ENVIRONMENT-PERU: High Winds, Extreme Cold in Preamble to El Niño

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Abraham Lama

LIMA, Jul 18 2002 (IPS) - The return of snow storms in southern Peru after a quarter century, and hurricane-force winds in Chile are the clearest signs, say experts, of the approach of El Niño, a cyclical warm current in the Pacific Ocean that causes climate disturbances worldwide.

A wave of freezing temperatures killed at least 60 people — mostly children — in the Andean high plains of Peru in the last week. The Alejandro Toledo government declared a state of emergency in eight Peruvian departments that were thrashed by temperatures that fell to 20 degrees below zero Celsius.

More than 150 tons of food, medicine and blankets had to be transported by helicopter to the affected areas, where thousands of peasant farmers have already lost at least 70,000 head of livestock, their main source of income. The unprecedented snowfall accumulated up to a metre deep, blocking highways and roads.

A million camelids, or 20 percent of the alpacas, llamas, vicuñas and guanacos (all relatives of the camel adapted to high altitudes), are in danger of dying from the extreme cold.

The intense cold affecting southern Peru and part of Bolivia, as well as the hurricane winds in Chile at first glance seem difficult to relate to an oceanic current of warm water.

“However, the origins of these meteorological disturbances are closely linked and, like the floods and drought, form part of the chain of climate phenomena that have the oceans and atmosphere playing the leading role,” said Peruvian scientist and journalist Tomás Unger.

Reports from the U.S.-based National Oceanic and Atmospheric Administration (NOAA) and from the Meteorological Agency of Japan indicate that the El Niño current is on its way to the South American coast from its origins off Australia.

El Niño, a cyclical phenomenon that occurs every three to seven years, usually causes torrential rains and floods in some regions, and severe drought in others, as it approaches the Americas.

Its most recent manifestation — from November 1997 to June 1998 — was not the most intense but was the most closely studied by scientists, armed with the latest technologies.

El Niño caused hundreds of deaths worldwide and material losses of more than 2.0 billion dollars in Chile, Ecuador and Peru, in the combination of the destruction of homes, roads and bridges, and the devastation of crops.

The climate phenomenon arises as a result of the periodic differential of atmospheric pressure between the eastern and western Pacific, giving rise to strong winds that push a giant “river” of surface water heated by the sun eastwards. The surface temperature of the water rises two to five degrees Celsius.

While snowstorms struck the mountains of Peru and Bolivia and hurricane winds thrashed northern Chile, intense typhoons killed 77 people in Japan, Taiwan and the Philippines, while Germany recorded winds of 150 kph.

According to NOAA, El Niño will reach the South American coast sometime during the Southern Hemisphere spring and summer (in other words, in the next three to six months) and will be relatively moderate, with an oceanic surface water temperature increase of two to three degrees Celsius.

If the prediction comes true and the temperature of the Pacific current off Ecuador and Peru does not rise more than two degrees, the two countries could be saved from the catastrophic floods recorded in 1982 and 1983.

El Niño is one of the natural phenomena most studied by the science world, which is beginning to cast a light on the global climate changes.

Although the ancient inhabitants of what is now Peru were fully aware of the unusual summer weather, with heavy rainfall occurring along the seaboard in a somewhat regular cycle, the first documented case dates back to 1578, when it destroyed the northern city of Lambayeque.

The Peruvian authorities have gathered information in recent years through a committee created by several local scientific institutes that work in cooperation with the international scientific community.

The interrelation of the climate phenomenon occurring in farflung regions around the world was not proved by scientists until the 1960s, when a coordinated research effort began in that direction.

Walter Munk, internationally renowned researcher at the Scripps Oceanography Institute in the United States, stresses that “the sea is key to understanding climate changes.”

“The small changes in the ocean’s temperatures influence the temperature of the air and the climate patterns of the entire planet,” he said.

Munsk explained that in the past it was thought that the only climate effect of the sea was to stabilise atmospheric temperatures and attenuate climate fluctuations, but now it is known that ocean currents are actors and factors in climate changes.

Peruvian expert Unger stated that “to understand the complex global climate interdependence one must turn to the concepts of fluid mechanics.”

In spite of their different names, he said, the Antarctic, Arctic, Atlantic, Indian and Pacific oceans really make up a single mass of water, just as the atmosphere enveloping the Earth is a single gaseous mass, though consisting of various layers.

“There is a very fluid internal movement in both masses, and also a fluid interconnection between them. For example, an increase in the temperature of the ocean surface causes evaporation, which increases the salinity of the remaining water, which then tends to descend. The warmed air, meanwhile, rises and attracts other air masses,” explained Unger.

Oceanographers point out that not only winds and the heat of the sun and the rotation of the Earth create the conditions underlying the existing marine currents. They also depend on the delicate balance between the temperature and salinity of the waters.

The study of salt content, the so-called thermo-saline exchange between the surface water and deeper waters that create the conditions for life of all marine species, is one of the most important aspects in the measurements taken by the electronic buoys that scientists have scattered around the world’s oceans.

Another factor to keep in mind in the intensity of these anomalous variations in the global climate is global warming, a process that began after the last ice age of the Pleistocene, but which human activity (the combustion of fossil fuels and widespread deforestation, for example) has accelerated.

“In world that is warming, the magnitude and rate of evaporation will increase, causing winds and storms that are increasingly more intense because the humidity carried by the atmosphere returns to earth in the form of rain and snow,” predicts Peter Rhines, oceanographer at the U.S. University of Washington.

The fear felt by scientists like Rhines is that, in the long term, global warming and the increased humidity of the atmosphere will paralyse the thermo-saline circulation of the seas, alter the delicate balance of the system of currents, and affect the planet’s climate patterns in unpredictable ways.

Taking advantage of the fact that at higher temperatures the speed of sound is faster in salt water, a programme was launched in 1999, known as the Acoustic Thermometry of Ocean Climate, to monitor the behaviour of the sea, a key factor of the climate in relation to the looming threat of global warming.