The Global Change Assessment Model (GCAM) is an integrated assessment tool for exploring consequences and responses to global change. However, the current iteration of GCAM relies on NetCDF file outputs which need to be output from the model and then exported for visualization and analysis purposes. Such a requirement limits the uptake of this modeling platform for analysts that may wish to explore future scenarios. In this work, we present a web-based geovisual analytics interface for GCAM. Challenges of this work include enabling both domain expert and model experts to be able to functionally explore the model. We explore the use of various aggregation layers, coordinated views and how choices of icons can enhance the understanding of the underlying data. Our primary focus is on understanding the simulated impact of climate change on sectors of the global economy. To demonstrate our work, we present a case study which explores the potential impact that the China south-north water transportation project in the Yangtze River basin will have on projected water demands.