As he assumes the presidency, Barack Obama must make climate-change legislation and investment in green energy top priorities. And he must be ready to take bold — and politically unpopular — action to address global warming.

The next U.S. president should not wait for Congress to act on climate-change legislation. Instead, he should make use of the Clean Air Act to begin controlling greenhouse gas emissions and to implement a national cap-and-trade program.

Stavros Dimas, environmental commissioner for the European Union, says the global economic crisis is no reason to lose focus on efforts to fight climate change. In an interview with Yale Environment 360, he talked about the lessons of the EU's emissions trading system, and why the U.S. should not give away permits in a cap-and-trade system — it should get something for them.

Environmentalists had been looking to a new president and a new Congress to pass legislation dealing with global warming next year. But with tough economic times looming, the passage of a sweeping climate change bill now appears far less likely.

Despite the potential for abuse, the concept of paying others to compensate for our environmental sins can be a valuable tool in helping reduce carbon emissions. But the world can’t simply buy its way out of global warming.

Oil isn't America's only fuel addiction. Inefficient and environmentally damaging, the corn-ethanol boondoggle will nonetheless be hard to stop.

Congress has repeatedly failed to extend the tax credits for renewable energy, which expire at the end of this year. The gridlock is discouraging investment in renewables and jeopardizing major solar and wind projects throughout the country.

Texas billionaire T. Boone Pickens has always been one to think big. But his sweeping 10-year energy plan for America faces obstacles that may be insurmountable.

The crackdown on dissent surrounding the Beijing Olympics has been a reminder of China’s lingering authoritarianism. Yet for all our differences, the U.S. and China — the world’s two largest emitters of carbon dioxide — have no choice but to work together to tackle climate change.