When a fish ends up in the frying pan in your kitchen, we know a fair amount about what it has cost the planet to put it there, thanks to life cycle assessments (LCA).
But until recently we have known little about how large a role plastic emissions have played in that equation.
The reason is that life cycle assessments generally don’t include plastic emissions in the data they are based on (inventory analysis) – and because of that, they aren’t included in the step that assesses the environmental impacts (impact assessment) either.
However, when we look closely at the environmental cost of fish for food and feed, plastic is a significant part of the equation: Each year 640,000 tonnes of fishing equipment – much of it made of plastic – is lost globally as a result of rough weather, wear and tear, or by accident.
NORSUS researches how to include plastic in LCA
NORSUS is working on several fronts to develop good methods for including plastic in LCA. For example in the Dsolve and MarILCA projects, where several NORSUS researchers are investigating marine plastic emissions.
Recently, "Expanding life cycle impact assessment to account for marine plastic emissions: a case study for the fishing industry”, written by NORSUS’ Cecilia Askham, Mafalda Silva and Valentina Pauna, amongst others, was published in The International Journal of Life Cycle Assessment.
The study takes a closer look at new conversion methods (characterisation factors) for including plastic emissions in life cycle assessments – both to test the methods in real-world situations, and also to investigate how much damage plastic pollution does to the ecosystem.
Fishing is a critical stage for ecosystem damage
When it comes to this last point, damage to the ecosystem, one stage in the life cycle clearly stands out, according to the study: the act of fishing itself.
The researchers have analysed two real-world cases: Cod fishing off the Norwegian coast (where the cod is intended for human consumption) and anchoveta fishing off the coast of Peru (where the anchoveta is intended as an ingredient in feed for Norwegian fish farms).
For cod fishing, the production of the antifouling treatment – which prevents organic matter from growing on the fishing boat hull – has the biggest negative impact on the ecosystem (shown in pink in the figure below). For anchoveta fishing, however, it is clearly entanglement (fish that gets entangled in lost or abandoned fishing gear) that has the highest negative impacts on the ecosystem.
Time affects the result
And although ghost fishing is already the largest impact factor by far – the researchers are clear that it could account for even more: The method used to convert lost fishing gear into environmental damage assumes that the gear causes damage for five years.
When adding more years to the equation, the potential for damage is much higher. The five-year time horizon was chosen, however, because the probability of entanglement decreases over time.
There are still a range of effects that plastic and its chemicals might have on ecosystems – and many of these still lack methods good enough to be included in life cycle assessments at present. However, including as many as possible is nonetheless an important step towards life cycle assessments that comprehensively capture every impact that abandoned, lost or discarded plastic can have.
The study is a part of Dsolve – a project where NORSUS collaborates with several partners from research and industry to develop smarter fishing gear.
Dsolve is a good example of a project where research and industry collaborate to the benefit of both: NORSUS gains access to empirical data and real-world cases that can be used to test theory and methods against reality – and thereby contribute to methodological development internationally, while the results from NORSUS’ research can be used to make better, more environmentally friendly products, and to make better choices.
