Circularity and sustainability are often seen as synonyms but is this exactly right? Circular economy is a manifestation of economic models that highlight business opportunities where cycles rather than linear processes, dominate. The circular economy (CE) is perceived as a sustainable economic system where the economic growth is decoupled from the resources use, through the reduction and recirculation of natural resources - this is how the review by Corona et al (2019) starts. The paper goes to crucially review some of the current metrics of circularity, given suggestions to how they could improved. I definitely recommend a reading. Many different approaches can fall under the ‘circular economy’ umbrella. Some examples? Companies offering collections of their used goods for recycling of the materials (think of some fashion brands doing this), or even companies themselves opening up ‘second-hand’ shops of their brand. These, however, are two very different approaches despite having a similar initial dynamic: consumer buys, then give back to company after using. In the first case, the materials must be processed, in the second case, they are resold as they are or maybe after little fixes. Circular Economy has been in fact defined also as “a regenerative system in which resource input and waste, emission, and energy leakage are minimised by slowing, closing, and narrowing material and energy loops. This can be achieved through long-lasting design, maintenance, repair, reuse, remanufacturing, refurbishing, and recycling.” You can already see how many different options one has to achieve circularity. Here comes the question then: Is all that is circular also sustainable? A little hint: it really depends On what? On our energy system. Remember: I already spoke about this concept that energy is our first sustainability issue! I will give you an example close to my research. Reuse of shells from shellfish aquaculture: Shells are being seen more and more as a tool towards sustainability. In part because of the CO2 storage potential, which largely depends on what you do with them afterwards and surely, throwing them in an open air pile of rubbish will not only risk the co2 being released back to the atmosphere, but it is a waste. Yes, because the material can be transformed as a lot of different things: from concrete, to fields fertiliser, from chicken feed additive (calcium) to ‘neoprene’. Can even use it to make glass! Or, you know, one can simply use them as they are to go and replenish some hard substrate to help regeneration of natural shellfish reefs, where the larvae really need some suitable hard substrate to settle. These different options have different amounts of processing involved: it goes without saying that some are highly energetic costly! The GAIN project (of which I was briefly part of during last year and coordinated by Ca’ Foscari University) really looked at circularity, in particular related to fish aquaculture byproducts and their different use, for example, as pet-food. You can find some reports here The papers still have to come out but some Life Cycle Assessment has found that currently it is not exactly ‘sustainable’ to transform the by-product. That is, using LCA indicators - and specifically the carbon footprint. And that is because we are still heavily relying on energy from fossil fuels to obtain these transformations. This opens all suits of follow up questions: 1- one confront the different uses of the byproducts between themselves (including the do-nothing and dipose option) but does not compare it against the production ex-novo of the second product (???). Why? Let’s think of the example of making paper out of byproduct of jam/juice industry. Surely, making paper ex novo would be worse. 2- Is really all and only about the ‘carbon footprint’ ? What about ethically, using the whole of the fish and respecting the killing of another animal? Should we really have to reduce this to a number? Questions that could be enclosed in a need to redefine sustainability And of course, a priority needs for the energetic transition!
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