That climate change occurs naturally is no reason to think it can't also occur artificially. That's like saying that since fire has existed since the earth began, there's no such thing as arson.
You also fail to understand the "oceans storing heat". We measure how much energy the earth absorbs and how much it radiates. The difference must go somewhere. The amount of atmospheric warming plus the ocean surface warming plus ice melting etc etc don't amount to enough to cover the amount of energy absorbed, so either those things are warming *more* than we measure, or the energy is going somewhere we don't measure. So the deep oceans are the best bet. If you have another theory (that doesn't involve the energy being waved away by the natural cycle fairies) then feel free to share.
Perhaps learn some physics first though, yes? (Why do Americans say "physics" but not "maths"?)