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

Today, the world produces more than 50 million tons of “mismanaged” plastic waste every year, and some researchers predict that this flood of plastic pollution will double by the middle of the century; In this week’s global plastic treaty negotiations, we could reduce that number by 90 percent.

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

That’s why most of the world’s countries are gathering in Busan, South Korea, this week to hash out the final details of a global treaty aimed at ending plastic pollution. In 2022, already 175 countries agreed to accept the legally binding treaty and they have spent the last two years debating what should be required, with particular disagreements over whether to impose limits on the production of new plastic.

To clarify the discussion, Douglas McCauley At the University of California, Santa Barbara, and colleagues used an artificial intelligence model trained on economic data to test how the policies under study would affect global plastic pollution. “I didn’t believe (eliminating plastic pollution) was possible,” says McCauley. “But it turns out you can get pretty close.”

According to their predictions, under current conditions, plastic pollution will roughly double to between 100 and 139 million tons by 2050. But a combination of four policies, all of which are still on the table. draft of the current treatyit was enough to reduce that by more than 90 percent.

The most influential of these was that plastic products contain at least 40 percent recycled material. That rule alone cut plastic pollution in half by mid-century. This effect is significant because it reduces the demand for newly made or “virgin” plastic, and also stimulates the demand for recycled materials, McCauley said. “Suddenly, there’s a huge market for recycling.”

But recycling on its own was not enough. “If your goal is to end plastic pollution, you have to do things throughout the life cycle,” he says. The deeper cuts were supposed to limit production of virgin plastics to 2020 levels. This production cap reduced plastic pollution by about 60 million tons per year by mid-century, according to the model. This change also had the greatest impact on the greenhouse gas emissions of plastic production, as the extraction of fossil fuels and the conversion of virgin plastics are emission-intensive processes.

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

Finally, a small tax on plastic packaging reduces pollution by ten million tons. The researchers based this estimate on case studies of people reducing their use of plastic in response to similar taxes, for example. 5 cent fee on single-use plastic bags in Washington, DC. The money raised by this tax could also be used to pay for other changes, such as building waste management infrastructure or improving recycling systems.

Royer, who was not involved in the research, says he believes all of these policies would help. Reducing the use of single-use plastic, such as grocery bags or plastic forks, through a tax or ban could also have an effect, he said. “If we look at plastic pollution in general, 40 percent of the plastic produced is single-use items.”

However, he stated that local regulations alone will not solve the problem. For example, California banned some single-use plastic bags a decade ago and banned all such bags this year. But most of the plastic pollution that washes up on its beaches originates outside the state: California’s plastic waste generally drifts into the Pacific Ocean from Asia or is left over from the fishing industry. “There are no limits,” says Royer.

That’s where a global pact comes in. 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 four main policies shown in the graph below together reduced all three measures, and in particular they reduced mismanaged waste by 91 percent.

In Busan, the countries have reached a deadline to decide on a final draft treaty, but they remain far apart on key issues. A key flaw is whether the treaty should include a production cap on newly made plastics, which the researchers found to be the second most influential policy. Plastic-producing countries and the petrochemical industry are opposed to production limits, instead of putting their support behind recycling measures.

An “ambitious coalition” of 68 countries, including the UK, is pushing for a treaty that will include both, with the goal of eliminating plastic pollution by 2040. researchers have also argued A limit on plastic production is necessary to end pollution. But last week, supporters of the production cap were upset the reports The US would not accept specific limits on plastic production. McCauley recently wrote an open letter – signed by more than a hundred researchers – urging the Biden administration. protecting a strong plastic pact.

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