Microplastics found in clouds raise concerns about climate change

In a startling discovery, scientists have identified the presence of microplastic particles in cloud water, shedding light on their potential contribution to climate change.

The research, conducted in Japan, reveals alarming findings about the extent of plastic pollution infiltrating Earth’s ecosystems and its potential impact on the environment.

The study, published in the journal Environmental Chemical Letters in August 2023, joins a growing body of evidence indicating that plastic pollution has pervaded most ecosystems on the planet.

Researchers have found plastic fragments smaller than 5mm, equivalent in size to a sesame seed, in the most remote corners of the Earth, as well as within the human body, including the blood, lungs, and placentas of pregnant women.

The scientists involved in this study stated, “To the best of our knowledge, this study is the first to detect airborne microplastics in cloud water in both the free troposphere and atmospheric boundary layer.”

Microplastics in clouds were detected at the summits of two of Japan’s tallest mountains, Mount Fuji and Mount Ōyama, at altitudes ranging from 1,300 to 3,776 meters.

Mount Fuji’s summit is located in the free troposphere, while Mount Ōyama extends into the atmospheric boundary layer, both within the lowest layer of Earth’s atmosphere.

Advanced imaging techniques were employed to identify the presence of microplastics and determine their types.

Shockingly, the cloud samples contained up to 14 pieces of plastic per liter of water, with sizes ranging from 7 to 95 micrometers, slightly larger than the average width of a human hair at 80 micrometres.

The researchers explained that plastics, initially hydrophobic, become hydrophilic (water-loving) after prolonged exposure to ultraviolet light.

What’s even more concerning is that the abundance of these polymers in some samples suggests they might have served as “condensation nuclei” for cloud ice and water.

Condensation nuclei are tiny particles upon which water vapor condenses in the atmosphere, playing a crucial role in cloud formation.

The scientists concluded, “Overall, our findings suggest that high-altitude microplastics could influence cloud formation and, in turn, might modify the climate.”

Microplastics originate from a myriad of sources, including microbeads in cosmetics, fertilizers, and the degradation of larger plastic objects like bags.

While research on microplastics in marine and terrestrial environments has been extensive, studies on airborne microplastics have been limited.

There are various pathways for microplastics to enter the atmosphere, including road dust, landfills, tire wear, and artificial grass. The ocean can also release microplastics into the atmosphere through sea spray and other aerosolization processes.

Hiroshi Okochi, the lead author of the study from Waseda University, emphasized, “This implies that microplastics may have become an essential component of clouds, contaminating nearly everything we eat and drink via ‘plastic rainfall.'”

Okochi referred to the presence of microplastics in the troposphere as plastic air pollution.

He warned, “If plastic air pollution is not proactively addressed, the risks of climate and ecological change could become a reality, leading to irreversible environmental damage in the future.”

Furthermore, airborne microplastics degrade more rapidly in the upper atmosphere due to intense ultraviolet radiation, releasing greenhouse gases and contributing to global warming.