Description of The Medieval Warm Period and Little Ice Age in IPCC Reports - 2007 Report (AR4)

2007 Report (AR4)

The 2007 report used more recent temperature reconstructions including (Esper et al. 2002), (Bradley et al. 2003a), (Jones and Mann 2004), (D’Arrigo et al. 2006). The IPCC concluded the warmest period prior to the 20th century very likely occurred between 950 and 1100...The evidence currently available indicates that NH mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn & Briffa 2006). However, the evidence is not sufficient to support a conclusion that hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval times (Jones et al., 2001; Bradley et al., 2003a,b; Osborn & Briffa 2006).