New Urbanism has traditionally positioned itself as an antidote to the soullessness of urban sprawl, with an emphasis on “soul” — the ineffable benefits in living in places built to human scale rather than breaking out hard metrics as to why dense mixed-use communities are both qualitatively and quantitatively better than the auto-driven suburb of single-family homes. But the 18th annual Congress for the New Urbanism is shaping up to be the year New Urbanists demand a seat at the table for fixing two of the most intractable problems facing America in the coming decades: public health and climate change.

The charge for the latter is being led by Peter Calthorpe, a founder of the movement whose firm is best known for the idea of “transit-oriented development,” i.e. building dense communities around train stops (and If that sounds like a no-brainer to you, it’s a testament to how far they’ve come) and Stapleton, the former Denver airport site that is now the largest New Urbanist community in America. But Calthorpe has something even bigger in mind: bringing urbanism to bear on the debate about how best to combat climate change, using metrics and software that quantifies the savings in both CO2 and dollars from denser urbanism. “This policy debate is going forward without us,” he said. “And I think it’s very important we inject ourselves into it, because we have the best solution for climate change.”

His lever is California Assembly Bill 32, the law mandating a state-wide reduction in carbon emissions to 1990 levels by 2020. The law is currently under attack from the California Jobs Initiative and its backers, which include Valero Energy Corp. and other oil refiners. They are seeking to delay implementation of the law until the state’s unemployment rate falls from 12.6% to 5.5% or less for four consecutive quarters. The state’s leading Republican contender for governor, former eBay CEO Meg Whitman, has said she would suspend the law if elected, and there is a growing campaign to place a referendum on a delay on the November ballot.

“If they win, you can give up on any climate change or energy policy at the federal level,” Calthorpe said, “because conservatives will say ‘if they couldn’t make it happen in California,'” there’s no way it would go over with the voters in the rest of the United States. “It’s a surgical strike; they want to kill this thing before it demonstrates its power and efficacy.”

At the heart of the debate around the law is how much it will cost to mitigate California’s carbon emissions, and it is here where Calthorpe began his discussion of climate change and urbanism. Quoting a McKinsey report, he noted that building conservation, transportation efficiency, and energy efficiency all save money while lowering carbon emissions, while opponents of A.B. 32 tended to focus on the technological measures that would cost money to lower them. The one thing McKinsey refused to consider was a profound change in the urban fabric; the American way life was non-negotiable.

Calthorpe was disgusted at this. “Urbanism is not on the table, really, when it comes to solutions for climate change. McKinsey leaves out urbanism altogether, assuming we’re not going to change our behavior when this” — he gestured at the slide — “is all at the service of an urban fabric and lifestyle that is fundamentally unsustainable.” He followed with a broadside at Al Gore, whose plan to solve climate change is “all technology, and no urbanism.”