1. What length intervals are significant? Is the interval too short to give a true pattern?
2. Global temperature changes have two causes- human activity and periodic shifts as a result of natural causes- insolation, axis shift, current shifts, etc.

pdq- Many checks are run on the climate models. They are accurate based on their data input. Are the divergences from observations the result of using too short intervals, our ignorance of the effects of minor physical changes in earth conditions?, or a combination of these factors?