El Niño likely to bring extreme weather across world, says World Meteorological Organisation

New Delhi: The world should prepare for the development of El Niño, which is associated with severe droughts in parts of southern Asia, Indonesia, and Australia as well as extreme rain, the World Meteorological Organisation (WMO) said on Wednesday. The effect of El Niño on rising global temperatures usually plays out in the year after its development and is likely to be felt globally in 2024, WMO added.

“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,” said WMO secretary-general Petteri Taalas.

El Niño is characterised by an unusual warming of waters in the eastern equatorial Pacific, which has a high correlation with warmer summers and weaker monsoon rains in India. La Nina is the meteorological opposite.

The typical impacts of El Niño include: increased rainfall in parts of southern South America, the southern United States, the Horn of Africa and central Asia. It can also cause severe droughts over Australia, Indonesia, and parts of southern Asia. During summer in the northern hemisphere, El Niño’s warm water can fuel hurricanes in the central/eastern Pacific Ocean and it can hinder hurricane formation in the Atlantic Basin.

Taalas said El Niño 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 said the likelihood of El Niño developing this monsoon season (June to September) is increasing. It added this would have the opposite impact on weather and climate patterns in many regions of the world to the long-running La Niña and likely fuel higher global temperatures. La Niña has now ended after persisting for three years. The tropical Pacific is currently in an ENSO-neutral state (neither El Niño nor La Niña).

“There is a 60% chance for a transition from ENSO-neutral to El Niño during May-July 2023, and this will increase to about 70% in June to August and 80% between July and September,” said WMO. “At this stage, there is no indication of the strength or duration of El Niño.”

Taalas said 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. “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.”

2016 was the warmest year on record because of the double whammy of a very powerful El Niño event and global warming. “The effect on global temperatures usually plays out in the year after its development and so will likely be most apparent in 2024,” said WMO in a statement on Wednesday.

There is a 93% likelihood of at least one year until 2026 being the warmest on record, and a 50:50 chance of the global temperature temporarily reaching 1.5°C above the pre-industrial era, according to a study last year by the UK’s Met Office, which is WMO’s lead centre for annual to decadal climate predictions.

India impact

A map WMO issued on expected rainfall patterns globally during El Niño years showed most parts of north, northeast, northwest, and central India experiencing dry periods during the June to September monsoon season. It shows largely wet months during the October to December northeast monsoon season in the peninsular region.

IMD director-general M Mohapatra said WMO is referring to climatology or the study of atmospheric conditions over a longer time period. “Normally, El Nino is good for the northeast monsoon but bad for the southwest monsoon but there is no one-to-one relationship.”

He added IMD is expected to issue an update on its monsoon forecast, including the likely date of the arrival around the end of May.

IMD last month forecast a “normal” monsoon at 96% (with an error margin of +/-5%) of the long-period average (LPA). The LPA for the monsoon season between June to September is 87 cm calculated for the period of 1971 to 2020.

The monsoon season, which begins on June 1, is crucial to India’s agriculture, one of the mainstays of its economy. It brings about 70% of India’s annual rainfall. Monsoon spurs farm produce and improves rural spending. Monsoon rains are a lifeline for about 60% of the country’s net cultivated area, which has no irrigation. The monsoon impacts inflation, jobs, and industrial demand. Good farm output keeps a lid on food inflation. Ample harvests raise rural incomes and help inject demand into the economy.

HT reported on Monday that an uncharacteristically cooler start to the summer is likely to persist for a few more weeks in parts of India and may hurt the arrival of the monsoon season. The rainy season is expected to anyway be sapped by the Pacific warming phenomenon El Niño .

Indian Institute of Tropical Meteorology climate scientist Roxy Mathew Koll said pre-monsoon temperatures over Indian landmass can be one among several of the factors affecting the monsoon onset dynamics. “I will be more concerned about the teleconnections with El Niño during the monsoon season.”

Koll said an El Niño can enhance the tropospheric temperature gradient by increasing the temperatures over Eurasia and thereby weaken the monsoon winds. “Even though land surface temperatures cool with rains, the [latent] heat is released to the troposphere/atmosphere over the land. So, land surface temperatures alone do not drive the monsoon.”