In most of Africa, wood is a vanishing resource, and these stoves use far less of it than the ones currently in use.
Literal
Wood [topic-は] Africa [possessive-の] majority [in-において] vanishing-go resource is-[and-であり], these stoves [topic-は] currently being-used things [than-よりも] much wood [possessive-の] consumption [subject-が] is-little.
Two big written-style features. ~において ('in, with respect to') is the formal/written equivalent of ~で. 消えゆく is a literary participial form of 消えていく ('go on vanishing'), with 行く contracted to ゆく — a poetic flourish typical of essay style. であり is the conjunctive form of である ('is'), used to chain clauses together in formal prose. ずっと ('much, far') intensifies the comparison.