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.

It's overconsumption, not population growth, that is the fundamental problem: By almost any measure, a small portion of the world's people — those in the affluent, developed world — use up most of the Earth's resources and produce most of its greenhouse gas emissions.

They’re calling it “global weirding” the way in which rising temperatures are causing species to change their ranges, the timing of their migrations, and the way they interact with other living things. And the implications of all this are only beginning to be understood.

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.

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.

The clearing of Indonesia’s rain forest for palm oil plantations is having profound effects threatening endangered species, upending the lives of indigenous people, and releasing massive amounts of carbon dioxide into the atmosphere.

Scientists have long believed that thawing permafrost in Arctic soils could release huge amounts of methane, a potent greenhouse gas. Now they are watching with increasing concern as methane begins to bubble up from the bottom of the fast-melting Arctic Ocean.