The Medieval Climate Anomaly in the Mediterranean Region.

The Medieval Climate Anomaly (MCA) is a preindustrial phase of pronounced natural climate variability with a core period from 1000 to 1200 CE. The paper presents a synthesis that integrates palaeotemperature records from the Greater Mediterranean Region encompassing the past 1,500 years based on multiproxy data from 79 published land and marine sites. MCA warming dominated the Western Mediterranean (Iberia, NW Africa) as well as the northern land areas of the Central and Eastern Mediterranean region. MCA cooling prevailed in the Canary Current Upwelling System, southern Levant, and some sea areas of the Central and Eastern Mediterranean. Previous palaeoreconstructions suggest persistent positive Atlantic Multidecadal Oscillation (AMO+) and North Atlantic Oscillation (NAO+) conditions during the MCA, while the Little Ice Age was dominated by an AMO− and NAO− regime. During the past 150 years, AMO+ conditions are typically associated with warming episodes in the Mediterranean area. A similar relationship appears to have also been established during the MCA as the majority of all Mediterranean land sites experienced warm climate conditions. In contrast, the NAO typically leads to a characteristic west‐east temperature dipole pattern in the basin, as documented for the last decades. During NAO+ conditions the Western Mediterranean is generally warm (and dry), while large parts of the Central and Eastern Mediterranean are cold. Similar trends seem to have been developed during the MCA when the NAO+ regime led to consistent warming in the Western Mediterranean, while a significant number of sites with MCA cooling existed in the Central and Eastern Mediterranean. Plain Language Summary: Mediterranean climate has been warming significantly over the past 100 years with anthropogenic climate change having become a key issue. In order to better understand modern climatic change, developments need to be placed into a longer‐term preindustrial context to compare with times when human CO2 emissions did not yet play a major role for climate. This paper integrates data on Medieval temperature trends from 79 published Mediterranean land and marine sites. Our synthesis shows that the Western Mediterranean (Iberia, Northwest Africa) as well as the northern land areas of the Central and Eastern Mediterranean region have experienced a warm phase 1000–1200 CE, corresponding to the so‐called "Medieval Climate Anomaly." Contemporaneous cooling occurred in other parts of the Greater Mediterranean region, namely, in the southern Levant, some sea areas of the Central and Eastern Mediterranean, and the Canary Current Upwelling System. The regional differences in Medieval Mediterranean temperature trends show a pattern, which partly resembles modern multidecadal temperature variability in the area. The main drivers of these patterns appear to be Atlantic ocean cycles (AMO, NAO), which episodically shift between positive and negative phases and lead to characteristic temperature effects in the region. Key Points: The Western Mediterranean and northern land areas of the Central and Eastern Mediterranean region were warming during Medieval timesMedieval cooling prevailed in Canary Current Upwelling System, south Levant and some sea areas of the Central and Eastern MediterraneanPositive phases of the AMO and NAO ocean cycles appear to have led to temperature patterns in Medieval times similar to those of today [ABSTRACT FROM AUTHOR]