El Nino may disrupt monsoons

Weather conditions that promote El Nino persistent, says Met department; drought feared

 
By Dinsa Sachan
Last Updated: Saturday 04 July 2015

Several El Nino years have coincided with droughts in India

In its first monsoon forecast in late April, the India Meteorological Department (IMD) had announced that monsoons would be normal this year and there was a little chance of El Nino—associated with dry spells west of the Pacific—arriving in the second half of the season. But of late, IMD seems to have shifted its stand. Now the weather agency is openly admitting El Nino could influence the monsoons set to hit Kerala coast by June 6. In recent years,  strong correlation between El Nino and aberrant weather has been observed. Several El Nino years have coincided with droughts in India—2009 being a prime example. IMD's warnings have important implications for the country's agriculture, 60 per cent of which is rain-fed.

D S Pai, director of long-range forecasting at IMD, however, is guarded in his remarks. “There has not been any change in IMD's stand. We had maintained in our long-range forecast given out in April that there is a noticeable chance of El Nino re-emerging later during the season,” he says. He adds that it's just that the conditions favouring El Nino have persisted, so the prospect of El Nino occuring seems more likely now. “Anyway, it's difficult to get a clear picture of El Nino in April. Things take shape only in May and June.” He informs that in it's June forecast, the Met department would be able to inform whether El Nino is strong enough to influence the monsoon and whether there is a probability of the occurence of drought.

Why is El Nino so dreaded?

El Nino/La Nina-Southern Oscillation or ENSO is an ocean-atmospheric phenomenon that occurs in a cycle. La Nina, which is one part of the cycle, is signified by a decrease of 3-5°C in sea surface temperature across the Equatorial Pacific Ocean and it is favourable for monsoons in India. El Nino, which is La Nina’s counter-phenomenon, is often accompanied by drought in India and heavy rainfall in the Pacific coast of Latin America.

Over the years, research has shown there is an association between El Nino and deficient rainfall in India. However, all El Nino years are not deficient in rainfall. Pai says 1997 saw the strongest El Nino phenomenon in the last century, but the monsoon rainfall that year was 101 per cent of long-period average (average of 50 years), which means it was marginally more than 89 cm. The five major droughts of the past 20 years—1982, 1987, 2002, 2004 and 2009—were accompanied by El Nino. A research analysis between 1880 and 2004 by Krishna Kumar of Indian Institute of Tropical Meteorology (IITM) shows that in 13 instances of El Nino occurrence, India experienced normal monsoon rainfall, while in 10 instances rainfall was below normal.

Degree of uncertainty

World Meteorological Organisation (WMO) in its latest update has maintained a guarded stand on El Nino. It says that while El Nino could emerge later in the season, there's still some uncertainty about it's occurrence. “Uncertainty regarding neutral or El Nino conditions for later in 2012 is due to questions over whether the warming of the Pacific Ocean will be large enough to cause changes in the atmosphere, which is a necessary condition to sustain an El Nino event,” WMO states.

Will 2012 be a drought year?
 
• Five major droughts of the past 20 years—1982, 1987, 2002, 2004 and 2009—were accompanied by El Nino
 
 
• A research analysis for the period between 1880 and 2004 shows that in 13 instances of El Nino occurrence India experienced normal monsoon rainfall, while in 10 instances rainfall was below normal
 
• The Bureau of Meteorology of Australia has said that five of seven climate models that it has been looking at this year indicate there will be increased warming over the Pacific Ocean over the next few months—June to September—and that indicates a strong probability for El Nino occurrence. Two models show neutral El Nino conditions.
 
The Bureau of Meteorology of Australia has said that five of seven climate models that it has been looking at indicate there will be increased warming over the Pacific Ocean over the next few months—June to September—and that indicates a strong probability for El Nino occurrence. Two models show neutral El Nino conditions.

While the jury is still out on whether El Nino is going to strongly impact the monsoon, the government still needs to gear itself up. In 2009, there was a massive deficit in rainfall—it fell short of the long-period average by about 54 per cent. Until June, IMD had maintained there was a very slim chance of El Nino occuring and there was little reason to panic. But panic it did when later in July models clearly showed there was El Nino ahead.

Jayashree Sengupta, development economist with Observer Research Foundation in New Delhi, says, “If there are alarms of El Nino being raised, then the government better kick into gear.” She says that the agricultural sector's growth has dived by 3 per cent in the last quarter and the economy looks bleak. “A drought can make things worse. In 2009, because of government's unpreparedness, the drought was mismanaged which lead to food inflation.”

Sengupta says that government should gear up to be able to import crops like potato and onion in the event of a drought, and they need to plan it now. She says other things to look out for are ways to prevent water bodies from going dry. “There's little government can do about it right now, but they could think of innovative ways like lining the water bodies with plastic if the need arises,” Sengupta suggests.

However, another prominent weather scientist says it is too early to panic. Sulochna Gadgil, monsoon expert and an honorary professor at the Centre for Atmospheric and Oceanic Sciences at the Indian Institute of Science in Bengaluru, says that it's not time to press the panic button yet even though there is a high possibility of an El Nino.

“El Nino is a very complicated system, and the alarm that has been raised may turn out to be false. We should wait until IMD's next forecast in June to get a clear picture.”

Gadgil adds that El Nino played a role in the droughts of 2002, 2004 and 2009, but the there was more to 2009's drought than meets the eye. “The deficit in June was actually caused by extreme warm conditions in the equatorial Indian Ocean. However, these conditions do not exist this year,” she adds.
 

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