The solar power boom in Germany, Spain, and parts of the United States has been fueled by government subsidies. But now some U.S. states — led by New Jersey, of all places — are pioneering a different approach: issuing tradable credits that can be sold on the open market. So far, the results have been promising.

With skepticism growing about the chances of reaching a climate agreement next month in Copenhagen, Rajendra Pachauri, chairman of the Intergovernmental Panel on Climate Change, says he is “cautiously optimistic” that a treaty can still be signed. But in an interview with Yale Environment 360, Pachauri says the global community may have to move ahead without any commitment from the United States.

Interfering with the Earth’s climate system to counteract global warming is a controversial concept. But in an interview with Yale Environment 360, climate scientist Ken Caldeira talks about why he believes the world needs to better understand which geoengineering schemes might work and which are fantasy — or worse.

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.

If a cap-and-trade bill passes Congress this year, it may include weak emissions targets and will likely need to be strengthened in the years to come. One way to guide future policy: create a Global Climate Change Index that could be used to track global warming’s impacts.

In the Yaak Valley of Montana, environmentalists have been talking to loggers, snowmobilers and other longtime opponents of wilderness protection about the future of public lands. Their accord is part of a cooperative effort that could lead to the first wilderness-area designation in the state in a quarter century.

In an interview with Yale Environment 360, John Kerry praises the carbon cap-and-trade legislation now being debated in the U.S. Senate, describes its importance to upcoming climate talks in Copenhagen, and explains how he plans to help the landmark legislation clear the Senate and become law.

Tighter restrictions on mountaintop removal mining are simply not enough. Instead, a leading climate scientist argues, the Obama administration must prohibit this destructive practice, which is devastating vast stretches of Appalachia.

As carbon cap-and-trade legislation works it way through Congress, the environmental community is intensely debating whether the Waxman-Markey bill is the best possible compromise or a fatally flawed initiative. Yale Environment 360 asked 11 prominent people in the environmental and energy fields for their views on this controversial legislation.

The United States powered its rise to affluence with fossil fuels, and China resents being told it should not be free to do the same. So as negotiators prepare for crucial climate talks this December, the prospects for reaching agreement remain far from certain.

As Congress struggles over a bill to limit carbon emissions, a cap-and-trade program is already operating in 10 Northeastern states. But the regional project's mixed success offers a cautionary warning to U.S. lawmakers on how to proceed.

Two prominent — and iconoclastic — environmentalists argue that current efforts to tax or cap carbon emissions are doomed to failure and that the answer lies not in making dirty energy expensive but in making clean energy cheap.

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 days of freely dumping greenhouse gases into the atmosphere are coming to an end, but how best to price carbon emissions remains in dispute. As the U.S. Congress debates the issue, Yale Environment 360 asked eight experts to discuss the merits of a cap-and-trade system versus a carbon tax.

For spurring the transformation to a low-carbon economy, the federal and state governments, universities, and the private sector must join together to create a network of energy research institutes that could speed development of everything from advanced batteries to biofuels.

In an interview with Yale Environment 360, Bill McKibben explains why he’s now focused on organizing a citizens movement around climate change — and why he believes this effort is critical for spurring world leaders into action.

With global warming pushing some animals and plants to the brink of extinction, conservation biologists are now saying that the only way to save some species may be to move them.

With carbon cap-and-trade legislation now on Washington’s agenda, companies and interest groups have been hiring lobbyists at a feverish pace. For every member of Congress, there are now four climate lobbyists, many of them hoping to derail or water down the effort to reduce greenhouse gas emissions.

Secretary of State Hillary Clinton’s trip to China could be the first step in forging a partnership between the world’s largest emitters of greenhouse gases. A leading China expert sets forth a blueprint for how the U.S. and China can slow global warming and strengthen their crucial relationship.

NASA’s Robert Bindschadler, a leading expert on glaciers and ice sheets, is part of an international team monitoring a large and fast-moving glacier in West Antarctica. In an interview with Yale Environment 360, he explains the dramatic impact this unstable mass of ice could have on global sea levels.