I remember reading a book in my early teens (2000-2005) in Polish — though most probably a translation — of a fictionalized "prophecy" of an East-European/Slavic/Russian wise-woman/seer. The book couldn't be new back then and probably came from the '80s or '90s.
In it, the author (male) introduces this wise woman and re-tells her prophecy. It is a story of an eco-terrorist group taking over some nuclear arsenals and wreaking planet-wide havoc upon all humanity. Like, the planet is literally obliterated to get rid of all living humans. What remains in the end are some isolated groups of the guerillas, enjoying their last moments on Earth at drug-laden orgies.
Coming down to details, the book's protagonist is a male (maybe an astronaut?). He is surprised to see in the news some high-tech flying saucers dropping mini nuclear bombs, controlled by said terrorists. At some point in the story he gets into a mansion housing cryocapsules with the owning family's members. One, containing a male, was damaged and the body thawed without proper procedure, so the guy was dead. Another hosted a woman (the male's wife or fiancée?) and the protagonist was able to unfreeze her. She was of course devastated by the news of the other guy's demise. No recall of what her opinion on the complete destruction of Earth was though.
They travel together, sheltering from the bombs and the wacko terrorists, even using some military equipment (armoured vehicles) in the process. They even get to see one of the aforementioned orgies, where they meet the terrorist's leader, a somewhat repulsive fellow. They fall in love, manage to escape Earth on board of a generation spaceship, which they use for near-lightspeed travel to hasten the passage of time on Earth due to relativistic effects. They return after some time, and if I recall well inhabit an island. Earth seems back on track, with nature overtaking the destruction, they have kids. One day (no idea how he got there, but he might have used a similar strategy as the protagonists) the terrorists' leader attempts to harm one of them or their children using a bow and arrow. Around that the book ends, using the primitive weapon as a parable.
This is the best I could put together at this time of the day. Searching for eco-terrorists using nuclear weapons in Google was vague enough not to give me any valuable hints, not even anything by Baba Vanga. Please help me identify this one!