Nearly half the Amazon could be lost in the next 20 years Pristine forests may be reduced to less than 5 percent. provided by Environmental Media Services

study by Smithsonian Institution researchers and their colleagues published in Science magazine last month predicts that up to 42 percent of the Amazon forest in Brazil could be lost or heavily damaged by 2020 if current land-use trends continue. In addition, unspoiled forests in the region could be reduced to less than 5 percent. Such destruction is possible, the study found, if current exploitation of the Amazon is not curtailed and the Brazilian government implements a set of planned development projects in the Amazon basin called "Avaça Brasil" (Advance Brazil). The study was conducted by a team of scientists from the United States and Brazil, led by Dr. William F. Laurance of the Smithsonian Tropical Research Institute. The Amazon is the largest tropical rainforest and the largest river basin in the world. It supports indigenous communities and ecotourism industries, and helps to absorb greenhouse gases from the atmosphere. The Avança Brasil projects, planned for 2000-2007, will span large expanses of the basin to boost industrial agriculture, timber and mining. Many projects will create corridors between densely populated areas and the remote Amazonian frontier that will open the area to unregulated colonization, logging and land speculation. The researchers developed models to integrate data on deforestation, logging, mining, highways and rivers, and existing and planned infrastructure projects. Laurance and his colleagues prepared two different scenarios: the optimistic one predicts that almost 28 percent of the region will be deforested or heavily degraded. The other scenario predicts that only 4.7 percent of pristine forests will remain and nearly 42 percent of the region will be deforested or heavily degraded. The two models were rerun without Avança Brasil projects, and in their absence the models showed a sharp decrease in forest degradation. The Amazon is currently losing nearly 5 million acres a year in Brazil, an area bigger than the state of Connecticut. The forest shelters the largest biodiversity on the planet and one-fifth of the world's fresh water. It helps to regulate regional climate, protects the soil and lessens the impact of floods.