Wikipedia is, in fact, the closest thing to a people's encyclopedia that currently exists, in terms of its popularity. More people read Wikipedia than any other encyclopedia. That doesn't mean Wikipedia relies on a democratic definition of truth. If we did, we would have to state, as a fact, that God exists, because a majority of the world's English-speaking people believe that claim to be true. Fortunately for God, he's still got some gaps to hide in, so for the time being the existence of God is not a scientific question. But anthropogenic global warming certainly is, and this is probably one of the aspects of scientific consensus that stands in greatest contradiction to popular belief. The vast majority of ordinary people display no detectable concern about continuing to burn fossil fuels, and a sizable fraction either deny that burning fossil fuels can possibly influence the climate, or doubt that the influence would be harmful. Wikipedia can certainly report on who believes what. We have a List of scientists opposing the mainstream scientific assessment of global warming.