The CMIP7 scenarios are a necessary update to climate model projections, reflecting the ever-changing nature of human behavior and the climate. The author argues that the update is a natural and expected part of the scientific process, rather than a policy shift or admission of failure. The scenarios are updated to be continuous with observed changes, reflect current policies and aspirations, and account for a wider range of factors, including emissions of GHGs, land use change, and anthropogenic impacts on dust and fire. The author emphasizes that the high-end scenarios, such as RCP85 and SSP5-85, are important for understanding tipping points and the impacts of a warmer world. However, the author also acknowledges that there are real issues with the way the CMIP project has grown up, including the misuse of projections and the need for annual updates. The author suggests that a serious critique of the climate modeling enterprise should focus on these issues, rather than on the RCPs themselves.
