IIT Madras-led study shows how human activity affects aerosol and climate

New Delhi, Aug 26 (IANS) A research by the Indian Institute of Technology (IIT) Madras has shown the profound influence of human activities on cloud-forming aerosols.

The team, along with collaborations from Max Planck Institute for Chemistry in Mainz, Germany, studied the procedure called ‘Cloud Condensation Nuclei’ (CCN) along India’s coastal regions.

Research surrounding the interaction of aerosols -- tiny, suspended particles in air essential for cloud formation and precipitation -- is a critical area that continues to generate the largest uncertainties in climate change predictions.

With climate models heavily reliant on computer simulations, the established measurements and findings provide empirical data that can help refine these models, thereby reducing uncertainties.

“Aerosol-cloud interactions are intrinsically complicated, and these findings underscore that human activities can dramatically influence underlying processes. This is critical information for negotiating future atmospheric dynamics,” said Dr. M. Ravichandran, Secretary, Ministry of Earth Sciences, and a renowned climate scientist who was not part of this study.

The team at IIT Madras observed a startling 80-250 per cent increase in CCN concentrations following the Covid-19 lockdown.

This surge, as clearly shown by the study, resulted from more frequent new particle formation (NPF) -- a process where aerosol particles are formed from gases through complex chemical processes in the atmosphere -- post-lockdown, as human-caused emissions slowly rebounded.

This surge in freshly formed particles was the direct driver of the increase in CCN concentration.

These findings, published in the American Chemical Society's ES&T Air Journal, highlight how human behaviour directly affects the planet’s climate systems. The shift from predominantly cleaner marine air to polluted continental sources post-lockdown indicates the complex relationship between human activity and aerosol dynamic behaviour.

The research also found that anthropogenic organic matter was the dominant factor in the growth of these new particles, challenging the common belief that organic particles inhibit cloud formation.

“Our research reveals that anthropogenic emissions strongly influence aerosol behaviour, particularly in how they form clouds. These findings challenge existing models and propose new avenues for understanding how human activities shape climate patterns,” said lead researcher and atmospheric scientist Prof. Sachin S. Gunthe, also a faculty member in the Environmental Engineering Division, Department of Civil Engineering, IIT Madras.

The researchers are optimistic that these insights will help climate scientists reassess their models and approach to studying aerosol effects on climate change.

--IANS

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