For a long time I thought anthropogenic climate change was all a load of nonsense. I was assisted in that view because i tend to be suspicious of anything put forward by "greenies", and there was a friend of the family who was a leading oceanographer (now deceased) who seemed to be a skeptic. Also, I know someone well who has some scientific credentials (not a lot, but more than the average person) who is an avid denier and talks a convincing line.
At one stage I read a lot of arguments on a site similar to this, which gave me a head start to do my own critical research. I won't go into details, but I am fairly certain now that anthropogenic climate change is really occurring. Some of the suggested solutions I still don't agree with.