- 1School of Environmental Sciences, University of East Anglia, Norwich, UK
- 2Department of Atmospheric Science, Colorado State University, Fort Collins, USA
- 4Institute for Physics of the Atmosphere, Deutsches Zentrum für Luft- und Raumfahrt, Oberpfaffenhofen, Germany
Understanding the relationships between internal variability and forced climate feedbacks is key for using observations to constrain future climate change. Here we probe and interpret the differences in these relationships between the idealised climate change projections provided by the CMIP5 and CMIP6 experiment ensembles. We find that internal variability feedbacks better predict forced feedbacks in CMIP6 relative to CMIP5 by over 50%, and that the increased predictability derives primarily from the slow (>20 year) response to greenhouse gas forcing. A key novel result is that the increased predictability is consistent with the greater resemblance between patterns of internal and forced temperature change in CMIP6, which suggests temperature pattern effects play a key role in predicting forced climate feedbacks. In general, we find that forced feedbacks are more predictable when the response more closely resembles El Niño, with amplified East Pacific warming and cloud changes reflecting a weakened Walker circulation. Despite the increased predictability, emergent constraints provided by observed internal variability are weak and largely unchanged from CMIP5 to CMIP6 due to the relative shortness of the observational record.
How to cite: Davis, L., Thompson, D. W. J., Rugenstein, M., and Birner, T.: Links between internal variability and forced climate feedbacks: The importance of patterns of temperature variability and change, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20967, https://doi.org/10.5194/egusphere-egu25-20967, 2025.