Global City-Level| Marine and coastal ecosystem services | Status: Completed
The Current Returns: The Social Benefit-Cost Ratio of Plastic Interception in Rivers
"The Current Returns” project aims to deliver a social Cost-Benefit Analysis (CBA) of plastic interception interventions in rivers from The Ocean Cleanup in three cities: Kingston, Guatemala City, and Jakarta. Using the concept of Ecosystem Services (ES), this study quantifies the economic value of ecosystem services provided, estimates the economic impacts of plastic pollution on these services, and evaluates the benefits of river-based plastic interception under three scenarios.
16 ecosystem services are assessed, including fisheries, coastal protection, recreation, and biodiversity, across five ecosystems: coral reefs, mangroves, seagrass meadows, beaches/coastal areas, and open sea. Monetary values are estimated using a mixed-methods approach combining literature review, the Ecosystem Services Valuation Database (ESVD), and local data collection, capturing both market and non-market values. For six ecosystem services, value transfer functions were developed and applied to enable location-specific value estimates.
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Outcomes
River interception interventions provide substantial societal and economic returns by preventing plastic from entering downstream ecosystems. The highest benefits are observed for sectors dependent on ecosystem services, including fisheries, coastal protection, and recreation. Strategic investment in interception systems is cost-effective and complements broader plastic pollution mitigation efforts, including ocean cleanup initiatives such as the GPGP project. These findings highlight the importance of integrating urban plastic management into municipal planning and environmental policy.
Key Findings
Under the baseline scenario, all three cities show benefit-to-cost ratios (BCR) of one or greater: $1.05 for Jakarta, $12.14 for Kingston, and $17.07 for Guatemala City. Combined, the average BCR across all cities is $6.48, meaning that for every dollar invested in river interception, there is an average return of $6.48 in social value of ecosystem services. Compared to the previous study on Great Pacific Garbage Patch (GPGP) cleanup, which had a BCR of $1.02, the urban river interventions deliver significantly higher returns per dollar invested. These results are consistent with other studies: Chaerul and Rahayu (2019) reported BCRs of 1.6 - 4.5 for municipal waste treatment in Indonesia, Phuang et al. (2023) found a similarly positive BCR for plastic waste management pathways, while Jin et al (2018) found BCRs between 0.68 - 5.0 for ES values for a cleanup of the Boston Harbor.
Scenario Analysis
The baseline results are tested against two additional scenarios: technological improvements and policy improvements. In the technology scenario, costs increase by 1.5 times to achieve a 90% effectiveness of cleanup, compared to the current performance of interceptors (70% for Kingston and 80% for Guatemala City). In the policy scenario, improvements in waste management practices reduce the plastic impact from 5% to as low as 1%, depending on the scale of plastic reduction and the corresponding decrease in impact and costs. Both scenarios yield lower BCRs than the baseline due to disproportionate increases in costs (technology scenario) and reduced need for intervention (policy scenario).
Economic Impacts
Net economic benefits of river cleanup range from $95 million in Jakarta to $1.12 billion in Guatemala City over 75 years (2% discount rate). Potential losses in ecosystem services
under inaction range from $128 million in Jakarta to $1.39 billion in Kingston, with a total baseline loss of approximately $2.7 billion across the three cities.