Kochi: An El Niño is on its way. On April 11, the India Meteorological Department (IMD) in April predicted that an El Niño is likely to develop during the southwest monsoon.
On May 3 came a warning from the United Nations’ World Meteorological Organisation (WMO): brace for the upcoming El Niño, it told the world.
This climate pattern is often associated with warmer weather or heavier rainfall across the world. Across most of South Asia, for instance, an El Niño causes a normal to below normal southwest monsoon. These changes in weather patterns that can cause droughts and floods affect crops, people and livelihoods.
The El Niño is still evolving, and will affect the upcoming monsoon in India – though by how much is not certain yet – climate scientists said. On May 5, the South Asian Climate Outlook Forum (SASCOF), a regional body which also makes monsoonal forecasts, predicted that many parts of South Asia will likely witness normal to below normal rainfall during the 2023 southwest monsoon.
An El Niño year
Fluctuating sea surface temperatures in the tropical Pacific Ocean combined with atmospheric changes result in a complex climate pattern: the El Niño Southern Oscillation (ENSO), which impacts weather patterns worldwide. The ENSO occurs in three phases. Two are almost contrasting climate phases: the El Niño and the La Niña. An El Niño occurs when the tropical Pacific Ocean warms up, and is associated with weak monsoons and reduced rainfall in many regions, including most of south Asia.
For instance, nearly half of the droughts that occur in the monsoon in India tend to be associated with an El Niño, wrote Raghu Murtugudde in The Wire Science. However, an El Niño can also cause increased rainfall in some parts of the world too, such as in southern South America, the Horn of Africa and central Asia.
The La Niña is associated with cooler ocean waters in the tropical Pacific, and results often in higher rainfall in some places such as Indonesia. The third is a neutral phase – when neither the El Niño nor the La Niña are at play.
Due to the ENSO’s impacts on weather and the associated floods and droughts, knowing details of the onset of El Niños or La Niñas can help governments, administrations and policymakers plan adaptation measures better, and in time.
That’s why, on May 3, the WMO asked the world to prepare for the onset of an El Niño this year. As per the update, the tropical Pacific is currently in an ENSO-neutral state, after being in a La Niña phase for the last three years.
There is a 60% chance for a transition from ENSO-neutral to an El Niño during May-July 2023. This will increase to about 70% in June-August and 80% between July and September, per the WMO update.
“The world should prepare for the development of El Niño, which is often associated with increased heat, drought or rainfall in different parts of the world. It might bring respite from the drought in the Horn of Africa and other La Niña-related impacts but could also trigger more extreme weather and climate events. This highlights the need for the UN Early Warnings for All initiative to keep people safe,” WMO Secretary-General Petteri Taalas said in a press release.
Earlier in April, the IMD had predicted the possibility of El Niño conditions developing during this year’s monsoon season. However, it still predicted a normal monsoon, with rainfall amounting to 96% of the long period average (LPA, or rainfall recorded over a particular region for a specific amount of time, averaged over a long period like 30 years). Anything ranging from 96-104% of the LPA is seen as a normal monsoon.
The update predicts above normal rainfall in some areas including parts of south and east India, the northeast and parts of Jammu and Kashmir. It forecasts below normal rainfall in many parts of central, western and northwestern India. State governments are being provided with customised forecasts to prepare in advance, an IMD official told Hindustan Times.
Below normal rainfall in south Asia
In most of South Asia, El Niños are associated with reduced rainfall and droughts. As per the South Asian Climate Outlook Forum’s (SASCOF) outlook for June to September issued at its 25th session in April, normal to below normal rainfall is likely during the 2023 southwest monsoon season (June-September) over most parts of South Asia.
The SASCOF is part of a worldwide network of regional climate outlook forums sponsored by WMO and its partners and aims to promote collaboration and information-sharing on climate prediction. Experts from south Asian countries and other regional and international climate centers participate in it, including representatives of all national meteorological and hydrological services in South Asia, the IMD and the Indian Institute of Tropical Meteorology (IITM).
Below normal rainfall is likely to occur over some areas in northwest, central and north-eastern parts of south Asia, as per the outlook. On the other hand, some far northern and northwestern reaches, and parts of eastern and southern South Asia will experience above normal rainfall. The outlook also shows that parts of western, northwestern and central India may face below normal rainfall, while most parts of India will experience above normal maximum temperatures.
Additionally, above normal minimum and maximum temperatures are likely over most parts of South Asia, though not over some areas such as the foothills of the Himalaya.
‘Will impact monsoon’
The El Niño is evolving now, and is forecasted to be in a mature state by June-July, though the peak will be by the end of the year, Roxy Mathew Koll, climate scientist at the Indian Institute of Tropical Meteorology told The Wire.
What can India expect as the El Niño arrives?
“So definitely there will be an impact on the monsoon this year. Just that we don’t know how much,” Koll said.
Generally the potential impacts are a delayed monsoon, which can also mean a cyclone developing close to monsoon onset, Koll said. “It can also mean weak monsoon winds that result in deficit rains across parts of the country.”
Currently, IMD forecasts show some deficit in north India, but don’t show a very strong impact as in a severe drought, he added.
Meanwhile, Union agriculture secretary Manoj Ahuja asked states to ensure that enough seeds be made available for the planting of the kharif or wet season crops, in a means to prepare for the impacts of the oncoming El Niño, reported PTI.
“We should be prepared for the worst situation. There are chances of less rains and there are chances that El Niño conditions might not occur. There should be complete preparedness at the state level,” Union Agriculture Secretary Manoj Ahuja was quoted as saying at a National Conference on Agriculture (Kharif Campaign 2023).
India’s maize, soya bean and rice production could be affected by the El Niño, the United Nations Food and Agriculture Organisation (FAO) said on May 5.