The state of deep carbon modeling today resembles that of climate modeling 40 years ago, when models of the atmosphere, oceans, sea ice and glaciers, forests, and land surface were all partially developed but were not integrated. In today’s geoscience, models exist of the workings of the Earth’s core, the lower and upper mantle, the crust, and of particular processes such as volcanism and plate tectonics, but no system or framework embraces all of these, especially across time scales ranging from thousands to hundreds of millions of years. Funds from this grant support efforts to integrate two popular models: MELTS, Mark Ghiorso’s model of the thermodynamic properties of magmas, and DEW, a model developed by Dmietri Sverjensky that simulates the behavior of water and water-dissolved carbon in the deep Earth. Funds will support the development of an integrated model that will be open source, freely available, released to the scientific community, and suitable for integration into the larger Deep Carbon Observatory (DCO) system of models. Also funded is a workshop that will introduce the new model to the DCO community. Development of comprehensive numerical simulations of the origins, movements, and forms of deep carbon has emerged over the past three years as a major, integrative goal of the Deep Carbon Observatory. The proposed integration of melts and fluid models, if successful, represents significant progress toward to achieving that goal.