Recent Cloud Controlling Factor Analyses Indicate Higher Climate Sensitivity

Journal article

Plain Language Summary: The equilibrium climate sensitivity (ECS) is a measure of the Earth's temperature response to a doubling of atmospheric carbon dioxide. However, climate model projections of the ECS remain highly uncertain. Clouds respond to CO 2 ${\text{CO}}_{2}$ ‐driven environmental changes (e.g., increasing surface temperature) which can amplify or dampen climate change. Such cloud feedbacks have been pinpointed as a dominant source of uncertainty in the ECS. Cloud‐controlling factor analysis derives relationships between meteorological variables and clouds in an attempt to reduce uncertainties in model projections of the cloud feedback. Our separate high‐ and low‐cloud controlling factor frameworks yield robustly positive estimates of the overall cloud feedback (with less than 0.5% probability of being negative). We subsequently evaluate the downstream constraints on the ECS, following three distinct approaches. In all cases, we find a shift toward higher values, but note that the shape of the constrained ECS distribution is strongly dependent on our prior assumptions, including the climate models considered.

Authors: Wilson Kemsley, S; Nowack, P; Ceppi, P

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Geophysical Research Letters
• Volume: 53
• Issue: 3
• Article number: e2025GL118366
• Publication date: 2026-01-31
• Acceptance date: 2026-01-15
• DOI: 10.1029/2025gl118366
• EISSN: 1944-8007
• ISSN: 0094-8276
• Language: English
• Keywords: cloud feedback; climate sensitivity