Earth and Climate Science (ATCC, 2011), which indicated that a short-term spike in solar flux is not unprecedented. In contrast, no abrupt changes of tropical cyclone intensity or frequency have occurred during the Maunder minimum. Nevertheless, strong Maunder minimum-like trends in the output of the Royer et al. (2011) global climate model, particularly in relation to the GMST, are observed. Because solar activity has been known to alter climate throughout the ice age, it is possible that the Royer et al. (2011) findings suggest that variations in solar activity may have played an important role in triggering the Maunder minimum. In this study, we examined the impact of the ancient solar modulation on human-caused climate change during the last