Monsoon jitters: On rain deficit and droughts

Episodes of drought in India happen when the monsoon fails in July and August 

June 20, 2022 12:10 am | Updated 01:19 am IST

The monsoon landed early in Kerala, three days ahead of the normal date of June 1. The journey upward of its western branch has since then been timely but lacking in vigour. The latest IMD figures suggest that the monsoon is running an 8% deficit. Central India, which has the largest swathe of land dependent on rainfed agriculture, has only got 52% of the rain that is due; the southern peninsula has a 22% deficit. Only India’s east and north-eastern parts are battling the diametrically opposite problem of too much rain, with floods in Assam and Meghalaya submerging entire villages. The northwest of India, where the monsoon is yet to arrive, and reeling under a series of heatwaves, is battling a rainfall deficit of 33%. The monsoon rainfall is critical to kharif sowing and so a faltering June has raised concerns in several quarters. However, there is little to be worried about at this juncture. June rainfall, particularly in the first fortnight, is historically patchy and contributes less than 18% of the monsoon rainfall. Meteorologists maintain that there is no correlation of the timing and advent of the monsoon rainfall with its eventual performance. Because of the large variance inherent in June rainfall, the IMD has historically chosen not to issue forecasts for the month, unlike for July and August. The latter two are considered the key monsoon months and responsible for supplying nearly two-thirds of the monsoon rains. Episodes of drought in India and those that are linked to agricultural failures are when the monsoon fails in these two months.

In fact, the real worry that lingers over the horizon is rainfall in July and August. On May 31, as part of its updated forecast, the IMD gave an optimistic picture. The June to September rainfall over the country was likely to be 103% of the Long Period Average, and central India was likely to get “above normal” rainfall as was the southern peninsula. The monsoon core zone, which consists of most of the rainfed agriculture regions, too is expected to receive “above normal” rain. In previous years, there has been a pattern of ‘normal’ and ‘above normal’ rains being forecast only for them to dry up for large periods in July and August, followed by a sudden surge in September. This pattern may help deliver the numbers but is not always beneficial for kharif sowing. The expectations of a good monsoon are premised on the persistence of a La Niña, the converse of the El Niño and characterised by a cooling of the Central Pacific waters. However, the Indian Ocean Dipole (IOD), another index of significance to the monsoon, is expected to be negative. Whether the La Niña can compensate for the dampening of the IOD remains to be seen.

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