How much innovation is needed to protect the ocean from plastic contamination?

Plastics are non-biodegradable, and increasing accumulation of plastic debris in the ocean is a major cause for concern. The World Economic Forum, Ellen MacArthur Foundation, and McKinsey & Company claimed in 2016 that technological innovations can solve the plastic problem. Such a claim raises an as yet unanswered question: how much technological innovation is needed and is it economically feasible? We offer answers to this question via a system dynamics model that we developed to simulate different scenarios aimed at controlling plastic debris entering the global ocean. Our results show that ocean cleanup technologies could achieve a 25% reduction in the level of plastic debris in the ocean below 2010 levels in 2030. However, this would require removing 15% of the stock of plastic debris from the ocean every year over the period 2020-2030, which equates to 135 million tons of plastic in total (metric tons). The implementation cost of such an ocean cleanup effort would amount to €492 billion-€708 billion, which represents 0.7%-1.0% of the world GDP in 2017 - this calculation is based on unit costs in €/kg estimated in The Ocean Cleanup project feasibility study. The Ocean Cleanup project alone is designed to collect 70,320 tons of plastic debris over a 10 year period. Removing 135 million tons of plastic debris would require investing in 1924 similar cleanup projects. These results help to assess the economic feasibility of removing such large volume of plastics. Moreover, our results provide quantitative confirmation that technological solutions alone are not sufficient to solve plastic pollution issues. A portfolio of diverse solutions - not only technological ones - is likely to have greater technical, political and economic feasibility. Our model shows that such a combined portfolio implemented over the period 2020-2030 could reduce the ocean plastic stock to 2013 levels (94 million tons) by 2030.