On the anniversary of the Deepwater Horizon explosion, the worst fears about the long-term damage from the oil spill have not been realized. But the big challenge is more fundamental: repairing the harm from the dams, levees, and canals that are devastating the Mississippi Delta and the Louisiana coast.

With contaminated water from Japan’s crippled Fukushima nuclear complex continuing to pour into the Pacific, scientists are concerned about how that radioactivity might affect marine life. Although the ocean’s capacity to dilute radiation is huge, signs are that nuclear isotopes are already moving up the local food chain.

The Japanese earthquake and tsunami remind us that we exist in geologic time and in a world where catastrophic events beyond our predicting may occur. These events — and the growing specter of climate change — show how precariously we exist on the surface of a volatile planet.

The devastating tsunami in northeastern Japan is only one of many that have battered Japan over the eons. In an interview with Yale Environment 360, tsunami and earthquake expert Lori Dengler describes the historic and paleological record of tsunamis across the Pacific, and what it may mean in the future for Japan and the western United States.

Numerous companies are moving ahead rapidly with plans to mine copper, gold, and other minerals near hydrothermal vents on the ocean floor. But in an interview with Yale Environment 360, marine biologist Cindy Lee Van Dover warns that without environmental safeguards the unique ecosystems of deep-sea vents could be severely damaged.

As concerns grow in the U.S. about the environmental impact of hydraulic fracturing, or “fracking,” to extract natural gas from shale, companies have set their sights on Europe and its abundant reserves of this “unconventional” gas. But from Britain to Poland, critics warn of the potentially high environmental cost of this looming energy boom.

As agriculture and energy production have made strides toward becoming more sustainable, the world’s fisheries have lagged behind. But restoring our beleaguered oceans to health will require an emphasis on diversification and conservation — and a more sensible mix of fishing practices.

Grizzly bears mating with polar bears. Red foxes out-competing Arctic foxes. Exotic diseases making their way into once-isolated polar realms. These are just some of the worrisome phenomena now occurring as Arctic temperatures soar and the Arctic Ocean, a once-impermeable barrier, melts.

An increasingly productive way of restoring fisheries is based on the counter-intuitive concept of allowing fishermen to take charge of their own catch. But the success of this growing movement depends heavily on a strong leader who will look out not only for the fishermen, but for the resource itself.

William Reilly led the national commission that investigated the Deepwater Horizon oil spill and says he was struck by the totally inadequate response plans that were in place. In an interview with Yale Environment 360, he talks about why it’s crucial to carry out the reforms needed to prevent future disasters.

The world’s oceans have been experiencing enormous blooms of jellyfish, apparently caused by overfishing, declining water quality, and rising sea temperatures. Now, scientists are trying to determine if these outbreaks could represent a “new normal” in which jellyfish increasingly supplant fish.

Researchers disagree about what the economic costs of climate change will be over the coming decades. But the answer to that question is fundamental in deciding how urgent it is to take action to reduce emissions.

The Chinese government has begun to make environmental records available to the public, empowering green groups and citizens as they try to force factories — and the Western companies they supply — to comply with the law.

The Cancun conference is being credited with keeping international climate talks alive. But the real potential for bringing emissions under control may lie in a Plan B, with nations acting on their own in moving toward a low-carbon economy.

It is a difficult idea to fathom. But the science is clear: Unless we change the way we live, the Earth's coral reefs will be utterly destroyed within our children's lifetimes.

The fringes of the coldest continent are starting to feel the heat, with the northern Antarctic Peninsula warming faster than virtually any place on Earth. These rapidly rising temperatures represent the first breach in the enormous frozen dome that holds 90 percent of the world’s ice.

As the economies of China and other Asian nations have boomed, demand for shark fins — a prized delicacy — has soared, leading to severe overfishing of many shark species. In an interview with Yale Environment 360, shark conservationist Sonja Fordham talks about the battle to save one of the world’s most magnificent fish.

In China, millions of tons of waste from livestock farms are causing severe water pollution and massive emissions of methane. Now, some large livestock operators are turning to biogas fuel production in hopes of creating “ecological” factory farms.

The number of salmon in the Pacific Ocean is twice what it was 50 years ago. But there is a downside to this bounty, as growing numbers of hatchery-produced salmon are flooding the Pacific and making it hard for threatened wild salmon species to find enough food to survive.

Climate policies that require public sacrifice and limiting economic growth are doomed to failure. To succeed, policies to reduce emissions must promise real benefits and must help make clean energy cheaper.

Last spring, conservation groups and timber companies signed an historic agreement to protect a large swath of Canada’s boreal forest. In an interview with Yale Environment 360, the Pew Environment Group's Steven E. Kallick, a key player in the agreement, explains why the accord is integral to a larger plan to eventually preserve half of Canada’s extensive boreal forests.