October 6, 2005
Weather Cycle Seen Reaching Limit in Dry Amazon
RIO DE JANEIRO, Brazil -- Drought in the Amazon rain forest, normally one of the world's wettest regions, shows the weather cycle is swinging to one extreme rather than signaling climate change, local meteorologists said Thursday.
Water levels on two major Amazon tributaries -- Madeira and Solimoes -- dropped to record- and 38-year lows respectively, creating long delays in river traffic, the main form of regional transport.
Dry weather also fanned huge forest fires, notably in the remote western state of Acre.
But weather forecasters added that elsewhere in continental sized Brazil, seasonal spring rains had started in the south and were spreading northwards through Brazil's major coffee belt and gradually into soybean areas in the center-west.
"The Amazon drought shows extreme climate variability, not climatic change," said Jose Marengo, researcher at the Weather Forecasting and Climatic Studies Center (CPTEC), part of the National Institute of Space Research (INPE).
Marengo said that normal rains were forecast for the south Amazon -- the states of Acre, Rondonia, southern part of Para state and northern part of Mato Grosso state.
"Rain is forecast in Acre in the next couple of weeks," he said, adding that the region is normally dry between June and September and wettest in December and January.
But we are a bit worried that there could be less rain than usual at the mouth of the Amazon, around Belem, he said, noting that extreme climatic events were occurring more frequently, "We could be seeing the first symptoms of changing cycles."
Meteorologists discounted a link between unusually severe hurricanes in the Gulf of Mexico and drought in the Amazon.
Dry weather in the Amazon is linked to warmer ocean surface temperatures in the Pacific and to low sunspot activity, said Expedito Rebello, head of applied meteorology at the government's National Institute of Meteorology in Brasilia.
"It's a phenomenal drought and could be linked to a warmer Pacific and little sunspot activity," Rebello said, noting extremely low water levels in the Amazon.
But he added that the weather cycle would reach a low next year and then start to moderate.
Paulo Etchitchury, director of private meteorologists Somar, said that the Pacific should start to enter a cooler period next Brazilian summer and this could result in a weak La Nina weather pattern.
"It won't affect summer rains and it's still very early to talk about next winter," he said, adding that La Nina doesn't necessarily signal a cold winter and extra risk of frost damage to Brazil's coffee crop, the world's biggest.
Brazil was in a transitional period between the dry May/August winter and rainy spring which started in south Brazil in September, Etchitchury said.
He said that this year weather conditions are in general seasonally normal in Brazil's main farming areas, except that drought in the Amazon could affect Mato Grosso, Brazil's main soy state.
"Rains in the south are replenishing a water deficit and providing reserves for summer soy and corn harvests, he said, adding, "Last September was hot and dry and people were worried about drought damage to crop flowering."