An unusual monsoon

The incidence of heavy downpours is steadily spiking

This year’s monsoon will go down in history for its several unusual features. For one, though the four-month monsoon season officially ended on September 30, the withdrawal of the monsoon is nowhere in sight. The India Meteorological Department (IMD) does not foresee the retreat to begin before October 10, many days after the previous most belated departure on October 1 in 1961. This would, thus, be the longest stay of the monsoon on record. Besides, rain this year is the highest in 25 years, with 10 per cent excess received till the end of September. Also, this is the first time since 1931 that the monsoon has rebounded after a poor start in such a manner as to wipe out the 33 per cent deficit in June and move ahead to end up in the above-normal category. This is largely due to the unusually heavy showers in the second half (August-September) of the season. Precipitation in September alone was 52 per cent above average, making it the wettest September in 102 years. 

This apart, the rainfall pattern has corroborated the notion that the determinants of normalcy about the monsoon’s onset and withdrawal, rainfall during the initial part of the season, and the frequency of extreme weather events are changing and need to be revised. The present “normal levels” were fixed in 1941 and are no longer valid, thanks, perhaps, to climate change. The monsoon now tends to turn up and depart later than their scheduled dates. Also, the monsoon now remains rather sluggish in the early part of the season. In seven of the past 11 years, rain in the first monsoon month of June has been below par. The incidence of very heavy downpours is also steadily spiking. Moreover, north-eastern India seems no longer to be a high-rainfall zone. After two decades (during the 1990s and 2000s) of good monsoons, the region has once again witnessed low rain. These variations in climate have major implications for agriculture, necessitating adjustments in the crop calendar and agronomic operations. Other water management practices, too, need to change.

The remarkable run of the monsoon is attributable largely to weakening of its nemesis El Nino (warming of the Pacific Ocean) and the simultaneous favourable turn in the Indian Ocean Dipole (temperature oscillations in the Indian Ocean) in July. Interestingly, the IMD managed to foresee the likely disposition of El Nino more accurately than most other global and domestic weather watchers, which felt it would continue to depress the monsoon. The IMD, therefore, managed to accurately capture the trend of rain though its estimates about the amount of precipitation proved to be off the mark. 

Importantly, the oddities of the present monsoon are not expected to affect the economy negatively. Crop output is anticipated to be normal in the current kharif season and better than that in the ensuing rabi, thanks to adequate residual soil moisture due to the late rains. The water stock in the country’s 113 reservoirs is 15 per cent more than that of last year and 21 per cent above the past 10 years’ average. Most dams had to open the floodgates to release surplus water. This bodes well for irrigation, hydel power production, and other water-based industrial activities. All this should help support economic activity.