The use of the Community Earth System Model in human dimensions climate research and applications

Earth system models (ESMs) are the primary tool used to understand and project changes to the climate system. ESM projections underpin analyses of human dimensions of the climate issue, yet little is known about how ESMs are used in human dimensions research. Such foundational information is necessary for future critical assessments of ESMs. We review applications of a leading ESM, the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM), to human dimensions topics since 2004. We find that this research has grown substantially over this period, twice as fast as CESM research overall. Although many studies have primarily addressed long-term impacts on physical systems with societal relevance, applications to managed, societal, and ecological systems have grown quickly and now make up more than half of CESM human dimensions work. CESM applications focused nearly equally on global and regional analyses, most often using multimodel ensembles, although the use of single simulations remains prevalent. Downscaling and bias correction of output was infrequent and most common for regional studies. U.S.-based, university-affiliated authors primarily drove human dimensions work using CESM, with only 12% of authors based at NCAR. Our findings identify important questions that warrant further investigation, such as reasons for the infrequent use of downscaling and bias correction techniques; motivations to continue to use older model versions after newer model versions have been released; and model development needs for improved human dimensions applications. Additionally, our synthesis provides a baseline and framework that enables continued tracking of CESM and other ESMs. This article is categorized under: Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate Change