Nuclear Winter Documentary 8th Day

LOCAL NUCLEAR WAR COULD BLOCK OUT THE SUN NOT JUST INTERCONTINENTAL WAR 

More recent peer-reviewed studies (which were done beginning in 2006-2007 and later by Robock, Toon, Turco, Stenchikov, Mills, et al) using modern computer models and current arsenals have demonstrated that these first studies were correct, but actually underestimated the long-term effects of nuclear war upon weather and climate.  

The more recent studies found that the black carbon soot and smoke from nuclear firestorms has a self-lofting effect when heated by the sun.  

This acts to keep the soot and smoke in the atmosphere much longer than the first studies anticipated. 

The studies done at NCAR by Thompson et al used faulty smoke injection models, which led to the mistaken finding that the smoke would be more rapidly rained out of the trophosphere (the lower atmosphere where weather takes place).  

Large forest fires in Canada later provided proof that the smoke would rise higher into the stratosphere. 

See this article in Scientific American for a more recent summary: 
http://climate.envsci.rutgers.edu/pdf/RobockToonSciAmJan2010.pdf?