I just noticed that we have an environment tag. It's used on 12 questions, 11 of which are ID questions (ten story-identification and one episode-identification), the last one being Where does the water to transform Dune into a non-desert planet come from? The tag wiki excerpt says:
Works focused on the care and protection of planetary environments and how protection of such an environment might impact the lives of inhabitants of that planetary environment.
It's the usual question: do we need this tag? and if so, how should it be used?
(Note that if the consensus is to nuke it, then this can be done with only two edits - both on questions which probably need tag edits anyway - followed by a moderator tag-merge. So "messing up the front page" considerations don't apply.)