There are a wide variety of reasons why plastic can be considered an environmental problem. For example, some questions already have covered the effect of plastic on climate change (See: How does plastic affect climate change? What is the environmental cost of recycling? Adding to these environmental problems, I shall highlight four key reasons why plastic is also an environmental pollution problem.
(1) Global plastic production has increased and as a result so has global plastic waste.
Plastics are popular as a material for two reasons. Firstly, due to their physical properties because they are lightweight, strong, inexpensive, durable, corrosion-resistant and molded into many different forms (Napper & Thompson, 2020). Secondly, plastics are favoured for economic reasons because the base product required to produce them are cheap, and plastic can be manufactured on mass. See question (What is the process for making plastic?) for a brief summary of how plastic is made. Consequently, plastic production has increased dramatically. A recent study of the production, use and fate of all plastics ever made found (Geyer et al., 2017):
- The global production of plastic resins and fibers has increased from 2 million tons in 1950 to 380 million tons in 2015.
- This means plastic production has increased at an annual rate of 8.4%.
This study calculated the use and fate of these plastics between 1950 and 2015 and estimated that 30% of plastics ever produced are currently still in use. Therefore, the remaining 70% of plastic is considered a waste product (plastic waste). Of this plastic waste:
- 12% has been incinerated.
- 9% has been recycled.
- 60% has been discarded in the natural environment or is accumulating in landfills. *
This study then projected plastic waste production in 2050 using the growth trend they calculated from 1950 – 2015. They found that by 2050, the amount of global plastic waste in the natural environments or landfills will have doubled in comparison to their 2015 estimate. If we were to be optimistic and assume that all plastics will end up in landfills rather than the natural environment, this is still a problem because there is only limited landfill storage space. However, general waste production (all rubbish that we put in our bins and tip sites) is set to triple by 2100 (Hoornweg et al., 2013). Therefore, rapid plastic waste production is part of a much wider problem regarding the unsustainable amount of waste that human populations create.
(2) The problem of single-use plastics
Plastic is frequently used as a single-use product. For example:
- According to the organisation plastic oceans, 50% of plastic produced ever year is for single-use application.
- Approximately 36% (or 146 million tons) of plastic produced in 2015 was used for packaging alone. (Geyer et al., 2017)
- In 2019, Coca-Cola produced 3 million tonnes of plastic packaging. This is equivalent to 200,000 bottles every minute.
The major problem with single-use plastics is that currently knowledge suggests that plastics may never biodegrade. A study reviewing plastic pollution in 2020, suggests that
- Plastic will first break down into smaller pieces known as microplastics (typically defined as <5mm in size) and then likely into even smaller pieces known as nanoplastic particles. The rate of this process known as fragmentation is controlled by various natural factors:
- Sunlight (UV radiation), mechanical breakdown (by wind or water erosion) and the chemical structure of the plastic in question (for background on the chemistry of plastics see: What is the process for making plastic?).
- Theoretically, it may be possible that plastic will degrade to an atomic size where it will biodegrade. This a process called mineralization. However, this process is likely on the timescale of thousands to millions of years.
- Current estimates suggest that all plastic waste produced ever is still in a form too large to biodegrade. Unless, this plastic has been burnt first.
Ultimately, a lot more research is required to be able to categorically state the long-term fate of plastic in the natural environment. But the current state of knowledge suggest that plastic biodegradation occurs on very long timescales. This differs to traditional materials such as paper, metals, wood and glass which on long timescales, are incorporated into natural recycling processes. Therefore, humans are taking a considerable risk by using such a long-lasting material as a single-use, disposable product. The outcome is likely a long-term environmental pollution problem.
(3) The effects of plastic on the environment
Plastic pollution once discarded into the natural environment has many negative impacts:
A review of plastic pollution impacts by Our World in Data summarized impacts on biology as:
- Entanglement – the entrapping and constricting of animals by plastic pollution. Globally, entanglement by plastic has noted in 344 individual species.
- Ingestion – Ingestion of plastic can happen unintentionally or intentionally by wildlife. Ingestion of plastic has been noted in 233 individual marine species. Ingested plastic reduces the desire for feeding, alter hormone levels and can affect the ability of wildlife to reproduce (Li et al., 2016)
- Interaction – Collisions or obstructions of plastic pollution with species. This is less common but includes such effects as the impact of plastic fishing gear damaging coral reef surfaces.
Human health impacts:
- Plastics contain additives (such as phthalates and bisphenol A, BPA) which are toxic chemicals (Thompson et al., 2009). Due to uptake by plants and ingestion by animals, these chemicals are incorporated into food chains. Consequently, 8 out of 10 people have measurable levels of phthalates in their bodies and 93% people have measurable amounts of BPA in their urine (Source: https://www.youtube.com/watch?v=RS7IzU2VJIQ).
- However, it is important to note that to date, there is little evidence to suggest adverse health effects of the consumption of such chemicals, especially given the small concentrations that tend to be measured in humans (Thompson et al., 2009).
Natural beauty impacts:
- Any amount of human waste improperly disposed in the environment is not pleasant. Ensuring that plastic is disposed of properly helps preserve the natural beauty of many aspects of our environment.
Geyer, R., Jambeck, J.R. and Law, K.L., (2017). Production, use, and fate of all plastics ever made. Science advances, 3(7), p.e1700782.
Hoornweg, D. et al. (2013). Waste production must peak this century. Nature Comment. Available at: <https://www.iswa.org/fileadmin/galleries/News/NATURE_Comment_waste.pdf> (Accessed: 24 June 2020).
Laville, S. (2019). Coca-Cola admits it produces 3m tonnes of plastic packaging a year [online]. The Guardian. Available at: <https://www.theguardian.com/business/2019/mar/14/coca-cola-admits-it-produces-3m-tonnes-of-plastic-packaging-a-year> (Accessed: 24 June 2020).
Li, W.C., Tse, H.F. and FOK, L., (2016). Plastic waste in the marine environment: A review of sources, occurrence and effects. Science of the Total Environment, 566, pp.333-349.
Napper, I.E. and Thompson, R.C., (2020). Plastic Debris in the Marine Environment: History and Future Challenges. Global Challenges, p.1900081.
Plastic Ocean (2018). Plastic Ocean - The Facts. Available at: < https://plasticoceans.org/the-facts/ > (Accessed: 24 June 2020).
Ritchie, H. (2018). Plastic Pollution. Available at: <https://ourworldindata.org/plastic-pollution> (Accessed: 24 June 2020).
Thompson, R.C., Moore, C.J., Vom Saal, F.S. and Swan, S.H., (2009). Plastics, the environment and human health: current consensus and future trends. Philosophical Transactions of the Royal Society B: Biological Sciences, 364(1526), pp.2153-2166.