India temperature trends continue to baffle climate scientists with one of the leading voices in atmospheric science, Dr. Loretta J Mickley of Harvard University, admitting that experts still don’t fully understand the forces shaping the country’s warming patterns. In an interview wirh Mickley explored the complex role aerosols play in India’s climate and why projections for the future remain highly uncertain.
Despite decades of rising global temperatures, India has warmed only about half as much as the rest of the Northern Hemisphere since 1950, based on NASA data using 1951–1980 as a baseline. While this may seem like a positive anomaly, it raises significant scientific questions.
Mickley, senior research fellow and co-lead of the Atmospheric Chemistry Modeling Group at Harvard Says “I’m curious about that comparison much of the warming in the Northern Hemisphere has been concentrated in high-latitude regions like Siberia and Alaska. It would be interesting to compare India’s warming with other regions at similar latitudes, such as Mexico.”
One of the main factors potentially suppressing India’s surface warming is aerosols fine particulate matter released into the atmosphere through industrial emissions, fossil fuel combustion, and crop burning. These particles interact with sunlight and clouds in complex ways. Reflective aerosols such as sulphates, can cool the surface by bouncing sunlight back into space. Absorbing aerosols like black carbon, on the other hand, trap heat in the atmosphere, which may warm the air aloft while cooling the ground below.
Mickley explained “In India you have both kinds reflective and absorbing aerosols coexisting that makes the climate response highly complex. It’s not as straightforward as in regions with predominantly one type.”
She referenced a 2021 study that observed a sharp drop in surface temperatures during the COVID-19 lockdown in Delhi despite reduced pollution levels. The study found that night-time land surface temperatures dropped by 2–4°C, possibly because the black carbon aerosols that usually warm the lower atmosphere were no longer present. This suggests that the height at which aerosols accumulate can also influence their warming or cooling effects.
Mickley acknowledged that such findings expose just how little scientists understand about the drivers of India’s surface temperatures. “There are many feedbacks including cloud formation and land atmosphere interactions that complicate the picture. The short answer is: I don’t know.”
She also pointed to two major reasons behind the uncertainty in India’s climate projections. First, there is limited understanding of the exact mix of aerosol types how much is reflective versus how much is absorbing. Second aerosol cloud interactions during the monsoon season remain poorly understood.
She also says “Aerosols can serve as cloud condensation nuclei and promote cloud formation, But absorbing aerosols like black carbon can also heat the atmosphere and reduce cloud cover by evaporating moisture. That kind of dual behavior is hard to model.”
A 2021 study in Climate Dynamics even suggested that reducing black carbon might alter monsoon patterns by strengthening winds and increasing moisture showing how complex and counterintuitive the effects can be.
Looking to the future, Mickley was cautious. “I can’t say for sure how India’s climate will evolve, but aerosols will play a big role. What we do know is that air pollution in the Indo-Gangetic Plain is dangerously high and is cutting lives short, especially for children and the elderly.”
She emphasized the need for clean air policies, such as a national Clean Air Act, though she acknowledged enforcement would be challenging. “Reducing pollution would benefit public health and could also help us better understand the climate but we still have a lot to learn.”
As India faces a complex and uncertain climate future, Mickley’s insights highlight a deeper truth: tackling pollution is as much about understanding the present as it is about preparing for what’s to come.