During the last four years, the southwest monsoon has been bountiful with normal and above normal rainfall from June to September. The big question is whether the country will be lucky the fifth time this year? Although this highly complex, dynamic system arrives with unfailing regularity, there are many factors responsible for its behaviour. One is the El Nino factor associated with the warming of sea-surface waters in the central and eastern tropical Pacific Ocean, which tends to weaken the southwest monsoon over India. The cooling of such waters is referred to as the La Nina factor, which results in a marked increase in rainfall. One reason India had a good run of southwest monsoons is the “triple dip” La Nina which extended over three consecutive winters. The cause for concern now is that the US weather agency, National Oceanic and Atmospheric Administration, has forecast that El Nino could return as early as June when the southwest monsoon hits the coast of Kerala.
As if on cue, the Union finance ministry issued a statement that the predictions of a return of El Nino could presage a weaker monsoon, resulting in lower agricultural output and higher prices. There is definitely a link between monsoon rainfall and agricultural output. During the last nine years, there were five years of normal and above normal rains (2016, 2019, 2020, 2021 and 2022) when India’s agricultural sector grew at an average annual rate of 4.6%. But when the rains were deficient or below normal (2014, 2015, 2017 and 2018) annual agricultural growth averaged only 2.4%.
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However, the El Nino factor could be at the “neutral level” during the next three months and its real impact on the southwest monsoon can be assessed by April, Mrutyunjay Mohapatra, director general of the India Meteorological Department, told FE. Discounting fears that the weather phenomenon could weaken the forthcoming monsoon and impact agricultural output, he stated that there were other factors that affect rains like the Indian Ocean Dipole and Eurasian snow cover. While positive Indian Ocean Dipole conditions are good for rainfall, negative conditions—due to cooler sea surface temperatures in the western Indian Ocean relative to the warmer sea surface temperatures in the eastern Indian Ocean—have the effect of suppressing monsoon bursts over the Indian subcontinent.Eurasian snow cover, the ninth-lowest reported in the last 67 years, has an inverse relationship with the monsoon, added IMD’s DG.
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While El Nino undeniably had an impact on deficient rainfall during 2014 and 2015, its impact is less clear on other episodes of below normal rainfall in the country. During 2017, warm neutral conditions prevailed during the first half of the monsoon season while cooler conditions characterised the second half, which led the IMD, in its end season report, to infer the absence of El Nino’s influence. Similarly, in 2018, the IMD stated that the direct impact of the evolving El Nino on the performance of the monsoon as a whole was limited. Greater clarity on El Nino will, of course, become available when the IMD makes its first long-term forecast for the monsoon by April. As the rains have a crucial bearing on India’s agricultural output, the IMD must beef up its capabilities in location-specific forecasting so that suitable adaptive measures can be taken by farmers during the forthcoming kharif season.