Carbon cycle research is often carried out in isolation from research on energy systems and normally focuses only on the biophysical patterns and processes of carbon sources and sinks. The Global Carbon Project represents a significant advance beyond the status quo in several important ways. First, the problem is conceptualised from the outset as one involving fully integrated human and natural components; the emphasis is on the carbon-climate-human system (fossil-fuel based energy systems + biophysical carbon cycle + physical climate system) and not simply on the biophysical carbon cycle alone. Secondly, the development of new methodologies for analysing and modelling the integrated carbon cycle is a central feature of the project. Thirdly, the project provides an internally consistent framework for the coordination and integration of the many national and regional carbon cycle research programmes that are being established around the world. Fourthly, the project addresses questions of direct policy relevance, such as the management strategies and sustainable regional development pathways required to achieve stabilisation of carbon dioxide in the atmosphere. Finally, the Global Carbon Project goes beyond the traditional set of stakeholders for a global change research project by seeking to engage the industrial and energy sectors as well as the economic development and resource management sectors in the developing regions of the world