New Delhi: Rainfall patterns over the Indo-Gangetic plains will undergo significant changes in the coming years due to climate change, a new study by Mahamana Centre of Excellence in Climate Change Research has warned.

The study by the centre under the department of science and technology, which projected the behaviour of rainfall patterns across the Indo-Gangetic Plains, shows that in the period spanning 2041-60, the mean monsoon rainfall recoded in June and July will reduce by around 40-70% compared with the average between 1986 and 2005.

The projections also show glaring alterations in pre- and post-monsoon rainfall trends. In the pre-monsoon season, spanning March to May, rainfall is expected to reduce by around 10-20%, the projections show. The post-monsoon season, however, is likely to increase drastically. There is expected to be an increase of around 80-170% in the October-December period by 2080-99.

The climate crisis is also likely to impact the intensity of rains, the reseachers said. For instance, moderate and rather heavy rainfall events are expected to see significant decline in the near and far future. On the other hand, the projections point towards an increase in higher rainfall category events, including very heavy and extremely heavy rainfall in both the near and far future periods.

“The mean thresholds for extremely heavy rainfall may increase by 1.9-4.9% during near future and far future. Further, the evolution patterns of various quantities, such as tropospheric temperature gradient, specific humidity, and mean sea level pressure, have been analysed to understand the physical processes associated with rainfall extremes. The strengthening in temperature gradient and enhanced atmospheric moisture content in the near future and the far future support the intensification in projected rainfall extremes over IGP,” the analysis read.

Independent experts and studies being conducted across the world in recent times have also warned of a major disruption in rainfall patterns in the Indo-Gangetic plains and other parts of India.

While the waxing and waning of monsoon rainfall is normal, climate change has doubled the variability factor of any weather event, an expert said.

“The capacity of air to hold moisture for a longer time has increased due to constant rise in land and sea temperatures. This, in turn, has influenced the intensity of monsoon rains,” said Roxy Mathew Koll, climate scientist at the Indian Institute of Tropical Meteorology in Pune. “For instance, the Arabian Sea has warmed since January, infusing more moisture over northern and northwestern India. This continuous supply of moisture fed to the weather systems leads to increased rains, which also results in extreme weather events.”