Scientists from NASA and a number of other institutions have recently been modeling the effects of a war involving a hundred Hiroshima-level bombs, or 0.03 percent of the world's current nuclear arsenal, according to National Geographic.

The research suggests five million metric tons of black carbon would be swept up into the lowest portion of the atmosphere.
The result, according to NASA climate models, could actually be global cooling.
While the global cooling caused by superpower-on-superpower war could be catastrophic (hence the term ""nuclear winter"") a small scale war could have an impact on the world climate, says National Geographic.
Models suggest that though the world is currently in a warming trend, small-scale war could lower global temperatures 2.25 degrees F for two-to-three years following war.
In more tropical areas temperatures could fall 5.4 to 7.2 degrees F.
But the likelihood of disaster over reversing global warming is a more imminent concern, according to TIME.
In addition, the extreme weather caused by even a mild nuclear winter would have a tremendous effect on crops and famines, including creating a 10 percent global decrease in precipitation, according to National Geographic. The soot could also cause tremendous harm to the ozone layer, allowing more ultraviolet rays to reach Earth.
The cons seem to outweigh the pros in the event of global cooling caused by even a small nuclear war.
(Source: huffingtonpost com.)