Scientists have spotted microplastics, tiny pieces of plastic smaller than 5 millimeters, in some of the most pristine environments on Earth, from the depths of the Mariana Trench to the snow on Mt. Everest to the mountaintop clouds of China and Japan. Microplastics have been detected in human brains, the bellies of sea turtles and the roots of plants.

Now, new research led by Penn State scientists reveals that microplastics in the atmosphere could be affecting weather and climate.

The study, published today (Nov. 7) in the journal ACS ES&T Air, demonstrated that microplastics act as ice nucleating particles, microscopic aerosols that facilitate the formation of ice crystals in clouds.

This means that microplastics could impact precipitation patterns, weather forecasting, climate modeling and even aviation safety by influencing how atmospheric ice crystals form clouds, explained Miriam Freedman, professor of chemistry at Penn State and senior author on the paper.

"Throughout the past two decades of research into microplastics, scientists have been finding that they're everywhere, so this is another piece of that puzzle," Freedman said. "It's now clear that we need to have a better understanding of how they're interacting with our climate system, because we've been able to show that the process of cloud formation can be triggered by microplastics."