As of 17 June, the monsoon has been making its stately progress across the Indian subcontinent, and has covered nearly two-thirds of the country. According to the India Meteorological Department (IMD), the spread of the monsoon in India’s northwest will be delayed, after it had initially appeared that the monsoon would arrive in the region weeks before schedule. The monsoon set in a couple of days late in Kerala, on 3 June, but since then, compiled rainfall records show that rainfall across the country has been a good 25% above normal.
It’s still too early to say how the monsoon will play out over the next three months. However, it is now clear that India will have to start preparing for an increasingly unpredictable monsoon over the coming years and decades due to climate change. A new study published in the journal Science Advances on 4 June confirms as much. The study, Remote And Local Drivers Of Pleistocene South Asian Summer Monsoon Precipitation: A Test For Future Predictions, looks to South Asia’s past to assess its hydroclimatic future.
A new study of monsoon rainfall on the Indian subcontinent over the past million years provides vital clues about the future impacts of climate change.https://t.co/ppEbOax9L3— Brown University (@BrownUniversity) June 7, 2021
Prepared by a team of scientists led by Steven Clemens, a professor of geological sciences at Brown University in the US, the report analyses changes in the monsoon’s intensity over the past 900,000 years. It does so by studying sediment core samples drilled from the floor of the Bay of Bengal in 2014. The sediments, which have preserved a record of monsoon activity over the past million years, helped the scientists form a clear picture of changing rainfall patterns over time. The key finding is that over the past 900,000 years, whenever the CO2 levels in the atmosphere have gone up, monsoon precipitation over South Asia has become both more intense as well as more unpredictable. This supports the prediction of other studies which have stated that the Indian monsoon is entering a period of heavier and wildly unpredictable rainfall as greenhouse gas (GHG) emissions increase.
Among others, the Ministry of Earth Sciences (MoES) report from last year, Assessment Of Climate Change Over The Indian Region, stated clearly that with continued global warming, monsoon precipitation over the rest of the 21st century will become more erratic, with more instances of extreme rainfall. The overall volume of rainfall will also increase.
In fact, India is already witnessing the changes in the monsoon. Over the past few years, no monsoon season has gone by without instances of intense floods as well as abnormal dry spells. “In our analysis of rainfall data over the last 70 years, we find a three-fold rise in extreme rains along the west coast and central India. This is because the monsoon winds over the Arabian Sea are now exhibiting large fluctuations due to a warmer environment," climate scientist Roxy Mathew Koll of the India Indian Institute of Tropical Meteorology (IITM), Pune, hsaid in a statement last year.
Another report, in January this year, showed that as the northern hemisphere heats up at a higher pace due to the loss of snow and ice cover in the Arctic circle and the Himalaya, a band of tropical heavy rainfall is moving steadily north and will soon cause devastating monsoon flooding in southern India. It is clear that the monsoon as we knew it doesn’t exist any longer.