Scenarios, projections, and climate-related risks

Socio-economic scenarios and resulting global warming levels structure the understanding of causal chains of greenhouse gas emissions, air pollution control, land-use changes, the response of the Earth system, climatic impact-drivers, exposure, vulnerability, adaptation responses, and climate-related risks. Following the French Academy of Sciences workshop on “The climate emergency, a turning point” (2024), this manuscript provides an overview of the concepts and methodologies underpinning the Sixth Assessment Report of the Intergovernmental panel on Climate Change (IPCC) regarding the development of scenarios and the assessment of risks from the perspective of the physical science basis of climate change, and selected recent updates and advances. It includes (i) a brief overview of the current state of the global and regional climate and impacts in France, (ii) an overview of future warming scenarios spanning socio-economic scenarios, (iii) constrained climate projections for global warming, and (iv) low-likelihood, high-impact outcomes which are relevant to inform robust decision-making and risk management.