'Super El Nino' could turn Amazon into dustbowl

The Amazon river could dry up and its lush vegetation turn into a dustbowl within 50 years because of global warming, British scientists warned yesterday.

The stark vision for the Amazon rainforest would result from a shift in rainfall patterns caused by changes in ocean currents in the Pacific, according to Dr Mat Collins, a senior research fellow at the Meteorological Office in Reading. "In our model, 50 years from now the Amazon dries up and dies," he told the British Association at the University of Salford yesterday.

He added: "There would be a reinforcing effect because, as the rainforest dried up, the carbon that is presently locked in its vegetation would be released into the atmosphere."

The chances of such a calamity are presently estimated only at between 10 and 20 per cent. But Dr Collins emphasised that this was a "preliminary" estimate.

Deforestation of the Amazon leapt by 40 per cent in the year to August 2002, after falling or remaining steady for the previous eight years. At the time, Brazil's Environment Minister described it as "highly worrying" and called for "emergency action" to halt the trend.

The key trigger for the gloomy scenario described by Dr Collins was a "super El Nino" - a larger version of the warm ocean current that every few years causes warm water to travel towards the eastern Pacific, bringing floods in western South America and drought in the west Pacific.

"Usually El Nino occurs once every three to seven years; it's a natural way that the climate varies," said Dr Collins.

"But when you increase global warming then you get more of these events."