Past black carbon deposition and sources in the European Arctic depicted from lake sediments and ice cores

The amplified climate effect of black carbon (BC) in the Arctic is widely acknowledged. Despite this, information on its deposition patterns and particularly sources are still scarce from the area. Arctic-wide atmospheric BC monitoring show decreasing BC concentrations since the 1990s. However, increasing amounts of BC deposition records from the area show more spatial variability in long-term trends, and some records suggest deviating trends between atmospheric BC concentrations and deposition. Particularly in the European Arctic (northern Fennoscandia and northwestern Russia) BC deposition trends seem to have increased in recent decades rather than decreased as suggested by models and observed for atmospheric concentrations. Such dissimilarities between atmospheric BC concentrations and deposition trends suggest different meteorological processes and sources driving these, which need to be further studied to understand the effects of different BC emissions on the Arctic climate. Although we have quantified different BC fractions from lake sediments and ice cores in the European Arctic indicating variable deposition trends during the last 300 years, the records suggest surprisingly similar sources of the deposited BC particles. Our future endeavors lie in further illuminating the sources of deposited BC in the Arctic and particularly studying the potential significance of Russian gas flaring and increasing peatland fires.