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"Down on the ground, however, the longstanding debate about the Amazon's role in global climate change is intensifying. The Amazon is the largest tropical forest in the world — bigger than all of Europe, with Brazil's section alone more than half the size of the continental United States. And it has always been assumed to be essential to inhibiting global warming by drawing in carbon dioxide during photosynthesis.
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Some scientists have suggested that indiscriminate deforestation has turned the Amazon into a net source of such gases, spewing huge amounts of carbon dioxide into the air.
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If in fact the Amazon is a net source of carbon gas emissions, or if the amounts of gas emitted and sequestered are in a rough permanent equilibrium, some of the fundamental assumptions of the 1998 Kyoto Protocol on climate change may have to be reconsidered. No one knows precisely the amount of greenhouse gases that Brazil is already pumping into the atmosphere. A national inventory of carbon emissions, due to have been announced four years ago, has still not been made public. And although the new left-wing government that took power in Brasília early this year was elected with the support of environmentalists, it has given no indication when it intends to publish those figures.
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Scientists at the National Institute for Amazon Research in Manaus estimate that carbon emissions in Brazil may have risen by as much as 50 percent since 1990. By their calculations, what is euphemistically called "land use changes" now produce annual emissions of 400 million tons of greenhouse gases, dwarfing the 90 million tons generated annually by fossil fuel use in Brazil and making this country one of the 10 leading emitters of greenhouse gases in the world. All across the Brazilian Amazon, the jungle is being razed for cattle pasture, crops, logging, highways and human settlements at an increasingly faster rate, contributing to fears that the climate balance here may soon be permanently tipped. Last year alone, the land that was deforested rose by 40 percent over 2001, to nearly 10,000 square miles, an area larger than New Jersey."
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http://www.nytimes.com/2003/11/04/science/earth/04AMAZ.html