Didn't 9/11 cause cooling in the USA?
I seem to recall that with all the flights grounded, the reduction in particulate matter in the atmosphere actually caused the climate to get cooler as the atmosphere lost some of it's ability to hold in heat at night.
Can't recall who actually did the study...And maybe I got it backwards...
But, could it be that the increased cloud cover from such an exchange would actually hold heat in and make it warmer?
Either way, lets hope we never find out.