Background/Question/Methods . Climate change remains a poorly understood and confusion to scientists, the general public and policymakers.  What are the robust conclusions from climate science?  What are the outstanding uncertainties?  It is helpful for scientists to have a firm grip on a few fundamental principles from theory and observation to use in communicating about climate change, and also know and communicate the critical unknowns.  In addition, there are a few misconceptions that frequently arise and form the entry point fr a great deal of controversy, whether well-intentioned or intentional.
Results/Conclusions .  In this talk, I will review the critical elements of physcal theory and climate science that underpin the scientific consensus on climate change.  I will review the legitmate uncertainties and controversy, and will also highlight a few persistent misconceptions.  This talk is intended as background to the balance of talks in the session, some of which will address more specifically communication tactics, strategy and materials to aid in communicating with different audiences.