Its disappearance and even growing unpredictability of arrival will devastate hundreds and millions of lives and lead to famine, migration, civil and inter-state strife
With the monsoon arriving in India, it is important to remember its critical importance to the country in terms of its impact on the economy and the lives of people. As to the first, it was as early as 1925 that the Royal Commission on Indian Agriculture described India’s economy as a gamble on the monsoon. Earlier, Viceroy Lord Curzon had said the same thing. According to the Economic Survey 2017-18, the country’s net irrigated area came to 34.5 per cent of the net sown area of 141.4 million hectares. Agricultural incomes fall when the monsoon is deficient or irregular, the latter making for unseasonal rainfall. According to the article, ‘Monsoon calling’ by Vinson Kurian in The Hindu BusinessLine in April 2015, since February this year, unseasonal rains destroyed crops in 11 million hectares spread over Rajasthan, Uttar Pradesh, Haryana, Madhya Pradesh, Maharashtra and Punjab. It can cause up to five per cent loss in this year’s wheat harvest.
A fall in agricultural incomes affects the entire national economy as the farm sector accounts for 14 per cent of it and about 50 per cent of employment in the country. A fall in the income of such a large section adversely affects its purchasing power and the demand for a wide range of manufactured products, to mention just one aspect. Unfortunately, things are likely to get worse. The Reserve Bank of India’s bulletin titled, ‘Monsoon and Indian Agriculture — Conjoined or Decoupled?’ dated May 11, 2015, observes, “Over the years, the volatility of monsoon outcomes has, in fact, increased undermining the accuracy of forecasting and contingent planning. Structural factors such as climate change and rising greenhouse emissions could be at work alongside one-off events such as El Nino.”
The monsoon is caused and impacted by a set of complex factors, including the Western disturbances emerging in the Mediterranean and travelling to the Indian sub-continent and El Nino caused by a quasi-periodic heating of the waters of the Pacific Ocean off the Peruvian coast in South America. In India’s case, the major cause is the heating of the Indian sub-continent’s landmass during summer. As the warm air above it rises upwards, cool, precipitation-laden air from the Arabian Sea in the south-west and the Bay of Bengal in the south-east moves in and takes its place.
The danger lies in the fact that the temperature difference driving this movement will decrease if, thanks to global warming, ocean waters become hotter, which is what seems to be happening in the equatorial area. This will affect the inflow of monsoon winds, though the extent will depend on the degree of the reverse temperature difference. The massive presence of aerosols — minute particles suspended in the atmosphere — makes things worse. Caused by fossil fuel combustion, smoke from the burning of post-harvest plant stubble, the working of incinerators, smelters and power plants, and increase in the presence of dust particles following droughts, deforestation and over-grazing, aerosols absorb solar radiation —some of them even deflect them outwards — reducing the quantum of it reaching the earth’s surface, making it cooler. As pointed by Sunil Amrith, a professor at Harvard, in an article titled, ‘Pollution in India Could Reshape Monsoons’ in The Atlantic (January 21, 2019), “The intensification of agricultural production in India and the use of more water for irrigation has affected the moisture of the soil, its capacity to absorb or reflect heat. Crops reflect more solar radiation than forests, which tend to absorb it; the greater reflexivity of land planted with crops makes it cooler, once again weakening the temperature differentials that drive circulation and rainfall.”
The global climate regime being more closely inter-linked than one commonly thinks, the impact of all this extends beyond India. Here, again, it is best to quote from Amrith’s article, which is an adaptation from his new book, ‘Unruly Waters: How Mountain Rivers and Monsoons Have Shaped South Asia’s History’. “All this is shifting the monsoon’s patterns. Changes in circulation over the Indian sub-continent in turn affect the tightly integrated air-sea interaction that binds the Asian continent with the Indian Ocean, a system that already contains plenty of internal variability. Because of the way the Asian monsoon is linked to other parts of the planet’s climate, it is possible that aerosols over South Asia have global consequences. When all these effects are coupled with the impact of global warming on the ocean and the atmosphere, the instabilities multiply.”
There was a time when people thought that one could neutralise the effect of a bad monsoon by building dams and creating irrigation networks. Now one knows that dams lose their capacity to hold water through silt deposition by river waters flowing into them. Besides, storage of water in them reduces the strength of a river’s current downstream, increasing silt deposition. This in turn raises the level of its bed and the carrying capacity of water, which in turn causes floods. The latter are also caused by the release of water from dams to prevent these from bursting from the pressure of water flowing into them as a result of torrential rainfall. The devastating floods in Kerala last year were caused by the release of water from 35 of the State’s 39 dams. Besides, there are dam bursts, like the one in Ratnagiri in Maharashtra on July 3, 2019, which caused at least 23 deaths and rendered a number of persons missing.
The frightening question is whether the monsoon can altogether cease to occur if the land-sea temperature difference disappears or the seas get warmer? The consequences can be seen from the fact that, as Amrith points out, more than 70 per cent of the total rainfall in South Asia occurs just between June and September every year. Besides, to quote him again, “There are many monsoon systems around the world, but the South Asian monsoon is the greatest in scale and consequence. The Indian sub-continent constitutes the core of the monsoon system because of the geological history that has left India at the edge of the Eurasian landmass, which dominates the northern hemisphere. There India sits, facing the watery expanse of the southern hemisphere.”
The monsoon’s disappearance, and even growing unpredictability in its arrival, would devastate the lives of hundreds and millions of people and lead to situations ranging from famine, migration, civil and inter-state strife. If all this happens, a major cause will be global warming.
(The writer is Consultant Editor, The Pioneer, and an author)