Which still have negative repercussions on the environment. You don't just raise or lower the sea levels without having a major impact on the climate, inevitably just hurting the Pokemon they are trying to save.
Also, Team Magma was basically "Pokemon live on land, SO MOAR LAND" and team Aqua was basically "Water = life MOAR WATER". So Team Magma forgets that Pokemon live in the sea or something, and Team Aqua doesn't realize its basically flooding land mass people do live on.
Also, as I mentioned, Team Morons #1 and #2 fail science forever. I may not exactly be a geology expert (I study business), but even I could tell you that blowing up a landlocked volcano will not expand the land (or sea) one inch, but merely kill all of them horribly. I'd have let them do it, except it would have killed everyone at Lavaridge town as well. Otherwise it would've been pretty durn funny to watch natural selection in action.