Scientists have helped solve a longstanding mystery about how Earth remained habitable after oxygen first accumulated in its atmosphere more than 2 billion years ago, providing evidence that an ancient ocean chemistry sustained life-friendly conditions.

Marine plastic debris can persist for long periods and gradually break down into microplastics that are difficult to remove. Researchers from Ritsumeikan University used a system dynamics model to examine how reducing marine plastic inputs and varying the timing and intensity of cleanup could affect plastic accumulation by 2050. The findings show that halting plastic inputs is essential but insufficient on its own. Earlier cleanup of legacy macroplastics can reduce accumulation, but at higher costs.