Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

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Adaptation Actions for a Changing Arctic: Perspectives from the Barents Area

4.2.4 Air pollution and black carbon The adverse effects of fine atmospheric particulates on human health have been well documented, with no evidence of a safe level of exposure or threshold below which no effects occur (WHO, 2013). Black carbon (BC) appears to be a better proxy for harmful combustion-related particulate species than the undifferentiated particle mass. Thus reductions in human BC exposure should lead to a reduction in health effects associated with fine suspended matter (WHO, 2012). Visible light is strongly absorbed by BC, and the result is atmospheric warming (Bond et al., 2013). BC is formed during incomplete combustion and can be distinguished from other carbonaceous species in the atmosphere because it is formed in flames, is refractory, and is insoluble in water and common organic solvents (Bond et al., 2013). It also has a short atmospheric lifetime (about a week) and is removed via wet and dry deposition processes.As a result, emission reductions can drive rapid change in atmospheric concentration. Highly reflective surfaces, such as snow and ice in the Arctic increase light absorption by BC particles in the atmosphere. BC also absorbs light after deposition onto (and then into) snow and ice, where it accelerates the melt process (Pedersen et al., 2015). BC has made an important contribution to the observed rise in Arctic surface temperature through the 20th century (although carbon dioxide is still the major factor driving the rise inArctic temperature) (Quinn et al.,2008; Koch et al.,2011;AMAP,2015a). It may be technically possible to reduce global anthropogenic BC emissions by up to 75% by 2030 (Shindell et al., 2012; AMAP, 2015a; Stohl et al.,2015).As well as helping to slowwarming,BC emission reductions would also have significant health benefits (Anenberg et al., 2012; Shindell et al., 2012). Local emissions currently represent only a small fraction of the BC found in the Arctic, much of it having been transported into the Arctic via long-range transport from lower latitudes. However, higher latitude emissions are more likely to end up on the Arctic surface. In relative terms, emissions close to and within the Arctic region have a larger impact per unit of emission than those at more distant sites (AMAP 2015b). According to AMAP (2015a), the eight Arctic nations are responsible for about 30% of the Arctic warming due to BC. Thus emission reductions within the Arctic Council member countries could help reduce warming and lead to related health benefits, especially within the Arctic. The Barents area has relatively high BC emissions compared to other regions at the same latitudes.Anthropogenic BC emissions in the region were estimated at 40 kt in 2010, which is 9% and 0.6%of Arctic and global anthropogenic emissions,respectively. Hegg et al. (2011) reported significantly higher washout ratios for BC than previously measured, and suggested that the increase can be explained by snow riming within the accretion zone.Hirdman et al. (2010) reported a general downward trend in measured BC concentrations at the Zeppelin station on Svalbard, with a decrease of 1.4±0.8 ng/m 3 per year (2002– 2009). Forsström et al. (2013) measured BC concentrations in snow samples collected in the period 2007–2009 and found 11–14ng/g on Svalbard.Air originating from the eastern sector appeared to contain BC levels more than 2.5 times higher than air arriving from south to west (Forsström et al., 2009), andmay

reflect the combined effect of the atmospheric concentration gradient, orographic effects of the archipelago, and efficient scavenging of carbonaceous particles through precipitation. In the Barents area, flaring associated with gas extraction is the most important source, responsible for ~90% of anthropogenic emissions. Flaring refers to the practice,mainly used within the oil industry, whereby a large proportion of the associated gas is burned at the production site. However, estimates are based on very fewmeasurements (Stohl et al., 2013) and BC emission estimates are relatively uncertain (Bond et al., 2013). Other important BC sources are transport (mainly diesel engines; see Evans et al., 2015) and residential heating, both estimated to make roughly equal contributions to the emission balance. These emissions are usually concentrated in population centers, visible on a map of the region (Figure 4.11). The high share of flaring in the emission balance is because the Barents area overlaps large parts of the Russian production fields in western Siberia (shown in the eastern part of the Barents area in Figure 4.11), that account for most past and current oil production in Russia (Carbon Limits, 2013).There is a general lack of data for the Russian part of the Barents area (and Russia in general), and very little local and regional information available to date for constructing emission inventories.However, ongoing efforts (atmospheric modelling, regional inventories, measurements) are expected to improve the situation in the near future. There are some data for the Nordic countries – Norway, Sweden (Swedish Environmental Protection Agency, 2015) and Finland – but further work is encouraged on improving the basis for activity level data, spatial representation of emission information, and emission factors for major emission sectors, especially residential combustion (ACAP, 2014). Some regional assessments have recently been conducted. For example, Evans et al. (2015) estimated BC emissions from diesel sources in the Murmansk district

Black carbon, t/y

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Figure 4.11 Black carbon emissions in the Barents area (excluding wildfires). Graphic based on the global emission dataset (IIASA-GAINS, ECLIPSE v5) used in the most recent AMAP assessment on black carbon and tropospheric ozone (AMAP 2015a,b) and the ECLIPSE project (Stohl et al., 2015; Klimont et al., 2017).