Aerosols ‘shrinking’ India’s monsoon

Greenhouse gases cause concern, but scientists are more worried about particulates

July 02, 2017 10:37 pm | Updated 10:37 pm IST - New Delhi

Dust cloud impact:  The temperature over both land and sea is depressed by aersols, affecting the monsoon.

Dust cloud impact: The temperature over both land and sea is depressed by aersols, affecting the monsoon.

While greenhouse gases, or GHGs, are causing concern about the long-term fate of the Indian monsoon, researchers now think aerosols from vehicular exhaust, half-burnt crop residue, dust and chemical effluents may be weakening the life-giving rainy season even more than GHGs.

An Indian Institute of Tropical Meteorology, Pune, team led by climatologist R. Krishnan studying the likely monsoon impact of GHGs over the next century has come to this conclusion.

In 2015, Mr. Krishnan reported in the journal Climate Dynamics that a mix of GHGs, aerosols and changes in forest and agricultural cover was affecting the strength of the monsoon, which was known to be weakening over the last 50 years. This result was based on mathematical modelling and computer simulation. The relative contribution of the individual factors, however, was not clear then. “New simulations suggest that aerosols may be a far more important factor than GHGs,” said Mr. Krishnan, who spoke at a meeting of the Indian Academy of Sciences in Bengaluru last week. He said aerosols were “the major cause of weakening of the monsoon.”

New modelling

The scientist and his team used an upgraded forecasting model that was used this year by the India Meteorological Department for forecasts. The model will help prepare India’s first home-grown forecast of climate change from global warming, and be part of Intergovernmental Panel on Climate Change reports.

Dust clouds shield the earth from the sun’s rays, depressing land and sea temperatures. The monsoon, which is produced by the difference in temperature between the two, is thus weakened.

0 / 0
Sign in to unlock member-only benefits!
  • Access 10 free stories every month
  • Save stories to read later
  • Access to comment on every story
  • Sign-up/manage your newsletter subscriptions with a single click
  • Get notified by email for early access to discounts & offers on our products
Sign in

Comments

Comments have to be in English, and in full sentences. They cannot be abusive or personal. Please abide by our community guidelines for posting your comments.

We have migrated to a new commenting platform. If you are already a registered user of The Hindu and logged in, you may continue to engage with our articles. If you do not have an account please register and login to post comments. Users can access their older comments by logging into their accounts on Vuukle.