Climate change is here and happening - Maharashtra experience shows

Incidents of extreme weather are steadily on the rise.

 Climate change is here and happening - Maharashtra experience shows

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• The story: The July 2021 floods in Maharashtra were set to worsen as the IMD predicted very heavy and extremely heavy rains in six districts. Many have been killed due to landslides and other flood-related incidents, as the southwest monsoon was extremely active after a long break that ended July 13, 2021.
• Why this: The rainfall was caused by an off-shore region of extended low pressure known as a ‘trough’. This runs from the Gujarat coast to the Kerala coast and mainly induces rainfall along the western Indian coast. The India Meteorological Department (IMD) predicted that it may remain active for some more days.

1. It is subsidiary to the main monsoon trough which lies across the north Indian plains, with its western end in Rajasthan and the eastern end dipping into the north Bay of Bengal.
2. The ongoing floods may worsen as the IMD predicted very heavy and extremely heavy rains in six districts — Raigad, Ratnagiri, Sindhudurg, Pune, Satara and Kolhapur — for Saturday, July 24. The rains may get subdued by July 25.
3. One of the districts, Ratnagiri, broke a 40-year-old record for most rainfall in July. The district received 1,781 millimetres of rainfall between July 1 and July 22, while the average July rainfall is 972.5 mm.
4. The hill station of Mahabaleshwar in Satara district received 1,075 mm of combined rainfall July 22 and July 23. Kolhapur district received 232.8 mm rainfall July 23, which is almost 10 times the normal rainfall for the day. On the same day, Satara district also received seven times its normal rainfall.
5. The worst of these floods were in Mumbai as the city and its suburban areas received 180.4 mm and 234.9 mm rainfall respectively July 18, six and seven times the normal rainfall for the day for the two regions respectively.

• Extremes are up: A research paper published in the journal Nature in 2017 showed that the number of extreme rainfall events in central India have tripled between 1950 and 2015, while there is an overall weakening of the monsoon circulation.

1. West Bengal received the highest number of lightning strikes per square kilometer in 2020, followed by Jharkhand, according to South Asia lightning Report, 2020 by Earth Networks. (the company’s extensive network constantly monitors lightning strikes through thousands of sensors)
2. West Bengal, along with Bangladesh, received two million lightning bolts on ground — above 8 lightning strikes per square kilometer on average during 2020. Overall, 57 million lightning strikes were recorded in India, Bangladesh and Sri Lanka together. Around one-fourth of them were cloud-to-ground strikes and the rest were intra-cloud.
3. India received about 39.6 million intra-cloud and cloud-to-ground lightning strikes in 2020, a whopping 70 per cent of the total number in the region.
4. The country received nearly 89 per cent of all the lethal cloud-to-ground strikes in the world.
5. Only 4 per cent of Sri Lanka’s 14.5 million lightning pulses were ground strikes, a very unusual data according to experts.

• Link with climate change: Climate change, particularly warming, is contributing considerably to the rise of lightning strikes, as it enhances both heat and moisture, the key components required for lightning. All these heat waves cater to more thunderstorms, which, in turn trigger more lightning strikes. Bengal delta has been traditionally affected by the lightning strikes mainly during kalbaishakhi  winds (norwesters). But the number has increased in recent years.

1. The Bengal delta, encompassing the Indian state of West Bengal and Bangladesh, is one of the most vulnerable regions for climatic impacts, with high sea-surface water temperatures and cyclones, and lightning is just a corollary.
2. A study had projected that an increase in average global temperatures by 1ºC would increase the frequency of lightning by 12 per cent,

• Summary: Clearly, the global warming impact have started hitting home now.

 

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