... if sprawling development continues to fuel growth in driving, the projected 59 percent increase in the total miles driven between 2005 and 2030 will overwhelm expected gains from vehicle efficiency and low-carbon fuels. Even if the most stringent fuel-efficiency proposals under consideration are enacted, notes co-author Steve Winkelman, "vehicle emissions still would be 40 percent above 1990 levels in 2030 -- entirely off-track from reductions of 60-80 percent below 1990 levels by 2050 required for climate protection."

This is exactly right. Transportation emissions, which are mostly (but not entirely) auto-based, account for over half of the climate emissions from fossil fuels in the Pacific Northwest (where I live) and nearly as huge a percentage across North America. Under any realistic climate program, it is imperative that we reduce emissions from transportation. But even the rosiest assumptions about fuel efficiency and biofuels won't get us there: we'll need to reduce driving. The best way -- and maybe the only meaningful way -- is to invest now in climate-friendly urban form. Now, because the neighborhoods we build today will be with us for many decades. They will create the conditions of possibility -- or impossibility -- of reducing our transportation emissions.

I suppose I should mention that I haven't, you know, actually read the book yet. I'm just passing it along to the many smart readers of this blog who like to stay informed about these issues. But I do know some of the contributing authors, and I can vouch for their smarts. The full text is available here, as a big PDF.