Phenomenological solar signature in 400 years of reconstructed Northern Hemisphere temperature record

Abstract

We study the solar impact on 400 years of a global surface temperature record since 1600. This period includes the pre‐industrial era (roughly 1600–1800 or 1600–1900), when negligible amount of anthropogenic‐added climate forcing was present and the sun realistically was the only climate force affecting climate on a secular scale, and the industrial era (roughly since 1800–1900), when anthropogenic‐added climate forcing has been present in some degree. We use a recent secular Northern Hemisphere temperature reconstruction (Moberg et al., 2005), three alternative total solar irradiance (TSI) proxy reconstructions (Lean et al., 1995; Lean, 2000; Wang et al., 2005) and a scale‐by‐scale transfer climate sensitivity model to solar changes (Scafetta and West, 2005, 2006). The phenomenological approach we propose is an alternative to the more traditional computer‐based climate model approach, and yields results proven to be almost independent on the secular TSI proxy reconstruction used. We find good correspondence between global temperature and solar induced temperature curves during the pre‐industrial period such as the cooling periods occurring during the Maunder Minimum (1645–1715) and the Dalton Minimum (1795–1825). The sun might have contributed approximately 50% of the observed global warming since 1900 (Scafetta and West, 2006). We briefly discuss the global cooling that occurred from the medieval maximum (≈1000–1100 AD) to the 17th century minimum.