Efficacy of plastic shopping bag tax as a governance tool : Lessons for South Africa from Irish and Danish success stories

Worldwide, litter emanating from irresponsibly disposed single-use, ultra-thin, plastic shopping bags made from high-density polyethylene is a growing environmental concern (Carman, Machain & Campagna 2015; Dikgang, Leiman & Visser 2012). The problems associated with single-use plastic bags (SUPBs) permeate all stages of the value chain, from production to consumption to disposal. The production of SUPBs results in the depletion of a non-renewable petroleum-derived polymer called high-density polyethylene (Muthu et al. 2013). Moreover, discarded SUPBs are easily carried away by wind, thereby causing air pollution (Wagner & Broaddus 2016). Irresponsibly disposed SUPBs also accumulate in the natural environment often blocking water drainage systems and provide the breeding ground for malaria-causing mosquitoes, which is a threat to public health (Ong & Sovacool 2012). Moreover, discarded SUPBs also diminish the aesthetic and recreational value of coastal tourism (Oyake-Ombis, Van Vliet & Mol 2015). Single-use plastic bags disposed in landfills are known to resist degradation. It is estimated that SUPBs take between 500 and 1000 years to decompose (Ong & Sovacool 2012). The prolonged degradation time constrains the already limited landfill capacity (Karlaitė 2016). Orientation: The negative environmental effects of single-use plastic shopping bags have prompted national governments to implement interventions to curtail their use. Plastic bag tax is gaining prominence as a single-use plastic shopping bag governance tool in several jurisdictions.


Introduction
Worldwide, litter emanating from irresponsibly disposed single-use, ultra-thin, plastic shopping bags made from high-density polyethylene is a growing environmental concern (Carman, Machain & Campagna 2015;Dikgang, Leiman & Visser 2012). The problems associated with single-use plastic bags (SUPBs) permeate all stages of the value chain, from production to consumption to disposal. The production of SUPBs results in the depletion of a non-renewable petroleum-derived polymer called high-density polyethylene (Muthu et al. 2013). Moreover, discarded SUPBs are easily carried away by wind, thereby causing air pollution (Wagner & Broaddus 2016). Irresponsibly disposed SUPBs also accumulate in the natural environment often blocking water drainage systems and provide the breeding ground for malaria-causing mosquitoes, which is a threat to public health (Ong & Sovacool 2012). Moreover, discarded SUPBs also diminish the aesthetic and recreational value of coastal tourism (Oyake-Ombis, Van Vliet & Mol 2015). Single-use plastic bags disposed in landfills are known to resist degradation. It is estimated that SUPBs take between 500 and 1000 years to decompose (Ong & Sovacool 2012). The prolonged degradation time constrains the already limited landfill capacity (Karlaitė 2016).
The environmental problems of SUPBs are worsened by their short lifespan as many are disposed after only single use (Yeow, Dean & Tucker 2014). Typical of a 'public bad', SUPBs litter equally affects polluters and non-polluters (Oosterhuis, Papyrakis & Boteler 2014). According to Morritt et al. (2014), the extent of the plastic bag litter that accumulates in seas and oceans is manifested by the Great Pacific Garbage Patch and the North Atlantic Sub-tropical Gyre. Upon entering the sea, plastics harm marine animals through ingestion (Wang et al. 2016). In 2017, the Statistic Brain Research Institute (2016) estimated that 46 000 plastic fragments were floating per each square mile of the ocean. In 2015, the global annual consumption of SUPBs was estimated at 1 trillion (Center for Biological Diversity 2015).
The pervasive use of SUPBs is spurred in part by the fact that they were traditionally given to shoppers free of charge at the point of purchase (Ohtomo & Ohnuma 2014). Plastic bag tax (PBT) is one of the tools widely used in efforts to curb the use of SUPBs (Homonoff 2013;Karlaitė 2016). The introduction of PBT has been a subject of contestations in several jurisdictions, and this explains its variations in effectiveness. Plastic bag tax was successfully implemented in Ireland, Belgium and Denmark (Convery, McDonnell & Ferreira 2007;Xanthos & Walker 2017). Conversely, in Bulgaria, China and South Africa, PBT failed to achieve the intended results (Dikgang et al. 2012;Larsen & Venkova 2014).
The ineffectiveness of PBT in some jurisdictions including South Africa has triggered several questions. For instance, Hagman et al. (2015) and Stephenson (2018) questioned whether PBT should be levied on consumers or plastic bag producers. There is also no consensus with regard to the determination of the optimum amount of PBT. In this regard, the debate revolves around the appropriateness of using the elasticity of demand and marginal costing as pricing models (Dikgang et al. 2012). The other concern is whether the administrative costs of PBT justify the return (Stephenson 2018). Some researchers (Dikgang et al. 2012;Minter 2015) also questioned whether the carbon footprint of SUPBs is significant enough to warrant such concerns. Other scholars (Klick & Wright 2012;Mangu-Ward 2015) also raised concerns over the environmental suitability of alternatives to SUBPs such as reusable shopping bags. On a more pessimistic note, Stephenson (2018) and Jory et al. (2019) cautioned about the possibility of the PBT to trigger unintended consequences, such as profiteering by retailers or tax evasion. Proponents of anti-PBT also argue that it is not justified as it is not backed up by a conclusive scientific environmental impact assessment (Karlaitė 2016). Another source of resistance is based on the concern that the PBT may precipitate massive job losses in the plastic manufacturing industry, especially in developing countries (Silva 2015). These divergent views have resulted in variations in the nature and scope of PBT implementation across the globe. For instance, the implementation of PBT varies in terms of the amount levied, how it is framed and the stage of the value chain where it is imposed.
The PBT debate is of significant importance to South Africa for two main reasons. In 2015, South Africa was ranked amongst the top 20 countries with plastic-littered coastal areas (Jambeck et al. 2015). Also, the fact that the PBT has been in effect for almost two decades without a major noticeable difference in plastic bag litter is a matter of great concern to environmentalists and policymakers (Dikgang et al. 2012;McLellan 2014;O'Brien & Thondlana 2019). Against this backdrop, the questions that are central to this study are as follows: (1) 'what are the challenges associated with the implementation of PBT in South Africa?' and (2) 'what lessons can South Africa learn from Ireland and Denmark's PBT success stories?' In an attempt to answer the aforesaid questions, this study employs a multinational case analysis as an initial attempt to harmonise the best practices in PBT implementation. This study also notes that the majority of previous studies on PBT, such as Dikgang et al. (2012), Homonoff (2013), Martinho, Balaia and Pires (2017) and Wagner (2017), were focused on a single-country assessment. This study seeks to contribute to the extant literature by conducting a multiple-case analysis with the objective of suggesting policy directions for effective implementation of PBT.

Conceptualisation of the plastic bag tax
Plastic bag tax is a market-based instrument used to discourage the use of SUPBs (Karlaitė 2016;Xanthos & Walker 2017). In its application, PBT is construed as part of environmental tax reforms aimed at mitigating the effects of pollution and climate change (Miller & Vela 2013). In some jurisdictions, PBT is framed as a levy, fee or charge (Muralidharan & Sheehan 2016). Thus, the terms 'tax', 'fee', 'levy' and 'charge' are interchangeably used in this discussion. The overriding objective of the PBT is to change the widespread behaviour of using SUPBs (Convery et al. 2007). From an economic perspective, the PBT is construed as a mechanism that compels polluters to bear the cost of environmental harm caused by SUPBs (Wagner 2017). From a consumer behaviour standpoint, PBT is aimed at disrupting the habitual use of SUPBs and fostering the performance of pro-environmental behaviour (Poortinga, Whitmarsh & Suffolk 2013).
In terms of implementation, PBT takes the form of either extended producer responsibility charge or indirect tax (Singh & Sharma 2016). Extended producer responsibility charge is imposed on producers whose activities are known to pose environmental harm (Bury 2010). It is an upstream charge internalised by the producer and is set at an amount that is as nearer as possible to the social cost of the negative externality to the society (Wagner 2017). This form of tax is regarded as effective because it compels corporates to engage in good environmental citizenship behaviours (Bury 2010).
Conversely, indirect tax is a downstream charge which is meant to be internalised by consumers at the point of purchase (Bury 2010;Eurostat 2016). Plastic bag tax in the form of indirect tax is criticised for being regressive because http://www.actacommercii.co.za Open Access it imposes the financial burden on consumers exempting corporates with large carbon footprints (Hagman et al. 2015). Indirect tax is also associated with high administrative costs such as collection costs and monitoring of retailer compliance. For instance, Convery et al. (2007) reported that initial PBT administrative costs in Ireland were more than €1.2 million. This administrative burden was also reported in Botswana where the government admitted its failure to fully track and collect PBT from retailers (Mogomotsi, Mogomotsi & Phonchi 2019).

Optimum amount of the plastic bag tax
There is no consensus on the best approach to determine the optimum level of PBT (Dikgang et al. 2012;Stephenson 2018). Extant literature is dominated by two approaches, that is, Pigouvian and price elasticity of demand. Pigouvian tax was popularised by Pigou (1960) who is regarded as the doyen of environmental tax. The Pigouvian approach sets the optimum level of tax by calculating the marginal external cost associated with a negative externality (Pigou 1960). The major failing of this approach is the inherent challenge associated with determining the optimum amount of tax that is commensurate with the respective environmental harm (Parry 2012;Stephenson 2018). With regard to PBT, Stephenson (2018) notes the challenge of determining the marginal damage caused by each discarded plastic bag. It is also reasonable to argue that the marginal external cost of plastic bag litter differs from land and coastal environments. In such instances, Digkang et al. (2012) challenged the economic wisdom of using a blanket PBT rate.
Using the price elasticity of demand approach, the PBT is set based on the relationship between the price of the plastic bag and the quantity of plastic bags demanded at the point of purchase (Nolan-ITU 2002). Unlike, the Pigouvian approach, this approach considers the income distribution of consumers and allows for a customised PBT structure (Dikgang, Leiman & Visser 2010). However, this approach has its own limitations. In economic theory, price elasticity of cheap products is known to be low (Stigler 1996). As the plastic bag often contributes an insignificant portion of a consumer's grocery bill, the PBT often lacks a deterrent effect. Another challenge, which was reported by Dikgang et al. (2012), is the challenge of assessing accurate pre-tax and post-tax plastic bag consumption statistics from retailers. Because of the challenges described above, Stephenson (2018) argued that the majority of PBT amounts tend to be more arbitrary than objective.

Theoretical underpinnings of the plastic bag tax
The reason behind the use of PBT gains theoretical support from the prospect theory. The theory posits that individuals' trait of loss aversion predisposes them to engage in acts that translate in gains and avoid behaviours that are associated with losses (Kahneman & Tversky 1979). In this context, the desire to avoid a loss associated with a tax is expected to motivate consumers not to use SUPBs. From a psychological perspective, the introduction of a tax on goods previously offered for free has the effect of inducing a shock reaction amongst consumers, which has the potential of constraining demand in the short-term (Kahneman, Knetsch & Thaler 1990).
The effect of a PBT is also assumed to be influenced by how it is framed. This view gains theoretical support from the framing theory, which posits that the framing of messages influences their effect in stimulating behavioural change (Goffman 1974). Consistent with the tenets of the framing theory, Borean (2013) observed that consumers perceive that the payment of a tax is mandatory whilst a fee or levy is voluntary. This view was also confirmed in a study by Muralidharan and Sheehan (2016), wherein a plastic bag charge labelled as a tax was found to be more effective than one framed as a levy or fee in changing behaviour related to the use of plastic shopping bags.

Materials and methods
This study utilised a case study methodology in the form of a comparative analysis of countries that have implemented PBT. This study was guided by a five-staged process of conducting case study research suggested by Creswell and Poth (2018) and Stake (1995). The process involved determining the appropriateness of a case study approach, case identification and sampling procedures; developing procedures for data collection; specifying data analysis techniques and reporting study findings.

Appropriateness of case study approach
A case study was deemed appropriate for this study because it is recommended for analysing context-dependent phenomenon with multiple sources of information (Creswell & Poth 2018;Stake 2005). There are differences in contextual factors that influence the implementation of PBT per each jurisdiction; and for this reason, the case study approach was considered appropriate. Also, the purpose of this study was to conduct a comparative analysis of identifiable countries that have implemented PBT. This was another key consideration for employing a case study design.

Identification of cases and sampling procedures
The case studies were drawn from a list of countries that have implemented PBT (Table 1-

Data collection procedures
Data were collected in South Africa, Denmark and Ireland. The three countries were selected for their difference in the manner they implemented PBT. Data were collected using document analysis because it is regarded as a key source of data in case studies that focus on public policy (Nielsen, Homberg & Stripple 2019;Yin 2014). Consistent with this view, policy documents, government reports, environmental organisation reports and peer-reviewed literature were used as data sources. Following the approach of Xanthos and Walker (2017), electronic databases such as SCOPUS, ProQuest, Web Science and EBSCO were searched systematically to gather data using keywords such as 'PBT', 'levy' or 'charge'. Data were collected for a period of 4 months, from February to May 2018. The following subsections provide the case study description.

Case study 1: Plastic bag tax in Denmark
Denmark is a Nordic country situated in Northern Europe.
To maintain the aesthetic value of its islands and Baltic Sea beaches, Denmark became the first country to implement a PBT in 1994 (Xanthos & Walker 2017). The tax, which was managed by the Danish Ecological Council, was in the form of an indirect tax imposed on manufacturers and importers of plastic bags. The tax was calculated based on the weight of the plastic bag (Newman et al. 2015). A weight-based PBT was aimed at reducing the amount of plastic material used during the manufacturing process (Convery et al. 2007). The tax was estimated to equate to the social cost of litter posed by SUPBs (Kasidoni, Moustakas & Malamis 2015;Wagner 2017). It was also designed in a manner that allowed manufacturers to pass the PBT to retailers who then used their discretion to charge consumers ( Table 1 summarises the amount of tax collected from the sales of plastic bags.
The effectiveness of the PBT is shown by Denmark's low plastic bag consumption per capita as compared to other European countries as illustrated in Figure 1.

Case study 2: Plastic bag tax in Ireland
During the 1990s, plastic bag litter was a major concern in Ireland, contributing almost 5% of the national litter (The Litter Monitoring Body 2005). Litter from plastic bags was so ubiquitous around coastlines and was commonly referred to as 'witch's knickers' (Ritch, Brennan & MacLeod 2009). In H u n g a r y L a t v i a L i t h u a n i a P o l a n d P o r t u g a l S l o v a k i a S l o v e n i a C z e c h R e p u b l i c R o m a n i a B u l g a r i a G r e e c e I t a l y E U -2 7 U K C y p r u s S p a i n M a l t a S w e d e n B e l g i u m F r a n c e N e t h e r l a n d s G e r m a n y A u s t r i a I r e l a n d L u x e m b o u r g D e n m a r k F i n l a n d   The tax amount was set by first estimating the amount consumers were willing to pay for a plastic bag and an amount six times the amount was set (Convery et al. 2007). Reusable shopping bags were exempted from tax subject to a retail charge of €0.70 per bag at the point of purchase (Xanthos & Walker 2017). Before the tax was implemented, the Irish government consulted and secured the cooperation of manufacturers, retail outlets and consumers (Earth Policy Institute 2014). The Irish government also educated the general public about the benefits that accrue to the natural environment when the levy is implemented The revenue is collected by commissioners who also audit and monitor retailer compliance. The revenue generated from the PBT is channelled to the Environmental Fund, which is under the auspices of the Department of Environment, Heritage and Local Governance. The Environmental Fund is used to finance environmentenhancing programmes such as landfill clean-ups and recycling centres as well as financing the costs of revenue collection (Convery et al. 2007;Larsen & Venkova 2014). Table 2 summaries the revenue generated from PBT.

Case study 3: Plastic bag tax in South Africa
Before the introduction of the tax, litter from discarded plastic bags was so rampant that it earned the moniker 'the new national flower' (Ritch et al. 2009). Before the tax, it was estimated that South African consumers were using 8 billion plastic bags per year (Dikgang et al. 2012 (Dikgang et al. 2012). Retailers were mandated to charge a fixed fee of 46 cents per plastic bag along with 3 cents levy (Larsen & Venkova 2014). The conditions for manufacturers included the regulation of the type of ink used for printing plastic bags, production of plastic bags with a minimum thickness level of 24 microns, transparency regarding disclosure of the costs of plastic shopping bags and prohibition of plastic bag imports (Dikgang et al. 2012).
The government collects PBT from retailers through the South African Revenue Service (SARS) and manages the disbursement of funds with a portion directed to environmental projects. In 2009, Nahman (2010 reported that only 13% of the revenue was directed to 'Buyisa e-Bag' a company which was dedicated to the recycling of plastic bags. For this reason, questions were raised in parliament pertaining to how the revenue is being used (Nahman 2010). During the first 3 months of implementation, an estimated 76% reduction in the consumption of plastic bags was reported (Hasson, Leiman & Visser 2007). Thereafter, an increase in the use of plastic bags was reported (Dikgang et al. 2012). In 2008, following pressure from manufacturers wherein they argue that the PBT will result in job losses, the PBT was relaxed resulting in a 46% decrease in the price of plastic bags (Knowler 2008). Around 2010, as consumers got accustomed to paying the tax and its deterrent effect was eroded (Dikgang et al. 2010) and an upward trend in the use of SUPBs was noted (Larsen & Venkova 2014). Overall, Dikgang et al. (2012) noted that the drop in the use of SUPBs was not sustained in the long term. Table 3 summarises the PBT revenue.

Data analysis
A two-staged process recommended by Creswell and Poth (2018) was followed to conduct data analysis. The first stage involved a within-case analysis in which a detailed description of each case was given. The second step involved a cross-case analysis which encompassed across-the-case analysis, theme identification, theme refinement and integration (Guba & Lincoln 1994;Yin 2009). Results of the comparison of three cases with regard to the implementation of PBT are discussed as follows:

Ethical consideration
This article followed all ethical standards for research without direct contact with human or animal subjects. Reference number: FOM2017.

Results and discussion
Acceptance of PBT, the importance of baseline assessment, governance of PBT, extended producer responsibility and necessity of monitoring and review emerged as major lessons for South Africa and are discussed in the following.

Acceptance of plastic bag tax
One of the critical factors for the success of any policy instrument, including PBT, is acceptance by key stakeholders. The Irish case demonstrates the importance of stakeholder mapping. The Irish government consulted key role-players such as manufacturers, retailers and consumer groups. Plastic bag tax awareness campaigns were also conducted to educate all stakeholders on the benefits of PBT. This resulted in a broader acceptance of PBT, smooth implementation and enforcement. Turning to South Africa, Hasson et al. (2007) reckoned that consultation was not comprehensively conducted in South Africa, and it resulted in resistance from manufacturers which led to the reduction of the tax in 2008. Similarly, Dikgang et al. (2012) attributed the poor support of the PBT in South Africa to limited pre-emptive advocacy campaigns aimed at consumer education. If the introduction of PBT reflects stakeholders' will as in the Irish case, the possibility of success is high. Conversely, PBT is bound to fail if it is used as a tool to coercive reluctant value chain stakeholders to change behaviour.

Importance of baseline assessment
The Ireland case demonstrated the importance of conducting a baseline assessment before PBT implementation. An analysis of the magnitude of the plastic bag litter problem and concerns of manufacturers and retailers was performed before tax roll-out. More importantly, an assessment of the amount consumers were willing to pay for a plastic bag enabled Ireland authorities to set a PBT amount that had a deterrent effect. A baseline assessment could have assisted South Africa to implement a PBT structure appropriate for a developing country. For instance, the current blanket rate is being criticised for being regressive (Dikgang et al. 2012;UNEP 2018). This is because as observed by UNEP (2018), in developing countries such as South Africa, plastic bags remain the most affordable means of carrying merchandise by low-income earners. As such, efforts to prohibit its use without affordable alternatives are likely to achieve limited success.  form of transparency, according to Baranzini and Carattini (2017), is critical for the acceptance of PBT as a policy instrument.

Necessity of monitoring and review
The Irish case also points to the importance of continuously reviewing PBT in order to maintain its deterrent effect. Ireland reviewed its PBT from €0.15 to €0.22 in 2007 and to €0.44 in 2009 and in this way the deterrent effect of the tax was sustained (Xanthos & Walker 2017). Although South Africa now reviews PBT almost every 2 years, the rate of ZAR0.08 as of 2017 was too little to enhance any behavioural change amongst consumers. This could be one of the most plausible reasons why the use of SUPBs is escalating. Dikgang et al. (2010) concurred that a small amount of PBT often constitutes a negligible amount of the household budget which often goes unnoticed. In its current form, the PBT in South Africa can be best described as a nudge, not a tax. In order to set an optimum and effective amount of PBT, Dikgang et al. (2010) stressed the importance of evaluating the effect of the PBT on the elasticity of plastic bag demand. This approach, according to Poortinga et al. (2013), has the potential of setting a tax amount that has a restraining effect on the use of SUPBs.

Extended producer responsibility
The Danish case also illustrates the importance of adopting an integrated value chain approach in implementing PBT. The Danish PBT was shared by manufacturers, retailers and consumers. This addresses perceptions, which were raised about selective application of the PBT in South Africa. In particular, the PBT structure in South Africa is regarded as against the principles of environmental justice as it places the burden on consumers, yet exempting manufactures with significant carbon footprints (McLellan 2014). Thus, South Africa should consider adopting the extended producer responsibility approach as it provides an incentive for producers to incorporate environmental considerations in the design of plastic shopping bags.

Implications of the study
The study findings have important implications for policymakers intending to use PBT as a policy instrument. In order to set an optimum amount of PBT with a prohibitive effect, it is important to evaluate the elasticity of plastic bag demand. An understanding of elasticity of demand allows policymakers to set a PBT amount that has a restraining effect. In addition, PBT for manufacturers, retailers and consumers is recommended as it permits externalities related to SUPBs to be internalised at each stage of the value chain.
In developing economies such as South Africa, there is also a need to move away from a regressive PBT as it disadvantages low-income earners.
Transparency on the utilisation of revenue generated from PBT is central to the acceptability of SUPBs tax. In this regard, South Africa's Department of Environmental Affairs needs to play a key role in directing the PBT revenue to finance environment-enhancing projects. Another key lesson for policymakers is to refrain from evaluating the effectiveness of the tax during the initial stages of implementation as a reduction in plastic bag use may be a result of the level of environmental awareness that accompanies the tax or loss aversion perceived by consumers. Policymakers in developing countries should also consider implementing a direct tax as opposed to indirect consumer-level tax. This is because the latter has huge administrative costs that may put a strain on the collection of revenues.
As the use of PBT and alternatives of SUPBs proliferates, there is also a need by policymakers to guide against unintended consequences. For instance, there are growing perceptions that some retailers are 'bagging' the PBT. Another worrying trend is the emerging of unscrupulous predictory entrepreneurs who are keen to cash on the green shopping bag mantra. For example, in South Africa, manufacturers of reusable shopping bags are being accused of exaggerating the environmental benefits of such bags (Department of Environmental Affairs 2017). This study acknowledges that promoting a circular economy in which discarded plastic bags can be reused for energy generation is the sustainable option.

Conclusion
The objective of this study was to assess the effectiveness of PBT as a mechanism to curb the use of SUPBs. Three case studies of countries that have implemented PBT were analysed. The study found that PBT can be effective as a plastic bag governance tool based on its success in Ireland and Denmark. The engagement of stakeholders, such as manufacturers, retailers and consumers, and enforcement are necessary for effective implementation. There is a need for transparency on how the revenue generated from PBT is utilised. There is also a need to continuously monitor and review the PBT in order to safeguard its deterrent effect as failure to do so results in a rebound effect on the use of SUPBs. This study concludes that the effectiveness of the tax should be assessed based on not only changes in the volume of plastic bags consumed but also on the environmental quality and acceptance of the tax by the public. In the long term, this study recommends an integrated framework for plastic bag litter management that encompasses both regulation and normative-based strategies. To achieve this, future studies may also evaluate the effectiveness of other interventions such as bans, recycling and voluntary initiatives using more case studies in order to develop an integrated framework to manage plastic bag litter.