Modeling the Global Plastic Pollution in Our Oceans

Plastic is everywhere—from our plastic bottles and straws to the inside of our phones and the clothes we wear every day. Its widespread use has left a legacy of trash, with large amounts of plastic spilling from landfills into oceans. The accumulation of plastic debris in our oceans has severely affected marine life and has even entered into the human food chain. In this project, we created a mathematical model to estimate global plastic waste-generation and ocean runoff using existing data from 1980 to 2015. Using a dynamic system, we calculated the amount of plastic that ends up in landfills each year, based on yearly global plastic production as well as recycling and incineration rates. Using country-specific data, we also modeled yearly ocean runoff as a percent of the plastic waste from coastal mismanaged landfills. Assuming a business-as-usual scenario, we used regression models to extrapolate to the year 2050 and estimated that the cumulative ocean plastic waste by 2050 will be between 710-1,070 MT, which is the equivalent of 444-669 grocery bags filled with plastic for every foot of coastline in the world. We then used our model to study how changes in governmental policies and corporate practices can help reduce ocean plastic pollution. In particular, we assumed (1) a ban on single-use plastics in high-income countries, and (2) improvements in waste-management infrastructures in regions of the world with high ocean runoff, and studied the reduction in global plastic runoff under these two scenarios. Finally, we studied the impact of various clean-up strategies such as ocean U-boat contraption boats or river filters has on plastic debris in our oceans. The effect of these clean-up strategies is very small given the magnitude of the ocean plastic pollution, but a significant reduction in ocean runoff can be achieved through improvements in waste management infrastructure and a reduction in single-use plastics in SE Asia.