It turns out that they're coming back without much help from environmental activists. As the New York Times reports on its front page today:
By one estimate, for every acre of rain forest cut down each year, more than 50 acres of new forest are growing in the tropics on land that was once farmed, logged or ravaged by natural disaster.
Why? Because more and more poor people have better things to do than slog around in muddy and poorly producing farms having babies, so they're abandoning farms and allowing forests to return. This is exactly what has happened in industrialized countries in the 20th century. In addition, researchers point out that forest regrowth is not limited to industrialized countries -- it also occurred between 1990 and 2005 in India, China, Turkey, Ukraine, Tunisia, Vietnam, and Malaysia. Roger Sedjo, a senior fellow at Resources for the Future earlier explained:
People ask us why reforestation occurs. The study confirmed a relationship between per capita income in countries and forest expansion. Environmental economists know that initial increases in per capita income are associated with the deteriorating environmental quality— and then there's a point at which it levels off as income increases. As income rises and countries become wealthier, we see environmental quality improving. We found something very similar with forestry. None of our 50 most forested countries with a per capita income of $4,600 or more had experienced deterioration in their forests. They were all either constant or positive, one of our most interesting discoveries.
The Times notes:
The idea has stirred outrage among environmentalists who believe that vigorous efforts to protect native rain forest should remain a top priority. But the notion has gained currency in mainstream organizations like the Smithsonian Institution and the United Nations, which in 2005 concluded that new forests were "increasing dramatically" and "undervalued" for their environmental benefits. The United Nations is undertaking the first global catalog of the new forests, which vary greatly in their stage of growth.
"Biologists were ignoring these huge population trends and acting as if only original forest has conservation value, and that's just wrong," said Joe Wright, a senior scientist at the Smithsonian Tropical Research Institute here, who set off a firestorm two years ago by suggesting that the new forests could substantially compensate for rain forest destruction.
It is true that rainforests in Indonesia, Brazil, and the Congo are still declining, but that is largely the result of a gigantic institutional failure. Governments do not recognize ownership of the land, so people rush to take what they can before the next guy can get it--the all too familiar process of an open access commons race to the bottom.
In any case, read the good news about rainforests (and the controversy) here.