Carbon emissions from Wisconsin's transportation sector fell 4 percent in the first half of 2008, an abrupt departure after a steady rise in emissions over the past decade that correlates with a rise in gas prices.

MANITOU EXPERIMENTAL FOREST, Colo. -- Rambling along Highway 67 through the Pike National Forest, it is easy to fly right past this section of the forest. Besides the simple roadside sign, a weather station and some scattered stone buildings, there is little to distinguish this 17,000-acre patch of forest from the 1.1 million acres of trees that surround it.

Newly minted environment exchanges in Beijing and Shanghai will allow Chinese companies to trade industrial air pollutants, but domestic trading of carbon dioxide emissions may be a ways off, international observers say.

Democratic aides in the House Energy and Commerce Committee are at work this month writing a major global warming bill aimed at achieving a 60 to 80 percent reduction by midcentury of heat-trapping greenhouse gas emissions.

When Virginia Gov. Tim Kaine (D) launched a bold climate change initiative last September calling for a 30 percent reduction in greenhouse gases by 2025, environmental groups cheered. Then Kaine extended the honeymoon by creating the Governor's Commission on Climate Change, appointing leaders from business, government, academia and nonprofits to craft a plan to shrink the state's carbon footprint. But Kaine now finds himself on shaky ground with environmentalists chagrined by their champion's strong support for coal-fired power, the largest U.S. source of industrial greenhouse gas emissions.

Americans still think global warming is the biggest environmental problem facing the world -- but not as much as they did a year ago, according to a poll released this weekend from ABC News, Planet Green and Stanford University.

NEW YORK -- The New York State Environmental Board voted today to adopt regulations that start state participation in the Regional Greenhouse Gas Initiative (RGGI), a 10-state agreement that establishes the first mandatory trading schemes for U.S. carbon dioxide emissions.

U.S. Geological Survey scientists hope a tule- and cattail-growing experiment in the Sacramento-San Joaquin Delta will help farmers rebuild sinking islands, combat global warming and make a profit.