SUNS 4353 Thursday 14 January 1999

Lima, Jan 12 (IPS/Abraham Lama) -- Droughts and cold fronts will hit Ecuador, Mexico, Peru, the United States, Mexico and north Chile this year; Argentina, Paraguay, Uruguay and south Chile will have heat waves; and heavy rains will swamp parts of Brazil and Colombia.

And meteorologists blame La Nina, the cold ocean current that disrupts weather patterns.

The Maritime Institute of Peru, IMARPE, and the Geophysical Institute of Peru have already warned the government, and in particular the Agriculture Ministry, that they have registered a Nina of extraordinary intensity off the country's coasts.

Similar findings were made by U.S.-based scientific agencies.

In contrast to El Nino, the warm ocean current that begins near the coasts of Australia, La Nina rises up from the ocean floor off South America's Pacific coast and causes temperatures to drop on the ocean's surface. It begins with stronger trade winds, which pushes the surface water previously warmed by El Nino from the western Pacific - off South America - toward Indonesia and Australia.

According to an IMARPE source, the sensors that monitor the Pacific Ocean's temperature, some of which are on the surface while others are anchored to the ocean floor, indicated the presence late last year of a large mass of water below the surface that was moving toward the coast of South America.

The source noted that along the Pacific Ocean's 3,000-square mile equatorial zone, the temperature dropped by about nine degrees between September and November, a much sharper drop than usual, which meant that the current La Nina was one of the most powerful in recent years.

Oceans surfaces play a major role in determining weather patterns throughout the world. Warmer ocean surfaces accelerate evaporation, causing torrential rain and floods, whereas cooler surface water usually makes for less rain.

According to Kevin Trenverth, a climate analyst for the National Oceanic and Atmospheric Administration (NOAA) of the United States, La Nina will not cause drought everywhere: in some parts of the Americas it will bring heat waves and heavy rain.

This year will be colder than usual in coastal areas and some highland regions in Ecuador, Peru, Chile, southern California in the United States and northern Mexico. These areas will also have less rainfall.

Abnormally hot weather is expected in parts of Argentina, Chile, Uruguay and Paraguay, while southern Colombia and northern Brazil are in for an extraordinarily wet year.

The last El Nino (1997-1998) caused several disasters around the world. It is estimated that Chile, Ecuador and Peru, the countries most affected in South America, suffered more than two billion dollars when floods destroyed crops, homes, roads and bridges.
The droughts La Nina usually causes are perhaps less spectacular than floods, but their social impact is high since they worsen food deficits, rural poverty and the rural-urban drift.

The alternating system of ocean winds and currents of which El Nino and La Nina are a part - called the Meridian Oscillation by scientists - occurs every year but its intensity reaches catastrophic proportions at intervals of two to eight years.

According to Michael McPhaden, a meteorologist of the University of Washington, a sharp El Nino is not always followed by an equally intense La Nina.

Citing an example of this, he said a moderate El Nino in 1986-7 gave way to one of the most intense cold fronts in the past 50 years and very severe droughts.