I might not be a geological scientist but I'm pretty sure they can predict the overall change in climate throughout history fairly accurately, actually. If you feel they can't, I'd go get an accredited source saying so and not just mentioning how you don't trust scientists.

Also, if the climate is changing in an unnatural way, another point of contention is, what exactly is causing it? I can be convinced fairly quickly that humans are affecting things somehow but exactly WHAT is doing it and by how much is completely unknown to me and probably most everyone.