Recently, the world has experienced a rare three consecutive La Nina event since 2020 and it has been predicted that the coming El Nino can have consequences across the globe, including India.
So, let us see its possible implications.
The upcoming El Nino:
The change in sea surface temperature associated with El Nino Southern Oscillation (ENSO) might seem marginal but is enough to disrupt weather patterns globally.
It can affect even the large-scale circulation of air in the polar stratosphere i.e. 8km above the Earth.
The US National Oceanic and Atmospheric Administration (NOAA) has reported that the equatorial Pacific Ocean will return to its neutral state between March and May of 2023, and it is likely that El Niño conditions will develop during the northern hemisphere’s autumn and winter.
How El Nino Southern Oscillation (ENSO) Operates?
The combined phases of La Nina and El Nino are termed El Nino-Southern Oscillation (ENSO).
The phenomenon affects rainfall patterns, global atmospheric circulation, and atmospheric pressure across the planet.
In the neutral state, (neither El Niño nor La Niña) trade winds blow east to west across the surface of the tropical Pacific Ocean, bringing warm moist air and warmer surface waters towards the western Pacific and keeping the central Pacific Ocean relatively cool.
Likely to exceed 5°C above the target of the Paris agreement:
During the process of ENSO, the rise and cooling process of seawater is simultaneous, however, the rise for a prolonged period can make significant changes in the upper atmosphere.
El Niño adds some extra heat to the atmosphere and is estimated can exceed to the 1.5°C threshold of the Paris agreement.
On the Australian coast:
During El Niño, scientists expect less rain, higher temperatures and increased fire risk, especially during winter and spring in the southern hemisphere.
As the globe heats up, some regions are warming faster than others. Australia can become 1.4°C hotter now than in the early 20th century.
In South America:
South American weather is significantly disrupted every time an El Niño event occurs;
flooding on the west coasts of Peru and Ecuador and
Drought in the Amazon and northeast, where the consequences of crop failures can reverberate across the continent.
Disease outbreak: During El Niño events, due to fall in precipitation and rise in temperature in Colombia, is linked to outbreaks of diseases spread by insects, such as malaria and dengue fever.
Higher temperatures during El Niño boost the rates at which mosquitoes breed and bite.
Less carbon intake: Later on, the Amazon rainforest dries and vegetation growth slows so that less CO? is absorbed from the atmosphere, a trend repeated in the tropical forests of Africa, India and Australia.
In Northern Europe:
The balance between high pressure over the Azores and low pressure over Iceland determines where the rain goes in Europe during winter by pushing the jet stream.
During El Niño winters, both pressure centres lose strength, and the jet stream brings wetter conditions to southern Europe.