As warming intensifies, scientists warn, the oxygen content of oceans across the planet could be more and more diminished, with serious consequences for the future of fish and other sea life.

Environmentalists in the U.S. are increasingly trying to use the Endangered Species Act to ease the impact of global warming on numerous animals and plants, including the American pika. The goal is not only to protect the habitat of at-risk species but also to force reductions in greenhouse gas emissions.

The polar bear has long been a symbol of the damage wrought by global warming, but now biologist Andrew Derocher and his colleagues have calculated how long one southerly population can hold out. Their answer? No more than a few decades, as the bears’ decline closely tracks that of the Arctic’s disappearing sea ice.

Primatologist Patricia Wright has spent the past 25 years studying — and protecting — Madagascar’s rich yet highly threatened biodiversity. Now, as many of the island’s remaining forests are being felled in the wake of a 2009 coup, Wright describes how she is helping organize the local residents and international conservation organizations to fight back.

Large corporations, not small-scale farmers, are now the major forces behind the destruction of the world’s tropical forests. From the Amazon to Madagascar, activists have been directing their actions at these companies — so far with limited success.

The images of pelicans and other Gulf of Mexico seabirds drenched in oil have stirred sadness and outrage around the world. But, says conservationist Melanie Driscoll, the unseen effects are probably far greater, with some birds perishing out of sight, far from shore, and others facing spill-related declines in the fish on which they depend.

A prominent marine biologist says the impacts of the oil gushing into the Gulf of Mexico will persist for years, no matter when the flow finally stops. What’s more, scientist Thomas Shirley says that most of the damage remains out of sight below the surface, as creatures succumb to the toxic effects of the rapidly spreading tide of oil.

Among the natural treasures at risk from the oil spill in the Gulf of Mexico is the Breton National Wildlife Refuge, created by Theodore Roosevelt to halt a grave threat to birds in his era — the lucrative trade in plumage. Now, oil from the BP spill is starting to wash up on beaches where Roosevelt once walked.

The chairman of the Intergovernmental Panel on Climate Change acknowledges it has been a rough few months for his organization. But, he argues, no amount of obfuscation and attacks by conspiracy theorists will alter the basic facts — global warming is real and intensifying.

With nearly $800 billion in drugs sold worldwide, pharmaceuticals are increasingly being released into the environment. The “green pharmacy” movement seeks to reduce the ecological impact of these drugs, which have caused mass bird die-offs and spawned antibiotic-resistant pathogens.

This April marks the 40th anniversary of Earth Day, an event that has attracted millions to environmental causes. But winning passage of meaningful legislation on climate change requires more than slogans and green talk — it demands intense, determined political action.

The pronghorn, a close relative of the antelope, is the fastest mammal in North America and an iconic creature in the American West, where an estimated 700,000 roam the high desert and plains. In recent years, however, intensive development has begun to eat away at the pronghorn’s territory. In a video report for Yale Environment 360, journalists Daniel Glick and Ted Wood examine the fate of a herd of pronghorn that has migrated for more than 6,000 years from the Grand Teton Mountains to their wintering grounds.

Across western North America, huge tracts of forest are
dying off at an extraordinary rate, mostly because of outbreaks of insects.
Scientists are now seeing such forest die-offs around the world and are linking
them to changes in climate.

The obscenely profitable market for bluefin tuna in Japan has led to years of overfishing and left the world’s bluefin population badly depleted. A ban on the bluefin trade, if adopted at international talks this month, would go a long way toward giving this magnificent fish a chance to recover.

Populations of many of the world’s wild cats are plummeting, with the number of tigers falling to roughly 3,200. In an interview with Yale Environment 360, Alan Rabinowitz, a leading wild cat biologist, lays out a vision of how populations of these magnificent creatures can be brought back from the brink.

As burgeoning human populations place greater pressure on wild areas, a strategy is emerging for preserving threatened lands and wildlife. Known as ‘rewilding,’ it involves expanding core wilderness areas, connecting them via corridors that allow humans and animals to co-exist, and protecting and reintroducing top predators.

The traditional parks model of closing off areas and keeping people out simply may not work in Africa, where human demands on the land are great. Instead, what’s needed is an approach that finds ways to enable people and animals to co-exist.

The treeless ecosystem of mosses, lichens, and berry plants is giving way to shrub land and boreal forest. As scientists study the transformation, they are discovering that major warming-related events, including fires and the collapse of slopes due to melting permafrost, are leading to the loss of tundra in the Arctic.

In the past dozen years, three new diseases have decimated populations of amphibians, honeybees, and — most recently — bats. Increasingly, scientists suspect that low-level exposure to pesticides could be contributing to this rash of epidemics.

Since the government's collapse after a coup last March, Madagascar's rainforests have been plundered for their precious wood and unique wildlife. But now there are a few encouraging signs, as officials promise a crackdown on illegal logging and ecotourists begin to return to the island.

As wild fish stocks continue to dwindle, aquaculture is becoming an increasingly important source of protein worldwide. Now, a growing number of entrepreneurs are raising fish in large pens in the open ocean, hoping to avoid the many environmental problems of coastal fish farms.