A Millennial-Scale Climatic Oscillation in Southern Chile
Fletcher, M.-S. and Moreno, P.I. 2012. Vegetation, climate and fire regime changes in the Andean region of southern Chile (38°S) covaried with centennial-scale climate anomalies in the tropical Pacific over the last 1500 years. Quaternary Science Reviews 46: 46-56.
In discussing their findings, the Chilean researchers say they found evidence for "persistent cool/La Nina ENSO states" during the periods 1300-1000 and 725-121 cal yr BP, which they identify as the "Dark Ages Cold Period and Little Ice Age, respectively." In addition, they report finding evidence of "low relative growing season moisture and warmer temperature that correspond well with evidence for persistent warm/ El Nino ENSO states (1500-1300 and 1000-725 cal yr BP)," which they respectively associate with the Roman Warm Period and Medieval Climate Anomaly. Last of all, during the transition from the Little Ice Age to the Current Warm Period, which occurred from 121 cal yr BP (AD 1829) to the present, they found evidence for "a dramatic landscape alteration associated with the arrival of exotic taxa and an increase in burning," which they attribute to European colonization of the area.
In light of such findings Fletcher and Moreno state that "the palaeoenvironmental history inferred from Laguna San Pedro provides important palaeoclimatic information for this part of southern South America that is poorly represented in the palaeoclimate literature." And that information buttresses the ever-increasing likelihood that the natural climatic oscillation that has alternately brought the entire globe the Roman Warm Period, the Dark Ages Cold Period, the Medieval Warm Period and the Little Ice Age is also what has ushered us into the Current Warm Period. And that realization leads to the logical conclusion that earth's current level of not-so-unusual-warmth has likely had nothing to do with the historical increase in the air's CO2 content that has accompanied the rise and progress of the Industrial Revolution.