Environmentalist and indigenous-rights protestors vow to take the fight to other pipeline projects as they leave the Standing Rock Sioux reservation in North Dakota.
Amid concerns about climate change and habitat destruction, thousands of citizen-scientists look to the skies to track the progress of birds as the Great Backyard Bird Count begins.
A new study makes the case that a mostly submerged landmass about two-thirds the size of Australia meets all the usual criteria for a continent.
What's next for the EPA? Some fear nominee Scott Pruitt's intentions, but others say the green revolution's momentum will limit damage.
Warm air and warm water bring more bad news for marine life.
El Niño brought unprecedentedly powerful waves to the Pacific Coast in 2015-2016, while droughts starved beaches of sediment, according to a new study.