What is an Earth System Model (ESM)? A coupled climate model is a computer code that estimates the solution to differential equations of fluid motion and thermodynamics to obtain time and space dependent values for temperature, winds and currents, moisture and/or salinity and pressure in the atmosphere and ocean. Components of a climate model simulate the atmosphere, the ocean, sea, ice, the land surface and the vegetation on land and the biogeochemistry of the ocean. An Earth System Model (ESM) is a coupled climate model that also explicitly models the movement of carbon through the earth system. SOCCOM scientists are studying several different ESM simulations run by GFDL as well as other modeling centers around the world. Model performance is evaluated with the help of standardized, observationally-based metrics.