U.N. scientists say a weather phenomenon that caused thousands of deaths a few years ago is expected to make another appearance in the coming months. But the scientists, at the World Meteorological Organization, say the phenomenon, known as El Nino, is not likely to do as much damage this time as it did when it last appeared.
Climate experts say the world this year will be spared the devastating floods and droughts that the El Nino caused in many regions of the world in 1997 and 1998.
So-called El Nino events occur when temperatures in the Pacific Ocean along the South American coast become substantially warmer. The warming ocean, coupled with changes in air pressure, can change the course of the upper air jet stream, leading to severe drought or flooding in many parts of the world. Flooding caused by the last El Nino is blamed for the deaths of thousands of people.
The director of the World Meteorological Organization's world climate program is Michael Coughlin. He says all the signals point to a slight warming of the Pacific Ocean. But he says this is considered good news because it indicates a weak El Nino. "This does not mean to say that we are not going to see some major weather anomalies around the world," he says. "The climate has many ways of turning up surprises and providing us with some severe events, floods in this location and droughts in other locations. But what we have seen at present is the fact that we do not see the same coherent pattern of droughts and floods in many parts of the world occurring at the same time."
Mr. Coughlin says the serious drought in Iran and Afghanistan, or floods in China or India, cannot be attributed to El Nino. He says they do not have the extensive severity that is characteristic of an El Nino event.
Although a weak to moderate El Nino is forecast, he says no one should be complacent. He says there still can be nasty surprises, but these are expected to be localized. Mr. Coughlin says regions of the Southern Hemisphere would be the most susceptible to unnatural weather. "If the El Nino does tend to develop, than one might expect that, for example, the rainfall across northern Australia may be less than normal," he says. "If the El Nino is going to kick in in southern Africa, in parts of Africa, we might see rainfall across Africa to be less than normal."
Mr. Coughlin says no one is making those kinds of forecasts now because the El Nino does not appear to be developing to that level of severity. But he says meteorologists will be closely monitoring the situation during the coming months to watch for possible changes in climate patterns.