doi:10.1038/nindia.2018.22 Published online 26 February 2018
Extreme rainfall events may increase over north India while central India may become drier as a result of global warming, a new simulation study predicting future monsoon activity says1.
R. S. Ajayamohan of New York University at Abu Dhabi, and co-workers in India and the US, simulated future trends in the activity of cyclonic atmospheric vortices or storms in the Indian region. For this they used monthly sea surface temperature data and a high resolution atmospheric model and made future projections for the period between 2071 and 2095.
Cyclonic atmospheric vortices or storms, collectively known as low pressure systems (LPS), originate each summer mostly over the Bay of Bengal. They travel northwest across central India bringing more than half of the total monsoon rains over the Gangetic plains.
Based on simulations, the researchers found that LPS activity shifts from ocean to land due to global warming. Future projections show that LPS activity will decrease by about 60% over the Bay of Bengal and increase over land by 10%. The researchers say this massive weakening of LPS activity over ocean and its shift towards land will make central India drier and escalate the likelihood of "increased precipitation extremes over northern India”.
The shift may give people less time to prepare for the storms or mitigate their effects thus making a major societal impact, the report warns.
1. Sandeep, S. et al. Decline and poleward shift in Indian summer monsoon synoptic activity in a warming climate. Proc. Natl. Acad. Sci. (2018) doi: 10.1073/pnas.1709031115