Or to put it another way - collectively, new SUVs have at least twice the pollution footprint of all the non-SUV cars made each year - and that footprint is growing.
Assume for a minute we get rid of all SUVs: Then we would still have a dilema because some groups of cars produce significantly more pollution the other groups of cars. We are not suddenly in the clear because SUVs are gone. Pollution is a growing and chronic problem in which all vehicles share blame. A solution would then be for EVERYONE to drive ONLY supersubcompacts which get 40+ mpg and have extremely efficient (clean) gas utilizing engines. Not great performers but then at least we will ALL be doing our part to protect our environment. Focusing solely on SUVs is not the solution. The fact remains that in addition to SUVs, many (I would hazard to guess most) people are driving cars that are not considered to be the most efficient available. The desire for design, comfort, performance make this unlikely. Until the auto manufacturers offer alternatives, a significant reduction in pollution emmisions will not occur. They must lead the charge and offer choices people will gravitate towards.