Recent studies show that wildlife in some African nations is declining even in national parks, as poaching increases and human settlements hem in habitat. With the continent expected to add more than a billion people by 2050, do these trends portend an Africa devoid of wild animals?

In the Yaak Valley of Montana, environmentalists have been talking to loggers, snowmobilers and other longtime opponents of wilderness protection about the future of public lands. Their accord is part of a cooperative effort that could lead to the first wilderness-area designation in the state in a quarter century.

Clearing land for cattle is responsible for 80 percent of rainforest loss in the Brazilian Amazon. But with Amazon ranching now a multi-billion dollar business, corporate buyers of beef and leather, including Wal-Mart, are starting to demand that the destruction of the forest be halted.

In a matter of years or decades, researchers believe, animals and plants already are adapting to life in a warmer world. Some species will be unable to change quickly enough and will go extinct, but others will evolve, as natural selection enables them to carry on in an altered environment.

As the International Whaling Commission debates whether to ban all whaling or to expand the limited hunts now underway, recent research has convinced some scientists that the world’s largest mammal should never be hunted again.

The environmental damage caused by mountaintop removal mining across Appalachia has been well documented. But scientists are now beginning to understand that the mining operations’ most lasting damage may be caused by the massive amounts of debris dumped into valley streams.

Marine biologist Jane Lubchenco now heads one of the U.S. government’s key agencies researching climate change — the National Oceanic and Atmospheric Administration. In an interview with Yale Environment 360, Lubchenco discusses the central role her agency is playing in understanding the twin threats of global warming and ocean acidification.

Wildlife biologists and climate scientists overwhelmingly agree that the disappearance of Arctic sea ice will lead to a sharp drop in polar bear populations. But some skeptics remain unconvinced, and they have managed to persuade the Canadian government not to take key steps to protect the animals.

Researchers throughout the world are working to produce biofuel from algae. But a few are trying a decidedly novel approach: Using an abundant and freely available source — human waste — to make the fuel of the future while also treating sewage.

As Borneo's rain forests are razed for oil palm plantations, wildlife centers are taking in more and more orphaned orangutans and preparing them for reintroduction into the wild. But the endangered primates now face a new threat — there is not enough habitat where they can be returned.

The Mekong has long flowed freely, supporting one of the world’s great inland fisheries. But China is now building a series of dams on the 2,800-mile river that will restrict its natural flow and threaten the sustenance of tens of millions of Southeast Asians.

By 2100, the world will probably be hotter than it’s been in 3 million years. In an interview with Yale Environment 360, paleoecologist Anthony D. Barnosky describes the unprecedented challenges that many species will face in this era of intensified warming.

The magnificent creature at the heart of the Greater Yellowstone Ecosystem now confronts two grave perils: the loss of its key food source because of rising temperatures, and increased killing by humans. A renowned grizzly expert argues that it’s time to once again protect Yellowstone’s grizzlies under the Endangered Species Act.

With global warming pushing some animals and plants to the brink of extinction, conservation biologists are now saying that the only way to save some species may be to move them.

With record-setting heat waves, bush fires and drought, Australians are increasingly convinced they are facing the early impacts of global warming. Their growing concern about climate change has led to a consensus that the nation must now act boldly to stave off the crisis.

Armed with vivid images from space and remote sensing data, scientists, environmentalists, and armchair conservationists are now tracking threats to the planet and making the information available to anyone with an Internet connection.

Two decades after the Exxon Valdez spilled 11 million gallons of crude oil into Alaska’s waters, the Prince William Sound, its fishermen, and its wildlife have still not fully recovered.

They’re calling it “global weirding” the way in which rising temperatures are causing species to change their ranges, the timing of their migrations, and the way they interact with other living things. And the implications of all this are only beginning to be understood.

Aided by new access to remote regions, researchers have been discovering new species at a record pace — 16,969 in 2006 alone. The challenge now is to preserve threatened ecosystems before these species, and others yet unknown, are lost.

Long an isolated land with abundant forests and biodiversity, Laos is rapidly developing as China and other Asian nations exploit its resources. One of the first casualties has been the wildlife, now being rapidly depleted by a thriving black-market trade.

Julienne Stroeve, a research scientist at the National Snow and Ice Data Center at the University of Colorado, has been closely monitoring the rapid loss of sea ice in the Arctic. In an interview with Yale Environment 360, she explains how the repercussions of that disappearance will be felt throughout the far north and, eventually, the entire hemisphere.