Specializing in bizarre-looking plants that grow in dry tropical terrain, Mexico-based plant biologist Mark Olson searches the world for species that have been found, filed away, and forgotten. His quest carries him to some of the most remote—and dangerous—spots on the planet.

Analysis of peat in an Australian volcano may yield clues as to what caused abrupt warming during the last Ice Age, disrupting climate on a global scale. The findings have sparked a debate as to what triggers temperature cycles—and whether the theory can be used to predict climate change.

On any given day during the United States tornado season—which begins later this month and peaks in May—there's a good chance that a twister will touch down somewhere in the country. Despite being so common, these dangerous and sometimes deadly storms remain shrouded in mystery.

Noisy, active, and ubiquitous, birds are one of the most effective alarm systems in nature, often warning other animals, including humans, of trouble in the neighborhood. Now the organizers of a global conference on bird conservation want more people to recognize what birds are telling us about the world environment.

Bill Stone's got one thing on his mind these days—going where no one has gone before. For the past four weeks, he and 39 international teammates have been rappelling, hiking, and digging day in and day out in hopes of breaking into Cheve Cave.

Researchers at Pennsylvania State University have developed a simple "reactor" that treats wastewater while converting electrons produced by resident bacteria into electricity. The still experimental and costly process might someday provide a clean energy source, effective wastewater treatment, and energy savings.

Pervasive environmental pollutants are triggering unnatural sexual changes in animals around the world, according to scientists. The scientists say the gender-bending effects of certain chemical compounds and human sewage pose a serious threat to polar bears, alligators, and other wildlife.

Can a new high-tech tool predict extinction-prone areas? Back from Brazil, biologist Stuart Pimm recounts the unpredictable Brazilian bird quest that put the tool to the test—and reveals what it's really like on a National Geographic research expedition.

Reefs in deep, dark, cold waters may teem with more life than is found in their shallow-water counterparts. Yet even before deep-sea corals have been documented they are being devastated by trawling. Scientists from 69 countries have petitioned world governments to do something to stop the carnage.

A Cold War laser technology designed to sniff out submarines has evolved into a fast-paced way to map uncharted coastline. The airplane-based approach could save ships from unknown hazards and help conserve coastal environment.

Between 45,000 and 28,000 years ago, Neandertals and early humans coexisted in Europe until the Neandertals died out. Why humans survived and Neandertals didn't has long puzzled experts. A seven-year study by 30 scientists suggests climate change triggered Neandertals' demise.

A dense, fine-grained wood hacked from Indonesian forests is the stuff of a real-life tale about smugglers, crime bosses, corrupt politicians, and wildlife teetering on the brink of extinction, according to an undercover investigation by an environmental activist group.

The coastal, saltwater forests of tropical trees and shrubs known as mangroves play a crucial role as nurseries for coral reef fish, scientists say.

Despite England's image of an overcast, rain-sodden land, many of its rivers and wetlands are starved of water. The main culprits, many people say, are the water-provision companies, which are draining aquifers to meet growing consumer demand. Unless consumers pay the "real price" of water, experts warn, Britain may become a dry country.