Environmental governance research (EGR) has been criticized for not being cumulative, despite the importance of cumulative knowledge for evidence-informed decision-making in addressing global sustainability problems. However, defining, measuring, and assessing knowledge cumulation in EGR remain challenging. This study presents a systematic effort to address this challenge. Next to conceptualizing knowledge cumulation, we developed metrics to gauge the potential of EGR for knowledge cumulation on the levels of individual articles and scientific community. We applied those metrics to the “Earth System Governance” (ESG) research community within the field of EGR and analyzed its body of research through publications emerging from the first seven ESG conferences, resulting in 362 journal articles. Employing a comprehensive coding scheme, we further analyzed a random sample of 100 of those articles. Our findings suggest limited potentials for knowledge cumulation within ESG research. At the community level, we found a diverse journal landscape, a core-periphery structure in citation networks and co-authorship patterns, heterogeneous research questions, and only a few shared reference works, concepts, frameworks, and variables. At the article level, we observed few literature reviews, little data sharing, infrequent application of theories and frameworks, a shortage of clear definitions, and insufficient reflection on limitations. Moreover, we found that midsized author teams advance the knowledge cumulation potential. The ESG community aligns with Whitley's notion of a “fragmented adhocracy” characterized by diverse but disjointed research efforts, which still may foster interdisciplinary exchange. Our suggested conceptualizations, metrics, and results lay the foundation for future comparative and in-depth research on cumulating knowledge.