This Working Group, including a NCEAS postdoctoral associate, will fill a series of critical gaps in the ability to quantify and understand the carbon balance of large regions. The Working Group will focus on three topics that are ripe for progress and where the current state of the science falls far short of the requirements for useful practical application or basic understanding. The focal topics are current land use, past land use, and disturbance. The Working Group will meet in one workshop on each of these topics, with a fourth workshop on integrated estimates of the carbon balance of Eurasia and North America. At each workshop, we will: 1) Review the status of the data; 2) Evaluate strategies for integrating to the continental scale; and 3) Consider approaches for constraining estimates with observations. This Group will synthesize the role in carbon balance of three factors in time and space, and it will expand the suite of processes represented in large-scale carbon balance models.