Mint Explainer: How a strong El Nino will affect India’s monsoon and agriculture

The formation of an El Niño is likely to affect the production of major crops and even change trade routes to their markets. What does this mean for India and how will it affect the southwest monsoon, cyclone formation and agriculture? Peppermint Let’s take a look.

What are the different predictions of the Indian Meteorological Department and the Australian Bureau of Meteorology?

El Niño, which is associated with the warming of equatorial Pacific Ocean waters, often disrupts the June–September monsoon. The India Meteorological Department has said that El Nino may emerge in the monsoon season starting June, although the mean sea surface temperature (SST) over the Pacific Ocean may not exceed 1.5°C over the entire season. The increase in SST is currently at 0.9 °C. An increase of up to 1 °C is considered a weak El Niño and an increase of 1 °C to 1.5 °C is classified as moderate. The Australian Bureau of Meteorology, on the other hand, predicts El Niño will take hold, increasing SST by 3°C by October and 3.2°C by November.

What if the Australian Bureau of Meteorology’s forecast turns out to be correct?

Indian meteorologists do not see SST increasing beyond 2.5 °C. However, since El Nino is more powerful this year, there are high chances that India will get marginally less rainfall than normal. During El Nino, the monsoon winds weaken and the air sinks over the Indian mainland, preventing cloud formation and rain. If rainfall remains unevenly distributed in July, which is a crucial month for sowing of kharif crops, their yield may be affected.

Predictions of a ‘Super El Niño’ could lead to higher inflation and slowing growth with increased weather fluctuations in the form of heatwaves and unseasonal rains. Prices of key crops such as rice, wheat and pulses are already high and a failed monsoon will push up food inflation further.

How is the track record of the Australian Bureau of Meteorology?

Australia’s Meteorological Department has one of the most extreme and accurate forecasts of when an El Niño will develop. It correctly predicted the Super El Niño that peaked at 2.6°C in November and December of 2015. Another accurate prediction was in 1997, when El Niño caused the SST to rise by 2.4 °C. Latest prediction – that by November the SST will increase by more than 3 °C. If it turns out to be true, it will break all records.

How will the extremely strong El Nino rainfall during the Northeast Monsoon in October-November affect Indian agriculture?

The northeast monsoon nourishes India’s soil for rabi crops (mainly wheat, barley, gram and mustard). Climate scientists say that this winter’s rainfall cannot yet be predicted with complete confidence. However, historical data indicates that in an El Nino year, northern India usually receives higher than normal rainfall during the winter months due to higher-than-normal Western Disturbances. These Western Disturbances are low-pressure areas that originate in the Mediterranean Sea and move eastward, bringing rain to North India in winter. Other factors are at work here besides El Niño. Oceanic-atmospheric conditions over the Atlantic Ocean can also change the frequency of Western Disturbances.

How does El Nino affect the formation of cyclones?

El Nino had no role in the formation of the recent Cyclone Biperjoy. Such cyclones usually form in the Arabian Sea between April and early June. In October–December, El Nino suppresses cyclone activity in the Bay of Bengal. In El Nino years, both the frequency and intensity of cyclones in this basin are below normal. In La Nina years, post-monsoon cyclones are more frequent and more intense than usual. There is also no link between the El Niño-Southern Oscillation (ENSO) and cyclones.

UPDATE: June 25, 2023, 04:19 PM IST