OK, here goes. To begin, I agree with Bulldogg6404 that
Rock + citrus = limestone
is surely correct. But then I think the "burning liquid skies" must be referring to
(I guess this is what hint 3 is about, but in any case it seems far the most obvious interpretation of those words) and then
there is an obvious connection between musical limbo and acid rain mitigation, via a pun between "base" (opposite of acid) and "bass" (low musical notes/instruments). And you can turn limestone into lime (calcium hydroxide), which is a base and is sometimes added to water as an anti-acid-rain measure.
There is the small difficulty that
it's not the limestone that's being added to water; you can make lime from limestone but they aren't the same thing. (And it feels a bit weird to explicitly turn "lime" into "limestone" at the start and then turn it back again a line or two later :-).)
but KoA has confirmed in comments that this is what he meant anyway. OK, so the property we're looking for is, then, that of being
and now we take that word and
tnsert "the sound of a beverage" into the word "basic", perhaps between "S" (snake) and "I" (me). That makes "bastic", which isn't exactly a word (it seems to have a slang usage that must be derived from the thankfully-mostly-defunct use of "spastic" as a term of abuse, and it was a bit of technobabble in Doctor Who once) -- but maybe that's OK since the two ingredients are meant to be meaningless on their own.
If so, then
presumably the second ingredient will also be a non-word, and we'll have to combine them somehow, and surely "hit them with a spoon" means "spoonerize". So it'll be BASTIC PL---- giving PLASTIC B---- or something of the kind.
OK, on to the second ingredient. We need something that means "steal without asking" and
begins with PL. I wondered about PLUNDER but actually more likely, I think, is PLAGIARIZE or PLAGIARISE (which also emcompasses "claim it as your own"), and if we can reduce this to its first four letters then we get BASTIC PLAG, hence PLASTIC BAG, which seems like a pretty reasonable answer.
So, why that many letters? Well,
if you take the number 100 ("a century") and then pretend it's a 3-bit binary number, that number is four. So that's the number of letters you take from the start of PLAGIARIZE.
So, in case you missed it above, the answer is
whose impact on the environment is pretty familiar to us all.