Your statement unfairly characterizes the noted scientific backgrounds of some of the panel members, who most certainly understand natural climate change and variation. Check out Karl Turekian as an example.
It appears that Karl Turekian has performed outstanding research on minute aspects of our environment (such as The 222Rn and radium isotopes measured in groundwaters, cosmic dust flux to Earth, salinity of coastal waters, planetary degassing and Oxygen isotope signatures preserved in seawater)of our complex environment. He has also taught global environmental change; I would be curious to see his curriculum for that course.
However, my comment stands if he supported the questionable report. People at his level sometimes are too busy to pay attention to the essence of a document or report that they have trusted their associates to produce.
IMO there has yet to be a comprehensive systems analysis of the effects of climate change. To be complete the anaylsis would include the assumptions, methodology, and data used, stated in plain English for readers to judge for themselves.