Super El Nino is building up that could ruin monsoon. But, it has failed before

India's southwest monsoon, which delivers nearly 70% of the country's annual rainfall between June and September, is the backbone of its agriculture and water supply. And El Nino, historically, has been its enemy.

In Short

• El Nino often weakens India’s monsoon, causing droughts
• 60% of El Nino years since 1951 had below-average rainfall
• Not all El Ninos cause drought; location of warming matters

Every year as June approaches, farmers, policymakers, and weather forecasters across India watch one thing closely; whether El Nino is brewing in the Pacific Ocean.

And the reason to do so is simple.

India's southwest monsoon, which delivers nearly 70% of the country's annual rainfall between June and September, is the backbone of its agriculture and water supply. And El Nino, historically, has been its enemy.

El Nino is a natural climate event where a large stretch of water in the central and eastern Pacific Ocean warms up abnormally. This warming disrupts wind patterns across the globe, and for India, it typically weakens the monsoon winds that carry moisture-laden clouds over the subcontinent, causing droughts in a number of regions.

Historical data backs this up.

Between 1951 and 2022, about 60% of El Nino years saw below-average rainfall in India. Every major drought on record has been linked to an El Nino event.

So when forecasters spot one developing, the alarm bells ring. But there's a twist when it comes to the worrying phenomenon.

El Nino, it turns out, doesn't always deliver on its threat.

This article originally appeared in Hindi and you can read it here.

THE TIMES EL NINO FAILED

Of the 17 major El Nino events recorded over the last seven decades, at least five produced normal or above-average rainfall in India, defying every forecast.

The most apt example came in 1997–98, when one of the most powerful El Nino of the 20th century formed over the Pacific.

Scientists around the world braced for catastrophic drought in India. Instead, India received above-average monsoon rains that year and no major drought followed.

Similar surprises unfolded in 1983 and 1994, when strong El Nino conditions coincided with rainfall that was 12% or more above normal. In 2006, a weak El Nino came and went without disrupting the monsoon at all.

So what saved India's rains?

The answer lies in a competing ocean phenomenon called the Indian Ocean Dipole (IOD).

IOD is essentially El Nino's nemesis that occurs in the Indian Ocean.

When the western part of the Indian Ocean warms up while the eastern part cools, a "positive IOD" forms and strengthens the moisture-carrying winds that feed India's monsoon.

In 1997, a powerful positive IOD effectively cancelled out El Nino's disruptive influence, delivering good rains despite the Pacific's fury.

Scientists also point to another factor, which is another simple fact that not all El Ninos are the same.

When warming is centred in the central Pacific, called El Nino Modoki, its impact on India tends to be more severe.

When it sits further east, as it did in 1997, the disruption to Indian monsoon winds is weaker.

HARDER TO FORECAST

The relationship between El Nino and India's monsoon has become even less predictable in recent decades.

Climate change is warming the Eurasian landmass, which increases the temperature difference between land and sea, something that actually strengthens monsoon winds and partially offsets El Nino's influence.

A landmark 2006 study by climate scientist KK Kumar and colleagues found that while all of India's worst droughts have been linked to El Nino, not all El Nino events lead to droughts.

It also noted that the location of warming in the Pacific matters as much as its intensity. Interestingly, even a weak El Nino can cause severe drought, as seen in 2002 and 2009, when rainfall fell to just 78% of normal.

Weather agencies like the India Meteorological Department (IMD) now use multi-factor models that account for the IOD, Indian Ocean temperatures, Pacific warming patterns, and global temperature trends together, rather than relying on El Nino alone.

India, thus, needs to keep in mind that El Nino is a risk, but not a guarantee of disaster.

But with monsoon forecasting still an imperfect science, the wisest approach remains preparedness, ranging from water conservation, contingency crop planning, and not treating a potentially devastating natural phenomenon as fate.

- Ends