Passing the warm periods in Holocene in Central Asia - evidences from the ice-core records

The current climate change debate raises the question of whether air temperature has ever been higher than today in thousand-years historical past of Central Asia, and what was the state of the glaciers as the major water resources of Central Asia. A possible solution to this problem is the development of long-term isotope-chemistry records derived from the ice-cores to reconstruct the past climate and atmospheric circulation patterns dynamics. Analysis of five deep ice-cores with several millennium climatic records derived from Central Asian glaciers: Western Kun Lun (Thompson et al., 1997), Siberian Altai (Aizen et al., 2016), Tien Shan (Takeuchi et al., 2010), Mongolian Altai (Herren et al., 2013) and Pamir (Aizen et al., 2019) recovered the rates of air temperature, accumulation of snow/precipitation, sources of moisture, and dominant atmospheric circulation patterns over the Central Asia.

The most glaciers of Central Asia are not remnants since the Large Glacier Maximum (LGM), as were believed (Grosswald, et al., 1994; Kuhle, 2004). Ones of the known remnants since the LGM are the Western Kun Lun icecaps at elevations over 6000 m asl. Perhaps, the large glacier massifs in Central Pamir and in Central Tien Shan with snow accumulation areas over 6000 m asl are also the remnants since LGM. Glaciers with snow accumulation areas below 6000 m asl did not survive the Bolling-Allerod (BA) or Holocene Climate Optimum (HCO) warm periods. However, most glaciers above 4000 m survived the Medieval Warm Period (MWP). The causes of inconsistency of Central Asian glaciers during the BA and HCO interstadials are considered through estimation of level of aridity, the changes in d-ex/δ¹⁸O relationship, regime of precipitation, and major circulation processes of that time for each studied areas. The sources of moisture, intensity of warming, prevalence of atmospheric circulation patterns in the warm periods of BA, HCO, and MWP were compared with the climatic conditions of the current period of climate warming.