The passive voice is not specific to the English language, but I feel that this voice is more common in English than in other languages, at least in formal texts.
I think this is particularly true for impersonal passive constructions like "is believed to" or "is thought to". For instance: "Global warming is thought to be caused by human activity." Here, there is no explicit mention of who is thinking. The sentence implicitly refers to a large consensus. This kind of phrasing is very common in scientific articles written in English.
What about the usage of the passive voice, and specifically the impersonal passive voice, in formal Esperanto writing? Is it possible to translate my example as Tutmonda varmiĝo estas pensata kiel kaŭzata de homa agado? If yes, is it considered good style? Another possibility would be to use oni: "Oni (kutime) pensas ke tutmonda varmiĝo estas kaŭzata de homa agado." Does it sound better?
It is maybe just a matter of style. I looked at the few scientific texts in the Fundamenta krestomatio, but it did not give me a clue.