The Global Gridded Crop Model Intercomparison (GGCMI)
The GGCMI Initiative brings together a diverse international community of crop modelers for climate impact assessment, model intercomparison and improvement at the global scale.

Background and Motivation
In 2012 AgMIP led a GGCM Intercomparison fast-track project in coordination with the Inter-Sectoral Impacts Model Intercomparison Project (ISI-MIP). This fast-track included 7 GGCMs and focused on updating the state of knowledge on climate change vulnerabilities, impacts, and adaptations using the most current library of climate model outputs (CMIP5). The fast-track culminated with the submission of 6 papers to a special issue of PNAS (see Figures 1 and 2 for example results from that assessment). Starting in 2013, we are developing a new set of protocols for the next phase of the GGCMI, which will focus on data quality, harmonization, model evaluation, and improvement.

Objectives
Build a lasting community of GGCM researchers that will collaborate to perform coordinated global and regional high-resolution impact assessment and model intercomparison studies to improve GGCM applications and our understanding of climate impacts on global food production and regional and temporal variations in these responses.

Membership
The GGCMI includes more than 20 modeling groups from more than 10 countries. We encourage new model groups to get involved in the project. For those groups that only have experience running models regionally, the project can provide the necessary data products and support to scale their existing frameworks up to global simulations.

Coordination
The GGCMI is being coordinated by a team from the University of Chicago and Argonne National Laboratory (ANL) Computation Institute, the NASA GISS Climate Impacts Group, and the Potsdam Institute for Climate Impacts Research. The coordination team will establish a consistent methodology, including simulation protocols and comparison metrics, for intercomparison and improvement of gridded model applications.

Data and IT
The coordination team will also provide access to a database of assimilated gridded environmental, socio-economic, and climate datasets, as well as all outputs and analyses to enable individual and collaborative studies within the GGCMI network. The GGCMI will leverage an existing archive and IT infrastructure developed at ANL to facilitate data sharing and discovery for the 2012 fast-track. This resource, already serving 10 TBs of climate and impact model outputs for the AgMIP and ISI-MIP communities, will be updated and managed as an ongoing resource for the impacts community for years to come.

Timeline
The phase II project will span three years, with the first two years dedicated to model intercomparison, evaluation, and improvement. In the 3rd year, GGCMI participants will undertake a new global assessment of climate change vulnerabilities, impacts and adaptations.