WASHINGTON -- Sen. John W. Warner's bill to limit greenhouse gas emissions died in the Senate yesterday. Supporters failed to muster the 60 votes needed to limit debate and vote on the bill.

The bipartisan backers of the Climate Security Act claimed a moral victory, though, as 54 senators supported the plan to cut global-warming emissions by 66 percent by 2050.

"We laid the foundation for this very important legislation," Warner said at a news conference after the floor vote.

"I'd like to discreetly and quietly disappear," he said. "I don't seek any legacies."

Warner, R-Va., is retiring in January after 30 years in the Senate.

The vote to end debate failed with 48 senators voting in favor and 36 against. Six senators, including presidential candidates Barack Obama, D-Ill., and John McCain, R-Ariz., were not present but indicated they support the bill.

Senate Republican leaders had argued the bill, if enacted, would raise gas prices, and President Bush had threatened a veto.

Senate environment committee Chairwoman Barbara Boxer, D-Calif., said that next week, she would begin working with colleagues to improve the bill so it is ready for the new president next year.

"The Clean Air Act took 10 years. This will not take 10 years," she said. "Time is not our friend."

The bill's major element -- a cap-and-trade system that allows polluting companies to buy emissions credits from companies that emit less -- appears to have support, Boxer said.

The challenges ahead are with individual industries, she said. Adding funding for coal, agriculture and manufacturing interests may get the bill support it now lacks.

Coal industry officials said the bill's $16.7 billion investment in carbon-capturing technology was not enough to greatly reduce emissions at the roughly 600 coal-fired power plants across the country.

"It isn't just the research and development," said Luke Popovich, a spokesman for the National Mining Association. "We really have to think about the sizable investment of essentially converting a fleet of power plants eventually to a technology that neutralizes carbon emissions."