In today’s modern world, every thing that we use goes through a series of stages–from production to consumption and finally disposal. Products such as plastics progress through a linear system by which they originate from raw resources, become usable products (reaching the peak of their value), and end up as “waste”. It is their improper disposal and release into our environments that result in what we know as plastic pollution. In order to understand plastic pollution, from its source to its “end” as a pollutant, it is essential to conceptualize the life cycle of a plastic product “from life to death”.

In my first introductory blog post, we have seen the video of the Life Cycle of A Plastic Bottle. In this blog post, we examine this in further detail.

life-cycle-analysis2

As shown in the above diagram, the conventional model sees products such as plastic bags moving through three major stages in its existence as a useful product, from “cradle” to “grave”. A plastic bag are born from natural resources when we take crude oil, heat it to convert it to polyethylene, and manufacture it into the form of a bag. After it is used to package goods and carry groceries, it is discarded to landfills to rot away as waste. While the conventional product life cycle model may (arguably) work for products such as paper and food which decompose (relatively) quickly when left naturally, it meets a problem with plastic.

The following diagram depicts the problematic life cycle of a plastic bag. One of the major components of plastic waste is polyethylene terephthalate (PET), which is highly resistant to environmental biodegradation. Essentially, plastic serve a very brief “life span” where its usefulness is quickly exhausted and is then discarded as waste, meeting an eternal end in landfills and oceans. life-cycle-of-plastic-bag

What drives this unrelenting march of plastics to eternal end after death is the almost cost-free nature of  land-filling and incineration. To date, only three plastic disposal methods are routinely used on a large scale: landfill, incineration and recycling. While recycling addresses the environmental concerns of landfill and incineration, the process is “relatively inefficient and the diminishing quality of the polymer yielded is a limiting factor”(Webb et al., 2012). The process is also less cost-effective, and subsequently, there is less incentive for investment in recycling facilities. In addition to requiring large portions of land space, landfill and incineration both lead to the release of dangerous secondary pollutants into the environment. The disposed plastic debris, whether burnt or buried, are fated to remain in our lands, air and seas for “the next 1,000 years”–releasing toxins that concentrate in ecosystems and are absorbed by living organisms, killing millions of marine and coastal animals per year. The conventional cradle-to-grave life cycle of the linear economy produces an increasingly serious crisis of plastic pollution.

It is thus apparent that the linear product life cycle is deeply problematic in the case of plastic materials that do not simply biodegrade. How can we mitigate the crisis of a thousand years of plastic choking up our seas and land? The answer may be to rethink the life cycle model of plastics, which we shall explore in the next blog post.


References

Webb, H., Arnott, J., Crawford, R. and Ivanova, E. (2012). Plastic Degradation and Its Environmental Implications with Special Reference to Poly(ethylene terephthalate). Polymers, 5(1), pp.1-18.

CREA : Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria. (2016).Economia circolare e bioeconomia: prospettive di ricerca. [online] Available at: http://www.sviluppumbria.it/documents/20182/63899/Cristiano.pdf/22b27de0-6120-4237-96c1-68aed7390f20 [Accessed 11 Oct. 2016].

Factory Direct Promos. (2016). Life Cycle of a Plastic Bag. [online] Available at: http://www.factorydirectpromos.com/life-cycle-of-a-plastic-bag [Accessed 11 Oct. 2016].