Monday, November 19, 2012

New paper finds Siberian temperatures 5,000 years ago were up to 1.5C higher than today

A paper published today in Quaternary International reconstructs temperatures over the past 10,000 years and finds that July temperatures in Siberia were "equal or up to 1.5 °C higher than today between 6,000  and 5000 years [ago]" during the Holocene Climate Optimum.


Reconstructed temperatures shown in graph at left and indicate Siberian July temperatures were up to 1.5C higher than today from 5,000 to 6,000 years before the present [BP]


Holocene climate conditions in central Yakutia (Eastern Siberia) inferred from sediment composition and fossil chironomids of Lake Temje

  • a Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, 14473 Potsdam, Germany
  • b Kazan Federal University, Kremlyovskaya str., 18, 420018 Kazan, Russia
  • c St.-Petersburg Gerzen Pedagogical University, Moika 48, 191186 St. Petersburg, Russia
  • d North-Eastern Federal University, 58 Belinsky Street, Yakutsk, 677891, Russia
  • http://dx.doi.org/10.1016/j.quaint.2012.11.006
A 380 cm long sediment core from Lake Temje (central Yakutia, Eastern Siberia) was studied to infer Holocene palaeoenvironmental change in the extreme periglacial setting of eastern Siberia during the last 10,000 years. Data on sediment composition were used to characterize changes in the depositional environment during the ontogenetic development of the Lake Temje. The analysis of fossil chironomid remains and statistical treatment of chironomid data by the application of a newly developed regional Russian transfer functions provided inferences of mean July air temperatures (TJuly) and water depths (WD). Reconstructed WDs show minor changes throughout the core and range between 80 and 120 cm. All the fluctuations in reconstructed water depth lie within the mean error of prediction of the inference model (RMSEP = 0.35) so it is not possible to draw conclusions from the reconstructions. A qualitative and quantitative reconstruction of Holocene climate in central Yakutia recognized three stages of palaeoenvironmental changes. The early Holocene between 10 and 8 ka BP was characterized by colder-than-today and moist summer conditions. Cryotextures in the lake sediments document full freezing of the lake water during the winter time. A general warming trend started around 8.0 ka BP in concert with enhanced biological productivity. Reconstructed mean TJuly were equal or up to 1.5 °C higher than today between 6.0 ka and 5.0 ka BP. During the entire late Holocene after 4.8 ka BP, reconstructed mean TJuly remained below modern value. Limnological conditions did not change significantly. The inference of a mid-Holocene climate optimum supports scenarios of Holocene climatic changes in the subpolar part of eastern Siberia and indicates climate teleconnections to the North Atlantic realm
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