Amazon rainforest could be unsustainable within a decade

Edinburgh, Scotland -- Talk of saving the rainforests is as burned into the collective minds of people as refrains to "Save the Whales" and to "Make Love, Not War." Without action, however, the day when there are no tropical rainforests to talk about could come a lot sooner than people think, according to a Penn State Abington researcher.

Working from his office on campus, James (Bud) Alcock, professor of environmental sciences, has developed a mathematical model to study the effect of human-driven deforestation. Current deforestation rates of about 1 percent per year in the Amazon River Basin rainforest in Brazil could push the rainforests past the point where they can sustain themselves a lot sooner than many people think. The other key tropical rainforests are in the Congo River Basin in Africa and Southeast Asia. To use the two-million-square-mile Amazon River Basin as an example, Alcock said his model shows that if there is no immediate and aggressive action to change current agricultural, mining and logging practices, the rainforest could pass "the point of no return" in 10 to 15 years. When all is said and done, the model indicates that the rainforest could essentially disappear within 40 to 50 years. That is a far cry from the common belief among researchers that the forest is still 75 to 100 years away from total deterioration, if current patterns prevail, said Alcock.

"Because of the way tropical rainforests work, they are dependent on trees to return water to the air," said Alcock, noting that the sheer size of the Amazon River Basin has already been reduced by about 25 percent. "This interdependence of climate and forest means risks to the forests are much closer at hand than what we might expect, and we're doing very little because of the priorities of Brazil and The Congo. It's a very difficult problem because of several pressures. For example, you cannot say, 'leave the rainforests alone' when people are living in poverty."

Rainforests are dependent on high levels of precipitation brought on by daily rain, and a healthy forest holds onto the rain and returns it to the atmosphere so it can be recycled -- a process called evapotranspiration. Without a healthy base of vegetation, water runoff occurs at a higher rate, and it creates the potential for a highly unstable rainforest system.

There are those who espouse preserving small portions of the rainforest, but Alcock said damage to the overall system would probably limit the rain necessary to do that. Less rain could also mean more forest fires, further threatening the balance of the rainforest.

Alcock presented his findings today (June 25) at a joint conference of the Geological Society of America and the Geological Society of London titled, "Earth System Processes," in Edinburgh, Scotland.

While others have studied the effect of tropical rainforest deforestation on regional and global climates, Alcock said his study differs because it focuses on the local impact of the issues. In the Amazon River Basin, for example, loss of the forest would likely cause the extinction of many species of animals that thrive in such an environment, he said.

"There are already a large number of species that are endangered, because the forest itself is endangered," said Alcock. "We might be able to keep a few animals at the zoos, but we'd surely lose a lot of amphibians, reptiles and insects. We couldn't take them all."

Alcock decided to do the research so he could better explain the concept of feedback (exemplified by precipitation and evapotranspiration in the rainforest) to students in one of his introductory courses on earth systems. He hopes to advance his future studies by visiting the Amazon River Basin, or collaborating with someone who has done field research there.

Contacts: David Jwanier 610-648-3276. A'ndrea Elyse Messer 814-865-9481 (o)/ 814-867-1774 (h) [email protected]