Originally Posted by
Iscah
Lives aren't being sacrificed in the dark future, they've been killed by the Black Rose. It's explained when Urianger describes his "vision" (ie. relaying the Exarch's account of history from what is still our future, but his past) in 'Unto the Truth' - the "passive polarity" aspect of the gas reacted with the influx of passive-aspected aether from the First, driving it to spread far beyond its initial use on the battlefield. Vast numbers of the population die, the ground is poisoned, and the survivors go to war over what little remains.
We don't know if the Ascians can "sacrifice" what's already dead, but I would assume not.