Although greenhouse gas forcing is the principal driver of long-term changes in Earth’s temperature (Santer et al. 2017; Eyring et al. 2021), internal climate variability can produce substantial variations in the rate of surface and tropospheric warming on decadal and multidecadal timescales (Marotzke and Forster 2015; Mitchell et al 2020). Such variations have contributed to muted warming over individual decades (e.g., the 2000s) and have partially offset greenhouse warming over the full satellite era (1979 – present) in both the tropical and global domains (Flato et al. 2013; Gleisner et al 2015; Po-Chedley et al 2022). Reduced warming has been linked to a `La-Niña-like` pattern of surface temperature change (Kosaka and Xie 2013; Meehl et al 2014; Medhaug et al 2017; Po-Chedley et al 2021), which produces a negative cloud feedback (Zhou et al. 2016; Andrews et al 2018; Dong et al. 2019) and is associated with enhanced deep ocean heat uptake (Meehl et al 2011; Chen and Tung 2014).

This research will employ large ensembles of climate model simulations to better understand decadal and multidecadal warming fluctuations by analyzing the a) patterns of surface temperature change associated with muted/accelerated warming and b) the relative contribution of ocean heat uptake efficiency and climate feedback parameter to intra-ensemble variability in global mean surface temperature change. Since the relative importance of climate feedback versus ocean heat uptake efficiency likely varies by period, we also consider the influence of the time period and timescale on internally-driven global warming acceleration and deceleration.