the skrull planet had its atmosphere stripped, the left behind skrulls are either dying in the carnage of the attack or suffocating in the ruins - the whole poignancy of Kamala confronting Carol depends on that being a fact, otherwise it really was a meh moment (it was already too short and too frivolous to convey the proper emotional grimness of Carols decision)
I can accept the Water Planet still having some water left, enough for the singing population to survive even if the movie doesnt following up on the consequences to global climate and desertification