Environmentally friendly and even carbon-negative drinking straws exist, according to a new study. But the analysis also lays bare the potential for greenwashing, littering, and improper disposal to erode these benefits.
More than 50 billion disposable drinking straws are used each year in the United States alone. Small and lightweight, straws often escape from waste disposal streams and find their way to the sea, where they last for years and can harm marine life.
These cheap, quotidian objects have thus become the object of surprisingly intense environmentalist ire—and even bans on non-degradable straws in various jursidictions. In turn, this situation has spawned efforts to develop more sustainable straws.
The result is a dizzying array of polymer acronyms, brands, sustainability claims, and certification systems. Some straws are fossil-based and biodegradable; others are plant-based but non-biodegradable. But which disposable straw is best?
In the new study, researchers evaluated the sustainability, circularity, and biodegradability of 13 different drinking straws made from paper, bioplastics, conventional plastics, and plastics with fillers from oyster shells or agave plants.
They weighed and measured the straws, and gathered marketing, regulatory, and certification information from various documents and databases. They also subjected the straws to months in plastic tubs with a constant flow of seawater, a methodology they say provides a more accurate gauge of breakdown in the marine environment than the conventional approach of sealing them up in bottles of seawater.
A plastic straw made from recycled methane, a potent greenhouse gas, had the least overall effect on the environment, the researchers report in the journal Environmental Science & Technology.
The recycled-methane straw was the lightest, thinnest option, winning sustainability points for material efficiency. It was made from a plastic called polyhydroxyalkanoate (PHA) that can be composted on land and breaks down in the ocean in an estimated 15 months, more rapidly than many of the other straws tested.
An analysis of the carbon in the recycled-methane straw showed that it was ultimately derived from fossil fuels. But overall, this straw had a net-negative global warming potential, the researchers calculated.
Disposable straw marketing is also rife with “greenwashing.” “A few drinking straws marketed as better for the environment were still made of polypropylene, the same materials as conventional plastic straws,” says study team member Bryan James, a chemical engineer at Northeastern University. “These straws have received a fair amount of media attention and adoption, but won’t remedy the issue of persistent plastic in the ocean,” even if they include recycled or bio-based materials.
Paper straws are often promoted as a sustainable alternative to plastic ones. But while paper straws break down fastest in the marine environment—within roughly 11 months—they also use more material than plastic straws. And paper requires 10 to 100 times more water to produce than bioplastics (which in turn are more water-intensive than fossil-based plastics). All these factors resulted in a lower overall sustainability score than the recycled-methane straw.
Marketing materials for some straws emphasize that they can be composted. But just because they can be, doesn’t mean they will be. “The improper disposal of biodegradable plastics in landfill instead of compost can have a potentially significant climate change impact,” James says. “This finding provides additional support for investing in composting infrastructure,” which many municipalities lack.
For the recycled-methane straw, even improper disposal doesn’t cancel out the benefits of capturing methane to use as a feedstock. More broadly, making plastics from recycled methane has massive potential, the study suggests. Making all plastic packaging with recycled methane could offset about 30% of annual global methane emissions, the researchers calculated.
The study also highlights the need to evaluate sustainability claims based on real-world scenarios. “We are actively engaging with companies and brands to apply our marine biodegradation testing facility and evaluation methodology to their products,” says James. “We hope to see standardized certification schemes be developed so that consumers and policymakers can reasonably compare products much like a ‘nutrition facts’ label but for environmental impact and circularity.”
Source: James B.D. et al. “Strategies for Designing Circular, Sustainable, and Nonpersistent Consumer Plastic Products: A Case Study of Drinking Straws.” Environmental Science & Technology 2025.
Image: ©Anthropocene Magazine, AI-generated