From sandwich bags to tire treads, humans produce and discard about 400 million tons of plastic every year. Most of it is left behind to break down, releasing greenhouse gases and degrading into microscopic fragments that travel far beyond the point of origin
Microscopic pieces of plastic are turning up in Earth’s water, soil and air. They are everywhere.
A new article in the journal Nature highlights the global scope of this problem and features the research of Janice Brahney, a biogeochemist in Utah State University’s Quinney College of Agriculture and Natural Resources. Microplastics are altering the way Earth’s natural processes function on a planetary scale, according to the researchers.
Plastics often enter the atmosphere not directly from garbage, but from roadways, agricultural fields and the ocean. Tires grind against pavement and launch tiny particles into the air through turbulence. Wind lifts debris from plowed fields. Ocean waves churn insoluble plastic fragments — once food wrappers, soda bottles and shopping bags — into the sky to be carried across the globe.
“When these microscopic pieces of plastic are pulled into the atmosphere they can move almost everywhere,” Brahney said.
That includes lakes, rivers, national parks, forests, rangelands and more. Each year more than 1,000 tons of microplastics fall from the atmosphere onto the western United States — the equivalent of about 300 million plastic water bottles raining down onto the landscape.
This is more than just a pollution problem, Brahney said. This material is likely shifting the complex systems on which the planet runs.
Brahney is working with University of Utah’s snow hydrology expert, McKenzie Skiles, to examine how plastic dust changes the way sunlight is reflected or absorbed on snow surfaces, influencing the rate of snowmelt. She is also working to understand how plastic moves through terrestrial ecosystems, altering fundamental biological processes. These are critical and understudied pieces of the plastic pollution puzzle.
Other researchers are investigating how microplastics affect the ocean’s ability to store carbon, a process known as the biological carbon pump, one of Earth’s natural defenses against rising greenhouse gases. Findings like these add layers of complexity to the already challenging task of modeling climate change.
“Plastic pollution is one of the most pressing environmental and social issues of the century,” Brahney said. “There is still so much we don’t know about this issue, and it is already in motion, altering the future of the planet. The data we collect is crucial to understanding how plastic could reshape our world.”
Brahney’s ongoing research aims to change the conversation around plastic dust with a major synthesis of dust research that compiles research on dust pollution and details major gaps that still need to be urgently puzzled out.