A landmark bill which requires mandatory, not voluntary, limits on greenhouse gases with the goal of reducing the nation's emissions more than 60 percent by mid-century has been proposed in the U.S. Senate by Connecticut Independent Joe Lieberman and Virginia Republican John Warner. Republican Sens. Elizabeth Dole of North Carolina, Norm Coleman of Minnesota and Susan Collins of Maine are co-sponsors, as is Sen. Tom Harkin, D-Iowa.

Lieberman, head of the Senate Environmental and Public Works subcommittee, said, "It is the tipping point ... a breakthrough."

"We feel voluntary (actions) will not achieve the goal (or) the leadership the United States of America must take on this issue," Warner said.

The bill, named America’s Climate Security Act will probably pass with the 60 votes needed sometime next year. It will allegedly "establish the core of a federal program to reduce U.S. greenhouse gas emissions substantially enough between 2007 and 2050 to avert catastrophic global warming."

Essentially, the bill would impose greenhouse gas limits on emissions from the electric power, transportation and manufacturing industries, which together account for some 75 percent of greenhouse emissions in the United States. Lieberman wants to push for a vote in the Senate Environmental and Public Works subcommittee sometime within a few weeks and for a vote through the full committee before the end of this year.

Senator Barbara Boxer, chair of the Senate Environment and Public Works Committee, also endorsed the measure, which also calls for using emission allowances and money raised by auctioning the credits for funding research into technologies for reducing emissions, helping low-income Americans with high energy costs and protecting U.S. jobs.

Lieberman and Warner said their position is different from that of the Bush administration, especially in the belief that voluntary emission cuts will not do the job. Warner also said the bill, which will introduce a market-oriented cap-and-trade system in which allowances to emit greenhouse gases would be bought and sold, is consistent with his focus on national security.

PG&E Corporation Vice President of Corporate Environmental and Federal Affairs, Steven Kline, said, "We look forward to working with Senators Lieberman and Warner, Chairman Boxer and the other members of the Environment and Public Works Committee to further refine these concepts, ensuring that the final bill that emerges from the Committee is environmentally effective, economically sustainable and both encourages and supports the rapid development and deployment of the most efficient, lowest-emitting technologies throughout the economy."