In four decades as a marine biologist, Nancy Knowlton has played a key role in documenting the biodiversity of coral reefs and the threats they increasingly face. In an interview with Yale Environment 360, she assesses the state of the world’s corals and highlights conservation projects that offer hope of saving these irreplaceable ecosystems.

Innovative energy technologies are certainly essential if the world is to curb carbon emissions. But in response to a recent e360 article by the co-founders of the Breakthrough Institute, an economist argues we must also cap emissions or put a price on carbon in order to avoid the worst impacts of climate change.

Long ahead of the rest of the U.S. on environmental policy, California is taking bold steps to tackle climate change — from committing to dramatic reductions in emissions, to establishing a cap-and-trade system, to mandating an increase in zero-emission vehicles. The bottom line, say state officials, is to foster an economy where sustainability is profitable.

It is a pattern seen in various parts of the world — children being sickened from exposure to lead from mining activities. But the scale of the problem in Nigeria’s gold-mining region of Zamfara is unprecedented: More than 400 children have died and thousands more have been severely poisoned by exposure to lead dust.

Polar bears have long come ashore in Churchill, Manitoba, the self-styled ‘Polar Bear Capital of the World.’ But as summer sea ice steadily disappears in Hudson Bay, bears are being marooned on land for longer periods of time — and that is generating a lot of work for the Polar Bear Alert Team.

The long-held contention that rural forest communities are the prime culprits in tropical forest destruction is increasingly being discredited, as evidence mounts that the best way to protect rainforests is to involve local residents in sustainable management.

The world has never seen anything like China’s dizzying urbanization boom, which has taken a heavy environmental toll. But efforts are now underway to start using principles of green design and smart growth to guide the nation’s future development.

Twenty years ago, an historic environmental summit in Rio de Janeiro produced groundbreaking treaties and high hopes that pressing issues would be addressed. But as organizers prepare for the Rio+20 conference in June, there is little on the agenda to suggest any substantive action will be taken.

Two of the world’s leading experts on the world’s top marine predator are now in Antarctica, tagging and photographing a creature whose remarkably cooperative hunting behavior and transmission of knowledge across generations may be rivaled only by humans.

Canada’s Nunavut Territory is the largest undisturbed wilderness in the Northern Hemisphere. It also contains large deposits of uranium, generating intense interest from mining companies and raising concerns that a mining boom could harm the caribou at the center of Inuit life.

For two decades, TRAFFIC’s Tom Milliken has tracked the illicit ivory trade that has led to the continued slaughter of Africa’s elephants. In an interview with Yale Environment 360, Milliken talks about the recent increase in ivory seizures and the criminal gangs that supply Asia’s black market for ivory.

From Brazil to Borneo, new roads are being built into tropical forests at a dizzying pace, putting previously intact wilderness at risk. If we hope to preserve rainforests, a leading researcher says, new strategies must be adopted to limit the number of roads and reduce their impacts.

China has undertaken ambitious reforestation initiatives that have increased its forest cover dramatically in the last decade. But scientists are now raising questions about just how effective these grand projects will turn out to be.

The Japanese government is launching a large-scale cleanup of the fields, forests, and villages contaminated by the Fukushima nuclear disaster. But some experts caution that an overly aggressive remediation program could create a host of other environmental problems.

Geographer Edward Carr has worked extensively in sub-Saharan Africa, where climate change and other environmental threats present a growing challenge. In an interview with Yale Environment 360, Carr talks about why any outside aid to the developing world must build on the inherent capability of the local residents.

Biologist Roger Payne played a key role in helping end the wholesale slaughter of whales. In an interview with Yale Environment 360, Payne discusses the mysteries of these legendary marine mammals and the threats they continue to face.

The Australian government will begin imposing a tax on carbon emissions in mid-2012. But large giveaways to industry mean Australia’s scheme doesn’t go nearly far enough in reducing the nation’s CO2 emissions or providing economic stimulus.

Scientists and conservationists are increasingly relying on heat- and motion-activated camera traps to study rare or reclusive species in remote habitats. And the striking images they provide are proving to be a boon for raising conservation awareness worldwide.

The acidification of the world’s oceans from an excess of CO2 has already begun, as evidenced recently by the widespread mortality of oyster larvae in the Pacific Northwest. Scientists say this is just a harbinger of things to come if greenhouse gas emissions continue to soar.

More than half of the timber now shipped globally is destined for China. But unscrupulous Chinese companies are importing huge amounts of illegally harvested wood, prompting conservation groups to step up boycotts against rapacious timber interests.