The House Energy and Commerce Committee released a broad discussion draft (PDF) bill Tuesday that promises to transform the economy in a bid to slash emissions to avoid the worst impacts of climate change.

The American Clean Energy and Security Act calls for greenhouse gas emissions reductions slightly more ambitious than targets proposed by President Barack Obama: reductions of 3 percent below 2005 levels by 2012, 20 percent below 2005 levels by 2020, 42 percent below 2005 levels by 2030, and 83 percent below 2005 levels by 2050.

The bill rests on a greenhouse gas cap-and-trade program but doesn’t say whether the permits in the trading system would be auctioned off or given away for free.

But it does advocate for a renewable energy portfolio standard of 6 percent by 2012, which would increase incrementally until 2025, when a quarter of electricity in the U.S. must be drawn from renewable sources. It would also introduce a sweeping efficiency program of standards and investments targeting transportation, buildings and residences, as well as funding to slow global deforestation.

“Nations of the world look to the United States for leadership in addressing the threat of and harm from global warming,” the bill said. “Full implementation of this Act is critical to engage other nations in an international effort to mitigate the threat of and harm from global warming.”

Reps. Henry Waxman (D-Calif.) and Edward Markey (D-Mass.) included several recommendations of the blueprint released earlier this year by the U.S. Climate Action Partnership (USCAP), such as addressing the obstacles to “clean coal” deployment and the use of offsets, although at a lower amount.

Greenpeace called the 648-page bill a good first step but said some issues needed to be resolved. It believes there are too many offsets in the bill -- two billion tons of carbon dioxide equivalent -- which it said could allow the emissions reduction targets to be technically met without any significant reduction in fossil fuel emissions for more than two decades.

Still, many agreed the introduction of the bill sends a message to negotiators gathering in Germany this week as part of a series of meetings leading up to a potential international treaty at the end of the year.

“This draft, which sets firm limits on the amount of greenhouse gas emissions and makes investments in clean energy and jobs, sends an important signal both domestically and abroad,” said Jonathan Lash, president of the World Resources Institute, said in a statement. “This signal is critical as international climate negotiations approach in December.”

"Capitol" -- CC licensed by Flickr user Matti Mattila.