The unaltered stomach contents of a dead albatross chick photographed on Midway Atoll National Wildlife Refuge in the Pacific in September 2009 include plastic marine debris fed the chick by its parents. (Chris Jordan)

Open pen aquaculture has suffered a great many criticisms these past few decades, but the most damning of all was shared with me only recently by a thoughtful New Brunswick marine biologist. As she explained it, the reason open-pen aquaculture remains so profitable, is because it’s not paying all its bills.

These pens, stuffed with salmon or trout as the case may be, don’t need regular cleaning, nor do their waters need refreshed. All their water is supplied by the ocean in which they float, and the mountains of manure, wasted food, pesticides and antibiotics moving through these pens are helpfully expunged by the workings of oceanography, spread throughout our bays and coastlines, or collecting in mounds below which no one is obligated to clean up, in spite of innumerable concerns for the health of people, fish and local ecology.

These are uncounted expenses, externalities which many industries have confidently ignored for generations, assuming the size of our blue and green globe will sort everything out in good time. It’s an old and dangerous idea which has become all the more absurd as our demands have grown on a finite planet. There are no shortage of examples.

Consider the manufacture of plastics, single-use or otherwise. The companies producing these products, in North America anyway, do so with widespread disregard for what happens after these plastics hit the market. Inevitably they are discarded where they don’t belong, filling parks and ditches, and even if they find their way into landfills we are obligated to bury them, or else allow them to disperse into our environment by way of wind or stream. The cleanup of such ecological catastrophes does not come at the expense of the manufacturer, but instead of charitable enterprises trying to engineer a solution to the impossibly difficult problem of unpolluting the remotest environments on Earth, namely our oceans.

A tax on carbon is an effort to count previously uncounted costs. It’s among the simplest, most commonsense measures a government could enact because it recognizes our atmosphere as a societal asset, a public resource, into which energy and transportation companies have dumped their waste for over a century at no significant charge. This uncounted cost drives climate change, the greatest threat we as a species has ever faced and whose economic costs will be otherworldly. I’ve heard this carbon tax greeted with griping from consumers, when in fact it’s an overdo measure to balance the scales. Fossil fuel is a lucrative industry precisely because it hasn’t paid its entire bill. If your solar farm does not emit carbon and you do not dump waste into a public resource – the atmosphere – then you should have an economic advantage over industries which do. Simple as that.

When the forestry giants of Nova Scotia brazenly clearcut what remains of our shattered wilderness they pay fees for using of public lands, but these fees in no way account for the centuries it will take our forests to recover; for the loss of biodiversity which, in some cases, cannot be regained; for the plumes of carbon released from exposed and rapidly decomposing forest soils; for the washing away of soils themselves and for compromising regional water cycles.

While gauging the value of modern industries we have elected to use an outdated scoreboard, one which ignores inconvenient costs at our own peril, and I can’t help but wonder, if we as a nation, or a planet, did indeed hold industry to account for these externalities, would we find that sustainable alternatives are, by comparison, enormously affordable? Next time you hear an industry defended for its profitability, trace those dollars backward to the costs uncounted.

Zack Metcalfe is a freelance journalist, columnist and author active across the Maritimes.