My first guess is: something like, Your Pal in Reality, or Your Pal in Realism. I'll guess again tomorrow.

I don't think we're really in danger of bringing on nuclear winter, which was the concept that drove both the U.S. and the Soviets to back off nuclear threats. I bet we're far closer to doing something evil and half-assed again, similar to what we did to Iraq but smaller scale.

Bush is so stupid and vicious, and Cheney so uncaring, sly and vicious, that they could use something else, like chemical or biological weapons. Even if they don't, and use "only" the sort of bombs they did on Iraq, they will just about complete their destruction of the world. Not like stopping the sun, but destruction of too much of the tenuous hold on civilization that the world had achieved.

Whereabouts, what does YPiR mean?

To invade Iran conventionally a nation would need 1.5 millions troops, 10,000 battle tanks, 1,000 fighter bombers and two naval fleets. The US lacks this kind of punch.
Some scientists predict that as few as 80 nuclear bombs dropped on Iran would deplete the ozone layer. This could wipe out all life on Earth.
The bombs could kick up enough dust to blot out the sun.