Week 4: Deforestation

Week Four: Deforestation
Brazilian Deforestation

Since 1970, 600,000 square kilometers of the Amazon rainforest has been lost through deforestation. Various causes have been cited, to include clearing for cattle grazing, colonization, agriculture, infrastructure expansion and logging.

Brazilians may suffer some resentment from other countries as they continue pollute the atmosphere with fossil fuel emissions and engage in their own deforestation. But many look at rainforests as the lungs of the planet ( http://ran.org/who_we_are/publications/factsheets ) as the vegetation pulls carbon from the atmosphere. A look at this satellite image from Rondonia, Brazil shows large tracts of deforestation.

Image courtesy NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

The image above shows deforestation in the state of Rondonia, Brazil. It was taken by the Advance Spaceborne Thermal Emission and Reflection Radiometer (ASTER) in August 2000. This false-color image of the Amazon shows tropical rainforest in bright red, while pale red and brown areas represent cleared land. The Jiparaná River appears blue. For more satellite images of Brazil, visit the Earth Observatory site. http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=4588

In answer to the question "how does climate change impact the Amazon?" Dr. Philip M. Fearnside of the National Institute for Research in the Amazon, discusses the hazard of continued deforestation.

Deforestation is progressing rapidly, and if continued for 20 or 50 years the results would be disastrous. However, it is very important not to succumb to the fatalism that so often affects discussions of Amazonia. What happens depends on human decisions. This includes not only the direct deforestation that is destroying the forest, but also the climate changes that threaten to destroy the forest even without further clearing. Global warming is believed to be the cause of observed increases in the frequency of El Niño events, which are caused by warm surface water in the Pacific Ocean. Most climate models now predict "permanent" El Niño-like conditions to develop in the Pacific. One climate model (the Hadley Center model of the UK Meteorological Office) shows this permanent El Niño resulting in catastrophic die off of Amazonian forest by 2080 if global warming is unchecked. Other models currently do not show the connection between El Niño-like conditions and drought in Amazonia. Unfortunately for us, the fact that El Niño causes droughts in Amazonia is known from direct observations - it does not depend on the results of climate models. This is obvious to anyone in Amazonia who saw the fires in the El Niños of 1982-1983, 1997-1998 and 2003. The threat of a "permanent El Niño" is therefore to be taken very seriously. Again, it depends on how seriously society takes the problem to be. If fossil-fuel combustion and deforestation are reduced to reflect the importance of the problem, then the worst could be avoided. If this does not happen, the danger of a "runaway greenhouse" escaping from human control becomes much greater. Disintegration of the Amazon forest, with release of the carbon stocks in the biomass and soil, would be a significant factor in pushing us into a runaway greenhouse. (Cited from mongabay.com. http://news.mongabay.com/2006/1023-interview_fearnside.html . October 22, 2006.)

Since 1975 Rondonia, Brazil has experienced a rapid growth in population due to immigration from surrounding states. Farmers have colonized the region adjacent to the main highway to take advantage of the cheap land offered by the government. See this three image analysis of the loss of rainforest between 1975 and 1992.