Explained: What is El Niño and would it affect India?

WMO warned that the likelihood of El Niño developing later this year was increasing

El Nino Representational image

On Thursday, the Climate Prediction Center of the US National Weather Service updated the ENSO Alert System Status and issued an 'El Niño' Advisory.  

The National Oceanic and Atmospheric Administration said there is a 56 per cent chance that when El Nino peaks in strength-- normally during the Northern Hemisphere winter--it will be a strong event, meaning that Eastern Pacific sea surface temperatures are at least 1.5 degrees Celsius higher than normal.

The World Meteorological Organization in a recent statement warned that the likelihood of El Niño developing later this year was increasing. "There is a 60 per cent chance for a transition from ENSO-neutral to El Niño during May-July 2023, and this will increase to about 70 per cent in June-August and 80 per cent between July and September,” according to an update which is based on input from WMO Global Producing Centres of Long-Range Forecasts and expert assessment.

WMO Secretary-General Prof Petteri Taalas stated, “We just had the eight warmest years on record, even though we had a cooling La Niña for the past three years and this acted as a temporary brake on global temperature increase. The development of an El Niño will most likely lead to a new spike in global heating and increase the chance of breaking temperature records.” 

What is El Niño? 

According to the National Oceanic and Atmospheric Administration (NOAA) El Niño refers to the above-average sea-surface temperatures that periodically develop across the east-central equatorial Pacific. It represents the warm phase of the El Niño Southern Oscillation (ENSO) cycle. 

El Niño has historically been the cause of a lot of droughts, floods and storms. It last occurred in 2018-2019, and happens irregularly with intervals of about two to seven years.

Each country has a different threshold to decide on what constitutes an El Niño. Environmental journalist Gloria Dickie wrote in Reuters, “National Oceanic and Atmospheric Administration calls an El Nino when ocean temperatures in the eastern and central equatorial Pacific, have been 0.5 degrees Celsius (0.9 Fahrenheit) higher than normal for the preceding month, and has lasted or is expected to continue for another five consecutive, overlapping three-month periods. The agency also looks at a weakening of the trade winds and cloud cover.”

South American fishermen were the first ones to notice the unusually warm waters in the Pacific Ocean in the 1600s. The name El Niño was first used by Spanish immigrants and it means "The Christ Child/ The Little Boy". It is a reference to Jesus Christ as El Niño usually happens during Christmas time.

The ENSO's discovery is attributed to two scientists. Sir Gilbert Walker discovered that the atmospheric pressure fluctuated over the tropical Indo-Pacific region, which he termed as 'Southern Oscillation'. In his papers published during the 1920s and ’30s, Walker gave statistical evidence for widespread climatic anomalies around the globe being associated with the Southern Oscillation pressure “see-saw.” Despite these discoveries, no physical connection was made between the El Niño and the Southern Oscillation till Jacob Bejerknes in the 1960s formulated the first conceptual model of the large-scale ocean-atmosphere interactions that occur during the El Niño episodes.

What happens during El Niño?

El Niño disrupts the usual supply of moisture and causes incessant rains and floods in some places and severe droughts in others. As the warm waters move eastward, across the entire Pacific due to weakened trade winds and gravity, it affects rainfall patterns in the west. 

Countries like Ethiopia, Guatemala, Somalia, Indonesia etc have been the worst hit by droughts, floods, storms and fires during these extreme weather changes. Governments all around the world are gearing up to deal with El Niño in the next few months by setting aside funds and forming disaster management bodies.

Some examples of the devastating impact of the El Niño in the Indian subcontinent are the droughts of 1877 and 2015. In 1877, the country saw miserable monsoons and failing rains. With droughts and deaths from starvation getting hold of the country from all sides, over 5 million Indians died in that famine. In 2015, coupled with agricultural loss, around 2,500 people died due to heat strokes. 

According to reports, between 2001 and 2020, India saw seven El Nino years. Of these, four resulted in droughts (2003, 2005, 2009-10, 2015-16). These years also saw kharif or summer-sown farm output decline by 16%, 8%, 10% and 3%, stoking inflation. Kharif harvests account for nearly half of the country’s annual food supply.

Raghu Murtugudde in The Wire Science wrote that nearly half of all the droughts that occur in India tend to be associated with an El Niño. 

El Niño impact on India 

The India Meteorological Department (IMD) delivered its first long-range forecast on April 11 during a press meet for this year’s monsoon. The IMD stated that there would be "about 60 pc chance for the onset of El Nino during May-July, rising to 70-80 pc during July- September period."

This year, El Niño is predicted to hit after a triple dip La Niña event. A triple dip La Niña, which is the opposite of an El Niño as it is characterised by cooler currents, is a rare rather unpredictable weather pattern where warmer waters get pushed towards Australia and Asia. 

The IMD has predicted that the effects of the El Niño will only be noticeable in the second half of the year. India is predicted to have lower-than-normal rains which will affect the agricultural sector. The rising atmospheric temperatures have also been a cause of concern with looming fears of heat strokes.

An IMD official told The Hindustan Times that state governments were being provided with customised forecasts to prepare in advance. The IMD will also be providing agro-meteorological advisory services and forecast for each of India’s 700-odd districts based on different rainfall scenarios, Krishi Vigyan Kendras, a network of federally-run farm centres.


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