Zapis zmian klimatu w ostatnich 200 latach w morfodynamice stoków oraz kriosferze Tatr i Karkonoszy = A record of climate changes over the past 200 years in slope morphodynamics and the cryosphere of the Tatra and Karkonosze Mountains

Abstract

Climate change has a huge impact on many forms of life and processes occurring on Earth. As high mountains have emerged as particularly sensitive to climate change, the Tatras, have long been a site for research on climate change and its impact on the environment. Debris flows are among the most spectacular hydrometeorological and geomorphological events occurring in high mountains, and given the long-term permafrost and large number of multiannual snow patches occurring in the Tatras, as well as the impact these exert on slope morphodynamics, it was also decided to examine the impact of climate change on selected elements of the cryosphere here. Equally, although the Karkonosze may not be counted as high mountains, but are at best intermediate between these and mountains of medium height, research of the same kind as in the Tatras has nevertheless been pursued at locations within this range. Lichenometric dating shows that the period with the greatest intensity of slope modelling in the two mountain ranges was the so-called “Little Ice Age”, the end of which is similar in the Karkonosze to in the Tatras. In both ranges, the 1930s and 1940s brought an upsurge in debris flows. Another phase of increased frequency of debris flows in the Tatras generally began in the 1970s and has continued through to the present day, while the analogous phenomenon in the Karkonosze Mountains began some 10-20 years later. Analysis of the intensity and duration of precipitation indicates that, in both the Tatra Mountains and the Karkonosze, daily precipitation totals are much less significant for the initiation of debris flows than the intensity of precipitation at given times. In the Tatras, it is sufficient for heavy precipitation of more than 1 mm/min to persist for at least 15 minutes, for debris flows to begin to occur. In the case of the Karkonosze, the duration of such heavy-rainfall events is slightly longer, with the presently-available (still scant) data suggesting 30 minutes is siffucient. The thickness of the cones analysed by GPR sounding in the Tatra Mountains is at least twice as great as that of the cones present at Maly Staw in the Karkonosze Mountains. This difference mainly reflects the size and shape of the sediment supply area and the type and dynamics of the morphogenetic processes providing the material from which the cones are formed. The Karkonosze Mountains currently lack any multiannual snow patches, though it seems very likely that 80+ years ago (at the end of the “Little Ice Age”), snow did cover parts of these mountains for almost the whole year. Existing debris glaciers in the Tatra Mountains, like the largest such glacier in the Karkonosze, displayed no activity during the “Little Ice Age”, despite the probable presence of permafrost in some of the Tatra rock glaciers. Despite the climatic differences between the Tatra and Karkonosze Mountains (mainly related to altitude and geographical location), a high degree of concordance is to be noted in the course of changes in morphogenetic processes discussed in this paper. These in turn relate to the latitudinal teleconnection phenonenon found by both climatologists and dendrochronologists. The impact of climate change on the activity of debris flows and the response on the part of snow patches/ glacierettes in the Tatra Mountains and the Karkonosze Mountains is seen to be similar to the impact and change reported in the Alps.