DAVIS, Calif. -- California and Australia have both thrown their weight behind carbon trading, but a joint collaboration will be some time off, regulators said at a forum put on yesterday by the two governments.

Linking greenhouse gas markets could lower costs for businesses that have to reduce their emissions, as well as gather momentum for wider acceptance of a cost on carbon, participants said.

Australia's system began in July 2012 with a fixed price of about $24 per ton of emissions levied on its top 350 emitters. In 2015, the government will transition to an auction-based system and will begin linking to the European Union's trading scheme.

California regulators downplayed the significance of talks between the two governments this week. "We're talking about forms of linkage, but we're not in any negotiations about signing anything," said Mary Nichols, chairwoman of the California Air Resources Board. California's program began this month with a cap on the 600 facilities that emit 25,000 tons or more of carbon dioxide equivalent per year. The cap is set to ratchet down until emissions reach 1990 levels by 2020; quarterly auctions began in November 2012 with a price floor of $10 per ton.

"One could exchange offsets without exchanging allowances," she offered as one possibility of a partial link. "I think we're just open to exploring those kinds of ideas with our partners because we all see that that's the next logical step in the programs that we're developing."

But Australian officials said they are eager to explore options.

A period of exploration

"We do think the link [with the E.U. system] will pave the way for other linking to occur, whether it be with state schemes ... or other national emissions trading schemes that we can now see emerging," said Mark Dreyfus, Australia's parliamentary secretary for climate change and energy efficiency. He cited Chile, South Korea and provincial systems in China as potential partners.

Nichols said she expects other jurisdictions to start pricing carbon by 2015, when Australia formally links with Europe and California's system is set to expand to include transportation fuels and natural gas.

"I think there is going to be a bigger market than there is now, but exactly how that will develop and what exactly we'll be trading and with how many partners, I think it'd be a mistake to try to speculate right now," she said. "But clearly we're open to these kinds of discussions, and we're using them as ways to all fine-tune our programs and just to explore what those links could be."

California is preparing to link with Quebec with its proposed regulations currently out for public comment before heading to Gov. Jerry Brown (D) for final approval. Of the seven Western states and four Canadian provinces that had once expressed formal interest in carbon trading, Quebec and California remain the only members of the Western Climate Initiative on track to begin trading in 2013.

Other state representatives urged more linkages. Quebec government representative Alain Houde said he thought the partnership between California and Quebec would attract some WCI jurisdictions back to carbon trading. "It will be a logical step to see some of those members coming back," he said.

"The more entities involved in the market, the bigger the market is, the more efficient will be the pathway to getting emissions down at the least cost," said Justin Johnson, deputy commissioner at the Department of Environmental Conservation in Vermont, which is one of nine states participating in the Northeast's Regional Greenhouse Gas Initiative.