Predicting carbon cycle feedbacks to climate: Integrating the right tools for the job

Organic matter (OM) is a critical component of Earth's carbon cycle, with strong potential to provide positive feedbacks to a warmer climate via enhanced release of carbon dioxide. Investigations of the fate of OM typically focus on large reservoirs (e.g., soils) and on abundant, relatively long‐lived compounds (e.g., lignin, a compound derived from the cell walls of woody plants), and the products of its decay. Many of these investigations are challenged by issues of scale. The appropriate spatial scale of many carbon cycling questions requires infrastructure beyond the means of most projects and temporal scales often impossible to achieve in a human lifetime. We advocate coupling flux measurements, parameters that ecosystem scientists often quantify, with compositional characterization of sources, reservoirs, and sinks, data often generated by organic geochemists. Combined, the approaches of these disciplines offer powerful tools to understand OM dynamics.