Tiny air particles and clouds are hiding some of India's warming

India is warming more slowly than many other tropical land areas, and scientists now understand why. From 2001 to 2024, the country warmed by an average of about 0.138 degrees Celsius per decade. In comparison, temperatures across northern tropical land as a whole rose about twice as fast, at roughly 0.280 degrees Celsius per decade.

The Cause

A new analysis shows that tiny particles in the air, along with increasing cloud cover, have blocked enough sunlight to hold back part of India's surface warming. Vijayakumar S. Nair of the Vikram Sarabhai Space Centre led the study, which used satellite measurements and data from ground monitoring stations. The researchers tracked aerosols, clouds, sunlight, and temperatures over a 23-year period. They found that aerosol changes reduced the warming trend by about 0.042 degrees Celsius per decade.

Changing Particles

Not all particles in the air have the same effect. While overall aerosol levels increased, especially across central India and the east coast, the actual mix of particles shifted. Black carbon and dust declined at many sites. The remaining mixture became better at scattering sunlight and less effective at absorbing it, meaning the growing number of particles did not produce as much surface cooling as expected. At the same time, low cloud cover increased across central and western parts of the country, blocking more incoming sunlight.

Future Risks

This masking effect means some of India's warming is temporarily hidden rather than absent. If that cooling influence weakens in the future as air quality improves, temperatures could respond differently.