This study uses climate projections from GFDL’s Earth system model (ESM2.1) to force an individual-based model for the larval stages of North Atlantic Cod at each of 5 cod spawning sites across the North Atlantic. The behavioral and physiological state of thousands of cod larvae is modeled in response to ESM projected physical and biological changes. The ESM-IBM coupling provides a unique means of exploring the mechanistic response of cod larvae to climate forcing.