http://www.sciencedirect.com/science/article/pii/S0301421507... (available without cost from http://earthjustice.org/sites/default/files/black-carbon/bou... )

"Jacobson (2002, 2005) suggested that, despite their lower fuel efficiency, gasoline cars were better for climate than BC-emitting diesel cars. However, Jacobson’s analysis relied on radiative forcing (RF) and climate equilibrium calculations, which is artificial and possibly misleading because any policy or technology will only be implemented for a finite period of time"