Research has found that stronger monsoon winds have contributed to a “surprising” 40% increase in summer monsoon rainfall over Northwest India – a typically semi-arid region – in the last decade, compared to the 1980s.
Dry regions becoming wetter
“The 40% increase came as a surprise to us, as it contradicts the widely accepted narrative that global warming is leading to dry regions becoming drier and wet regions becoming wetter. Here, we have the opposite,” says Ligin Joseph , postgraduate researcher in ocean and Earth science. Ligin is also the lead author of the research paper highlighting the findings.
The Indian Meteorological Department recorded above-normal rainfall in Northwest India, including the states of Delhi, Gujarat and Rajasthan, during the latest monsoon season.
Strong monsoon winds
The research team, which included collaborators at the National Oceanography Centre and IIT Bhubaneswar, has linked this unexpected phenomenon to stronger monsoon winds causing more evaporation over the Indian Ocean.
This has led in turn to an increase in moisture being carried from the Arabian Sea, in the northern Indian Ocean, to Northwest India – a typically semi-arid region.
Our study attributes the strengthening of the monsoon winds to the rapid warming of the Indian Ocean and the enhanced Pacific Ocean trade winds – both of which are heavily fed by climate change and global warming.
Ligin Joseph, PhD Ocean and Climate Physics
The study’s findings may impact future rainfall predictions in India. The Clausius-Clapeyron relation states that the water-holding capacity of the air increases by 7% per degree of global warming.
“Our findings suggest that future changes in India’s precipitation patterns will largely hinge on shifts in monsoon atmospheric circulation,” concludes Ligin.
