India’s monsoon has been intensifying, a new study in the Proceedings of the National Academy of Sciences of the US states, contradicting current climate models that show the rains weakening.
The report, in March, has sparked a debate among meteorologists, amid the rains’ growing unpredictability.
The June-September monsoon is critical for the country, as two-thirds of Indians rely on agriculture for livelihoods. A lingering drought has crippled Maharashtra, a major sugar and cotton producer.
Meteorology professor Bin Wang at the International Pacific Research Center, University of Hawaii, Manoa, and his team found that over the past 30 years, the summer monsoon, along with airflow patterns called the Walker circulations, had “substantially intensified”.
Current theory predicts that the Northern Hemisphere summer monsoon circulation should weaken under “anthropogenic” or greenhouse-gas-related global warming.
The study found that the monsoon was intensifying more from natural shifts, such as a rapidly cooling Pacific (9.5% increase) than due to greenhouse-gas-induced warming (2.6% per degree temperature rise).
India has begun investing in better monsoon prediction. American and Indian scientists will jointly predict this year’s monsoon.
While the US has committed $100,000 (Rs.43 lakh) annually towards the project, India’s share will be $480,000 (Rs.2.4 crore) a year over the next five years.
“These natural swings in the climate system must be understood to make realistic predictions…in the coming decades,” Wang said.