That's technically correct. But plenty of experts believe the role of man is uncertain, and some experts believe the role of man in affecting climate is insignificant. No scientific hypothesis can be considered established fact until there is virtually 100% agreement among experts in the field.
When an hypothesis, which is what anthropomorphic global warming is, becomes universally accepted among experts it becomes theory. Whether a theory is true is totally irrelevant. We can not use pure reason to tell how the natural world and its universe works. We must rely on observation and our models built upon observation. These models allow us to correctly predict what will happen given a specific set of circumstances. A scientific theory is fundamentally the specification of a model. When an observation is made that does not agree with the model, either the observation is wrong or the model is defective. In the latter case we extend our observations and try to develop a better model.
The anthropomorphic global warming hypothesis can not be considered a theory until one can accurately predict global temperature using data from man's activity on Earth. Only a brief reflection should convince even the dullest person that it's unlikely we will ever be able to do that unless man's activity dominates other non-predictable features affecting climate.
A far easier task is to eliminate certain factors as important. Carbon dioxide concentration below levels well above its current trace levels has been ruled out as a significantly contributing factor. The Hansen hypothesis, which specifically predicts that rising CO2 at its current levels will cause significant temperature rise, has been thoroughly disproved. The hypothesis is wrong and must be rejected. No model shows a rise in temperature from increasing CO2 in the amounts currently observable unless there is overall positive feedback. A number of recent studies have concluded that the overall feedback to rising temperature is negative, not positive. Feedback must be positive for the Hansen hypothesis to be valid. When temperature rises, the Earths atmosphere responds so as to decrease the extent of the rise; not to accelerate it, as positive feedback would!
