Scientists and meteorologists have termed this spell as unusual and rare and linked it with climate change.
Credit: Special arrangement
Extended heavy monsoon showers in Mumbai and Kolkata are due to global warming, according to climate experts and meteorologists.
Climate scientist Dr. Raghu Murtugudde, Emeritus Professor at the University of Maryland & retired Professor at IIT-Mumbai, stated that the global rise in ocean temperatures has been influencing weather patterns in India.
“Multiple typhoons are brewing in the Pacific Ocean, which is also witnessing warming due to climate change. Since these systems are huge and strong, their moisture demand is also high. These systems try to pull moisture from the North Indian Ocean, affecting the monsoon circulations. Under this external influence, weather systems have also formed in the Bay of Bengal. The low-pressure system that affected Kolkata was the result of this. With more systems expected in the Bay of Bengal, the withdrawal process of monsoon will get stalled for a bit. Places like Mumbai and Kolkata are likely to witness extended monsoon showers,” said Dr Murtugudde.
According to him, these erratic and unusual rainfall spells are directly linked to the abnormal warming of the oceans due to climate change.
“The seasonal cycle of surface temperatures is projected to shift, which would have implications for extreme weather events over the Indo-Pacific region. While the maximum basin-average temperatures in the Indian Ocean during 1980–2020 remained below 28°C (26°C–28°C) throughout the year, the minimum temperatures by the end of the 21st century will be above 28°C (28.5°C–30.7°C) year around, under a high emission scenario,” said Roxy Mathew Koll, Climate Scientist, the Indian Institute of Tropical Meteorology (IITM), Pune.
According to him, sea surface temperatures above 28°C are generally conducive to deep convection and cyclogenesis. Heavy rainfall events and extremely severe cyclones have already increased since the 1950s and are projected to increase further with increasing ocean temperatures.
“The recent spell of extremely heavy rainfall is quite rare. There was a low-pressure area persisting over Odisha and adjoining areas, which led to the formation of intense convective clouds over Kolkata. Due to the continuous moisture incursion from the Bay of Bengal, the clouds kept getting energy for a long period, making it more intense. The cloud build-up was static, resulting in extremely heavy rainfall in a shorter period.
The Bay of Bengal has been witnessing immense warming on account of rising temperatures, leading to more evaporation. In such a situation, a low-pressure area attracts more moisture from the oceans, making the weather activity more intense. While this is unusual, we need to be ready for more such situations in the coming times due to global warming,” said Mahesh Palawat, Vice President- Meteorology and Climate Change, Skymet Weather.