The purpose of this model-measurement intercomparison is to allow the international scientific community to evaluate the performance of biogeochemical models normally coupled to general circulation models (GCMs). Through a rigorous set of metrics, terrestrial models are scored based on their performance as compared to best-available site, field, and satellite observations. To this end, we encourage you to provide feedback on the experimental protocol, the metrics used to evaluate model performance, and the observational datasets available for use in the intercomparison.