Planning for the next century requires accurate models of the Earth system that include human activity and terrestrial ecosystem dynamics. The Joint Global Carbon Cycle Center research in integrated modeling aims to develop a new generation of global models embedding human behavior, economic, energy, and terrestrial ecosystem dynamics. These models will be adapted to fully exploit existing and new observation systems to increase robustness and empirical basis of future scenarios, enhancing our capabilities to evaluate and diagnose the interplay between human activities and the environment.