Who do we believe?  Good question.  In areas that one is really concerned about, read as many diverse sources as you can, keep an open mind to differing opinions being correct, and think about what makes sense.  I look at celebs touting concern of global warming and I read that they are going to conferences in private jets, caravans, huge carbon footprints. I guess when they start walking the walk, I might pay more attention to their talk.