Extreme weather stokes climate worries in Brazil

No one could say they hadn't seen it coming.

The sand dunes had been advancing for decades before, two years ago, they finally swallowed the houses of Raimundo do Nascimento and 12 other families in Ilha Grande, an island in the Parnaiba river delta in northeastern Brazil.

Standing on the 14-metre-high dune that now completely covers his old home, the 53-year-old Do Nascimento describes the landscape of his childhood - cashew trees as far as he could see. Not a dune in sight.

"It is beautiful now, but beauty brings misery," he said. "The cause of this is natural, but it is man-made as well."

Experts blame deforestation and population increases for the huge dunes that are advancing by about 25 metres a year, threatening to wipe the town of 8,500 people off the map. But they and residents also blame stronger winds and drier weather in recent years.

"The wind has been getting stronger. It is the motor of this process," said Luiz Roberto del Poggetto, an oceanographer whose firm was contracted by the government to find ways to contain the dunes.

A bout of extreme weather has reignited a debate about how climate change is affecting Latin America's largest country, home to most of the world's biggest rainforest and one of the world's bread baskets.

Unusually heavy rains in the north and northeast have made hundreds of thousands of people homeless and killed about 45. Meanwhile, southern Brazil has been hit by a series of droughts, devastating farmers and cutting by a third the flow of water over the famed Iguacu waterfalls.

President Luiz Inacio Lula da Silva has expressed concern.

"Brazil is feeling climate changes that are happening in the world, when there is a severe drought in a place that didn't have them, when it rains in places where it didn't use to," Mr Lula said in a recent radio broadcast.

While the exact effect of climate change is hard to measure due to a lack of historical data, it appears to be a factor in the extreme droughts and floods of recent years.

"We are seeing the warming and we are seeing conditions in many parts of the country that appear to be associated," said Carlos Nobre, a senior climate scientist at Brazil's National Institute of Space Research.

Southern states have suffered droughts in seven of the past 11 years and the first hurricane recorded in Brazil hit the southern coast in 2004. The Amazon area had its worst drought in decades in 2005.