As most scientists now recognize, the empirical studies that confirm the Medieval Warming to be unprecedented far outnumber those that statistically speculate otherwise - the latest research now confirms that South America was very hot during the Medieval Warming Period (MWP)
(click on chart to enlarge; source)
The research evidence keeps on mounting in regards to the unprecedented warming that the world experienced well before any industrial/consumer age CO2 emissions entered the atmosphere.
The adjacent chart from a new peer-reviewed study makes this very clear. Not only were the Medieval Warming temperatures some 2.9 degrees higher than the recent current modern warming, those unprecedented temperatures existed at atmospheric CO2 levels significantly below the claimed "tipping point" of 350ppm.
Once again, and for a region of the earth far removed from the North Atlantic Ocean and the lands that surround it, we have evidence for the existence of the Medieval Warm Period and its significant exceedance of the warmth of the Current Warm Period, clearly suggesting that there is nothing unusual, unnatural or unprecedented about earth's current level of warmth, nor is there any compelling reason to attribute the essentially non-existent 20th-century warming at Laguna Escondida to the concomitant increase in the atmosphere's CO2 concentration, for there was little to no increase in the air's CO2 content during the development of the much greater peak warmth (~2.9 °C) that was experienced at that location back in the middle of the MWP. [Julie Elbert, Richard Wartenburger, Lucien von Gunten, Roberto Urrutia, Daniela Fischer, Marian Fujak, Yvonne Hamann, Nicolas David Greber, Martin Grosjean 2013: Palaeogeography, Palaeoclimatology, Palaeoecology]
Previous climate-history postings and charts.