The often-disastrous weather shifts caused by El Niño may be easier to predict than previously thought.

An analysis published in this week's Nature shows that improved climate models would have given two years' warning of all the main El Niño events in the past 150 years. Most current models forecast only six to nine months into the future, and many researchers argue that El Niño is triggered by random wind bursts in the western tropical Pacific, making it very difficult to predict.

But the new analysis by Dake Chen of Columbia University, United States and colleagues, suggests instead that the more predictable ocean conditions are mainly responsible for causing El Niño.

El Niño can disrupt the timing and magnitude of monsoon rains, potentially leading to drought and famine. Climatic conditions caused by El Niño have been linked to deaths of tens of millions of people in countries such as Brazil, China, Ethiopia and India.

"Overall, the authors give an optimistic outlook for [El Niño] forecasting, at least for large events: predicting small ones remains much trickier," says David Anderson of the UK-based European Centre for Medium-Range Weather Forecasts in a news and views article in Nature. The real test of the new model, however, he adds, is whether "its success in predicting the future [will] match that of its performance in predicting the past".

Link to research article by Dake Chen et al in Nature

Link to news and views article by David Anderson in Nature

References: Nature 428, 733 (2004) / Nature 428, 709 (2004)