Read here. The world has not experienced the century long super-droughts that occurred during the extreme warming of the Medieval Period. As the graph below indicates, paleo-researchers documented the terrible drought conditions that afflicted the North American continent. Recent contemporary warming was no match to the warming that produced these drought conditions some 700 to 1,100 years ago. (click image to enlarge)
"Cook et al. find evidence of "a number of unprecedented megadroughts over the past millennium that clearly exceed any found in the instrumental records," including an amazing "epoch of significantly elevated aridity that persisted for almost 400 years over the AD 900-1300 period."...."during which time the truly unprecedented 400-year megadrought held sway. Consequently, because the AD 900-1300 time interval (representing the core of the Medieval Warm Period) was host to the most severe and long-lasting drought of the last eleven centuries, that period must also have experienced the warmest tropical temperatures of the last 1100 years."