Just how bad can a little nuclear war be?

Limited nuclear war would damage ozone layer

Pretty bad, it would seem:

Mills and colleagues found that a regional nuclear war in South Asia would deplete up to 40% of the ozone layer in the mid latitudes and up to 70% in the high northern latitudes.

"The models show this magnitude of ozone loss would persist for five years, and we would see substantial losses continuing for at least another five years," says Mills.

The scenario they looked at was for 100 Hiroshima size detonations between India and Pakistan. (Those two countries apparently have 110 warheads between them, so the figure is relatively realistic.)

On the other hand, it would cool global warming for quite a while. But those who sunbathe to get warm will all get skin cancer from no ozone.

On the whole, not a good idea. (Incidentally, what sort of early warning systems do both of these nations have? It wouldn't hurt to have international co-operation to make sure these countries can't launch by mistake.)