Brazil is losing its Amazonian forests to farmers at an unprecedented rate, satellite observations have shown. Their destruction has so alarmed the Brazilian Government that it called an emergency meeting, attended by the President, Luiz Inácio Lula da Silva.

The rate of loss jumped in the second half of last year and reversed a downwards trend that officials had hoped showed that the problem of deforestation was being controlled.

Only six months ago Brazilian ministers were celebrating figures that showed the lowest forest loss since the 1970s with 3,700sq miles being cleared in the 12 months up to July 2007.

Rises in food prices, however, encouraged farmers to return to hacking down forest areas to convert them into fields for crops such as soya. In the last five months of last year more 2,700sq miles of Brazil's Amazonian forests disappeared and conservationists believe that the rate will worsen in coming months.

Satellite images from Brazil's National Institute for Space Research (INPE) allowed the area of the lost forest to be calculated. Analysts fear that the area lost may be shown to be twice as large once more-detailed assessments of the images are completed.

The worst affected region, said Gilberto Cámera, of INPE, was Mato Grosso, which has borne the brunt of the clearances with more than 50 per cent of deforestation in the past six months taking place there. Pará and Rondônia were also badly hit, together accounting for almost 30 per cent.

“We've never before detected such a high deforestation rate at this time of year,” said Mr Cámara, at a news conference in Brasilia.

Marina Silva, the Environment Minister, blamed the increase costs of commodities, with farmers treating the Amazon as cheap and available land.

The emergency meeting was expected to discuss measures that could be taken to slow the destruction.

Details of the satellite analysis were announced today only a week after scientists at INPE had warned publicly that this year was likely to bring a rapid increase in deforestation.

“I think the last four months is a big concern for the Government and know they are sending people to do more law enforcement,” said Carlos Nobre, a climate studies expert. “But I can tell you that it [deforestation] is going to be much higher than 2007.”

In the past 40 years, 20 per cent of the Amazon forests have been cut down and in 2004 the highest rate of deforestation in Brazil was recorded when 10,400sq miles of the habitat, described as the world's lungs, disappeared.

Dr Nobre said that anti-deforestation measures had held back rather than erradicated the causes of deforestation. “All those drivers of change are there,” he said. “The three years of reduced deforestation did not bring by themselves a cure for illegal deforestation.”

Deforestation is estimated to be responsible for 18 per cent of the carbon dioxide emissions that are caused by human beings and are blamed for driving climate change.

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