Nuclear winter, would it happen?

[Vierstein]

Models suggest that the ash and fumes caused by cities set on fire by nuclear war would cause a nuclear winter.

Are these models still valid, or do more refined models suggest that such a scenario would not occour, or that even a limited nuclear war would cause an extended nuclear winter?

What is the update on the model of nuclear winter out of the 80s?

 

[Andre]

Robock et al 2007

Mills et al 2008