During the past decade, scientists have learned much about the complex naturalprocesses that influence climate variability and change, and our ability to modelclimate has increased significantly. We also have begun to better identify those partsof the climate system that are particularly important and not well understood andthat therefore limit our ability to project the future evolution of Earth’s climate. Oneof these critical areas is our understanding of the role of feedbacks in the climate systemand their role in determining climate sensitivity. Feedbacks are processes in theclimate system that can either amplify or dampen the system’s response to changedforcings. This study looks at what is known and not known about climate changefeedbacks and seeks to identify the feedback processes most in need of improvedunderstanding. It identifies key observations needed to monitor and understand climatefeedbacks, discusses ways to evaluate progress in understanding climate feedbacks, recommends ways to improve climate modeling and analysis for climate feedbacksresearch, and identifies priority areas for research.