The air has been taken out of the carbon trading market.

The only national carbon trading market in the U.S. will close its doors next month, due to stalled legislation in Congress and Republican gains in the midterm elections  -- a major setback in efforts to regulate so-called greenhouse gases, which environmentalists argue contribute to global warming.

Since 2003, the Chicago Climate Exchange (CCX) has operated a voluntary network where companies can pledge to meet annual targets for the emissions of carbon from their factories and businesses.

Those below the targets can sell surplus allowances or bank them; those above can purchase credits to offset their emissions — similar to President Obama's stalled "cap and trade" legislation

But according to an advisory posted to the exchange's website, participants simply didn't want to trade in carbon credits without a legal requirement that they do so. Jeff Sprecher, chief executive of the InternationalExchange and CCX's owner, confirmed to the Financial Times that participants in the CCX's cap-and-trade system wanted to pull out.

"The bulk of the users have said to us that they really don't want to continue to trade voluntarily in the absence of any credit for their work by the current administration," Sprecher said in an earnings call last week.

Sprecher told analysts that European markets for carbon credits were still going strong, but the business wasn't succeeding in the U.S.

"The businesses here are really loss-making businesses -- there is a very uncertain U.S. regulatory appetite for 'cap and trade,'" he added.

A CCX spokeswoman pointed out that the end of the market was expected, however; the program will conclude as scheduled at the end of the year, to be replaced with the CCX Offsets Registry Program.

The new program will allow users to offset gasses, rather than trade credits for their emissions. Should an executive take a lengthy flight, the new Registry will allow the company to purchase an offset for the gas emitted by the flight, in other words.

American Electric Power, one of the founding members of the CCX program, was unsurprised to hear of the conclusion of CCX.

"The waters have been poisoned for cap-and-trade legislation, at least for a couple of years," Bruce Braine, vice president of strategic policy at AEP, told Greener World Media.

"EPA has made it abundantly clear to everybody that they're just heading down a regulatory path now, and voluntary Climate Leader-type programs are no longer really relevant in their minds -- so there really isn't a lot you can do," he said.

The House passed a climate bill last year that would set a national 2020 emissions reduction target on greenhouse gas emissions and outlined a national emissions trading scheme. But Senate Democrats slimmed down the bill in July, abandoning the cap-and-trade method of cutting emissions.

Big Republican gains in Tuesday's midterm elections further diminished the prospects of further climate legislation passing Congress in the near term.

Globally, the voluntary carbon market stalled in 2009 after six years of growth, as the downturn in the global economy and uncertainty over future climate legislation curbed demand. The market shrank 47 percent last year to $387 million and by 26 percent in volume to 93.7 million metric tons of emissions.