The climate change assessment community relies on widely accepted definitions of risk and its components, e.g. hazard, exposure, and vulnerability, provided by the well-known international organisation Intergovernmental Panel on Climate Change (IPCC). Those definitions of risk have been changing through the years and are presented in a general and “common sense” form as they need to be understandable by the public society and accommodate notions of risk as embraced by different research streams. However, these definitions have proven ineffective in operational climate risk assessment procedures, which exposes the critical need for disambiguation. This paper addresses the lack of semantic clarity of risk and cognate concepts in the context of climate change assessment by unpacking the ontological commitments underlying the IPCC’s most recent definitions and glossary using the Common Ontology of Value and Risk (COVER) as a primary guideline. This study provides a more precise and refined ontological foundation of risk in climate change research that better aligns with the complexities of scenarios and assessments, and contributes to climate change research on mitigation and adaptation by supporting more effective communication and assessment of climate-related risks and humanity’s responses to them.