This chapter explores modelling scenarios with partial global ambition, defined in terms of limited policy stringency, partial coverage of the policies along the lifecycle of plastics, or incomplete global geographical coverage of policy measures. It presents projections of the plastics lifecycle for each scenario, highlighting that policy action can significantly reduce plastics use and environmental impacts below levels expected in the Baseline scenario by 2040, but all partial ambition scenarios presented in this chapter fall short of eliminating the leakage of plastics to the environment.
Policy Scenarios for Eliminating Plastic Pollution by 2040
Abstract
This chapter explores modelling scenarios that reflect stylised views of possible outcomes of the international negotiations when global ambition is partial. Each scenario is characterised by different levels of stringency across the various policy pillars, but all fall short of eliminating global plastic leakage by 2040.1 Specifically, the scenarios investigate the consequences for plastics use, waste and leakage from policy action that Figure 4.1:
is limited to downstream policies only (the Global Downstream High stringency policy scenario):2
has geographical coverage limited to a group of advanced economies, approximated as OECD and non-OECD EU countries (the Advanced economies Lifecycle High stringency policy scenario):
encompasses all lifecycle stages and all countries, but with limited stringency (the Global Lifecycle Low stringency policy scenario).
Source: Authors’ own elaboration
The three partial ambition scenarios vary significantly in the stringency of policy measures to curb production and demand and to improve design for circularity (the policy pillars that most directly affect plastics production and use). As a result, the effects on regional plastics exhibit significant differences across these scenarios. All three scenarios reduce plastics use – and waste generation – below Baseline levels in 2040, but these reductions tend to be quite limited and are furthermore insufficient to overcome growth in plastics use and waste in the Baseline compared to 2020 levels (Figure 4.2). The Global Downstream High stringency scenario does not contain any policies to curb production and demand and design for circularity. Some downstream policies, such as enhancing recycling, do affect plastics use by increasing the costs for primary plastics and by subsidising secondary plastics, however these effects are limited globally to 4.5% for plastics use and less than 3% for waste generation.
A comparison between use and waste generation in advanced economies in the Advanced economies Lifecycle High stringency and Global Downstream High stringency scenarios sheds light on the importance of upstream and midstream interventions in the policy mix, notably policies to curb production and demand and to foster eco-design. As expected, in the Advanced economies Lifecycle High stringency scenario, plastics use and waste are significantly reduced in OECD and EU countries in 2040 (by 28% and 22% relative to the Baseline, respectively), but remain largely unchanged in non-OECD, non-EU countries (+0.3% and -5%, respectively). The positive aspect of this result is that there is no significant leakage effect whereby ambitious policies in the advanced economies would lead to shifts in economic production that boost plastics use in other countries. Thus, the demand reductions in OECD and EU countries are effective and not mitigated by increases elsewhere. In fact, the policies to reduce demand in advanced economies lead to (i) a spillover effect of eco-design that extends the lifetimes of products globally and not only in advanced countries,3 (ii) a reduction of plastics embedded in exports to other countries and (iii) a reduction in plastic waste exported to other countries.
Although the Global Lifecycle Low stringency scenario envisions enhanced policies across the plastics lifecycle, the scenario projects only modest decreases in plastics use (10%) and waste generation (7%) below Baseline levels in 2040. Somewhat larger reductions are observed in OECD countries, reflecting their higher capacity to implement stringent policies. Plastics use and waste generation levels would still increase in this scenario by 2040 (by 53% and 59%, respectively, compared to 2020 levels).
Percentage deviation from the Baseline in 2040
Note: “Adv. econ.” stands for Advanced economies.
Source: OECD ENV-Linkages model.
Plastics intensity, measured as plastics use (in million tonnes) divided by GDP (in million USD), can be used as an indicator of efficiency in the production and use of plastics in the economy. Improvements in plastics intensity reflect a decoupling of economic activity from plastics production and use, and is thus an indirect indicator of the effectiveness of the policy pillar on designing for circularity. In line with projections for plastics use, the largest gains in plastics intensity are achieved in scenarios that contain measures to curb production and demand and to enhance eco-design. Specifically, the Advanced economies Lifecycle High stringency scenario leads to a significant reduction in plastics intensity in OECD countries, but virtually none in non-OECD countries. The early implementation of selected policies by 2030 – most notably the plastics tax and EPR schemes – significantly contribute to rapidly reductions in plastics intensity, with some additional effects occurring the subsequent decade. The Global Downstream High stringency scenario does not directly aim at upstream demand control, but has indirect effects on plastics use that also affect plastics intensity, as policies to enhance recycling make primary plastics production more expensive (see above). The Global Lifecycle Low stringency scenario reduces plastics intensity more than the Global Downstream High stringency scenario, especially after 2030, when the effects from the upstream policies begin to manifest.
Plastics use per unit of GDP, in tonnes of plastics per unit of sectoral output in USD (t/USD)
Note: The gradual decline in plastics intensity is driven by technological progress and structural change, as discussed in Chapter 2.
Source: OECD ENV-Linkages model.
The partial ambition scenarios all result in total waste volumes that are below Baseline levels in 2040, but well in excess of 2020 levels (as discussed above). With current policies (i.e. the Baseline scenario), this would mean increases in volumes of waste being recycled, incinerated and landfilled, but also increased volumes of mismanaged waste. Waste management shares, i.e. end-of-life fate shares, change only marginally in the Baseline scenario, including the reduction in the share of waste that is mismanaged in developing countries, due to rising income levels.4 If the policy agreement is combined with limited international co-ordination and support for actions downstream in the plastics lifecycle, there may be risks of insufficient technical and financing support to manage waste effectively. Importantly, capacity building required in a number of developing countries to establish well-functioning waste management systems, including adopting the necessary policy and regulatory frameworks, set up strong governance mechanisms and ensure stable financing that cover the operational costs of waste collection and sorting.
Recycling output in all three partial ambition scenarios is projected to increase compared to the Baseline scenario owing to the implementation of policies that incentivise both the supply and demand of recycled plastics (e.g. recycled content requirements, recycling targets, EPR schemes). The global share of waste that is recycled increases from 9.5% in 2020 to 14% in 2040 in the Baseline scenario, 41% in the Global Downstream High stringency scenario, 27% in the Advanced economies Lifecycle High stringency scenario and 25% in the Global Lifecycle Low stringency scenario (Figure 4.4).5 The largest increases in recycling output are foreseen in the Global Downstream High stringency scenario, thanks to a combination of significant improvements in waste collection, ambitious expansion of recycling infrastructure and a lack of measures to reduce waste streams. Specifically in non-OECD countries combined, the share of waste that is collected for recycling increases from 10% in 2020 to 38% in 2040 in the Global Downstream High stringency scenario. This also implies that significant scrap is available in this scenario to induce a shift from primary to secondary production, and thus most of the global growth in plastics use in this scenario is actually covered by secondary plastics.
In contrast, in OECD and EU countries the Advanced economies Lifecycle High stringency scenario achieves the same increase in recycling shares as the Global Downstream High stringency scenario, reaching 46% for this group of countries in both cases. The Global Lifecycle Low stringency scenario is less ambitious, reaching a recycling rate of 29% in OECD countries, and 22% in non-OECD countries. These findings illustrate that the broad agreement modelled in this scenario is indeed relatively shallow, resulting in less than a tripling of the recycling rate at the global level, versus a more than quadrupling in the Global Downstream High stringency scenario.
Another outcome of interest pertaining to end-of-life fate categories is mismanaged waste. The policy scenarios with the most stringent downstream policies achieve the best outcomes with respect to this measure. Specifically, the Global Downstream High stringency scenario reduces mismanaged waste in non-OECD countries from 81 million tonnes (Mt) in 2020 to 54 Mt in 2040 (a reduction of 55% compared to the Baseline level of 119 Mt in 2040), resulting in 9% of total waste that will remain mismanaged. The lack of measures to curb production and demand, and to slow down waste generation, implies that technical and economic barriers to collecting, sorting and (sanitarily) landfilling plastic waste in countries that have high levels of mismanaged waste in the Baseline scenario may prevent a full elimination of plastic leakage. This effect is also visible when comparing the Global Downstream High stringency scenario and the Advanced economies Lifecycle High stringency scenario for OECD regions: the latter scenario is more effective as it combines reductions in waste generation with improved collection and treatment. This results in virtually all mismanaged waste in OECD countries being eliminated in the Advanced economies Lifecycle High stringency scenario (with less than 1.5 Mt remaining in 2040), and a significant reduction in the Global Downstream High stringency scenario, with less than 3.5 Mt remaining in OECD countries (compared to almost 7 Mt in the Baseline). The main reason that some mismanaged waste remains in the Advanced economies Lifecycle High stringency scenario is that not all plastic waste can be collected; some streams evade the management system, such as waste from road markings, ghost fishing gear and uncollected litter.
Although the Global Lifecycle Low stringency scenario contains several incentives to reduce mismanaged waste below 2020 levels in all regions, significant amounts of mismanaged waste remain, especially in non-OECD countries: 50 Mt in 2040 vs 72 Mt in 2020.
Shares of waste management categories as a percent of waste generated in 2040, by region
Source: OECD ENV-Linkages model.
Secondary plastics in use in 2040 in million tonnes (Mt) across partial ambition scenarios, compared to 2020 levels and Baseline
Note: The percentages above the bars present the share of secondary in total use.
Source: OECD ENV-Linkages model.
The increased supply of scrap in the policy scenarios modelled also allows for an expansion of secondary plastics production (Figure 4.5). Global demand for secondary plastics in 2040 is projected to be 3.5 times that in 2020 in the Advanced economies Lifecycle High stringency and Global Lifecycle Low stringency scenarios, and 8.5 times that in 2020 in the Global Downstream High stringency scenario (equalling more than 5 times the Baseline level for 2040). The Global Downstream High stringency scenario projects very significant improvements in waste collection and recycling that result in an increase in the share of secondary plastics in overall production and demand, from less than 6% in 2020 to more than 30% in 2040. This reflects the supply push for the transition to secondary plastics. The recycled content target policy in turn implies a demand pull for secondary plastics. For OECD countries, the share of secondary plastics is about as large in the Advanced economies Lifecycle High stringency scenario (31%) as in the Global Downstream High stringency scenario (32%), but the volume of secondary plastics is lower, as demand for plastics and the supply of scrap are both lower.
In the absence of more significant reductions of total plastics use at the global level (see Figure 4.2), improvements in recycling and secondary plastics production (see Figure 4.5) would remain insufficient to prevent growth in primary plastics production (Figure 4.6, left-hand panel). Hence, the environmental and human health effects associated with primary plastics production, such as dependence on fossil-based feedstock, production-related greenhouse gas (GHG) emissions and exposure to chemicals of concern, would remain significant. Furthermore, the significant remaining volume of mismanaged waste (Figure 4.6, right panel) implies that plastics continue to leak to terrestrial and aquatic environments.
In million tonnes (Mt)
Source: OECD ENV-Linkages model.
Of the three partial ambition scenarios, the Global Downstream High stringency scenario performs best in terms of limiting growth in GHG emissions from production and conversion (Figure 4.7). Although total plastics demand increases significantly from 2020 levels, a significant share of production comes from secondary plastics, and the GHG emissions from production and conversion are lower than in other scenarios. However, large waste volumes and high recycling rates combine to substantially increase the GHG emissions associated with end-of life waste management. Furthermore, in the absence of policies to curb primary production (which is the main driver of GHG emissions), the contribution of plastics to GHG emissions continues to increase substantially compared to 2020 levels: GHG emissions grow by 30% in 2040 (from 1.8 gigatonnes of carbon dioxide equivalent [GtCO2e] in 2020 to 2.3 GtCO2e). The other two scenarios perform similarly, closing the gap by roughly half between Baseline growth and stabilisation at 2020 levels.
Greenhouse gas emissions from the plastics lifecycle in gigatonnes carbon dioxide equivalent (GtCO2e)
Source: OECD ENV-Linkages model.
The efforts modelled in non-OECD countries to improve waste management – including collection, sorting and treatment – in the Global Lifecycle Low stringency and especially in the Global Downstream High stringency scenarios would be responsible for a large part of global reductions in plastic leakage below Baseline levels (Figure 4.8). The enhanced stringency of downstream policies in OECD and non-OECD countries combined in the Global Downstream High stringency scenario could prevent 129 Mt of additional plastics leaking to the environment between 2020-2040 compared to Baseline, which projects cumulative plastic leakage of 519 Mt between 2020 and 2040. Thus, a cumulative 390 Mt of plastics would still leak to the environment between 2020 and 2040 despite stringent downstream measures to enhance recycling and close leakage pathways. With annal leakage still well above 10 Mt in 2040, further leakage would also occur after 2040.
In the other partial ambition scenarios, the avoided leakage remains limited to 41 Mt in the Advanced economies Lifecycle High stringency scenario and 58 Mt in the Global Lifecycle Low stringency scenario. In both scenarios, leakage of plastics to the environment does not stabilise over time, and thus the associated environmental burden would continue to grow after 2040. In the Advanced economies Lifecycle High stringency scenario, stringent policy action is limited to countries that already have low shares of mismanaged waste in the Baseline scenario. While there are some positive spillover effects from Advanced economy policies on plastic waste generation in other countries, these effects are limited, and – in contrast to the Global Downstream High stringency scenario – the Advanced economies Lifecycle High stringency scenario assumes developing countries are not incentivised to take ambitious action to close leakage pathways. In the Global Lifecycle Low stringency scenario, the main cause for increasing plastic leakage over time is a lack of policy stringency. Even if a broad agreement covering all four policy pillars was reached and implemented by all countries, low policy stringency of the measures implemented would result in a failure to stabilise global plastic leakage, let alone eliminate further leakage.
Leakage of plastics to the environment in million tonnes (Mt)
Source: OECD ENV-Linkages model.
Overall, strategies that do not include global policy action with high stringency for all four policy pillars, offer limited potential to reverse current trends. In the absence of broad stringent actions, the international community would fall far short the goal of eliminating plastic pollution for the foreseeable future.
← 1. The details of the numerical implementation of the policy scenarios in the modelling framework are presented in Annex B.
← 2. In line with the scenario descriptions in Chapters 1 and 3, a white background reflects current policies (as in the Baseline scenario); a semi-transparent background reflects low policy stringency and a fully coloured background reflects high policy stringency. Unlike in Figure 1.1 (Chapter 1) and Figure 3.2 (Chapter 3), here the different pillars are made explicit.
← 3. This is a model assumption reflecting the fact that technological advances tend to spill over to other countries, especially when a sufficient segment of the global market is implicated by such advances.
← 4. “Mismanaged” is included as a waste management category for accounting purposes; by assumption, no management costs are associated with this end-of-life fate.
← 5. Significant technical breakthroughs may be required to achieve the strong improvements in recycling envisioned in the scenarios modelled. These challenges are further discussed in Section 7.2 of Chapter 7.