By now, it's impossible to deny that, unlike passions mobilized around other types of pollution or facility siting with all the anthropological overtones of defilement and threats to health which register at a personal level, climate change has remained just an intellectual threat for the public. However, if the public health consequences of this CO2 dome research pan out, the threat becomes personal, visceral if you will.

And this can pack a serious political punch. If the findings hold up, they shred the logic of cap and trade as the basis for federal climate legislation because cap and trade would allow urban polluters to "offset" their carbon emissions out of town, but do nothing to enhance local health and safety. Time to hit the restart button. Substantiating this research could also drive a deeper wedge in American politics between cities and everywhere else and tell urban dwellers they are on their own. Good luck.

Driven wedges and a deepening gloom are in evidence everywhere on the climate action front in 2010. The litany is by now both familiar and painful. No federal climate legislation, no new international climate treaty, attacks on the entire climate enterprise in the wake of the leaked British university memos, detection of minor errors in the IPPC report and polls that find swooning support for any concerted climate action, especially among Republicans voters. But don't despair! Instead, consider what it means to legislate.

A crucial underlying reason for passing laws, rather than relying on the market and the zeitgeist, is that legislative goals are not universally shared or practiced. Laws, at the time of their enactment, express disagreement and conflict, not consensus, and one side or coalition of interests prevails. Only then do statutes start to generate their own support and legitimacy (or get thrown back into the political realm or overturned in court).

Let's rewind the tape and look for a more positive message in the CO2 dome study. Let's assume (because I don't know for certain) this CO2 that collects over cities rises up from urban sources rather than is attracted, magnet-like, from far away. In other words, it behaves more like the air pollutants we traditionally regulate at the state and local levels, ozone, acid gases and soot. Let's also assume that CO2 domes form over definable metropolitan areas rather than stopping neatly at political boundaries. So, San Francisco would include Oakland, Richmond and Berkeley. New York City encompasses counties in the tri-state area greater Los Angeles extends beyond the county line and ditto for Dallas-Fort Worth. We're talking about a lot of people.

Add to this the crucial fact that for the first time we have reason to believe that carbon dioxide is dangerous to the public's health right here, right now. Unlike climate change, which is harder for many to get alarmed over because it's not happening right here, right now (or if it is, its consequences are harder to detect), local sources of CO2 can been seen as dangerous and worthy of prompt public action and large-scale private initiative.

And that's not all. Can we dare to hope for the renaissance of urban influence in American politics? If the Stanford research proves robust, federal climate legislation — especially legislation that's economy wide and contains a stringent and declining cap — would highlight cities as high-value carbon resources, which will attract investment dollars for energy efficient, low carbon projects. Think of American cities as offset magnets that are hard to game. But a cap and trade regime is not the only feasible mechanism. If legislation relied on carbon taxes, cities could be assigned a favorable tax status to fast-track carbon dioxide reduction schemes. As money-magnets, cities could add funding to their own green building or clean energy laws, and don't forget mass transit and other programs new and old that are far in the lead of anything the federal government has done, but lack the resources to innovate and invest at a scale that will make a difference. Think of it as the chance of a lifetime to live under the stars, not under a dome.

i Mark Z. Jacobson, "Enhancement of Local Air Pollution by Urban CO2 Domes", Environmental Science & Technology, March 2010