China is on its way to becoming the world’s largest producer of renewable energy, yet it remains one of the most polluted countries on earth. A year after the Beijing Olympics, economic and political forces are combining to make China simultaneously a leader in alternative energy — and in dirty water and air.

As Borneo's rain forests are razed for oil palm plantations, wildlife centers are taking in more and more orphaned orangutans and preparing them for reintroduction into the wild. But the endangered primates now face a new threat — there is not enough habitat where they can be returned.

Biofuels ”“ made from algae and non-food plants ”“ are emerging as a potentially viable alternative to conventional jet fuels. Although big challenges remain, the reductions in greenhouse gas emissions could be major.

Over the past two decades, mountaintop removal mining in Appalachia has obliterated or severely damaged more than a million acres of forest and buried more than 1,000 miles of streams. Now, the Obama administration is showing signs it plans to crack down on this destructive practice.

The scrubby jatropha tree has been touted as a wonder biofuel with unlimited potential. But questions are now emerging as to whether widespread jatropha cultivation is really feasible or whether it will simply displace badly-needed food crops in the developing world.

New solar thermal technology overcomes a major challenge facing solar power: how to store the sun’s heat for use at night or on a rainy day. As researchers tout its promise, solar thermal plants are under construction or planned from Spain to Australia to the American Southwest.

Mostly conceived by international architects, China’s eco-cities were intended to be models of green urban design. But the planning was done with little awareness of how local people lived, and the much-touted projects have largely been scrapped.

The economic downturn need not halt the development of green energy. In fact, with renewable technologies improving dramatically and new U.S. policies emerging, continued progress toward an energy revolution is inevitable.

The number of vehicles worldwide is expected to reach two billion in the next two decades. Surprisingly, China where the demand for cars has been skyrocketing just may offer the best hope of creating a new, greener transportation model.

Yale University’s recently opened Kroon Hall is a state-of-the-art model of where the green building movement is headed. Yet even this showcase for renewable energy highlights the difficulties of creating a building that is 100 percent carbon neutral.

In a bold departure from past U.S. policies, President Barack Obama sees clean energy and “green jobs” as critical components of an economic stimulus strategy.

Geologist Yong Yang has serious concerns about plans for a massive Yangtze River diversion project. When he went public with them, he found out how difficult it can be to challenge a government decision in China. The third in a series on Chinese environmentalists.

Environmentalists from Bill McKibben and Paul Hawken, to Fred Krupp and Frances Beinecke offer President Obama their advice on the priorities he should set for the first 100 days of his administration.

In evaluating an economic recovery package, the new U.S. administration and Congress must weigh any proposed spending on highways or mass transit or wind-power transmission routes on the basis of clear criteria that would assess just how green the projects will be.

In an interview with Yale Environment 360, Amory Lovins, co-founder and chairman of Rocky Mountain Institute, says that world's biggest untapped energy source is efficiency. And retooling for energy efficiency will require "barrier-busting" at many levels. And government, Lovins says, "should steer, not row."

For four decades, American politicians have talked about ending U.S. dependence on foreign oil. But during the campaign and since his election victory, Barack Obama has made it clear that he finally intends to change the way America powers itself.

When industry began using NF3 in high-tech manufacturing, it was hailed as a way to fight global warming. But new research shows that this gas has 17,000 times the warming potential of carbon dioxide and is rapidly increasing in the atmosphere and that's turning an environmental success story into a public relations disaster.

Until now, geothermal technology has only been used on a small scale to produce power. But with major new projects now underway, deep geothermal systems may soon begin making a significant contribution to the world’s energy needs.

U.S. cities have been using green planning to spark economic development, helping create a real urban renaissance in America. With a new administration soon to arrive in Washington, these same approaches may finally start being used on a national scale.