An 800-year high-resolution black carbon ice core record from Lomonosovfonna, Svalbard

Abstract

Abstract. Produced by the incomplete combustion of fossil fuel and biomass, black carbon (BC) contributes to Arctic warming by reducing snow albedo and thus triggering a snow-albedo feedback leading to increased snowmelt. Therefore, it is of high importance to assess past BC emissions to better understand and constrain their role. However, only a few long-term BC records are available from the Arctic, mainly originating from Greenland ice cores. Here, we present the first long-term and high-resolution refractory black carbon (rBC) record from Svalbard, derived from the analysis of two ice cores drilled at the Lomonosovfonna ice field in 2009 (LF-09) and 2011 (LF-11) and covering 800 years of atmospheric emissions. Our results show that rBC concentrations strongly increased from 1860 on due to anthropogenic emissions and reached two maxima, at the end of the 19th century and in the middle of the 20th century. No increase in rBC concentrations during the last decades was observed, which is corroborated by atmospheric measurements elsewhere in the Arctic but contradicts a previous study from another ice core from Svalbard. While melting may affect BC concentrations during periods of high temperatures, rBC concentrations remain well preserved prior to the 20th century due to lower temperatures inducing little melt. Therefore, the preindustrial rBC record (before 1800), along with ammonium (NH4+), formate (HCOO−) and specific organic markers (vanillic acid, VA, and p-hydroxybenzoic acid, p-HBA), was used as a proxy for biomass burning. Despite numerous single events, no long-term trend was observed over the time period 1222–1800 for rBC and NH4+. In contrast, formate, VA, and p-HBA experience multi-decadal peaks reflecting periods of enhanced biomass burning. Most of the background variations and single peak events are corroborated by other ice core records from Greenland and Siberia. We suggest that the paleofire record from the LF ice core primarily reflects biomass burning episodes from northern Eurasia, induced by decadal-scale climatic variations.

A Holocene black carbon ice-core record of biomass burning in the Amazon Basin from Illimani, Bolivia

“…After melting the ice-core samples at room temperature and 25 min sonication in an ultrasonic bath, rBC was quantified using a single-particle soot photometer (SP2, Droplet Measurement Technologies, USA; Schwarz et al, 2006;Stephens et al, 2003) coupled to an APEX-Q jet nebulizer (Elemental Scientific Inc., USA). Further analytical details regarding calibration, reproducibility and autosampling method can be found in Osmont et al (2018). Replicate samples for the IL-99 ice core showed good reproducibility (r = 0.65, p<0.001, n = 243), in particular regarding rBC peak values and trends, while the resampled part in the period 0-2000 BCE (121 samples) showed notable agreement with the original dataset, thus confirming the reliability of our rBC analysis.…”

“…Data availability. The rBC data are available at the US National Oceanic and Atmospheric Administration (NOAA) data center for paleoclimate (ice-core sites) at the following address: http://www.ncdc.noaa.gov/data-access/paleoclimatology-data/ datasets/ice-core (Osmont, 2019).…”

“…In rBC ice-core records from the Arctic and Europe, a predominant anthropogenic contribution starting in the second half of the 19th century due to rising fossil fuel emissions was observed (Keegan et al, 2014;McConnell et al, 2007;Osmont et al, 2018;Sigl et al, 2013Sigl et al, , 2018. At Illimani, rBC concentrations follow a long-term increasing trend since the 1730 CE minimum.…”

“…Ice-core studies suggest that a variety of biomass burning proxies could be used to reconstruct paleofires (Osmont et al, 2018;Zennaro et al, 2014). Ammonium (NH + 4 ) has been widely analyzed in polar ice cores from Greenland (Fischer et al, 2015;Legrand et al, 2016) and Antarctica (Arienzo et al, 2017).…”

Tracing devastating fires in Portugal to a snow archive in the Swiss Alps: a case study

“…Arienzo et al, 2017;Fischer et al, 2015;Keegan et al, 2014;Legrand et al, 1992Legrand et al, , 2016De Angelis, 1996, Whitlow et al, 1994;Zennaro et al, 2014) and high-altitude glaciers (see e.g. Brugger et al, 2018aBrugger et al, , 2019aEichler et al, 2011;Osmont et al, 2018Osmont et al, , 2019Yalcin et al, 2006) have a high potential since they record fire activity from regional to continental scales and usually provide well-constrained chronologies (see e.g. Herren et al, 2013;Konrad et al, 2013;Uglietti et al, 2016).…”