Black carbon (BC) is fine particulate matter produced by the incomplete combustion of biomass and fossil fuels. It has a strong climate warming effect that is amplified in the Arctic. Long-term trends of BC play an important role in assessing the climatic effects of BC and in model validation. However, few historical BC records exist from high latitudes. We present five lake-sediment soot-BC (SBC) records from the Fennoscandian Arctic and compare them with records of spheroidal carbonaceous fly-ash particles (SCPs), another BC component, for ca. the last 120 years. The records show spatial and temporal variation in SBC fluxes. Two northernmost lakes indicate declining values from 1960 to the present, which is consistent with modeled BC deposition and atmospheric measurements in the area. However, two lakes located closer to the Kola Peninsula (Russia) have recorded increasing SBC fluxes from 1970 to the present, which is likely caused by regional industrial emissions. The increasing trend is in agreement with a Svalbard ice-core-BC record. The results suggest that BC deposition in parts of the European Arctic may have increased over the last few decades, and further studies are needed to clarify the spatial extent of the increasing BC values and to ascertain the climatic implications.

Black carbon (BC) particles contribute to climate warming by heating the atmosphere and reducing the albedo of snow/ice surfaces. The available Arctic BC deposition records are restricted to the Atlantic and North American sectors, for which previous studies suggest considerable spatial differences in trends. Here, we present first long-term BC deposition and radiocarbon-based source apportionment data from Russia using four lake sediment records from western Arctic Russia, a region influenced by BC emissions from oil and gas production. The records consistently indicate increasing BC fluxes between 1800 and 2014. The radiocarbon analyses suggest mainly (∼70%) biomass sources for BC with fossil fuel contributions peaking around 1960–1990. Backward calculations with the atmospheric transport model FLEXPART show emission source areas and indicate that modeled BC deposition between 1900 and 1999 is largely driven by emission trends. Comparison of observed and modeled data suggests the need to update anthropogenic BC emission inventories for Russia, as these seem to underestimate Russian BC emissions and since 1980s potentially inaccurately portray their trend. Additionally, the observations may indicate underestimation of wildfire emissions in inventories. Reliable information on BC deposition trends and sources is essential for design of efficient and effective policies to limit climate warming.

A widespread use of biofuels is a key recommendation of the Paris Agreement and leading international organizations. It is an important step to mitigate the global warming effects due to greenhouse‐gas emissions from fossil oils. To this aim, an analytical technique sufficiently cheap and compact, to foster its widespread adoption, is necessary. Herein, it is shown that a compact, laser‐based spectrometer is suitable to replace the few established techniques, which have been used to quantify the biofraction in fuel blends, so far. Measurements of the biogenic fraction in different fuel samples are reported, with a precision of 1% in the whole range (0–100%) of possible blends, confirming a performance comparable to the best existing technique. An onsite‐deployable saturated‐absorption cavity ring‐down (SCAR) spectrometer is used. The results demonstrate the potential of laser‐based instrumentation to do the accurate and precise measurements required for the certification of biogenic content of any hydrocarbon‐based material. Worldwide adoption of such laser‐based technology for biofraction certification can significantly boost the market of biofuels and can prove to be a disruptive methodology for assessing the biogenic content in plastics and polymeric materials.