As governments and corporations pledge to help the planet by planting trillions of trees, a new study spotlights an effective, low-cost alternative: letting tropical forests regrow naturally.

Abandoned US oil and gas wells and their associated land cover more than 2 million acres, a recent study estimates – an area larger than Delaware and Rhode Island combined.

Healthy seagrasses form underwater meadows teeming with fish and shellfish. A successful large-scale restoration project in Virginia could become a model for reseeding damaged seagrass beds worldwide.

For the first time in the US, a ballot measure will ask voters whether to restore wolves to a place where they've been eradicated. Coloradans have strong views on both sides.