In the 1970s, famed ecologist Thomas Lovejoy set up a research project in the middle of the Amazon to gather long-term data on the effects of breaking up eco-rich habitat. In this article from the Christian Science Monitor, a writer joins them to absorb what Lovejoy and his team have learned in their thirty years there, much of which is deeply troubling.
The steadily increasing losses of life and decreasing biodiversity within the world’s most important rainforest are worrisome for not only biological and climatic reasons, but also for human civilization. The rainforest stores huge amounts of carbon. Its biodiversity supplies and supports our food systems, from the tens of thousands of species of trees growing in the area, to the nuts and fruits that stock our pantries, and the medicinal uses found in both flora and fauna, such as venom from the bushmaster snake, which served as the basis for an important class of drugs for high blood pressure. Fires, drought, and deforestation have pushed the forest toward a tipping point. If much more of the Amazon disappears, the hydrological cycle it supports could collapse, endangering the whole planet.
Models differ on the severity of the threat, and there are a number of unknown factors – including fires and drought, which have been an increasing problem in recent years. But the potential is there, especially in the eastern Amazon, says Daniel Nepstad, executive director of the Earth Innovation Institute. “It’s the area of deforestation beyond which you start to inhibit rainfall so much that ... clearing leads to more drought, which leads to more fire and rainfall inhibitions as you lose vegetation,” Dr. Nepstad says.
Since 2000, the region has been hit by three unprecedented droughts, which led to substantially worse fires. “There’s this 90 billion-ton pool of carbon leaking out slowly with deforestation, and the potential for large belches of CO2 going into the atmosphere through forest fire is very, very real,” says Nepstad. “It’s actually happening; it’s not a hypothetical thing. Whether or not that locks us into a brand new climate in the Amazon [with half of the region dominated by grasslands instead of forest] remains to be seen, but it’s a potential.”
Early models indicated 30 or 40 percent deforestation might make the ecosystem break down and turn parts of the southern and eastern Amazon into savanna. Now, Lovejoy and others believe those other intrusions – climate change and fire – may have pushed the numbers down to 20 or 25 percent. And 17 percent of the Brazilian Amazon is already gone. Whatever the precise threshold, scientists don’t want to test it. “Nobody knew at the time of the Dust Bowl that those last trees they were cutting would push them over the edge,” says Lovejoy.