"The carbon Environmental Service (CARBONES) will provide the first multi-decadal reanalysis of the global carbon cycle and a service to provide a rolling update of this analysis. This will include the "essential climate variables" (defined by the Global Climate Observing System) of atmospheric carbon dioxide, leaf area and biomass in various categories. No integrated reanalysis includes these climate variables. This reanalysis will combine the primary long-term observations of the terrestrial and oceanic carbon-cycles (atmospheric concentrations, remotely-sensed surface properties and in-situ ecological measurements) using data assimilation techniques. The service will provide a well-founded baseline for predicting future responses of the carbon-cycle to climate change, and for services such as the Atmospheric and Land Service. It will also act as a benchmark for these core services during the period of overlap. The primary users for the reanalysis are climate modellers who need an initial condition for their predictions and, for the same reason, groups calculating changes in carbon stocks. Thus a benefit will be an independent check, globally, on reporting of carbon inventories for the United Nations Framework on Climate Change. Access to the results will be provided by a flexible and user-friendly web-interface The techniques used for the reanalysis will also be used, in conjunction with the core services, to provide a rolling update on the state of the carbon cycle. This will evolve towards an operational, integrated, carbon-cycle monitoring capacity as a potential downstream service."