ENVIRONMENT: Global Agency Hesitant to Confirm El Niño’s Return

By Gustavo Capdevila Reprint | | Print |

Gustavo Capdevila

GENEVA, Mar 27 2002 (IPS) - The first signs of El Niño, the periodic phenomenon that causes climate fluctuations and natural disasters around much of the world, have appeared along South America’s Pacific coast, but scientists are awaiting more definitive indications before they will confirm its presence.

The latest reports that the Geneva-based World Meteorological Organisation (WMO) received from Australia, where the warm ocean currents that create the El Niño effect originate, indicate there is a 50-percent chance that the phenomenon will occur this year, says Michael Coughlan, director of the WMO Climate Activities Programme.

The factors that lead scientists to believe that El Niño – a cyclical event occurring every three to seven years – has returned are the climate conditions of the eastern Pacific, with torrential rains, floods, mudslides and loss of human lives, as has occurred in Ecuador, Coughlan told a press conference.

Various weather reports from the last two to three weeks have described such conditions, which correspond to the typical traits of El Niño, said the official.

The WMO evaluations are the result of coordination with national meteorological services and with leading weather research centres, said the institution’s deputy secretary-general, Michael Jarraud.

Based on that information, the WMO announced in February that a warming trend had been observed in the surface waters of the eastern Pacific and could be interpreted as a precursor to El Niño.

The most recent episode of this climate phenomenon, in 1997 and 1998, was the most violent of the 20th century. It was followed by a phase known as La Niña, which involves cooler than normal water temperatures off the South American Pacific coast.

During the presence of El Niño, surface temperatures of the ocean are warmer than average in the central and eastern Pacific tropics.

The consequences are not limited to those areas, but extend across the planet, with devastating effects involving human and material losses, and damaging economies, particularly in developing countries.

Jarraud pointed out that the March-June period is critical for determining the development of either of the two climate phenomena.

WMO researchers report that the possibility that El Niño will manifest itself this year is much greater than last year, when La Niña began to dissipate.

The global situation favours the reappearance of El Niño, but that does not constitute a certainty of its return, said Jarraud.

The computer models used by scientists do not provide a clear answer, though they do tend to confirm that El Niño will develop this year.

There is still uncertainty, said Coughlan, pointing out that conditions in the eastern Pacific would indicate El Niño, but the influences it would normally have in the western Pacific have not yet been observed.

When El Niño appears on the coast of South America, droughts occur in the western Pacific, there is a reduction in tropical cyclones and hurricanes in the Atlantic, and rainfall patterns are affected in Africa, added the WMO official.

“The signals that we are seeing are very much confined to the eastern Pacific,” said Coughlan.

He mentioned the heavy rains that have occurred recently in Ecuador and Bolivia, where an unprecedented deluge hit La Paz. Peru has also reported unusually heavy rainfall.

In contrast, El Niño generally causes reduced precipitation in Australasia, and the tropical cyclones normally appearing in the western Pacific tend to shift eastward, even reaching Tahiti.

Deputy secretary-general Jarraud said it is still too early to predict the intensity of the phenomenon, if it were to occur. In the next two months, the WMO will have more information about the risk of a new El Niño episode, he stated.