Historical black carbon deposition in the Canadian High Arctic: a <i>></i>250-year long ice-core record from Devon Island

Abstract

Abstract. Black carbon aerosol (BC), which is emitted from natural and anthropogenic sources (e.g., wildfires, coal burning), can contribute to magnify climate warming at high latitudes by darkening snow- and ice-covered surfaces, and subsequently lowering their albedo. Therefore, modeling the atmospheric transport and deposition of BC to the Arctic is important, and historical archives of BC accumulation in polar ice can help to validate such modeling efforts. Here we present a > 250-year ice-core record of refractory BC (rBC) deposition on Devon ice cap, Canada, spanning the years from 1735 to 1992. This is the first such record ever developed from the Canadian Arctic. The estimated mean deposition flux of rBC on Devon ice cap for 1963–1990 is 0.2 mg m−2 a−1, which is at the low end of estimates from Greenland ice cores obtained using the same analytical method ( ∼ 0.1–4 mg m−2 a−1). The Devon ice cap rBC record also differs from the Greenland records in that it shows only a modest increase in rBC deposition during the 20th century. In the Greenland records a pronounced rise in rBC is observed from the 1880s to the 1910s, which is largely attributed to midlatitude coal burning emissions. The deposition of contaminants such as sulfate and lead increased on Devon ice cap in the 20th century but no concomitant rise in rBC is recorded in the ice. Part of the difference with Greenland could be due to local factors such as melt–freeze cycles on Devon ice cap that may limit the detection sensitivity of rBC analyses in melt-impacted core samples, and wind scouring of winter snow at the coring site. Air back-trajectory analyses also suggest that Devon ice cap receives BC from more distant North American and Eurasian sources than Greenland, and aerosol mixing and removal during long-range transport over the Arctic Ocean likely masks some of the specific BC source–receptor relationships. Findings from this study suggest that there could be a large variability in BC aerosol deposition across the Arctic region arising from different transport patterns. This variability needs to be accounted for when estimating the large-scale albedo lowering effect of BC deposition on Arctic snow/ice.

Observed and Modeled Black Carbon Deposition and Sources in the Western Russian Arctic 1800–2014

“…Study sites and BC emissions in their vicinity. (A) Locations of the study lakes (yellow dots), previously published lake sediment BC records from northern Finland (green dots), and Svalbard, ,, Greenland, , and a Canadian ice core records (green stars). The red line indicates the Arctic as defined by the Arctic Monitoring and Assessment Programme (AMAP).…”

Revised historical Northern Hemisphere black carbon emissions based on inverse modeling of ice core records

“…It showed a large influence of BC from boreal forest fires before 1890 (hereafter referred to as biomass burning (BB) BC), and that anthropogenic BC contribution peaked in the 1920s before decreasing during the last few decades of the 20th century. Since this record was published, several other ice cores have been developed from Greenland 20 – 25 , Arctic Canada 26 , Svalbard 27 , 28 , the continental United States 29 , Russia 30 , the European Alps 31 , 32 South America 33 the Antarctic 17 , 34 , 35 , the Himalayas 36 and the Tibetan Plateau 37 . These records show high interannual variability in large part because of year-to-year variability in transport and seasonal snow deposition at the coring sites, but robust multi-annual trends related to historical changes in regional emissions are clear.…”

Increased Fire Activity in Alaska Since the 1980s: Evidence From an Ice Core‐Derived Black Carbon Record

“…BC and NH 4 + have been considered reliable proxies of forest fires in ice cores from Greenland, along with other species including organic carbon, and formic and vanillic acid (Legrand et al., 2016). However, BC emissions from fossil fuel combustion have increased considerably since 1850 (Bond et al., 2007) and have affected BC trends in ice core records from Greenland (McConnell et al., 2007), and other Arctic sites (Osmont et al., 2018; Ruppel et al., 2014; Zdanowicz et al., 2018). Contrary to Greenland, in the Canadian sub‐Arctic, it was estimated that between 2007 and 2013, biomass burning contributed 59%–78% of annual BC during summer and 28%–32% during winter (Qi & Wang, 2019a).…”

“…Ice cores are natural archives exclusively fed by atmospheric input and can provide more detailed information including broader spatial and longer temporal histories of BC deposition in remote regions compared to other natural archives (e.g., tree rings, lake sediments, and peat bogs). There are a number of ice core records of BC from different regions including Greenland (McConnell et al., 2007) and Svalbard (Osmont et al., 2018; Ruppel et al., 2014) in the Arctic, the Canadian high‐Arctic (Zdanowicz et al., 2018) and sub‐Arctic (Mt. Logan; Menking, 2013), Washington State in North America (Kaspari et al., 2020), western and eastern Europe (Lim et al., 2017; Sigl et al., 2018), Tibet and the Himalayas (Barker et al., 2021; Kaspari et al., 2011; Wang et al., 2015), and Antarctica in the Southern Hemisphere (Bisiaux et al., 2012).…”