First of all, less of the use of the term "nuclear winter," tis utterly wrong for the situation.
It's all speculation when dealing with what ifs though.
Perhaps you dont quite understand what an invasion involves, seriously Darragh, the japaneese military were not interested in surrendering if they were invaded....it would have been a fairly unprecedented bloodbath. So its not speculation at all to say that many more (both allied and japaneese soldiers, and civilians) would have died otherwise. Don't get me wrong, I detest nuclear weapons, but the only thing that makes a difference in this case compared to the hundreds of other cities that got the crap bombed or shelled out of them is the after effect. Something which the Americans claim to have not really understood. Also, and this is a little disturbing, had the invasion had to occur the US military had given the order to make use of a number of nukes, the plans for the invasion are detailed
here, particularly interesting is this:
On Marshall's orders, Maj. Gen. John Hull looked into the tactical use of atomic weapons. He reported that perhaps seven bombs would be available by X-Day, which could be dropped on defending forces. Col. Lyle E. Seeman advised that American troops not enter an area hit by a bomb for "at least 48 hours"; the risk of fallout was not well-understood.
Whether 100,000 people got killed, 1 million or 1, in any circumstances, I don't reckon it's justified. No matter how many get killed. I think that's the point I was trying to make.
The biggest justification the US has for ending the war with the atomic bomb is that they didnt start it, total war was waged on them by another military and while they didnt have to reply in kind (ie bombing the crap out of Tokyo and everywhelse else) they were justified in doing so.
I really dislike how Hiroshima is viewed as the big crime of the second world war by the allies, when Dresden was far far worse. I mean really, Hiroshima ended the war that had lasted for something like a decade (Im including the chineese here because its only fair) Dresden was nothing but revenge.