If all food waste in the US found a second life as biogas and compost, this would almost completely offset its climate impact. But, it would also create a microplastic problem spread over a gigantic area.

This is the catch-22 described in a new study from Nature Food, which explores both the massive potential and the overlooked risks of tackling food waste. There is however a solution, say its authors, which is to design packaging and get much better at separating our waste.

The research, produced by the University of Vermont, was inspired by local recycling laws which require Vermont businesses and residents to keep food waste out of their bins, ensuring that landfills remain food-scrap-free. What would that look like, scaled up to the whole of the US? The researchers found out by gathering food waste recycling data from across the US, then running a detailed lifecycle analysis on anaerobic digestion to make biogas, and food waste composting measures. For each one they looked at the associated climate emissions, nitrogen and phosphorus loading on waterways, and plastic pollution. Then they compared these two recycling measures with the alternative and all its associated impacts: dumping food waste in a landfill. 

This revealed that food recycling brings some seriously big wins for climate and nutrient pollution. Firstly, it would reduce the climate burden of food waste by between 89 and 99% in the US. Converting food waste into biogas and compost cuts nitrogen pollution by between 49 and 54%, and phosphorus loading by 78 to 98%, compared to current landfill-focused measures. 

However there’s a huge polluting underbelly to this otherwise logical solution: that is the 20,000 extra tons of plastic pollution that would be tilled into the soil as compost and organic byproducts from anaerobic digestion each year. How does plastic even come into it? Because so much of our food is now coated and packaged in this material, and it is a challenge to completely remove it. 

Much of our food goes bad while still encased in plastic, and people can’t always be relied upon to peel plastic off rotting food and put it into a different bin. Equipment designed to separate old food and plastic in commercial settings involves a degree of mechanical error, which could result in potentially industrial scales of plastic entering food waste streams. Ultimately, countrywide food waste recycling would increase plastic soil pollution “by an order of magnitude, even with highly effective (99% efficient) separation technologies in place,” the researchers write. 

So how to unpick this mess? A starting point would be to design better packaging, and the researchers find that encasing our food in biodegradable materials would decrease the 100-year accumulation rate of plastic in agricultural soils by up to 99%. But biodegradable materials aren’t the whole solution and they bring challenges of their own. 

Others may argue that the more effective approach lies in reducing how much single-use packaging we use, and questioning how much of it we need in the first place — a solution that requires global systems change, far beyond the US.

Porterfield et. al. “Food waste recycling in the USA can reduce climate and nutrient pollution impacts yet risks plastic accumulation in soils.” Nature Food. 2026.

Image: Based on Karolina Grabowska/Unsplash