As numerous organisations, institutions, and individuals announce plans to go ‘plastic free’ - or at least reduce their plastic use - momentum around the issue of plastic waste, much like plastic itself, has not gone away.
With the Government considering further measures, such as banning plastic straws, it is worth examining in depth the wider environmental implications of moves towards a more ‘plastic free’ society.
Through their connection to fossil fuels – in both production and transportation - plastics make a significant contribution to man-made climate change, accounting for 6% of global oil demand and rising US methane emissions from associated gas extraction. Yet the interaction between tackling the twin problems of plastic waste and plastic’s contribution to climate change is potentially more complex than first appears.
Plastic pollution and climate change
Plastics are produced through ‘cracking’ and refining fossil fuels, whereby the fossil fuel - either gas or oil – is broken down into constituent hydrocarbons and re-forged into plastic resins.
The production and transport of plastic causes carbon emissions, although estimates vary as to the exact carbon footprint of plastic, in line with variation in production methods. The Beverage Industry Environmental Roundtable, a coalition of global beverage companies working to improve sustainability in the sector, estimated that one 500ml plastic water bottle (about 10 grams) has an average total CO2 footprint of 82.8 grams. For context, the production of four plastic bottles produces approximately the same amount of greenhouse gas emissions as travelling one mile in a medium-sized petrol car.
Turning to the emissions from the general production of plastic resin, the US Environmental Protection Agency (EPA) has put forward an estimate of over 1.15 grams CO2 equivalent greenhouse gas emissions per gram of plastic resin produced. If transport and other associated emissions are included, plastic resin causes roughly 1.5-3.3 grams of greenhouse gas for every gram produced in total.
Plastic production has risen from 2 million tonnes in 1950 to 381 million tonnes in 2015, with only 9% of plastic discarded since 1950 estimated to have been recycled. Production is set to increase substantially, reaching 34,000 million tonnes by 2050.
Rising plastic production will exacerbate both the problems of litter and climate change. By 2050, the plastic industry is predicted to account for 15% of global greenhouse gas emissions. With around 8 million tonnes of plastic ending up in the oceans every year, this not only represents a significant hazard to the marine species and human health, but considerable wastage of resources and inefficiency.
Recycling and a circular economy
Recent studies have suggested that plastic alternatives, such as paper bags, have a significantly higher energy footprint than those created from virgin plastics. In contrast, emissions from recycled plastics are significantly reduced relative to both paper and virgin plastic production, generating significant energy, financial, and resource savings. This fact bolsters the much broader case for a more efficient, 'circular economy' approach.
A circular economy is an alternative to the traditional, linear, 'make, use, dispose' structure, with resources (defined in terms of materials, water, energy and carbon, as well as natural and social capital) kept in use and at their highest value for as long as possible, reducing waste and improving efficiency.
Its main advantages include energy savings and insulation from potential raw material supply and price shocks. The Environmental Services Association suggested that a more circular economy could increase UK GDP by £3 billion a year, with a 2011 study for the Government suggesting £23 billion of economic benefits from low or no cost improvements available to businesses in the UK.
In terms of plastic, a circular economy approach emphasises recyclability, with a particular focus on increasing recyclable packaging and infrastructure. However, the extent of possible plastic recycling is limited, with some estimates suggesting only a maximum of between 36-56% could be recycled at current technology levels. Likewise current UK recycling rates have recently stalled, with some plastic items - such as the notorious disposable coffee cup - not easily recyclable and rejected by variable local recycling guidelines.
But achieving a perfect circle is difficult, with potential leakage into the environment particularly concerning for plastic, given its adverse impacts on marine species and ultimately human health. This underscores the need to develop and deploy biodegradable plastics and alternative materials.
Biodegradable plastics include a broad range of materials - some biological and others petrochemical based - which can undergo 'normal' thermal decomposition into different compounds.
However, such materials are significantly more expensive to produce than standard plastics. Likewise in some cases they require specific conditions in which to safely decompose, with 'biodegradable’ not necessarily the same as ‘compostable’. As a result, they do not necessarily eliminate litter-based pollution problems, meaning that demand reduction policies, as well as measures to encourage less harmful alternative materials, should be considered.
Alternative materials such as cotton or stainless steel both have significant energy footprints. Their main advantages are their long-term reusability and the low risk they present when accidentally introduced into the ecosystem.
The longer life-span of reusable items therefore goes some way to mitigate the short-term drawbacks of higher energy consumption. Additional carbon emissions can in turn be mitigated through the continued decarbonisation of the electricity supply and the development of carbon capture and storage technology.
Supply and demand
As shown by BP's announcement that the plastic reduction drive has the potential to reduce oil demand, it is clearly possible to tackle both problems simultaneously.
Environmental policymakers should be wary of unintended consequences. As policy and media attention continues to focus on how to address public concern over plastic pollution, its concurrent impact on climate change should also be a primary consideration. A joined-up - not single-issue silo – approach, therefore, is essential.
Philip Box is a researcher at Bright Blue