Warming and Cooling: The Medieval Climate Anomaly in Africa and Arabia. (11th November 2017)

• Record Type: Journal Article
• Authors: Lüning, Sebastian; Gałka, Mariusz; Vahrenholt, Fritz
• Is Part Of: Paleoceanography. Volume 32:Number 11(2017)
• Page Start: 1219
• Page End: 1235
• Publication Date: 2017-11-11
• Subjects: late Holocene -- paleotemperature -- Africa -- Arabian Peninsula; Paleoceanography -- Periodicals; 551.46
• DOI: 10.1002/2017PA003237
• Languages: English
• ISSNs: 0883-8305

Abstract

Abstract: The Medieval Climate Anomaly (MCA) is a well‐recognized climate perturbation in many parts of the world, with a core period of 1000–1200 Common Era. Here we present a palaeotemperature synthesis for the MCA in Africa and Arabia, based on 44 published localities. The data sets have been thoroughly correlated and the MCA trends palaeoclimatologically mapped. The vast majority of available Afro‐Arabian onshore sites suggest a warm MCA, with the exception of the southern Levant where the MCA appears to have been cold. MCA cooling has also been documented in many segments of the circum‐Africa‐Arabian upwelling systems, as a result of changes in the wind systems which were leading to an intensification of cold water upwelling. Offshore cores from outside upwelling systems mostly show warm MCA conditions. The most likely key drivers of the observed medieval climate change are solar forcing and ocean cycles. Conspicuous cold spikes during the earliest and latest MCA may help to discriminate between solar (Oort Minimum) and ocean cycle (Atlantic Multidecadal Oscillation, AMO) influence. Compared to its large share of nearly one quarter of the world's landmass, data from Africa and Arabia are significantly underrepresented in global temperature reconstructions of the past 2, 000 years. Onshore data are still absent for most regions in Africa and Arabia, except for regional data clusters in Morocco, South Africa, the East African Rift, and the Levant coast. In order to reconstruct land palaeotemperatures more robustly over Africa and Arabia, a systematic research program is needed. Key Points: Onshore Africa and Arabia experienced a warming trend during the Medieval Climate Anomaly (MCA), except at the southern Levant which cooled Most circum‐African upwelling systems intensified during the MCA, producing a cold anomaly; nonupwelling marine areas saw MCA warming Large parts of onshore Africa and Arabia lack suitable paleotemperature information, warranting a systematic research program to fill this important data gap