Sen. Barbara Boxer on Thursday put her political muscle behind a bill that would tax carbon and methane emissions linked to global warming and use the money for consumer rebates and to finance a raft of new clean-energy projects.

The California Democrat, who heads the Senate Environment and Public Works Committee, is co-sponsoring legislation written by a fellow panel member, Sen. Bernie Sanders, I-Vt.

The bill faces little to no chance of passing and is sure to face fierce opposition from industry groups and congressional Republicans, some of whom doubt that the planet is heating up at all.

Boxer was undaunted by the political difficulties and urged lawmakers to act before it’s too late.

She pointed to dire warnings from four climate scientists, who told her committee Wednesday that the latest evidence shows the Earth will be at least 8 degrees warmer by the end of the century. Rising sea levels will flood or swallow coastal cities and devastating floods, droughts, tornadoes and heat waves will become common, they warned.

“If that wasn’t an alarm bell, there isn’t any,” Boxer said at a Capitol Hill news conference, surrounded by environmental groups. “We won’t close our eyes to it.”

Under the proposal, companies would pay $20 per ton of carbon or methane they emit. The tax would increase by 5.6% for each of the next 10 years. Burning coal, oil and gasoline releases carbon. Methane is the byproduct of natural gas, which is cleaner than the other fossil fuels and is coming in wide use across the USA.

Sixty percent of the revenue would go to pay monthly rebates for citizens and legal U.S. residents who are bound to face higher electric bills as utilities pass on the tax to consumers.

The rest would go toward “weatherizing” 1 million homes each year to make them more energy-efficient, increasing renewable-energy supply by setting up new wind- and solar-power projects, and creating a fund to attract private investment for clean-energy development.

Boxer wants to hold hearings on the legislation in the spring.

The carbon tax was originally proposed by a conservative British economist named Arthur Cecil Pigou. It’s still a non-starter among congressional Republicans.

It may gain popularity if it’s part of a bigger package of business tax cuts and other incentives conservatives support, said Manik Roy, a vice president at the non-partisan Center for Climate and Energy Solutions.

In exchange for the carbon tax, Congress could consider ending the tax on overseas earnings repatriated to the USA — earnings on which the companies have already paid foreign taxes, said Roy, whose group supports a carbon tax as long as its paid for.

As a stand-alone bill, the carbon tax lacks broad support, Roy said.

“Sen. Boxer and Sen. Sanders … are the environmental gold standards. We are very unlikely to get the environmental gold standard in this Congress,” he said.

Conservatives blasted the proposal as a bad idea that would devastate the economy by raising prices across the board.

Nick Loris, an energy policy analyst at the Heritage Foundation, said the tax would do nothing to encourage people to change their energy-wasting habits. Instead, it would punish oil, gas, coal and natural gas producers and utilities, though fossil fuels supply 85% of the country’s power, he said.

Boxer will run into stiff opposition even in the Democratic-majority Senate because many lawmakers think a tax on emissions has “huge economic costs and minimal environmental gains,” Loris said.

Climate change has gained political momentum since the election, and Boxer has made it one of her top priorities for the 113th Congress.

President Obama discussed it during his inaugural address and again Tuesday during the first State of the Union speech of his second term. If Congress doesn’t do more to combat climate change, Obama vowed to issue executive orders to cut pollution and increase the use of renewable energy.

Environmental groups plan a rally on the National Mall on Sunday to urge lawmakers to tackle the issue.