Analyzing changing lands
The United Nations Food and Agricultural Organization (FAO) maintains a database of detailed satellite images taken over the last 20 years through the Global Forest Resources Assessment, an initiative that dates back to 1946. The FAO releases a new global assessment every 10 years.
Working closely with the FAO, Gibbs analyzed satellite data for more than 100 randomly selected sites across the tropics. By comparing satellite images taken of each specific site in 1980, 1990 and 2000, Gibbs was able to clearly see whether croplands were expanding, and if so, what they were replacing.
She examined more than 600 satellite images from the FAO and other organizations, and noticed a clear trend: "What we found was that indeed forests were the primary source for new croplands as they expanded across the tropics during the 1980s and 1990s. So cropland expansion, whether it's for fuel, feed or food, has undoubtedly led to more deforestation, and evidence is mounting that this trend will continue."
For example, Gibbs' data show that between 1980 and 2000, more than half of new cropland came from intact rainforests and another 30 percent from disturbed forests, "This is contrary to what some biofuel proponents have suggested is occurring today," she said.
"This is a major concern for the global environment," Gibbs said. "As we look toward biofuels to help reduce climate change we must consider the rainforests and savannas that may lie in the pathway of expanding biofuel cropland."
The FAO is in the process of collecting and interpreting the data for the current decade. "This will be important to provide more recent information about expansion of croplands occurring in the midst of the biofuels boom," Gibbs said.
Although Gibbs recogni
|Contact: Louis Bergeron|