The world has a “once-in-a-lifetime” chance to tackle plastic pollution by securing an ambitious UN treaty in negotiations next month, Dame Ellen MacArthur has said.

Countries are meeting in Busan, South Korea, in November for the final round of negotiations to develop a legally binding agreement on plastic pollution, tackling the production, design and disposal of plastics.

After her retirement from professional sailing, Dame Ellen launched the Ellen MacArthur Foundation, which works with businesses and education providers to accelerate the shift to a “circular economy”.

She said the UN treaty must give businesses and countries certainty to invest in tackling the problem.

A circular economy sees materials from plastics to agriculture being reused, regenerated and recycled rather than becoming waste and pollution, helping tackle climate change and nature loss, as opposed to a “linear economy”, in which goods are produced, consumed and discarded.

Plastics are just one symptom of a linear economy that is extractive, consumptive, wasteful and polluting, Dame Ellen said, adding that it could not be how the economy worked in the future.

She said a global commitment launched in 2018 by the foundation and the UN with businesses to eliminate plastics they did not need, innovate the plastics they need to make them recyclable and to recycle what is made had seen those involved outperform the market in tackling plastic waste.

But businesses alone cannot fix this global problem and shifting the whole industry would require policy rules, Dame Ellen said, adding this was something that plastic packaging companies involved in the global commitment wanted.

“The emphasis on the treaty needs to be in building that circular economy for plastics, with the most ambitious treaty we can have which will enable the stability for businesses to invest in a circular economy for plastics, which is what they need to do, and countries to invest in recycling those materials,” she said.

“You need an ambitious treaty to warrant the investment.”

She said the treaty needed alignment on defining and phasing out problematic packaging and chemicals of concern, and bringing in “extended producer responsibility” schemes which charge a tax on materials to support recycling.

“This is a once-in-a-lifetime opportunity to set some global rules for plastic which help to shift us towards a circular economy.

“If we can agree on something that’s robust enough to enable the investment to start the ball rolling, or to – because in many cases, the ball is rolling – to speed up that rolling ball, especially in some of the territories where it’s not, then we have the stability to invest.”

She warned there was a risk the treaty could be so watered down that it would not provide the stability for businesses, countries or financial instruments to invest in a circular economy for plastics.

“This is a once-in-a-lifetime opportunity, and this is the moment for countries to be as ambitious as possible.”

Businesses have called for global rules and a level playing field, she said, adding: “We need countries to match it and go for as ambitious a global treaty as we can to bring some stability to the investment that’s needed for that sector as a global economy.”