The best thing to wish for?
For a long time, nuclear holocaust has been regarded as the worst possible event that could befall mankind. However, there may come a time in my lifetime when all the alternatives are much worse: it may become the best possible thing for us.
Under a wide range of respectable analyses, the world must cut its carbon emissions by a large percentage. It does not look like we will achieve this: the industrial countries have undertaken to cut their emissions only by a small percentage, and are not even going about that very wholeheartedly.
There is a point of no return to avoid: if too much carbon is emitted, the world will heat up in such a way that soil, plants and eventually the sea will emit more carbon than they absorb. In such an event, the world will become uninhabitable by anything more advanced than fungi.
If any powerful country comes to realise that the world is only a very few years away from that point, it will be in that country's interests to start a nuclear war, with the aim of killing most of the Earth's population. It will be considerably easier to keep a few thousand people alive in nuclear fallout-proof bunker for a few decades than to keep anyone alive for the millennia required for the Earth to cleanse itself of a massive amount of greenhouse gas. The human race would probably survive, instead of almost certainly becoming extinct.
The incentive to start (rather than merely to participate in) such a war is that starting it gives you more warning, and thus more chance to prepare by putting people in bunkers.
Bastards are very ingenious people; we can count on them not to miss a trick like this.
If we want to prevent our old nightmares becoming our future dreams, we have to work fast.