The newest IPCC report (AR5) has produced a fiasco of science falsehoods, distortions, misrepresentations that is being torn asunder.
In a nutshell, the "policymaker community" is the bureaucracy-engine that is responsible for all the lies designed to mislead the public, journalists and elected officials. To accomplish this, the IPCC bureaucracy utilizes "decision-based evidence making", which is explained in this short video. (video source)