Into the Arctic Haze...

How might increased Asian industrialisation lead to obesity in an Arctic indigenous population? Read on to find out!

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Breathe in...breathe out...pure, clean, fresh Arctic air...mmmm...just what you want a bottle of when you're on the Tube. Yes?

Actually, it seems that the air in the Arctic might not be as detoxifying-ly lovely as I imagine it to be. Which is disappointing. It's also very worrying, in terms of the implications it holds for the Arctic ecosystem. 

The so-called 'Arctic haze' - which comprises particulate organic matter and sulphate, along with other compounds - is a tangible indication that all is not well with the Arctic atmosphere. Although it had been noticed previously, it wasn't until the 1970s that this mysterious smog was attributed to human industrial activities (Law & Stohl, 2007). But how does that work, when emissions in the Arctic region are relatively low? As discussed by Law and Stohl (2007), pollutants are transported to the Arctic from lower latitudes (such as Eurasia), where they then persist in the environment; the haze is particularly strong in the late Winter and early Spring when there is little precipitation to remove pollutants from the atmosphere. 

It's quite difficult to find a good picture of 'haze'! But I think this one does the job.
Source: www.redorbit.com

To be honest, we could be here for hours, talking about all the different components of the Arctic haze and their effects...Instead, let's focus on just one (but trust me, it's an important one): mercury.

Coal-burning is a major contributor to atmospheric mercury
pollution. Source: www.ft.com

While mercury is released into the environment via natural sources (for example through the weathering of rock and volcanic eruptions), it's no coincidence that emissions have risen steeply since the start of the industrial revolution (AMAP, 2011). Indeed, human activity accounts for approximately 30% of annual mercury emissions to the air (with an estimated 1960 tonnes released in 2010), compared to 10% from natural sources (UNEP, 2013). The remaining 60% can be explained by 're-emissions', the majority of which are also likely to be of anthropogenic origin (UNEP, 2013). Coal burning - which released 475 tonnes of mercury in a year (2010) - is an important source, however measures are being taken to reduce the amount of pollution produced during this process (UNEP, 2013). When looking at anthropogenic emissions, Asia is currently the largest contributor of mercury to the atmosphere, accounting for almost 50% (UNEP, 2013). Before I stop bombarding you with figures, it must also be remembered that mercury pollution is not restricted to the atmosphere: mercury concentrations in the top 100 metres of the ocean have increased two-fold over the last century owing to human emissions (UNEP, 2013).

So, although we intuitively know this probably isn't good for the planet, what does it actually matter? Well, seeing as this mercury is able to reach the Arctic in just a few days (when transported by air currents...it can take decades to be transported in the ocean), it has important consequences for the Arctic ecosystem (AMAP, 2011). 

A fluffy creature (or Vulpes lagopus to be more precise). Arctic
foxes are one of the species affected by mercury bioaccumulation.
Source: www.news.softpedia.com

Mercury can be found in many forms; in low oxygen environments (for example wetlands or the seabed) it is converted from an inorganic form to methylmercury, which is highly toxic (AMAP, 2011). Methylmercury is able to enter the food chain, where it then bioaccumulates, reaching levels in apex consumers that can be a million times greater than those in organisms at the bottom of the food chain (AMAP, 2011). This is obviously detrimental to these animals (which include the Arctic fox, polar bear and ringed seal), as demonstrated by the mercury-induced neurochemical effects observed in the toothed whale (Bocharova et al., 2013; AMAP, 2011). However, it also has implications for the Arctic indigenous populations that traditionally rely on these animals for food. In a problem known as the 'Arctic Dilemma', there must be a trade-off between the amount of mercury indigenous people are exposed to, and the nutritional benefits of these foods (AMAP, 2011). In order to limit their mercury intake, indigenous populations can be advised to eat alternative foods, but this can be damaging not only culturally but physically, since imported processed foods can increase the risk of heart disease and obesity...(AMAP, 2011).

So there we are, we've come full circle - that is how increased Asian industrialisation could lead to obesity in an Arctic indigenous population.