La Niña

La Niña and El Niño are opposite phases of what is known as the El Niño-Southern Oscillation (ENSO) cycle. The ENSO cycle is a scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the east-central Equatorial Pacific.

La Niña is essentially the strengthening of the normal conditions while El Niño is weakening of the normal trade winds (or even reverse). La Niña is sometimes referred to as the cold phase of ENSO and El Niño as the warm phase of ENSO. These deviations from normal surface temperatures can have large-scale impacts not only on ocean processes, but also on global weather and climate.  They have the ability to trigger extreme weather events like droughts, floods, hot and cold conditions, globally.

During La Niña, below-average air pressure covers Indonesia and the western tropical Pacific and above-average air pressure covers the eastern tropical Pacific (the region between Peru and Papua New Guinea). In these conditions the central and eastern equatorial Pacific waters are substantially cooler than usual, which causes the thermocline to tilt further, causing warm water to pool against South-East Asia and Australia. The rain follows the location of the warm water, so South-East Asia and Australia experiences above average rainfall, while South America experiences below average rainfall.

Currently, Numerical models suggest that the La Niña has reached its peak at a moderate level and is likely to taper soon to turn neutral by Mar-May of 2021. Occurring after a gap of nine years, La Niña this year is expected to be a moderate one, which means the impact on crops would be modest.

La Niña & Agriculture

The timing of a La Niña onset is key to determine how its consequences will impact on agriculture. The La Niña weather system could roil global food production, sending prices higher, as potential droughts and floods bring upheaval to a suite of key agricultural commodities from Southeast Asia to South America.

The highly anticipated phenomenon has officially formed, after the last significant La Niña event occurred in 2011. During that period, upheaval in commodity production led to steep increase in world food prices, with the United Nations’ Food & Agriculture World Food Price Index surging to a record in February 2011, up 37% from the end of 2009.

The weather phenomenon is already creating an impact on the production of crops such as wheat, corn, soybean, coffee, sugarcane, palm oil with concomitant effect on prices.

International Grains Council’s (IGC) commodity price indices in November shows that agricultural prices have shot up between 8 and 30 percent in the last three months including wheat index (up 9 percent), maize index(up 29 per cent) and soybean (up 17 per cent), the Grains and Oilseeds Index (GOI) surged 13 percent surged during the reported period. Sorghum, barley and sugar have also moved up.

Currently, the dry outlook over the near term for Argentina remains the key bullish factor for International Corn, Soybean and Wheat market. Palm oil also gets benefit from lower output of rival soy oil.

La-Niña & India: Winter to be colder than normal

La Niña conditions usually bring colder than normal winters in India. Winter may be relatively harsher and longer in North & North-West India. The winter months of January and February will see the impact of La Niña conditions over North India as a couple of western disturbances are likely to bring widespread snowfall to the western Himalayan region.

While La Niña conditions enhance the rainfall associated with the Southwest monsoon, it has a negative impact on rainfall associated with the Northeast monsoon, which is confined to the Southern peninsula. This year the phenomenon has a partial verdict for southern states. Northeast Monsoon is going to conclude shortly on a positive note.

The diurnal temperature variation (difference between day and night temperatures) could create erratic winter conditions impacting agricultural practises during the Rabi season in most subdivisions of north, northwest, central and a few subdivisions of east India.