Truth about plastics and the environment: Why perception is not always reality

Truth about plastics and the environment: Why perception is not always reality

23 July 2020

Imperial College London published the paper Examining Material Evidence The Carbon Fingerprint at the beginning of this month. The authors compare plastic to other materials used in packaging.

Executive summary

Only 2% of British people consider plastic, compared to other materials used in packaging, to contribute the least greenhouse gases to the environment from its production, use, and post use treatment. Whilst in absolute numbers it is a fact the least impactful. Plastics do have a large carbon impact - accounting for 3.8% of global greenhouse gases emissions - but it is wrong to assume that alternative packaging materials would perform better, and it is important to consider the carbon benefits that arise from plastics use.

When considering the production and manufacturing of the main alternatives to plastic for a 500ml bottle, other packaging types (fibre, glass, steel and aluminium) emit more greenhouse gases than plastic bottles, with glass bottles being the highest emitter overall. By way of example, if all plastic bottles used globally were made from glass instead, the additional carbon emissions would be equivalent to powering around 22 large coal-fired power plants. This is equivalent to the electricity consumed by a third of the UK.

Life-cycle assessment (LCA) is a useful tool which should be more widely used to evaluate environmental impacts of packaging alternatives over their life-time, from the extraction of raw material to the disposal or recycling of packaging at the end of its life. Undertaking LCAs to compare the environmental performance of alternative materials for different packaging applications is essential if we want to take into account the environmental impacts associated with the whole life-cycle of packaging (mining, manufacturing process, logistics, usage and end-of-life route).

Results can vary significantly from one study to another, depending on key parameters and assumptions. For example, the risk of producing more food waste because of the packaging design and shelf life is not always considered in LCAs while this can have a large impact on the packaging carbon contribution.

In this study, a total of 73 publications on LCAs comparing different types of packaging were identified and reviewed. By assessing many different studies we can draw some general conclusions about the range of results and what the majority of analysis determined. Findings indicate that in the applications it is used, most of the time, plastic packaging performs better than its alternatives, and mainly due to its very lightweight properties.

Transport distance and method, sources of electricity generation, packaging shape and weight, all significantly influence the LCA results and should be considered on a case by case basis. It is also important to consider the full life cycle of the material, such as, for plastic the prospecting and mining stages.

The waste management route in place to treat packaging at its end of life, is also shown to be a critical factor explaining variations of LCA results for the same packaging. Recycling always wins over virgin production on all environmental indicators. For plastics, there seems to be consensus that recycling saves between 30% and 80% of the carbon emissions that virgin plastic processing and manufacturing generate.

If all plastic were recycled this could result in mean annual savings of 30 to 150 million tonnes of CO2, equivalent to stopping between 8 and 40 coal-fired power plants globally.

The findings of this study demonstrate that if we really want to tackle the environmental issues we face with plastics today then removing, reducing, reusing or recycling the plastic packaging placed on the market is the way forward. This approach is more certain and reaps better results than waiting and hoping for solutions not yet commercialised or switching to alternative available materials respectively.

Considering that only around 9% of plastics are currently being recycled worldwide, there is a lot that can be done to improve things. We can see that where the right policy drivers are in place, this is already happening, with regulatory statutes that themself deliver fiscal actions on business. In the UK, the various measures planned in the UK Waste and Resources Strategy planned by DEFRA, such as the extended producer responsibility scheme, the deposit return scheme and the harmonisation of waste collection associated with a clear labelling system, as well as HM Treasury proposals for a plastic packaging tax are all good steps for creating a fully functioning circular and sustainable system for packaging.

In concert with the widespread application of renewable energy and demand-management strategies, increasing the recycling of plastics have the potential for both curbing the growing life-cycle GHG emissions from plastics, and also preventing them from entering the marine environment.

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