The global carbon cycle (CC) is a key environmental literacy issue related to climate change, ocean acidification, and energy sustainability. Understanding the CC requires interdisciplinary knowledge informed by multiple science disciplines such as biology, chemistry, earth science, and physics. To examine the core principles and interdisciplinary nature of CC, we interviewed 10 experts from various science disciplines and asked them to create their own models of the carbon cycle. We utilized the data to identify emerging core concepts of CC and discover commonalities and differences across the experts' models in the context of interdisciplinary understanding. The concepts and interdisciplinarity were compared with those of CC-related topics in the U.S. Framework and Next Generation Science Standards. Most experts demonstrated a breadth of interdisciplinary knowledge based on their disciplinary backgrounds. The experts hold a wider set of ideas about CC than is present in the standards. Many topics not included in the standards could feasibly be added (e.g., the process of carbon sequestration into the ocean and rocks and CO2 emissions by volcanic activity). This study generates concrete recommendations for science standards to guide the revision of existing curricula or to guide the development of new interdisciplinary approaches to teaching global CC.