Many groups are trying to solve global problems with national perspectives, as if one nation by itself could correct ozone depletion, acid rain or ocean pollution. The most pressing problems facing humanity can ONLY be solved in a global context. Most people and groups don't have the time, money, nor attention span to review the available research to arrive at a realistic overview of our global situation. This factor alone is one of the largest barriers to widespread understanding and reaching consensus on implementing solutions. Lack of standard tools, information and models to reach consensus on key issues.
Important information is buried in technical jargon and academic terminology.
The content and meaning needs to identified, abstracted down to something manageable, and re-communicated in an interesting way, so it can be widely understood and applied. Lack of widely shared images and understandings on which to base or create consensus and action agendas. True agreement is reached through common understanding. Underestimating the consequences, rates and magnitude of problems AND underestimating meaningful alternatives. Going past points of no return .