That remains to be seen. CO2 is fairly innocuous, and already makes up a large percent of the volume of air. It's theorized that it leads to climate change (that being said, 8000 years ago Europe was also in an ice age, yet it thawed without mankind's help), but for the present time the amount of deaths that can be directly blamed on CO2 from cars (remember, people and animals create more CO2 than vehicles) is non-existent. Even if mankind's CO2 use does tip the scale enough to definitively kill millions, more CO2 is produced from power plants, ships, industrial ranching and burning forests than is produced by cars (especially VW cars).

On the other hand, the other gases released by diesel-burning automobiles do show direct health consequences, and VW has done the most to propagate diesel vehicles...

> CO2 is fairly innocuous, and already makes up a large percent of the volume of air.

Its fairly innocuous at naturally occurring levels, which are not a "large percent" of the air. Nitrogen, Oxygen, and -- if you want to be extremely generous and say that "almost 1%" is "a large percent" -- Argon are the only things that have a remotely plausible case for being a large percent of the atmosphere, and together make up around 99.9%.

Carbon dioxide makes up a large percent of the remaining ~0.1%, but...

> CO2 is fairly innocuous, and already makes up a large percent of the volume of air.

397 ppm, to be exact, or 0.0397%.