I think the point with the fluctuating temperatures and CO2 levels is that we are accelerating the change now more than at any time in history, and introducing CO2 into the atmosphere at an alarming rate. This CO2 remains there for some 30-40 years which is why we need to act now. There's a wonderful little film going round called Chasing Ice that shows this really well.
I think even the experts realise that more clarification of data is needed but they are doing something about this. Nasa have a great little project going on you can read about it here: