Turkeys got help for 75 years from conservation agencies. Coyotes spread across half the country all on their own. Why have these animals succeeded? How have they changed the environment?

Ultralight aircraft are guiding crane chicks toward Florida wintering grounds. Dangers remain, but it’s a step ahead for Americas’ largest flying bird, once reduced to 21 animals.

The ozone layer protects Earth from UV rays: Twenty-two years after a treaty to protect ozone, how is the layer doing? What has happened to the ozone hole above Antarctica?

As Earth warms, should we try huge geoengineering projects to cool the climate? Would adding iron to fertilize ocean plants withdraw enough carbon dioxide to slow warming — or backfire?

Companies are marketing genetic tests direct to consumers. Some tests can be lifesavers. But many tests return confusing results, which even doctors have a hard time interpreting.

Three giant new reserves, extend 50 miles out from shore, will protect coral reefs, fish, clams, and other life forms. But how effective are marine protected areas?

Oils in spent coffee grounds are easily converted into biodiesel — a renewable source of transportation energy. Bottoms up for CofFuel?

Carbon tax or carbon trading? As the United Nations gets set for (another!) pow-wow on global warming, policy wonks are focusing on two mechanisms to reduce carbon pollution. Which gets more control at a lower price: carbon tax or carbon cap-and-trade?

Each hour, the ocean dissolves 1 million tons of carbon dioxide from burning fossil fuel. As the water grows more acidic, sound travels further. What will happen to marine mammals, which rely on an exquisite sense of hearing?

Rapid melting of Canadian ice sheet suggests that Greenland’s massive ice cap could melt and raise sea level much faster than predicted within a century.