Development, stability and degradation of permafrost have strongly been connected with natural climate fluctuations of cold and warm periods during the Quaternary earth history of the past two million years. Cold stages were the long-range periods of permafrost aggradation. Interglacial periods were characterized by extensive permafrost degradation.
Circum-arctic Permafrost dynamics and Quaternary environmental dynamics are investigated with a multidisciplinary approach is the in joint German-Russian, German-Canadian and German-American projects for two decades.
Characteristics of frozen sediments and ice structure therein inform how the permafrost deposits have been formed and transformed. Ice wedges can say something about the composition of the winter precipitation before thousands or tens thousands of years. Pollen and plant seeds provide information on vegetation changes depending on temperature and humidity variations. The past environment and its changes could be reconstructed using fossil bioindicators like insect remains, mammal bones, diatoms, ostracods, shell-bearing amoebas, and mussel and snail shells, since many creatures have adapted to the special habitat conditions.
Other long-term environmental and climate archives such as polar ice caps, marine or lacustrine sediment sequences are scarcely available in the vast areas arctic mainland. Therefore, permafrost sequences are the only archives far-reaching in the Quaternary past, which are there available and enhance the global network of palaeoenvironmental archives.
It reveals how the sensitive arctic landscapes and living in them plants, animals and micro-organisms have reacted to climate warming and cooling of the past. The result is a patchwork of information of different accuracy, temporal and spatial resolution, which enables on the one hand to infer from palaeoenvironmental reactions to past climatic conditions, and on the other hand to observe the reactions of the Arctic environment and the periglacial ecosystems to long-term global climate variations. From this, conclusions for expected future changes can be drawn if, for example, the today visible trends of global warming continue.
The studies are part of the AWI Research Program, Topic 3: "The Earth System from a polar perspective - data modeling and synthesis"
Dr. Georg Schwamborn
Dr. Sebastian Wetterich