Whom do you call Alarmist, whom a Skeptic?

… that I was asked a few weeks ago at a public discussion with a lay audience. This question was of course lingering around for a while, and I tried to avoid answering it, because I was concerned it would lead to a discussion about people. I think now that we can discuss this issue without referring to specific people, but to concepts. When preparing a talk, given to a group of journalists, I found an answer, which is mostly consistent with an analysis by Quentin Quencher on this weblog.