A global evidence-based strategy that includes practical and measurable interventions aimed at reducing plastic pollution is urgently needed to combat the increasing pressure on terrestrial and aquatic ecosystems. Despite several inter-regional regulative efforts and international conventions, there is no clear agreement on intervention strategy.
Winnie W. Y. Lau, Yonathan Shiran, Richard M. Bailey, Costas A. Velis, James E. Palardy.
«Designing an effective global strategy requires an understanding of the mitigation potential of different solutions and the magnitude of global effort needed to appreciably reduce plastic pollution.»
The authors developed six scenarios to estimate effects on interventions for reducing plastic pollution over the period 2016 to 2040. The scenarios were calculated based on projected growth in demand for plastic based on country-level population size, per capita plastic use and loss rates, and data on waste generation and waste management processes.
To account for differences in per capita plastic use and loss rates by geography, the global population was split across eight geographic archetypes according to World Bank income categories and United Nations urban-rural classifications. Populations were further differentiated by their distance to water to estimate relative flows of plastic pollution to terrestrial versus aquatic systems. Waste management pathways and movement rates of waste in the environment and municipal solid waste plastics were modelled according to the three main material categories determining their waste management pathways. Lastly, microplastic sources were placed in the model as: synthetic textiles, tires, plastic pellets, and personal care products
The scenarios were then defined by classes of interventions such as reduction, substitution, recycling and disposal. The intervention classes were crossed with eight system interventions:
In sum this gave six scenarios for the period 2016-2040
This scenario describes the scale of the plastic pollution problem without intervention, and provides a baseline from which to compare alternative intervention strategies. In the BAU scenario the annual rate of plastics entering aquatic systems from land increased 2.6-fold and pollution retained in terrestrial systems increased 2.8-fold.
This scenario modeled current commitments made to reduce plastic pollution assuming full, future implementation. These commitments only reduced plastic pollution into aquatic and terrestrial environments by 6.6% and 7.7%, respectively.
This scenario had the highest municipal plastic waste management costs (i.e., collection, sorting, recycling, and disposal). Compared with BAU, annual combined terrestrial and aquatic plastic pollution rates were reduced by 57%.
This scenario had the lowest municipal plastic waste management costs (i.e., collection, sorting, recycling, and disposal). The costs were calculated assuming 3.5% discount rate and are net of revenues from sale of recycled plastic feedstock and electricity generated from plastic incineration for energy Compared with BAU, the annual combined terrestrial and aquatic plastic pollution rates were reduced by 45%.
This scenario focused on upstream solutions, where interventions occur pre-consumption. Potential solutions were assessed for 15 major plastic applications against criteria such as technology readiness, unintended consequences related to health and food safety, consumer acceptance and affordability. Substitution options were assessed in relation to the potential for scaling to meaningful levels within the modeling period. Under this scenario, annual terrestrial and aquatic plastic pollution in 2040 was reduced by 59% . Annual plastic production in 2040 decreased by 47% relative to BAU (2016 level production).
This scenario presented an integrated and total change of the global plastic system achieved through implementation of the entire suite of upstream and downstream interventions. In this scenario, annual combined terrestrial and aquatic plastic pollution decreased by 78% relative to BAU in 2040.
The System Change scenario had the lowest overall costs, driven by a reduction in plastic waste generation achieved through reduced plastic demand, substitution by alternative materials, and increased recycling. Compared to the BAU scenario these interventions cost 18% less, as waste collection costs are offset by savings from reduced plastic production and higher revenues from recyclate sales. In this scenario, improved product design and economics of recycling enabled an increase in recycled plastic feedstock, achieving an 11% reduction in virgin plastic production in 2040 relative to production in 2016. This scenario moves toward achieving a circular economy in which resources are conserved, waste generation is minimized and GHG emissions reduced.
«The analysis indicates that urgent and coordinated action combining pre- and postconsumption solutions could reverse the increasing trend of environmental plastic pollution. Up to 78% of the plastic pollution problem can be solved by 2040 through the use of current knowledge and technologies, at a lower net cost for waste management systems compared with that of BAU.»
Maximum foreseen application of pre- and post–consumption solutions are needed to avoid a massive build-up of plastic in the environment. Only a coordinated global action using a systems perspective can ensure reduced plastic consumption; increased rates of reuse, waste collection, and recycling; expanded safe disposal systems; and an acceleration of innovation in the plastic value chain.
The results of this research underline the urgency with which extensive interventions are needed. Despite a considerable reduction in annual plastic production and an increase in the proportion of municipal solid waste effectively managed in the best-case system change scenario, a substantial quantity of plastic waste remains mismanaged, and huge quantities of plastic continue to accumulate in the environment.
The research team notes that even if this system change is achieved, plastic production and unsound waste management activities will continue represent an environmental problem due to greenhouse gas emissions and plastic pollution. Therefore, development of resource-efficient and low-emission business models, reuse and refill systems, sustainable substitute materials, waste management technologies, and effective government policies are needed, and should be supported with finance redirected from virgin plastic infrastructure.
Increased ambition in the commitments of businesses, governments, and the international community are needed to solve the ecological, social, and economic problems of plastic pollution and achieve near-zero input of plastics into the environment.
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