What will it take to solve our planet’s plastic pollution crisis?

The world currently produces more than 50 million tons of “mismanaged” plastic waste each year, and some researchers predict that this flood of plastic pollution will double by mid-century – but they also say that if countries manage to If we negotiate a global plastics treaty this week, we could reduce that figure by 90 percent.

Plastic pollution ends obstruct ecosystems on land and at sea. “This impacts all levels of the food chain, from phytoplankton cells to humans,” explains Sarah-Jeanne Royer at the University of California, San Diego. Plastics are also responsible for around 5 percent of greenhouse gas emissions.

That’s why most of the world is meeting this week in Busan, South Korea, to iron out the final details of a global treaty to end plastic pollution. In 2022, 175 countries already agreed to adopt the legally binding treaty and have spent the last two years debating exactly what that should require, with particular disagreements over setting limits on the production of new plastic.

To bring more clarity to the debate, Douglas McCauley At the University of California, Santa Barbara and colleagues used an artificial intelligence model trained on economic data to test the impact of planned policies on global plastic pollution. “I wasn’t convinced that (eliminating plastic pollution) was actually possible,” McCauley says. “But it turns out you can get pretty darn close.”

According to their projections, under current conditions, plastic pollution should double to reach between 100 and 139 million tonnes by 2050. But the combination of four policies, all still relevant in the future, current draft treatywere enough to reduce this figure by more than 90 percent.

The most notable of these was the requirement that plastic products contain at least 40 percent recycled material. This rule alone cut plastic pollution in half by mid-century. This effect is so important because it reduces demand for newly manufactured or “virgin” plastic while also boosting demand for recycled materials, says McCauley. “Suddenly there is a giant global market for recycling. »

But recycling alone was not enough. “If your goal is to end plastic pollution, you need to act across the entire life cycle,” he says. Deeper reductions required limiting the production of virgin plastics to 2020 levels. This production cap would reduce plastic pollution by about 60 million tons per year by mid-century, according to the model. This change also had the greatest impact on greenhouse gas emissions from plastic production, because extracting fossil fuels and transforming them into virgin plastic involves emissions-intensive processes.

A third policy, spending $50 billion on waste management, reduced pollution by about as much as the production cap – especially if those funds were spent in low-income countries with poor infrastructure, which are also the most inundated by plastic pollution. “When you start talking about global finance, (the amount of money needed) is not that important,” McCauley says. “Building a sanitary landfill is not like building a port.”

Finally, a small tax on plastic packaging reduced pollution by tens of millions of tons. The researchers based this estimate on case studies of how people reduced their plastic use in response to similar taxes, such as 5 cent fee on single-use plastic bags in Washington DC. Money raised from such a tax could also be used to finance other changes, such as building waste management infrastructure or improving recycling systems.

Royer, who was not involved in the study, says she thinks all of these policies would be helpful. Reducing the use of single-use plastics like grocery bags or plastic forks via a tax or ban could also make a difference, she says. “If we look at plastic pollution in general, 40% of plastic produced is single-use items.”

However, she stresses that local rules alone will never solve the problem. For example, California banned some single-use plastic bags ten years ago and this year banned all such bags. But most of the plastic pollution that washes up on its beaches comes from outside the state: California’s plastic waste typically drifts across the Pacific from Asia or is discarded flotsam from the shipping industry. fishing. “There are no borders,” says Royer.

This is where a global treaty comes into play. The researchers showed how implementing different policies around the world would reduce three things: the volume of mismanaged plastic waste, the production of new plastics and plastic-related greenhouse gas emissions. The combination of the four key policies, illustrated in the graphic below, resulted in a reduction of all three measures, and in particular a 91 percent reduction in mismanaged waste.

In Busan, countries have now reached the deadline to decide on a final draft treaty, but they remain far apart on key issues. One of the main differences is whether the treaty should include a production cap on newly manufactured plastics, which researchers say is the second most impactful policy. Plastic-producing countries and the petrochemical industry oppose production caps and instead support recycling measures.

A “highly ambitious coalition” of 68 countries, including the UK, is pushing for a treaty that would include both, with the aim of eliminating plastic pollution by 2040. researchers also supported a cap on plastic production is needed to end pollution. But just last week, proponents of a production cap were dismayed by reports the United States would not support a specific limit on plastic production. McCauley recently wrote an open letter – signed by more than a hundred researchers – to the Biden administration, urging it to support a strong plastic treaty.

“We are at a pivotal moment,” said Erin Simon to the World Wildlife Foundation, an environmental advocacy group, in an email to the press. “Our last chance to reach an agreement that could end the flow of plastic into nature is within reach, but only if countries come to the negotiating table with a clear vision and the determination to get the job done . »