Microplastics found in clouds – and may worsen climate crisis | environment

Science already knows that microplastics – polymer particles less than 5 millimeters in size – are everywhere: in the oceans, in the water we drink, and even inside the human body. But according to a new study by researchers in Japan, they may also be present in clouds.

Led by Hiroshi Okuchi, a professor at Waseda University, Japanese scientists traced the path of so-called microplastics in the atmosphere as they spread into the biosphere. The work was published in August In the magazine Environmental Chemistry Letters.

“Microplastics in the free troposphere are transported and contribute to global pollution. If the problem of ‘plastic air pollution’ is not addressed proactively, climate change and environmental risks could become a reality, causing irreversible environmental damage and serious problems in the future.” “. Okochi warns In the current situation.

According to the authors, 10 million tons of these fragments end up in the ocean and find their way into the atmosphere. This means that microplastics may have become a primary component of clouds, contaminating almost everything we eat and drink through “plastic rain.”

The researchers say that although most studies on microplastics have focused on aquatic ecosystems, few have investigated their impact on cloud formation and climate change as “suspended particles.”

Straight from the clouds

To investigate the role of microplastics in the troposphere and the boundary layer of the atmosphere, the team collected water from clouds on the upper and southeastern ridges of Mount Fuji and the summit of Mount Aoyama. The elevation in these Japanese regions ranges from 1,300 to 3,776 metres.

Using advanced imaging techniques, the researchers identified the presence of microplastics in cloud water and examined their physical and chemical properties. They identified nine different types of polymers and one type of rubber.

Most of the polypropylene (a resistant plastic used in packaging, toys, and various other products) detected in the samples was degraded and contained carbonyl (C=O) and/or hydroxyl (OH) groups.

Furthermore, the presence of hydrophilic polymers in the cloud water was abundant, indicating that they were removed as “cloud condensation nuclei.” According to the authors, these results confirm that microplastics in the atmosphere play a key role in the formation of rapid clouds, which could ultimately affect global climate.

The accumulation of these particles in the atmosphere, especially in the polar regions, could lead to significant changes in the ecological balance of the planet, leading to a serious loss of biodiversity.

According to Okochie, microplastics in the atmosphere decompose much more quickly in the upper atmosphere than on Earth due to intense ultraviolet radiation, and this decomposition results in the release of greenhouse gases. “As a result, the results of this study can be used to consider the implications of these particles in future global warming projections.”