MUMBAI: India’s green cover has been absorbing more carbon than it emits annually over the past decade, but its ability to do so declines during extreme climate events like droughts, according to a study by researchers at the Indian Institute of Science Education and Research (IISER), Bhopal. The findings highlight the critical role of vegetation in mitigating and adapting to climate change.
How India’s Green Cover Balances Carbon
Vegetation plays a key role in the carbon cycle, absorbing carbon dioxide (CO₂) from the atmosphere through photosynthesis and releasing it back via respiration. The overall balance between CO₂ uptake and release is termed the Net Ecosystem Exchange (NEE).
- Negative NEE: Indicates that vegetation is storing more carbon than it emits.
- Positive NEE: Suggests that vegetation is releasing more carbon than it absorbs.
“For the last decade, India’s ecosystems have consistently absorbed more carbon than they emitted, with annual NEE estimates ranging from 380 to 530 million tonnes of carbon per year,” said Dhanyalekshmi Pillai, Associate Professor at IISER Bhopal and Head of the Max Planck Partner Group Germany.
Climate Extremes and Carbon Sequestration
While this level of carbon sequestration is impressive, it is not constant. Researcher and co-author Aparnna Ravi noted that climate extremes, particularly droughts, reduce the efficiency of carbon absorption, making it a concerning trend as climate change intensifies.
Vegetation Types and Their Role in Carbon Absorption
Scientists also examined how different types of vegetation across India contribute to CO₂ absorption:
- Evergreen forests: Highly efficient at capturing CO₂ through photosynthesis.
- Deciduous forests (Central India): Emit more carbon due to higher plant respiration surpassing primary productivity.
- Croplands: Less effective at carbon absorption per unit area than forests, but their extensive spread across India helps remove significant CO₂ from the atmosphere.
Advanced Technology for Carbon Sequestration Analysis
The study utilized a technology-driven approach combining:
- Highly resolved plant fluorescence (“glow”) observations
- Advanced physics-based computer models
- Satellite data from instruments like TROPOMI (Sentinel-2 satellite)
This method, more sensitive than conventional global techniques, provides detailed insights into ecosystem responses to climate change.
Call for Policy Action
With increasing climate extremes impacting carbon sequestration, Pillai emphasized the need for effective climate policies and ecosystem management aligned with national action plans.
This groundbreaking research was conducted in collaboration with experts from:
- Max Planck Institute for Biogeochemistry (Germany)
- University of Exeter (United Kingdom)
- National Remote Sensing Centre (India)
“Green vegetation is helping reduce global warming, but its sequestration potential is not limitless. Under climate extremes, its ability to store carbon is declining—this is concerning,” Pillai warned.
