Advocates of federal action to address climate change had little to cheer about in 2010. The prospects may be even grimmer this year, with nearly every important committee chair in the now Republican-controlled House dismissing the threat of global warming or the human contribution to it.

As Congress dawdles and denies, some states are moving forward. Massachusetts recently announced a plan to curb emissions from homes, cars and factories by one-fourth below 1990 levels over 10 years  considerably more aggressive than President Obama’s commitment in Copenhagen to reduce emissions 17 percent below 2005 levels. The plan relies on existing technologies to produce more power from renewable sources like wind, tougher energy-efficiency standards for buildings and more investments in mass transit.

Massachusetts will also benefit from its participation in the Regional Greenhouse Gas Initiative, a 2008 agreement among 10 Eastern states, including New York, to reduce carbon dioxide emissions from power plants. These emissions have already dropped dramatically in the region, in part because utilities have been switching from coal to cleaner-burning natural gas.

The Massachusetts announcement follows California’s approval of a cap-and-trade program requiring 360 large enterprises, including refineries and power plants, to gradually reduce emissions to help achieve a statewide reduction of 15 percent from current levels by 2020  just under Mr. Obama’s target.