Is human activity altering the planet on a scale comparable to major geological events of the past? Scientists are now considering whether to officially designate a new geological epoch to reflect the changes that homo sapiens have wrought: the Anthropocene.

The oil slick spreading across the Gulf of Mexico has shattered the notion that offshore drilling had become safe. A close look at the accident shows that lax federal oversight, complacency by BP and the other companies involved, and the complexities of drilling a mile deep all combined to create the perfect environmental storm.

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.

Earlier this year, climatologist Ellen Mosley-Thompson led an expedition to drill into glacial ice on the Antarctic Peninsula, one of the world’s fastest-warming regions. In an interview with Yale Environment 360, Mosley-Thompson explains what the Antarctic ice cores may reveal and describes what it’s like working in the world’s swiftly melting ice zones.

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.

Once, on both sides of the Atlantic, fish such as salmon, eels, and, shad were abundant and played an important role in society, feeding millions and providing a livelihood for tens of thousands. But as these fish have steadily dwindled, humans have lost sight of their significance, with each generation accepting a diminished environment as the new norm.

As the world warms, sea levels could easily rise three to six feet this century. But increases will vary widely by region, with prevailing winds, powerful ocean currents, and even the gravitational pull of the polar ice sheets determining whether some coastal areas will be inundated while others stay dry.

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.

A new study says the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, the study concludes, current changes in ocean chemistry due to the burning of fossil fuels may portend a new wave of die-offs.

The shrinking ice cap atop Mount Kilimanjaro is Africa’s most famous glacier. But the continent harbors other pockets of ice, most notably in the Rwenzori Mountains of western Uganda. And as temperatures rise, the Rwenzori’s tropical glaciers — located as high as 16,500 feet — are fast disappearing.

As governments, businesses, and homeowners plan for the future, they should assume that the world’s oceans will rise by at least two meters — roughly seven feet — this century. But far too few agencies or individuals are preparing for the inevitable increase in sea level that will take place as polar ice sheets melt.

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.

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.

On the eve of the Copenhagen conference, a group of scientists has issued an update on the 2007 report of the Intergovernmental Panel on Climate Change. Their conclusions? Ice at both poles is melting faster than predicted, the claims of recent global cooling are wrong, and world leaders must act fast if steep temperature rises are to be avoided.

For months, hopes that a climate treaty would be signed at the upcoming Copenhagen conference have been raised, then dashed, then raised again. Now, with prospects waning that a binding accord on reducing greenhouse gas emissions can be reached this year, ten environmental leaders and climate experts outline for Yale Environment 360 what they believe can still be accomplished at Copenhagen.

Amid a growing call for reducing atmospheric concentrations of CO2 to 350 parts per million, a group of economists maintains that striving to meet that target is a smart investment — and the best insurance policy humanity could buy.

In her long career as an oceanographer, Sylvia Earle has witnessed the damage that humanity has done to the Earth’s oceans. But in an interview with Yale Environment 360, she says there's still time to pull the seas back from the brink.

As the international community focuses on climate change as the great challenge of our era, it is ignoring another looming problem — the global crisis in land use. With agricultural practices already causing massive ecological impact, the world must now find new ways to feed its burgeoning population and launch a "Greener" Revolution.

The natural landscape of South Korea has been largely re-engineered, with nearly every river damned or forced into concrete channels. Now the government is reviving plans for a mammoth water project that would dredge and develop hundreds more miles of waterways and put added stress on the country's remaining wildlife.

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.