President Bush is urging Congress to open the U.S. coasts and the Arctic National Wildlife Refuge to oil and gas drilling. But America must ultimately wean itself off fossil fuels. The question is whether it makes the transition now — or waits until every last one of its unspoiled places has been drilled.

With soaring prices for agricultural goods and new demand for biofuels, the clearing of the world's largest rain forest has accelerated dramatically. Unless forceful measures are taken, half of the Brazilian Amazon could be cut, burned or dried out within 20 years.

As the public seeks answers about the future impacts of climate change, some climatologists are growing increasingly uneasy about the localized predictions they are being asked to make.

Paleontologists and geologists are looking to the ancient past for clues about whether global warming will result in mass extinctions. What they're finding is not encouraging.

The world's greatest lake, holding 20 percent of the planet's surface fresh water, has long remained one of the most pristine places on earth. Now, as Russia's economy booms and its climate warms, the Siberian lake faces new threats.

The burgeoning amount of carbon dioxide in oceans is affecting a lot more than coral reefs. It is also damaging marine life and, most ominously, threatening the future survival of marine populations.

By taking bits of a single gene, scientists are using DNA barcoding to identify new species. If a portable hand-held scanning device can be developed, one ecologist says, it could “do for biodiversity what the printing press did for literacy.”