El Nino set to return with hotter summer

New Delhi: Planet-warming threshold of 1.5 degrees Celsius (1.5°C) is feared to be breached this year, triggering a cascading impact on India's weather patterns, including the monsoon. Rain patterns in India are also expected to get altered with the return of El Niño this year.

Climate scientists and meteorological agencies the world over say that El Niño will exacerbate climate change-related impact and cause the planet's temperature to briefly cross the 1.5°C warming threshold.

With El Niño set to return this year, an already warming Earth and ocean surface due to global climate changes could see unprecedented and extreme weather events. As the Pacific heats up, the Indo-Pacific region could see stark weather, ranging from heatwaves and floods to droughts.

Indian meteorologists are of the view that the actual impact of El Niño on the rainy season is too far away to predict. "There are only some models predicting an El Niño during the approaching monsoon season. It is too early to hazard a guess because the long duration forecast of the El Niño is less accurate," according to Mrutyunjay Mohapatra of India Meteorological Department (IMD).

Several global models are predicting El Niño to appear around the second half of the year, which are the crucial rain-bearing months.

El Niño occurs when the surface water in the Equatorial Pacific becomes warmer than average and the east winds blow weaker than normal. The weather pattern generally occurs every three to five years.

El Niño is part of a much bigger global weather variation known as the El Niño-Southern Oscillation (ENSO), which refers to changes in sea level air pressure patterns in the Southern Pacific Ocean.

ENSO's 'neutral' conditions eventually developing into El Niño are still in the realm of possibility. "But traditionally, El Niño has not been good for Indian monsoons. Just how severe El Niño will be and whether it will happen will get clearer by March," said the IMD chief.

Data shows that El Niño has had an overbearing impact on Indian rainfall and 80 per cent of the El Niño years have seen below-normal rains in the country, while others have also been outright drought years.

The southwest monsoon, which starts in June and ends in September, is the lifeline for Indian farmers and a key determinant in the broader economy as it provides over 70 per cent of the annual rain that the country gets.

"During El Niño, a lot of accumulated heat gets released, from which we get what we call a 'mini global warming'. At a global level, we are not sure, but locally we might see a temperature increase by 1.5°C," said Raghu Murtugudde, an Earth system scientist.

The latest report by Australia's Commonwealth Scientific and Industrial Research Organisation said the influence of climate change on El Niño and La Niña events, in the form of ocean surface temperature changes in the eastern Pacific, will be detectable by 2030. This is four decades earlier than previously thought.

"What climate change does is roll the dice. Events that will happen every 50 years will start happening every 20 years and so on.

Terra flood, for instance, was a once-in-100-year event but happened two/three times after that. The event return period has started to get shorter. We must watch out for what global warming is already doing and how El Niño will bump it up," said Murtugudde.