A Causal Examination of the Solar Influence on Holocene Climate

Abstract

Abstract Variations in Total Solar Irradiance (TSI) have long been hypothesized to influence global mean surface temperature (GMST) on multidecadal to millennial timescales, but empirical evidence has remained elusive. Here, we explore the link between solar variability and climate over the pre‐industrial Holocene, when anthropogenic influences were minimal, using the causal inference framework of Convergent Cross‐Mapping. We analyze pairings of two temperature targets (a GMST reconstruction and the central Greenland GISP2 record) with two TSI reconstructions across a range of timescales. Our results indicate a discernible influence of TSI on temperature in ∼80% of parameter configurations: stronger but less consistently significant for GISP2, weaker but consistently significant for the global mean. This suggests that solar forcing was a minor–but detectable–driver of global Holocene climate fluctuations, an empirical insight that may serve as a benchmark for evaluating whether climate models correctly capture such subtle, nonlinear dynamics.