We need more quantity and more extensive data. Impact models need better, updated scientific information. In the 1996 IPCC Report, economic impacts were based on impacts established in the 1980s. Rather, they are necessary for the learning process, which is still very much in progress. Projections will be partially influenced by the bias and orientation of the person making the projections.
Models are good at some projections and poor on others .
Overall, GCMs are not yet predictive tools, vehicles for setting policy, or research and development. They are, however, invaluable in learning. Continued warming month after month year after year will not occur. Even if you do not have this continual monthly or annual warming, does not mean that climate change is not occurring. Similarly, if you see warming year after year, you should not assume that man-made climate change is occurring.