I'm trying to find a short story that I read in the mid to late 90's, or perhaps as late as the early 2000's. I believe, but am by no means certain, that it was published in Asimov's Science Fiction, but I went through the magazine's bibliography from 1990-2005 on the Internet Speculative Fiction Database and was unable to find a title that sounded promising with a synopsis to fit. To be clear, there were a number of stories with promising titles for which I could find no synopsis at all. Unfortunately it's also entirely possible that I read the story in a secondhand collection of stories from the 50's or 60's and am just remembering wrong, though my recollection of the style and tone of the story was definitely more modern. Sorry for the uncertainty.
The setting of the story was Earth in the near future. The Sun had been completely obscured by something (passing cloud of space dust/alien veil of darkness/something else entirely) and the people of Earth were slowly starving and/or freezing to death in the dark.
The characters were two men who had built a bunker to try to wait out the darkness. The oceans had already frozen over, and the men were waiting for the atmosphere to cool enough for it to liquefy then freeze.
The other plot point involved some passing travelers, one or two men and two women, and it was either stated or implied that the bunker dwellers were planning on murdering the men in order to take the women captive.
I clearly recall that the blurb at the beginning of the story stated that this was going to be written into a book at some point, but I was never able to find that book, and my googling abilities have had no success at finding the story itself. The cloud in Fred Hoyle's "The Black Cloud" behaves very similarly and has similar consequences, but it's not that.