Permafrost is a crucial component of the Earth system, representing a key intersection point of soil physical and carbon cycle dynamics, yet has been poorly represented in Earth system models. None of the ESMs of the CMIP5 generation included permafrost carbon dynamics, and many had poor representation of soil thermal dynamics. Subsequent to CMIP5, a number of key improvements have been made to address these shortcomings, including strategies for including permafrost carbon dynamics in models, as well as methods and datasets for benchmarking both the physical and biogeochemical components of the models. I will discuss recent progress and outstanding challenges that remain in understanding and quantifying the role that permafrost soils may play as feedback agents in the Earth system.