Significant progress has been made on the NCAR Whole Atmosphere Community Climate Model - eXtended (WACCM-X) during the past two years. WACCM-X is the thermosphere-ionosphere extension of WACCM, which in turn is the whole atmosphere version of the Community Atmosphere Model (CAM), a major component of the Community Earth System Model (CESM). Thus, WACCM-X not only couples the entire atmosphere-ionosphere system, but can be coupled to ocean, ice, and land models as well. Recent additions and improvements include completion of ion-neutral chemical processes, updated heating and cooling rates, adjustments to atmospheric dynamics to account for variations in mean molecular mass, equatorial and auroral electrodynamics, and fully 3D ionospheric transport.

We have conducted simulations of anthropogenic change by comparing pre-industrial, present day, and future scenarios for carbon dioxide, methane, ozone, sea surface temperatures, and atmospheric response. These largely confirm past work with thermosphere-ionosphere modeling and observation, showing that the upper thermosphere cools at a rate of several degrees per decade under present rates of carbon dioxide change, and that this change is largely driven by the effect of lower thermospheric cooling on scale heights. Changes in middle atmosphere temperature, methane, and ozone, have much smaller effects on the thermosphere. Thermospheric cooling causes the ionosphere to also contract to lower altitude, but with small changes induced in F-region density, and complex effects on ion temperature. Whole atmosphere modeling has great power to fully explicate the coupling of these mechanisms, and, ultimately, the effect of dynamical changes throughout the system.