By Colin Packham
SYDNEY (Reuters) - Australia's weather bureau said on Tuesday there were clear signs El Nino was developing in the eastern Pacific, raising concerns over the potential impact of the weather event on agriculture at time of soaring global food prices.
El Nino is a periodic warming of the eastern equatorial Pacific Ocean and its arrival comes as fears grow about soaring global food prices. Severe drought in the United States has withered the corn crop, sending prices up 60 percent in two months. Soy prices have also jumped after drought in South America.
The Australian Bureau of Meteorology said although El Nino development stalled in the second half of July, "over the past fortnight indicators such as the Southern Oscillation Index (a gauge of atmospheric pressure) and trade wind strength have shown renewed trends that are consistent with the early stages of an El Nino event."
Japan's weather bureau said on Friday the weather pattern was underway.
However, the Australian weather bureau said it was being "conservative", stressing that its outlook was consistent with the U.S. National Oceanic and Atmospheric Administration, and not at odds with the Japanese weather bureau.
"At the moment, the ocean is looking El Nino-like, but the atmosphere is still not playing ball," Andrew Watkins, climate manager at the Australian Bureau of Meteorology, said.
"The trade winds have only just backed off and the Southern Oscillation Index is only just creeping up to El Nino thresholds."
Australia's climate model predicts a "mild" El Nino, but Watkins warned it was difficult to gauge the impact.
"Most likely the El Nino will be a relatively weak event in the grand scheme. Having said that, weak events have had strong impacts in Australia like 2006/07 was not a particularly strong event but had a strong impact on Australia," Watkins said.
An El Nino is normally associated with drier conditions across the east coast of Australia, potentially damaging important export crops such as wheat, which is heavily reliant on rains during the spring to summer period to boost yields.
Australian wheat production is forecast to dip this year from the record 2011/12 season and dry weather across Western Australia has seen forecasts downgraded in recent weeks.
The big unknown is how intense and how long the developing El Nino phenomenon will be. An intense El Nino can cause widespread drought in Australia, parts of Africa, Southeast Asia and India, but also bring rains to other parts of the globe.
The U.N.'s Food and Agriculture Organization said last week the world was closer to a repeat of a 2008 food crisis because of a spike in food costs.
(Reporting By Colin Packham; Editing by Ed Davies)
