Stopping new plastic from reaching the sea is not enough on its own. A system dynamics model published in September 2026 in Communications Earth & Environment by Professor Takuro Uehara (Ritsumeikan University, Japan), Dr. Mateo Cordier (Université de Versailles-Saint-Quentin-en-Yvelines) and Laurent Lebreton (The Ocean Cleanup) shows that halting all new plastic inputs into the ocean by 2050 would reduce the plastic accumulated at sea by only 51.4% compared with business as usual.
The reason is fragmentation. Large plastic items already in the ocean keep breaking down into microplastics, which are far harder to remove. Without cleanup, microplastics would make up 58.4% of the plastic remaining in the ocean by 2050.
The model compares two paths. Combining source reduction with early removal of large debris brings the 2050 total down to about 7,312 kilotons, against 10,168 kilotons when cleanup is delayed. The faster path costs more, about €3.4 billion a year compared with €1.0 billion, but it stops macroplastics before they fragment into microplastics that can no longer be recovered.
