BENGALURU – Scientists from the Indian Institute of Tropical Meteorology (IITM) have made a significant breakthrough in understanding the global carbon cycle, identifying a crucial missing piece of data that could refine global climate change strategies. Their groundbreaking study, conducted in collaboration with Kaziranga forest officials, reveals that Indian ecosystems absorb the most atmospheric carbon dioxide (CO2) during the pre-monsoon season, not the rainy season as previously assumed.
The findings, published in Agricultural and Forest Meteorology, challenge conventional wisdom and highlight a critical gap in global climate models, which have historically lacked ground-based data from regions like India. According to Pramit Kumar Deb Burman, the lead author of the study, this missing information is vital for accurate national carbon cycle assessments and the development of effective mitigation policies.
The Pre-Monsoon Advantage
The IITM team’s research shows that while the monsoon season brings water, the thick cloud cover it creates blocks sunlight, significantly limiting the process of photosynthesis in plants and, consequently, their CO2 uptake. In contrast, the pre-monsoon period offers ample solar radiation, allowing forests to absorb CO2 at a much higher rate. This seasonal variation is a key factor that has been largely absent from global climate models.
“This information is missing in climate mitigation strategies,” Burman stated, emphasizing the importance of their “bottom-up” approach, which relies on detailed ground-level observations rather than a “top-down” approach using only satellite data.
The Ground-Level Difference
For four years, the researchers meticulously compiled data using the Eddy Covariance technique, a method that measures the exchange of gases and energy between the atmosphere and an ecosystem. Instruments placed on the ground collected data multiple times per second, providing a far more detailed picture than daily satellite measurements. The team also measured CO2 flux from the soil, accounting for the carbon released by microorganisms.
To validate their findings, they combined physics-based models with biological observations. By physically measuring plant growth and comparing it to their calculated CO2 uptake, they confirmed their theory. The results were clear: plants in the Kaziranga region showed more significant growth in the pre-monsoon period, matching the data on increased CO2 absorption.
A Global Impact
This study is a vital link between different scientific approaches to calculating the carbon budget. It provides the ground-based data needed to validate existing models and reduce the uncertainties in both ground and satellite observations.
Burman noted that without regional data from India, climate projections have relied on older, secondary datasets. This new research provides a crucial corrective, helping to “find out how much uncertainty is in those data sets.”
The findings not only offer a clearer picture of India’s role as a carbon sink but also underscore the importance of local data in building a more accurate global understanding of climate change. As the world works to combat rising CO2 levels, this research from the heart of India’s forests provides a powerful new tool for informed decision-making.