Hey she was paid to perform a service and she is doing so. If whoever is living in the basin wants cooler weather I'm sure Celestia can be bribe..I mean paid to take care of the issue. Its a free market afterall!
i would second this opinion, but imagine what would come of it. the mane 6 would then have to defeat an evil celestia. or perhaps the next bearers of the elements of harmony will have to do it, due to the fact that it would probably be 1,000 years from that point in time. either way, she will wreak havoc upon equestria, and, at the same time, discord would follow her due him probably making a pact with her to do as she says at all times, and make ponyville the chaos central of equestria, such as was his original plan.
Well, Discord is what I think they're calling "reformed" now. Yes, he has that special connection with Celestia, maybe Luna also. I think that maybe he would still be disappointed in her, considering he's now being good mostly because of Celestia. And, the Mane 6 would probably be deceased or something before Celestia finally snaps. And in between the time the Mane 6 pass away and the time that there are new bearers of the elements, maybe Luna would banish her? It's just a little prediction, no reason to get our tails in a twist.
He is an Ahuizotl, translating to spined-beast (I think. Its late and my lore is fuzzy). They are a creature from Aztec lore. They are said to hunt humans and specifically enjoy fingernails, hair and skin I think. They lurk by the waters edge and use their hands to drown victims.
So yeah, these things are kinda messed up. Love Mlp for the dark undertones they slide into the show. Like Griffons for instance.