by artificial means vs unnaturally

by artificial means and unnaturally both are adverbs.

Word	Noun	Adjective	Verb	Adverb
by artificial means	No	No	No	Yes
unnaturally	No	No	No	Yes

As adverbs, by artificial means and unnaturally are synonyms defined as:

by artificial means and unnaturally: not according to nature; not by natural means

Other synonyms of by artificial means include artificially.

by artificial means (adverb)	unnaturally (adverb)
not according to nature; not by natural means	not according to nature; not by natural means
	in an unnatural way
	in a manner at variance with what is natural or normal