Wednesday, May 22, 2013

New paper finds another non-hockey-stick in the Russian Subarctic

A new paper published in Quaternary Research reconstructs temperatures over the past 10,000 years in the Russian Subarctic, and finds temperatures were about 1C higher than the present during the Holocene Climate Optimum ~8,000 years ago. The authors also find a linear non-hockey-stick increase in temperature over the past 3,000 years to the present-day. 

Figure 6. Chironomid-inferred changes in mean July air temperature at Lake Kupal'noe (K-TJuly), plotted together with the corresponding record from Lake Berkut (B-TJulyIlyashuk et al., 2005) near the Kola White Sea coast (Fig. 1). Open circles and dotted line represent unsmoothed data from Lake Kupal'noe. Samples that had poor fits to TJuly are marked as white stars. Thick solid and dashed lines represent LOESS–smoothed records (span = 0.20, order = 1). The horizontal thin dashed line indicates the assumed present-day TJuly [July temperature] value at Lake Kupal'noe. Aquatic invertebrate zones (Ai-1 to Ai-6) follow Fig. 5.
Holocene climate variability on the Kola Peninsula, Russian Subarctic, based on aquatic invertebrate records from lake sediments

  • a Institute of Ecology, University of Innsbruck, Technikerstraße 25, A-6020 Innsbruck, Austria
  • b Institute of North Industrial Ecology Problems, Kola Science Centre, Russian Academy of Sciences, 14 Fersman St., Apatity, Murmansk reg., 184209 Russia
  • c Geological Institute, Kola Science Centre, Russian Academy of Sciences, 14 Fersman St., Apatity, Murmansk reg., 184209 Russia
  • d Department of Geology, Quaternary Sciences, Lund University, Sölvegatan 12, SE-223 62 Lund, Sweden


Sedimentary records of invertebrate assemblages were obtained from a small lake in the Khibiny Mountains, Kola Peninsula. Together with a quantitative chironomid-based reconstruction of mean July air temperature, these data provide evidence of Holocene climate variability in the western sector of the Russian Subarctic. The results suggest that the amplitude of climate change was more pronounced in the interior mountain area than near the White Sea coast. A chironomid-based temperature reconstruction reflects a warming trend in the early Holocene, interrupted by a transient cooling at ca. 8500–8000 cal yr BP with a maximum drop in temperature (ca. 1°C) around 8200 cal yr BP. The regional Holocene Thermal Maximum, characterized by maximum warmth and dryness occurred at ca. 7900–5400 cal yr BP. During this period, July temperatures were at least 1°C higher than at present. The relatively warm and dry climate persisted until ca. 4000 cal yr BP, when a pronounced neoglacial cooling was initiated. Minimum temperatures, ca. 1–2°C lower than at present, were inferred at ca. 3200–3000 cal yr BP. Faunal shifts in the stratigraphic profile imply also that the late-Holocene cooling was followed by a general increase in effective moisture.

No comments:

Post a Comment