With the U.S. Senate considering several climate bills and an international forum on climate change convening next week, Pennsylvania Republican Sen. Arlen Specter has been touting his own bill to reduce greenhouse gases, a tour that brought him to Pittsburgh yesterday.

He visited the Siemens Stationary Fuel Cells plant in Churchill -- a subsidiary of Germany's Siemans AG that has been researching the conversion of coal into synthetic natural gas, which can be used to efficiently produce electricity.

Last month, he visited a power plant east of Harrisburg and touched on some of the same themes he discussed yesterday: namely, that the reduction of industrial carbon emissions is key to healing the environment and curbing global warming.

Promoting fuel-cell technology, and the researchers who nurture the technology to commercial viability, is an important part of the proposed "Low Carbon Economy" act, a piece of legislation being sponsored by Mr. Specter and Sen. Jeff Bingaman, D-N.M. The legislation has the support of some major electrical companies, as well as the AFL-CIO and the United Mine Workers of America.

The bill, introduced in the summer, would set a national, mandatory cap on greenhouse emissions, allowing businesses with lower emissions to sell "credits" to facilities with larger carbon emissions. The goal is to reduce U.S. greenhouse gas emissions to "avoid the problems of air pollution" and the "very imminent threat of global warming," he said yesterday.

Mr. Specter's bill would try to reduce carbon emissions to 2006 levels by 2020 and to 1990 levels by 2030, via the caps and research-and-development funding provided under the bill. Still, there are several competing bills -- the leading one, sponsored by Sens. Joe Lieberman and John Warner, has made it out of subcommittee and could be up for a Senate vote in 2008.

But handicappers have said that an alliance of political opponents, industry lobbyists and environmental groups that think the bills don't go far enough could ruin the chances of any climate bill emerging from the 110th Congress. Further, President Bush has not signaled support of carbon caps.

Meanwhile, critics say Mr. Specter's proposal is flawed -- some prefer outright carbon taxes to the "cap-and-trade" method. Others note the Bingaman-Specter bill contains a provision that allows companies to buy an unlimited number of $12-per-ton emission credits directly from the federal government, instead of from companies that operate more efficiently. That could cancel out the mandatory caps, but Mr. Specter and proponents note that the proceeds from selling the credits would go to fuel and energy technology research.

Rep. Tim Murphy, R-Upper St. Clair, echoed Mr. Specter yesterday in his opinion that Congress has done too little for too long on the issue of greenhouse gases.

"Whether you're concerned about the condition of the planet, or the condition of one's wallet," he said, referring to high gas and energy prices, "we're in a situation where other nations, such as China, open up a new coal-fired power plant every day with no scrubbers, [no] equipment on it to clean the air."

It's time to be responsible stewards of the environment while also crafting a bill that attracts the support of energy firms, manufacturers and coal producers, Mr. Murphy said.

Mr. Specter's tour of Siemens came just a week before representatives from a number of nations are set to convene in Indonesia for a United Nations conference on climate change, pollution and greenhouse gases.