They’re in the world’s water, air, food and even in our blood — and now researchers in Japan have discovered microplastics in clouds, raising the specter of super-contaminating “plastic rainfall” and possibly affecting the Earth’s climate.

Analyzing cloud water samples from high-altitude mountains in Japan including Mt. Fuji, researchers from Waseda University in Tokyo found nine different types of polymers and one type of rubber in the airborne microplastics (AMPs) they detected.

“Research shows that large amounts of microplastics are ingested or inhaled by humans and animals alike and have been detected in multiple organs such as lung, heart, blood, placenta, and feces,” notes a summary of the study, which was originally published in the journal Environmental Chemistry Letters.

“Ten million tons of these plastic bits end up in the ocean, released with the ocean spray, and find their way into the atmosphere,” the summary continues. “This implies that microplastics may have become an essential component of clouds, contaminating nearly everything we eat and drink via ‘plastic rainfall.’”

Earlier this year, researchers from the Indian Institute of Technology, Patna discovered AMPs in the city of Patna’s rainwater, with polyethylene, terephthalate and polypropylene being the most common polymers found.

In the Japanese study, the researchers found that “the presence of hydrophilic (water-loving) polymers in the cloud water was abundant, suggesting that they were removed as ‘cloud condensation nuclei.’”

“These findings confirm that AMPs play a key role in rapid cloud formation, which may eventually affect the overall climate,” they added.

Accumulation of AMPs in the atmosphere — especially around the Earth’s poles — could also upset the planet’s ecological balance, with devastating effects on biodiversity.

“AMPs are degraded much faster in the upper atmosphere than on the ground due to strong ultraviolet radiation, and this degradation releases greenhouse gases and contributes to global warming,” Waseda University professor Hiroshi Okochi, who led the study, said in a statement. “As a result, the findings of this study can be used to account for the effects of AMPs in future global warming projections.”

“If the issue of ‘plastic air pollution’ is not addressed proactively, climate change and ecological risks may become a reality, causing irreversible and serious environmental damage in the future,” Okochi added.