The Amazon basin contains one-third of the Earth's tropical forests in an area of more than five million square kilometers. So far, much of this rainforest remains intact. But some scientists warn much of the Brazilian Amazon could be deforested during the next 20 years.
A scientific study released early this year predicted that less than one-third of the primary growth rainforest in Brazil will remain by the year 2020 because of economic development. Using a more pessimistic scenario, the study predicted less than five percent of the rainforest will be standing.
The study, produced by scientists at Brazil's National Amazonian Research Institute (INPA) said this rate of deforestation would be caused by building new roads and highways that would spur population growth and development.
INPA's Philip Fearnside, who is one of the authors of the study, says he and his colleagues looked at the history of development in the Amazon, and measured the rate of deforestation that occurred when roads were built.
Since 1965, a network of highways has been built in the Amazon, some running north to south, others east to west across the vast stretches of jungle. From satellite photographs and other evidence, it appears that roughly 75 percent of the deforestation of the rainforest occurs within a 50-kilometer band along a paved road.
Mr. Fearnside says their studies show further development will lead to increased deforestation. "We used the history of what had happened when roads were built and paved and so forth in the past, how fast the deforestation expanded out from these different roads, and then put this information into a geographical information system, with all of the infrastructure projects that have been announced ... and then projected what would happen up until 2020.... It was very dramatic because you can see the way deforestation spreads through the region," he said. "It showed a tremendous amount deforestation, including a large emission of greenhouse gases, which can be attributed to these projects."
The Brazilian government plans to spend billions of dollars in coming years for a series of infrastructure projects, including highway construction, railway lines, and hydroelectric plants under a program, called Forward Brazil.
The objectives of the Forward Brazil program are to foster economic development and integrate the Amazon region more closely with the rest of the country.
Proponents of the program say Brazil must develop the Amazon. The head of a Rio de Janeiro business council that advises the government on strategic affairs, former general Rubems Bayma Denys, argues Brazil cannot neglect such a huge swath of its territory. "It is necessary for any country to have its highways," he said. "The Amazon region, which represents 60 percent of the country's territory, cannot be left completely unoccupied, without development or progress. Now development has to be sustainable, and it will be done that way."
It is a powerful argument, and one that carries a lot of weight in a country where, 29 percent of the population, 46 million people live below the poverty line.
But scientists like Philip Fearnside warn that once the rainforest is cut down, it cannot be replaced. "Deforestation throws away the opportunity to use the forest because once it is transformed into cattle pasture it is not realistic to expect to regenerate a forest of a similar type, on the scale that things are happening here in the Amazon," he says. "So because the kinds of land use that are replacing the forests are not sustainable, most of it is for cattle pasture either directly, or after using it for a few years for manioc, rice, and annual crops, one has a great loss here."
But so far, deforestation has affected just 15 percent of the Brazilian Amazon, and development supporters are quick to point out that the rest remains intact.
Retired general Denys says it is thanks to Brazil's policies that so much of the rainforest remains. "Brazil has been protecting the Amazon since its independence," he says. "We did not open the river or the territory up to massive colonization in the 19th century, despite international pressures. So it is thanks to the Brazilians that the Amazon exists today. Can it be as a result of protecting this region in the face of international commercial pressure that Brazil cannot incorporate this territory into its national economy?"
It is a question still unanswered. But most scientists and environmentalists would urge extreme caution, before proceeding with further development in the Amazon's fragile ecosystem.