An international study led by the Indian Institute of Technology Madras (IIT Madras) has highlighted the significant influence of human activity on aerosol behaviour and its role in cloud formation along India’s coastal regions.
The study, conducted between March and July 2020, examined cloud-forming aerosols known as Cloud Condensation Nuclei (CCN). Researchers found that concentrations of CCN increased by 80–250% following the COVID-19 lockdown as human emissions began to rebound. The increase was linked to new particle formation in the atmosphere, demonstrating how directly human behaviour can affect climate systems.
The findings were published in the American Chemical Society’s ES&T Air Journal and co-authored by researchers from IIT Madras and international institutions. The team included Prof. Sachin S. Gunthe, coordinator of the Centre for Atmospheric and Climate Sciences, IIT Madras, Aishwarya Singh, a former PhD student at IIT Madras and now a post-doctoral researcher at the Max Planck Institute for Chemistry in Mainz, Germany, and Prof. R. Ravikrishna of IIT Madras.
Prof. Gunthe said the research shows that anthropogenic emissions strongly influence aerosol behaviour, particularly in how they form clouds. He added that the findings challenge existing models and propose new directions for understanding how human activity shapes climate patterns.
Aishwarya Singh said the lockdown provided a natural experiment, allowing researchers to observe how a cleaner atmosphere reacts to the return of emissions. She said the observations showed that a cleaner environment can be highly sensitive to new emissions, altering aerosol-cloud interactions in ways that affect climate predictions.
Prof. Gunthe further emphasised that real-world measurements provide clarity that computer models alone cannot achieve. He said such work lays the foundation for more accurate climate projections, which are essential for informing policy and environmental management.
Prof. Ravikrishna noted that predicting the future of climate requires a rigorous understanding of present conditions. He said measurements provide an essential context to refine and improve climate models.
The study challenges the common assumption that organic particles hinder cloud formation. It found that anthropogenic organic matter played a dominant role in the growth of new particles, increasing CCN concentrations despite their lower ability to attract water compared to inorganic particles. In coastal regions, this led to greater cloud development, showing that under certain conditions organic particles can support, rather than inhibit, cloud growth.
Dr M. Ravichandran, Secretary of the Ministry of Earth Sciences, Government of India, who was not part of the research, described aerosol-cloud interactions as highly complex. He said the findings underscored that human activity can significantly influence these processes, making the results critical for future studies on atmospheric dynamics.
Researchers said the study underscores the importance of combining advanced computer models with field data to better understand and predict climate change. They expressed hope that the findings will help reassess climate models and guide more accurate strategies for managing environmental challenges.
Also read | Garo Hills Council employees have not been paid for 43 months: Why?