New Projections: Microplastics in the Environment Could Multiply by 2060

Microplastics have become a pervasive issue in the environment, found in land, air, and oceans. Recent research suggests that the quantity of microplastics could significantly increase over the next few decades, even with proactive measures taken to combat poor waste management practices globally.

Researchers from France, in a study published in the journal Science Advances, modeled the trajectory of global plastic cycles from 1950 to 2100. Their findings indicate that the amount of plastic entering the oceans each year may peak at 23 million tons by 2045. This increase in plastic waste will likely lead to higher concentrations of microplastics, primarily as larger plastic items disintegrate over time.

The foundation of their calculations was based on a 2022 study by the Organisation for Economic Co-operation and Development (OECD), which analyzed plastic waste development under various scenarios, from maintaining current practices to implementing ambitious global initiatives. The researchers noted that the political tools across all scenarios included taxing plastic products, enhancing recycling efforts, increasing product durability, expanding landfill capabilities, strengthening producer responsibility, and providing financial support for developing countries.

In their latest calculations, the researchers categorized plastics into three size categories:

• Macroplastics (larger than 5 millimeters)
• Large microplastics (0.3 to 5 millimeters)
• Small microplastics (smaller than 0.3 millimeters)

These latest estimates are considerably higher than those provided in the OECD's report. For instance, the OECD estimated that 1.7 million tons of macroplastics entered the oceans in 2019, while the new research suggests this figure could be as high as 6.1 million tons. When factoring in both large and small microplastics, the total annual plastic influx to the oceans could reach 16 million tons.

The researchers attribute the discrepancies in the data to their reliance on direct measurements and estimations of plastic quantities in marine environments, as opposed to the OECD's reliance on population density and national economic statistics.

According to the current study, the overall amount of plastic in the oceans could rise from 263 million tons in 2015 to 1.2 billion tons by 2060, even under scenarios that assume significant political intervention. Other scenarios could yield even higher estimates.

As for small microplastics in the upper layers of the oceans (up to 50 meters deep), their concentration, in the best-case scenario, may increase from 6.2 nanograms per liter in 2015 to 19 nanograms by 2060, and in the worst case, it could reach 27 nanograms. Meanwhile, the atmospheric concentration of these small microplastics could grow from 23 nanograms to between 74 and 100 nanograms per cubic meter during the same period.

Even if no further plastics were to enter the oceans due to ineffective waste management post-2060, the amount of microplastics would continue to rise. This is because existing plastic waste will continue to fragment at an estimated rate of 3 percent per year.

The future state of the oceans will heavily depend on how plastic waste is managed, particularly in coastal regions, where an estimated 100,000 landfills exist in low-lying areas that are often unsealed and susceptible to erosion. This condition allows plastics to seep into marine environments. The recovery of these ecosystems will also depend on the effectiveness of these landfills in containing plastic and microplastic waste.