The integrated Earth System Model (iESM) project is a collaboration between three national laboratories to create a first-generation earth system model with a fully integrated human systems component. As part of the project, the Global Change Assessment Model (GCAM) will be coupled with the Community Earth System Model (CESM). Pacific Northwest National Laboratory developed and houses the GCAM integrated assessment model, which will be used in the coupled model to represent human activities affecting land use and greenhouse gas emissions. A group at Oak Ridge National Laboratory is working with the Community Land Model, a portion of the CESM. At Lawrence Berkeley National Laboratory (LBNL), a team is working with the full CESM model. The primary objective of the project is producing a fully integrated model code with the elements of these models. The iESM project is concerned with exercising the coupled system for exploring future bioenergy systems evolution, hydrology, climate adaptation, and climate mitigation. The project is divided into three major tasks:

1. Create a first-generation iESM with both the human components of an integrated assessment model and the physical characteristics of an earth system model
2. Further develop components and links within the iESM and apply the model to improve our understanding of the coupled physical, ecological, and human systems
3. Add realistic hydrology, including freshwater availability from surface water, ground water, and desalinization