Emberverse/WMG

The change was to prevent Second Impact from occuring.
We know from what  told Rudi, plus some of his visions earlier in the books, that the earth was headed towards a bad future before the change. . Since the change occured before 2000, and because this is the WMG section, I say that the change to stop SELEE from initiating Second Impact. Discuss.

Also, anyone that could make the title work, feel free to help me there.

Factions of are responsible for all of Stirling's alternate Earths.
Draka Earth: Completely unbelievable? No! . Peshawar Lancers? . Conquistador? .
 * Alternatively,

Rudi won't leave an heir.
Rudi and Mathilda have decided to wait until after the epic continent-wide war against the demon worshipers is finished to have children. Makes sense, right? Mathilda getting pregnant during the war would not only be dangerous for her, but would take a skilled fighter out of the battle and endanger everyone. So everyone's planning on them estabilishing a dynasty after the war and uniting everything west of the Cascades. Except that Rudi is fated to die in battle, and therefore before he has children. There'll be no heir tying all the kingdoms together, and eventually Mathilda's mother will try to conquer the west through force instead of marriage. With or without the cooperation of Mathilda, who wouldn't have any ties left to the other kingdoms.
 * Actually, while Rudi is fated to die in battle, it's only specified that this will occur before he's old and grey. There's no indication that he will die in the war against the C.U.T. In fact, Odin (or possibly 'Odin') predicts in THE SWORD OF THE LADY that -if- he acquires the Sword of the Lady, "his shall be a line of Kings that lives long in glory, and forever in the tales of men. And I should know, since I wrote it... 8-).
 * I don't doubt that this poster is Stirling - I've seen him all over the Internet, and this is definitely his style - but I don't think an author could survive without prevaricating at least a little bit about things like this. So, for the record, it's set in stone that Rudi will see the face of his first child, because Juniper prayed for it and as far as I remember, she has a perfect track record as far as that goes. Beyond that, Rudi could die at any time.
 * The seer in the neo-Viking settlement in northern Maine also confirmed the vision, saying that Rudi would hold his newborn son in his arms before his death. If double-blind experiments apply to post-apocalyptic psychic visions, then we have confirmation that Rudi will leave at least one heir.
 * At one point there's also a brief vision of Mathilda happily giving birth.
 * Jossed in a sample chapter of The Tears of the Sun where Rudi has a vision of him and Mathilda playing with their kids.

What's going on with 'giving humanity time' isn't a straightforward The World Is Not Ready
It's not really clear how sending civilization back for another go-round is going to help avert the bad futures seen (which seem to be some sort of ultra greenhouse effect and the replacement of humanity with other sorts of intelligences, possibly AI or radical transhumans) ... unless Rudi's visions of them become widely known and widely believed, and remembered and still believed centuries later, which doesn't seem all that likely (as he doesn't seem to be publicizing them - though perhaps he might after the immediate CUT crisis is resolved).

So maybe what's really going on is more of a subtle "butterfly effect" push. Perhaps the very existence of the Change - a massive, universal event which really looks supernatural - as something which will be pretty much undeniable in history even centuries to millennia later will mean that belief in the supernatural never becomes less common (or relevant to everyday life) as technology advances again, changing humanity's attitude toward science (and therefore technology) in perhaps subtle but crucial ways.