Carbon dioxide, CO2, makes up less than one-twentieth of 1% of Earth's atmosphere. How does this relatively scarce gas control Earth's thermostat?

Dorian, the 2nd most powerful Atlantic hurricane on record, has devastated the Bahamas, with the death toll expected to rapidly rise as rescue work gets under way.

If you go by cartoons and T-shirts, you might think evolution proceeds as an orderly march toward a preordained finish line. But evolution has no endpoint in mind.

The ArchaeoGlobe Project assessed knowledge on human land use over the past 10,000 years, through the contributions of more than 200 archaeologists. It concluded that, by 3,000 years ago, most of Earth was already transformed by hunter-gatherers, farmers and pastoralists.

Nearly 40,000 fires are burning in Brazil’s Amazon rainforest, the latest outbreak in an overactive fire season. Don’t blame dry weather, say environmentalists. These Amazonian wildfires are a human-made disaster.

On tall ice structures high in the Chilean Andes, researchers found algae growing on snow. They don’t entirely understand how the algae are able to bloom.

New analyses of Saturn's rings reveal how and when they were made, from what, and whether they'll last.

Most people don’t associate the US Pacific Northwest with earthquakes, but maybe they should. It’s home to the 600-mile (1,000-km) Cascadia megathrust fault, stretching from northern California to Canada’s Vancouver Island.

Are the gentle blinks of fireflies flashing a favorite part of your summer evenings? An entomologist explains some lightning bug basics.

Birds spend a lot of time and energy singing, but they don't do it the same way in every season of the year. And some can't sing at all. What's the purpose of birdsong?