I would be very surprised if we caused a Calamity, but I strongly suspect that we're going to be thrust into a situation where a Calamity (or more accurately, a Flood), is a very real risk or we go to a shard where a flood has happened--again. Alexandria makes it clear enough that other shards were certainly being primed for rejoining and us beating the Ascians has put them all in dire peril.

So in terms of causing a Flood, in a weird indirect way, we may all already have.