Fate of the Amazon

If current patterns continue, 40 percent of the Amazon rainforest will be gone by mid-century, according to a study published in the journal Nature. Much of the forest is going up in smoke, burned to clear land for agriculture -- principally soybean cultivation and cattle ranching. The rate of destruction has nearly doubled in the past decade. 9,000 square miles of forest (a New Hampshire's worth) were cleared in 2004.

The loss is an environmental catastrophe of the highest order. Not only will it mark a massive decrease in the world's biodiversity but it could also reinforce climate change. Computer models suggest that the forest will "die back" in response to increased drought, in turn releasing more carbon dioxide into the atmosphere.

By contrast, models suggest that if the proper steps are taken to protect the resource 73 percent of the original forest could be left standing in 2050, with carbon emissions reduced accordingly. Since that outcome benefits the entire world, scientists argue that affluent countries should be willing to foot the bill.