Late Quaternary climate variations reflected in Baltic sea sediments
|Location||International Geological Congress,oslo 2008|
|Holding Date||18 August 2008|
Late Quaternary climate variations reflected in Baltic sea۱:place> sediments
Harff, Jan۱; Endler, Rudolf۲; Emelyanov, Emel۳; Kotov, Sergey۴; Moros, Matthias۲; Olea, Ricardo A.۵; Taranenko, Irina۴
Sediments have accumulated at high rates and resolution in the Baltic Sea, making them ideal for the study of late Pleistocene to Holocene climate and environmental history in Northern Europe and the North Atlantic۱:place> realm. Organic carbon, inorganic geochemical compounds, grain size and physical properties have been successfully used as proxies for paleo-temperature, primary production, hydrographic circulation pattern and precipitation. The variability of these sediment parameters mirror secularly changing depositional conditions determined by climatically-driven sea level change and glacio-isostatic adjustment which controls the coupling of the Baltic Sea۱:place> hydrographical regime with the ocean.
During the late Holocene when the Baltic basin was permanently connected with the Atlantic Ocean the Baltic sedimentary facies reflects the dynamics of the atmospheric circulation of the North Atlantic۱:place> and its modification due to changes Eurasian anticyclones at the centennial scale.
On the other hand, there are components within the sedimentary facies that express environmental parameters as detritus supply or organic primary production that are periodically changing at annual to decadal scales.
We have compared different sediment proxies with climatic reconstructions from Greenland۱:place> ice, tree-rings and Scandinavian lake sediments. Refined with Singular Spectrum Analysis, all the records have been analyzed on periodicity via Fourier analysis.
Time series analysis covering a time span of the last ۱۱.۰۰۰ years reveals different periodicities of climate proxy-parameters, with the higher frequencies reflecting regional and local patterns. Particularly prominent is a ۹۰۰ year period found in Baltic, North Atlantic, and Greenland۱:place> proxy data that seems to be of global relevance. This period, also present in late Quaternary sun activity records, explains not only to the Late Glacial to Middle Holocene record, but also to the more recent climate variations from the Dark Ages to the Medieval Climate Optimum, the Little Ice Age, and the Modern Warm Period. According to our data analysis the current phase of anthropogenic global warming coincides with a phase of naturally increasing temperature of the atmosphere. Periodicity analysis allows the development of predictive scenarios of the future climate changes based on mathematical models of proxy-data variability from sediments and ice cores.