After sampling the skies over two Japanese mountains, scientists have found microplastics in the clouds.
The finding underscores the extent to which the small particles have invaded nearly every part of the Earth, where they can harm living creatures and even potentially influence the climate, the researchers from several Japanese universities wrote in a paper in Environmental Chemistry Letters.
The researchers collected samples of cloud water above Mount Fuji, Japan’s highest mountain, and Mount Oyama over several months. Using advanced imaging techniques, they identified nine different plastic polymers, along with some rubber.
Their presence in clouds is especially concerning, the researchers wrote, because some of the microplastics they found had molecular structures that could help to seed clouds, spurring them to produce ice or water. The particles could also contribute to cloud formation, which would affect their cooling impact on the Earth.
Microplastics have previously been found in oceans, rivers, and even in the lungs of wild birds. They take centuries to decompose, which makes them a growing threat to most ecosystems as humans continue to use and discard plastic. Discovering microplastics in the lowest layer of the atmosphere — where clouds form — is further evidence of the ubiquitousness of microplastics.
“Microplastics may have become an essential component of clouds, contaminating nearly everything we eat and drink via ‘plastic rainfall,’” scientists said in a statement.