Lull before the storm

the final countdown has begun. Yet again, the Pacific is all set. Its depths are surging as it braces to deliver nature's most troublesome 'little one'. The birth pangs are driving the world into frenzy. Yes, El Nio -- named after the Spanish appellation of 'little one' -- is about to make a comeback and turn the world topsy-turvy.

Recently, scientists from the us National Oceanic and Atmospheric Administration (noaa) reported that surface temperatures of the Pacific Ocean near the South American coast warmed by 2C in February 2002 -- a strong sign that the Pacific is headed for an El Nio condition that could last for more than a year. "In the wake of certain oceanic and atmospheric circulation patterns and their recent evolution, we have concluded that El Nio conditions will develop in the tropical Pacific over the next six months," said Vernon Kousky, a climate specialist with noaa.

The term El Nio is used to describe the disruption of the ocean-atmosphere system in the tropical Pacific. During an El Nio event, the prevailing trade winds weaken and the equatorial counter-current strengthens, causing warm surface waters in the Indonesian region to flow eastward to overlie the cold waters of Peru. This has great impact on the wind, sea surface temperature and precipitation patterns in the tropical Pacific. Adverse changes in these disrupt global climate patterns and wreak havoc worldwide in the form of floods and droughts (see 'Winds of Change', Down To Earth, Vol 6, No 14, December 15, 1997).

Historically, El Nio episodes have occurred every two to seven years. The last El Nio event in 1997-98 -- the most intense in the world history so far -- had killed 24,000 people across the globe and led to a loss of us $34 million. It has been nearly four years since the end of the destructive 1997-98 El Nio which was followed by three years of La Nia -- a cooling weather pattern in the eastern tropical Pacific.
Red alert! Predictions about the present resurgence of El Nio were made in January 2002, when the tropical Pacific Ocean started warming. These predictions were corroborated by enhanced cloudiness and precipitation over the equatorial central Pacific -- a phenomenon that occurred for the first time since the last El Nio episode in 1997-98. Along with this, in Peru, cold-water fish anchovies were replaced by tropical species -- a sign typical of the early stages of El Nio.

Wind data for the Pacific Ocean obtained by us National Aeronautical Space Administration (nasa) indicate episodes of reversed trade winds that are responsible for unseasonable cyclone conditions in the northwest and southwest Pacific. These are also said to be a precursor of a future El Nio.

A research team led by W Timothy Liu, a senior scientist at nasa's Jet Propulsion Laboratory (jpl), used wind speed and direction data to detect a shift in the trade winds on February 25, 2002.

The winds shifted from their normal easterly direction to a westerly direction, blowing from Indonesia towards the Americas along the equator.

"In addition to unusual cyclonic activity, such a reversal of trade winds trigger waves of warm water, which are early indicators of future El Nio conditions," said Liu. "During periods of reversed trade winds, which last from a few days to a week or more, equatorial westerly winds generate a counter-clockwise vortex in the northern hemisphere and a clockwise vortex in the southern hemisphere. Once spawned, the resulting waves travel across the Pacific and reach the coastline of the Americas in approximately one or two months, warming the waters of the eastern Pacific and creating El Nio conditions when the effects are accumulated."

Sustained wave activity could have a major impact on global weather patterns, according to jpl oceanographer William Patzert. "If trade wind patterns continue to experience reversal through the us spring and summer, the resulting strong, warm waves will cross the Pacific like a conveyor belt, depositing warm water near South America where the ocean is normally cold," he said. "Such a 'warm pool' could alter weather all over the planet, with rains that would normally soak the western Pacific shifting toward the Americas, and places such as Indonesia and India becoming drier."

"The first region on the globe to experience El Nio impacts would be the tropical Pacific. The Pacific northwest will experience drier than normal conditions in the fall," said Kousky. According to noaa's administrator Conrad Lautenbacher, the warming conditions in the tropical Pacific will continue to develop until early 2003. However, he added, it is too early to determine the potential strength of the future El Nio or the exact weather conditions it would usher in. "At this point we cannot say whether this El Nio would develop along the same lines as the intense 1997-98 episode." Indian scenario
for countries like India, the resurgence could have major implications. Historical records indicate that El Nio events have coincided with droughts and floods in various parts of the country. However, noaa's prediction seems to be of no significance for the New Delhi-based Indian Meteorological Department (imd).

When questioned about it, H R Hatwar, director of imd's Northern Hemisphere Exchange Centre, was caught unawares. He says that by making such predictions noaa is trying to create unnecessary panic. Ironically, India uses noaa's monitoring system for investigating the early stages of El Nio -- one of the parameters taken into account by imd for forecasting monsoons. "Since it is too early for us to forecast the monsoons, predicting El Nio's effects is out of question. Moreover, El Nio is just one of the 16 factors affecting our monsoons. Therefore, even if there is a resurgence, there are no reasons to worry," asserts Hatwar. He opines that there is no direct link between Indian monsoons and El Nio.

Biswajit Mukhopadhyay, director of publications, imd, agrees with him. "The co-relation between the Indian monsoon and El Nio events is very poor. There are as many refutes about it, as there are claims," he says. "The present warming of the Pacific does not translate into a good for a bad monsoon or India."

Even the scientific community seems to be having a laid-back attitude. "The Indian weather pattern has far too many variables involved for a simplistic reading of the future. Moreover, there is no one-to-one relationship between El Nio and monsoons," says S K Dube, professor at the Centre for Atmospheric Sciences, Indian Institute of Technology (iit), Delhi.

However, there are some who do not lightly dismiss the crucial link. M Rajeevan, director of long-range forecasting for imd, Pune, says that at least 50 per cent of El Nio events in the past have been associated with droughts in India. These include drought years like 1918,1965,1972, 1982 and 1987. "Our present understanding is not enough to ascertain the fact that another El Nio event would not affect Indian monsoon severely," states Rajeevan.

According to Murari Lal, chief scientist of department of atmospheric sciences, iit, Delhi, there are 50 per cent chances of India suffering from adverse affects of a future El Nio, depending on the intensity of the phenomenon. "If there is an El Nio, our monsoon could be delayed for a while," he says.

D R Sikka, former director of Pune-based Indian Institute of Tropical Meteorology (iitm), voices the same opinion. "In case of a resurgence, it is certain that we would not have an excess monsoon. The areas likely to be affected are north western and central India including Punjab, Rajasthan, Haryana, western Uttar Pradesh and Madhya Pradesh. For countries like Indonesia, it would mean a bad monsoon," says Sikka. According to him, 60 per cent instances of El Nio phenomenon in the past have resulted in a bad monsoon for India. Besides affecting the rainfall patterns, there are other ways in which El Nio takes its toll on India. For instance, the World Metrological Organisation had linked El Nio with the 1998's unprecedented heat wave in Orissa that killed 2,000 people.

In the wake of such ground realities, India should not ignore the looming threat posed by the 'little child'. According to Lal, a contingency plan should be prepared by the government by involving non-governmental organisations as well as local people's committees. Such plans can help minimise devastation to a great extent. But if organisations like imd continue to overlook the obvious then we might find ourselves caught in a quandary.

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