The National Academies recently released a report on driving and the built environment in which they concluded that increasing job and population density in city centers would benefit the environment by reducing vehicle travel, energy use, and CO2 emissions. (We reported on the release of that report a few weeks ago.) Two years ago, Smart Growth America and a number of other organizations collaborated on a report called Growing Cooler which similarly demonstrated the impact of our built environment on curbing climate change. However, Growing Cooler’s findings showed that the built environment’s impact on the environment was far greater than the conclusions of the National Academies’ report. Reid Ewing, Arthur C. Nelson, and Keith Bartholomew of the University of Utah’s Metropolitan Research Center (none of whom work for Smart Growth America) have issued a response to the authors of the National Academies report detailing how their original numbers remain more valid than the “moderate” findings of the new report.