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.

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.

In response to industry pressure, the U.S. Food and Drug Administration has failed to set adequate restrictions on mercury levels in fish. Now the Obama administration must move forcefully to tighten those standards and warn the public which fish are less safe to eat.

In the last eight years, vast areas of offshore Alaska have been opened to oil drilling. Now, a conservationist argues, the Obama administration must reverse the Bush-era policies if the state is to avoid irreparable harm to Arctic wildlife and to some of the most biologically productive waters on earth.

Hard-pressed by economic straits, illegal panners are tearing up Zimbabwe’s countryside in search of gold and diamonds. They leave behind a trail of destruction: devastated fields and forests, mud-choked rivers, and mercury-tainted water. Andrew Mambondiyani reports from eastern Zimbabwe.