Other than the widely discredited hockey-stick style of temperature reconstructions, the empirical evidence continues to expand, supporting the well known historical anecdotal information about the Medieval Warming.
A new peer-reviewed study by Kaniewski et al. provides important evidence of the Medieval Warming Period (MWP) in the Middle East region of the world. An analysis of pollen from a Syrian sediment core confirms an extended state of higher temperatures during the MWP's low atmospheric CO2 environment.
"Based on analyses of pollen found in a 315-cm-long sediment core retrieved from alluvial deposits within the floodplain of the River Rumailiah in the coastal Syrian lowland, Kaniewski et al. were able to identify key plant functional types that allowed them to construct pollen-derived Biomes (PdBs) similar to those employed by Tarasov et al. after which they were able to relate "the ratio of PdB warm steppe (WAST) divided by PdB cool steppe (COST) to local temperature...The end result of this endeavor was their identification of the timeframe of the MWP (AD 1000-1230) and their finding that at approximately AD 1130, the MWP exhibited "warmer temperatures compared to AD 2000,..." [D. Kaniewskia, E. Van Campoa, E. Paulissend, H. Weisse, J. Bakkerc, I. Rossignola, K. Van Lerberghef 2011: Global and Planetary Change]