If dust were the only potential killing mechanism over the long term, then Pope might have a point. However, there are many other possible agents resulting from an asteroid impact which could do the job as well.

Until we actually observe a large impact on Earth, we have no way of knowing the exact sequence of events which might ensue, but we may expect that they will be significant, and deadly.

--from the above link
"The researchers suggest that the relatively low angle of the Yucatan impact propelled a ballistic fireball downrange into North America. The fireball carried a two-mile-deep layer of vaporized rock and other material sheared off the Yucatan. The killing zone of matter cascaded through the atmosphere at near orbital speed, across North America and eventually around the globe. "

If there is any source of fuel for this kind of ignitor, then the whole planet might well go up in flames.

In any event, this globe-circling sheet of fire and rock must have resulted in complete disruption of the atmosphere, if not its total destruction.

Thanks for raising this topic.

sp