Click here to watch "Melting."

In what is shaping up to be one of the year's most intense debates on Capitol Hill, Senate Democrats are pushing climate change legislation that could upend the way the country regulates greenhouse gases. The Climate Security Act (also known as the Lieberman-Warner bill) calls for a 70 percent cut in emissions of greenhouse gases by 2050 and would set up a cap-and-trade system for businesses, which would now have to pay the government for polluting.

Few actually expect the bill to pass this year. But the debate which began on Monday could set the stage for the 111th Congress and a new president to take action early in 2009. And special interests are lining up on both sides of the aisle.

The Club for Growth is spending $250,000 to run TV and radio ads opposing the bill in four key states. The ads target Sens. Lamar Alexander, R-Tenn., Robert Byrd, D-W.Va., Jay Rockefeller, D-W.Va., Elizabeth Dole, R-N.C., Jon Tester, D-Mont., and Max Baucus, D-Mont., whom a spokesperson said were chosen to represent a cross-section of legislators who have not denounced the bill.

A Montana version (subscription) of the TV spot presents the Climate Security Act as "another huge, costly government program" that the nation cannot afford. An announcer claims that the bill would cost Americans untold amounts of money in the form of job losses, tax increases and even higher energy costs.

A similar radio spot (subscription) running in North Carolina adds that "while Americans shoulder the economic burden, developing nations such as China and India would get a free pass."

Club for Growth President Pat Toomey said in a press release announcing the ads: "While the benefits of the Lieberman-Warner bill are dubious at best, the costs to our economy will be massive."

The Environmental Defense Fund is fighting back against what they see as climate-change cynics, however, launching a $4 million campaign to build momentum for the legislation. "These ads are an effort to mobilize everyone who is sick of having our economy and environment hostage to imported oil," said Keith Gaby, communications director for the EDF's National Climate Campaign, in a press release.

"Grounded" (subscription) expresses the environmental lobby's fears that the well-entrenched oil and coal industries will "do anything to drive this bill into the ground." A man touts the potential benefits of the climate change legislation -- "investment in cleaner technology," creation of "manufacturing jobs" and an expansion of "renewable energy" -- as oil barrels fall from the sky, hitting him on the head and burying him deeper and deeper into the ground. "Don't let special interests win and America lose," an announcer pleads. "Pass the Climate Security Act now."

Another humorous EDF ad, "Melting" (subscription), features a talking candle that melts while he sarcastically suggests that there's no need to be in a hurry to address global warming. "Sure, climate change is a problem; but let's not rush into anything," the wax man suggests, as his face starts to deform. "Hey, we could get companies to volunteer to cut their pollution. That's a prudent plan," he quips, at this point nothing more than a puddle of wax. An announcer adds: "The Climate Security Act will protect our kids' future and create jobs, but only if we move quickly."