Cancún, Mexico—Another year, another round of U.N. climate talks. This year's discussions in Cancún are likely to end much as last year's haggling in Copenhagen did—without a firm global treaty to stop drastic climate change. But the stalemate has led to an intriguing side development: Large, multinational corporations are starting to play an outsized role in the negotiations. If world leaders can't agree on how best to cut carbon emissions (and, so far, it's not clear they can), then the world's CEOs may start taking the lead. But is that really a positive development?

Consider some examples: On the very first day of the Cancún talks, the Consumer Goods Forum, a coalition of more than 400 of the world's largest manufacturers and retailers, pledged to use its market might to help stop deforestation by 2020. The forum also pledged to phase out the use of hydrofluorocarbons—refrigeration gases that are thousands of times more potent than CO2—by 2015. This week, Wal-Mart came out in support of a major global forest-preservation initiative, REDD, and has announced plans to expand its sustainable palm oil policy. To top it all off, the Mexican government announced that it had secured $55 million in private low-carbon investments since the beginning of the talk—all this while wealthy nations struggle to come up with funds to finance carbon reductions in the developing world.

It's clear that private companies are stepping in to do what the public sector hasn't been able to do—take concrete steps and shell out money to reduce greenhouse gases. Indeed, many officials are starting to treat these firms as major actors akin to governments. "I'm sure in the future [the Cancun conference] is going to be remembered as the moment when you have an additional part of the COP that is related with business,” predicted Bruno Ferrari, Mexico’s secretary of the economy. Last week, hundreds of businesses leaders staged their own climate summit. The message seemed clear: NGOs and non-profits haven't been able to fix the climate problem, so let's see if the private sector can.

Can they? It's clear that private companies can act much more nimbly than governments. The measures taken by the Consumer Goods Forum and Wal-Mart will start taking have real effects on global greenhouse gases immediately, whereas a formal climate treaty won't materialize until at least next year in Durban, South Africa—if that.

But there's also cause for concern. The companies making bold pronouncements about cutting emissions are, after all, the same ones who profited from putting all that carbon in the air in the first place. These companies realize they can attract publicity from bolstering the climate talks. But what happens after all the photo ops have been staged and the easy climate actions have been taken? "Businesses will have plenty of low-hanging fruit for next ten years, but if we don’t agree to a binding treaty to force further mitigation by then, we’re screwed,” says one NGO activist at the conference.

Indeed, some activists point out that if all these companies were as concerned about climate action as they claim to be, they'd be doing more in their own countries to push for change. "We are seeing more and more companies reflecting a broader mix of industries coming to the [U.N. climate talks," says Gary Cook, a policy analyst with Greenpeace. But, he grumbles, "many of them are not talking this talk back in their capitals or using their political influence in a meaningful way to demand greater government action. … In the mean time, they are letting trade associations—like BusinessEurope or the US Chamber Commerce—claim to speak for them.” The Chamber of Commerce, for instance, helped defeat legislation to curb carbon emissions in the United States. (Plus, of course, many of the companies that are currently singing out of the green hymnal have worked hard in previous years to bog down U.N. negotiations.)

What's more, these private-sector climate leaders are, as you'd expect, always self-interested. At a "Green Solutions" event in Cancun, Bruno Ferrari, Mexico's secretary of the economy, shared the stage with Graeme Sweeney, who is Shell's executive vice-president for future fuels and CO2. Sweeney used every opportunity to emphasize the importance of funding R&D for carbon capture and sequestration—a promising but completely unproven technology to reduce emissions from coal plants. While Shell's commitment to climate action is nice, it also seems to be a glorified form of lobbying.

Ultimately, it may not be the case that every action needed to avert global warming will be good for Shell's bottom line—or Wal-Mart's. That's why there should be a role for the public sector, to make painful but necessary decisions about climate change. But seeing as how the diplomats here at Cancun are poised to avoid making any tough decisions at all, it's looking increasingly likely that responsibility for protecting the planet will fall to the private sector.

Corbin Hiar is an associate editor at PBS MediaShift and climate blogger for UN Dispatch.

(Flickr photo credit: tcktcktck)