You are free to ignore whoever you wish to ignore. However I believe that the AGW crowd have a flawed understanding of what science actually consists of. I happen to believe that science requires comparing an idea against the real world. I "deny" that comparing ideas against a computer model is science.
This lack of confidence in computer models is I believe a fundamental distinction between those who believe that AGW is "undeniable" and those who believe the hypothesis should be questioned as much as any other unproven idea. Unproven, that is, by comparing the idea with meatspace observations rather than computer simulations that are intended to be 100% perfect replacements for the real world.
Has some warming occured in the last century based on temperature measurements? Yes. Probably. By a small amount. Less than 1 degree. Does that mean it will continue over the next century or accelerate? That is simply unknown at this time. The only way to know is to wait and take more measurements. Anything else is no better than guessing. It's certainly not how science is done. It is not a viable method to ascertain how closely your idea matches the reality out there in the complexity of the real world.