Read here. Map source here. Another peer-reviewed study provides high resolution evidence that the world's climate is impacted by an oscillation that occurs approximately every 1,500 years. This oscillation produces rapid climate change, which most likely explains the global warming rebound experienced since the Little Ice Age.
"On the southern coast of the English Channel, Billeaud et al. (2009) studied offshore-derived sediments in the macrotidal setting of Mont-Saint-Michel Bay, France, where they conducted a high-resolution sequence stratigraphy analysis of the intertidal to subtidal wedge, utilizing juvenile shells, peat and organic-rich bulk sediment.....The work revealed that "rapid climate changes, with ~1500-year periodicity, are recorded in the sedimentary successions.....Such results add to the overwhelming evidence provided by other paleoclimate records that have shown, in their words, that "Holocene climate was punctuated by widespread cooling events, recurring every ~1500 ± 500 years (Bond et al., 1997; Bianchi and McCave, 1999; Broecker, 2000; Mayewski et al., 2004; Debret et al., 2007; Allen et al., 2007)."...And since this periodicity suggests that the world was fully ripe for a recovery from the last of these coolings (i.e., the Little Ice Age), 20th-century global warming is seen to be neither unusual, unnatural nor unprecedented..."