El Nino threat underlines need for preparedness

Harender Raj Gautam

WEATHER forecasts point to a transition to an El Niño state in the second half of this year. The Food and Agriculture Organisation (FAO) has reported that drier conditions will generally be observed in West Africa, Southern Africa, India, South-East Asia, Australia, northern areas of South America and Central America in the El Nino period. The World Bank had estimated that the 1997-98 El Nino cost governments $45 billion. However, in a recent study published in the journal Science, scientists have claimed that the average El Nino costs the global economy about $3.4 trillion and the strong one in 1997-98 caused losses to the tune of $5.7 trillion.

El Niño is a climate pattern that describes the unusual warming of surface waters in the eastern tropical Pacific Ocean. El Niño is the ‘warm phase’ of a larger phenomenon called the El Niño-Southern Oscillation (ENSO). La Niña, the ‘cool phase’ of ENSO, is a pattern that describes the unusual cooling of the region’s surface waters. The World Meteorological Organisation has stated that the probability of El Niño developing this year has increased from 15 per cent in April-June to 35 per cent in May-July, reaching a significantly higher likelihood of around 55 per cent during June-August. Meanwhile, the India Meteorological Department (IMD), in its ENSO bulletin, has foreseen a sharp rise in the probability of El Nino developing during the southwest monsoon.

The El Nino climatic pattern has been affecting rainfall trends in India. Severe droughts have been accompanied by El Niño events. The last major El Nino event was in 2015, when monsoon rainfall in India was 13 per cent lower. However, the IMD has forecast that the monsoon rainfall is likely to be 96 per cent of the Long Period Average (LPA) with a model error of ± 5 per cent.

Warming and droughts are the major consequences of El Nino and it has been reported that a 1°C rise in mean temperature would reduce yields of wheat, soybean, mustard, groundnut and potato by 3-7 per cent. El Niño reduced the global mean crop yield of wheat, rice and maize by 1.32 per cent, 1.33 per cent and 0.37 per cent, respectively, but increased it for soybean by 1.9 per cent. India’s experience with El Nino has been associated with poor rainfall and droughts. An analysis of India-specific episodes of El Nino years since 1956 reveals that foodgrain production declined in 57 per cent of those episodes. Twelve El Nino episodes in 38 years had led to a 9.7 per cent drop in normal rainfall and a 5.7 per cent fall in kharif foodgrain production. This affects the entire agriculture sector, impacting the overall GDP growth of the country.

El Nino affects crops due to heat and drought stress. At the cellular level, as stress becomes severe, there is a loss of membrane integrity, cell membrane leakage and protein breakdown, and finally, if stress is very severe, there can be plant starvation and collapse. In 2022, a heatwave coincided with the grain-filling and development stage of wheat, leading to yellowing and shrivelling of the grain, forced maturity; this resulted in reduction of yield up to 15-25 per cent. In the case of vegetables, a significant impact was observed, especially in tomato and cucurbits. Higher body temperature and loss of appetite were observed in milch animals, causing a reduction in milk yield up to 15 per cent. The extreme temperatures resulted in a drop in egg production and increased broiler mortality. The Finance Ministry has also raised concerns over the possible impact of El Niño conditions on India and cautioned that if monsoon rain is deficient, it could lead to lower agricultural output and higher prices. CARE Ratings, in ‘El Nino & Its Impact on Indian Economy’, has noted that based on the data for the past 50 years, it can be said that on an average, an episode of a strong or moderate El Nino has led to deficient rainfall or drought-like situations in India which not only affected agricultural production adversely but also corresponded to lower GDP growth. However, the Ministry of Agriculture and Farmers’ Welfare has projected a record wheat production of 112.7 million tonnes (MT) in the current crop season.

As there is an imminent threat of El Nino, climate mitigation and reduction in vulnerability can help in reducing the risk. The National Innovation on Climate-Resilient Agriculture (NICRA), launched in 2011, is a major initiative of the Central Government; climate-resilient technologies are being demonstrated in 151 risk-prone districts of the country and promising technologies are being identified for each district. These technologies minimised the impact of the heatwave of 2022 and could achieve yields to the extent of 95-97 per cent of the normal in the case of wheat.

The Indian Agricultural Research Institute has developed three heat-resistant varieties (HDCSW-18, HD-3410, HD-3385) by incorporating genes that are responsible for the mild vernalisation requirement preventing premature flowering. PBW 766 (Sunehri) of Punjab Agricultural University has also been evaluated to have a higher yield with minimum reduction under heat stress. For rice, the International Rice Research Institute has developed drought-tolerant varieties such as Sahbhagi Dhan in India, Sahod Ulan in the Philippines and Sookha Dhan in Nepal. The average yield advantage of drought-tolerant varieties over drought-susceptible ones is 0.8-1.2 tonne per hectare. Assessment efforts require sustained international cooperation on monitoring and research so that we are well prepared with contingency plans through climate-resilient technologies to mitigate the adverse impact on agricultural production.

What is El Nino?

El Nino is a weather phenomenon that occurs when ocean temperatures in the central and eastern Pacific Ocean rise above normal. The warming causes changes in atmospheric patterns, leading to a weakening of the monsoon circulation over the Indian subcontinent. As a result, the Indian monsoon tends to be weaker and less reliable during El Nino years.

Why is it a concern for monsoon rain

The Met office has forecast normal monsoon rainfall this year. However, the likelihood of an El Nino weather pattern developing during the June-September monsoon season raises the possibility of less-than-normal rain. In the past, India has experienced below-average rainfall during most El Nino years, sometimes leading to severe drought that destroyed crops and forced the authorities to limit the export of some foodgrains.

Monsoon and agriculture

• The monsoon provides about 70% of the annual rain in India and impacts key crops such as rice, wheat, sugarcane, soybean and peanuts. Agriculture contributes about 19% to India’s $3-trillion economy and employs more than half of the population.
• Increased agricultural production could ease export restrictions on sugar, wheat and rice. Conversely, drought necessitates importing food and maintaining export restrictions. In 2009, poor rains forced India to import sugar, driving global prices to record highs. Reuters

The author is retired professor and HoD, Plant Pathology, Dr YS Parmar University of Horticulture and Forestry, Nauni, Solan (HP)

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