Global Surface Temperature Response to 11-Yr Solar Cycle Forcing Consistent with General Circulation Model Results

Abstract

The 11-year solar cycle is associated with a roughly 1Wm-2 trough-to-peak variation in total solar irradiance and is expected to produce a global temperature response. The sensitivity of this response is, however, contentious. Empirical best estimates of global surface temperature sensitivity to solar forcing range from 0.08 to 0.18 K [W m-2 ]-1. In comparison, best estimates from general circulation models forced by solar variability range between 0.03-0.07 K [W m-2]-1, prompting speculation that physical mechanisms not included in general circulation models may amplify responses to solar variability. Using a lagged multiple linear regression method, we find a sensitivity of globalaverage surface temperature ranging between 0.02-0.09 K [W m-2]-1, depending on which predictor and temperature datasets are used. On the basis of likelihood maximization, we give a best estimate of the sensitivity to solar variability of 0.05 K [W m-2]-1 (0.03-0.09 K, 95% c.i.). Furthermore, through updating a widely-used compositing approach to incorporate recent observations, we revise prior global temperature sensitivity best estimates of 0.12 to 0.18 K [W m-2]-1 downwards to 0.07 to 0.10 K [W m-2]-1. The finding of a most-likely global temperature response of 0.05 K [W m-2]-1 supports a relatively modest role for solar cycle variability in driving global surface temperature variations over the 20th century and removes the need to invoke processes that amplify the response relative to that exhibited in general circulation models.

Assessment of Solar Variability Through the Analysis of TSI Observations Recorded by the FY3E/JTSIM/DARA Radiometer

“…Our main result is that C3, C4 and C5 do not show many differences at the level of the solar minima (i.e. and supporting recent analysis (Schmutz, 2021;Amdur & Huybers, 2023). Finally, Figure A8 shows the TSI composite time series C3 and C4.…”

“…A comprehensive discussion of the robustness of these various methodologies is out of the scope of the presented work. Readers can refer to Dudok de Wit et al (2017); Scafetta and Willson (2019); ; Amdur and Huybers (2023).…”

Solar cycle as a distinct line of evidence constraining Earth’s transient climate response

“…Amdur et al 55 considered the period 1959–2019, including Solar Cycle 24, without removing the nonlinear trend. The year 1959 is a solar max and 2019 a min, which by themselves include an imbedded trend from solar max to solar min.…”

A Meta‐Analysis of Studies Attributing Significance to Solar Irradiance

“…The role of solar activity in affecting climate is one of the most debated aspects of global climate variability (Bard & Frank, 2006; Solanki, 2002). Although a growing body of research has found evidence of solar variability controlling or pacing climate (Anchukaitis et al., 2013; Bond et al., 2001; F. S. Hu et al., 2003; Wang et al., 2005), much research has also demonstrated the limited impact of these minor radiation fluctuations (Amdur et al., 2021; Chiodo et al., 2019). Further, solar irradiance has been used to detract from the influence of anthropogenic greenhouse gas forcing on climate (Meunier & Reis, 2015; W. Soon & Legates, 2013; W. W.‐H.…”