectly, increasing land temperature and depleting soil moisture, while climate oscillations (El Niño, Indian Ocean Dipole) further weaken ISM rainfall. Human interventions play a critical role: high Human Modification Index and low Forest Landscape Integrity Index in Himalayan and central Indian forests indicate degradation, exacerbated by population growth (40–60% in forest regions). These activities disrupt moisture recycling, intensifying ecological droughts and triggering a feedback loop with vegetation browning—evident in eastern IGP croplands and Himalayan forests. The consequences are far-reaching: reduced crop yields threaten food security (India as a global breadbasket), weakened forest carbon sinks, and potential ecosystem collapse. To mitigate risks, the study advocates integrating ecological droughts into climate policies and adopting nature-based solutions (e.g., drought-resilient crops, agroforestry, and forest restoration). It emphasizes aligning strategies with global initiatives like REDD+ and Land Degradation Neutrality. Limitations include reliance on remote sensing data and a 20-year temporal scope, but the findings provide a foundational framework for managing ecological droughts in India and analogous monsoon-driven regions, underscoring the need for balanced water resource management and ecosystem protection to ensure sustainability.
Sources:
Communications earth & environment
https://www.nature.com/articles/s43247-025-02694-3 .
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System
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