New Zealand's forest used to be home to millions of kiwi. Now there are only 68,000 left.

At the International Seabed Authority’s ocean-side headquarters, delegates from dozens of countries strolled through breezeways adorned with the works of Jamaican artists as the United Nations-chartered organization’s annual meeting began its second week.

As recently as the 1980s, gray seals effectively were extinct on Cape Cod.

In the days after President Donald Trump’s announcement to withdraw from the Paris Climate Agreement, more than 1,200 cities, states, universities, and corporations declared, "We are still in."

Did the Montreal Protocol fix the ozone hole? It seemed so.

Britain is phasing out its coal-burning power plants, with the last one slated to be shuttered by 2025, if not sooner.

Eleven thousand years ago, the invention of agriculture made stable food supplies possible for the first time. In a relative blink of the eye, farming whisked aside 2 million years of hunting and gathering.

A century or two from now, people may look back at our current era — with its record-breaking high temperatures year after year, rapid disappearance of Arctic sea ice, and gradually rising sea levels — as part of a much cooler and far more desirable past.

Pope Francis has warned history will judge world leaders who do not act as he blasted climate change sceptics in the wake of Hurricanes Irma and Harvey.

The rapid growth of digital data has been a boon to researchers and conservationists.