Someone with no more than the most basic understanding of biology, ecology and climate rejecting the consensus with no findings of their own to provide makes them a conspiracy theorist.
Eh, perhaps we can be careful with the term ‘conspiracy theorist’. A conspiracy theory is that others have conspired to hide the truth. No need to think about conspiracies yet. Someone who looks at the ocean and says, meh, that’s flat, is just doing science at the most basic of levels. Somebody who heard vaccines increased autism is just someone who believes someone. It’s an academic survey at the most basic of levels.
Thus I’d like to coin the term, negligible science.
And if I’m considering my family’s health, or how to sail to India, I’d better trust the non-negligible science.
Of course, the global consensus that Australia exists is a deliberate lie sustained by powerful conspirators; so that’s a conspiracy theory: on top of the negligible science wherein I haven’t seen Australia recently so it doesn’t exist. (That one time was just a placebo Australia. You can tell because the kangaroos looked like people in suits.)