Feedbacks are processes in the climate system that can either amplify or dampen the system's response to changed forcings. This study looks at what is known and not known about climate change feedbacks and seeks to identify the feedback processes most in need of improved understanding. It identifies key observations needed to monitor and understand climate feedbacks, discusses ways to evaluate progress in understanding climate feedbacks, recommends ways to improve climate modelling and analysis for climate feedbacks research, and identifies priority areas for research.