The next time it starts to snow, you might want to reconsider opening your mouth to catch a snowflake. Microplastics have now been discovered in clouds, as revealed by a recent study by researchers at Waseda University in Tokyo.
These tiny plastic particles were found hovering above Mount Fuji, and they could potentially impact cloud formation and subsequently influence the climate, as detailed in their publication in Environmental Chemistry Letters.
Humanity’s ceaseless production of over 8 billion tons of plastic, with less than 10% being recycled, has led to its ubiquitous presence. Due to its resistance to degradation, plastic persists in the environment for centuries, fragmenting into smaller particles that infiltrate our food, bodies, and surroundings.
While the exact harm these minuscule particles pose to humans remains unclear, certain plastic chemicals are suspected to disrupt reproduction, stress responses, immune function, and development. Microplastics imperil marine life and birds in oceans, with limited research indicating significant threats to mammals, based on studies involving rats and mice.
The recent study underscores the emerging concern of microplastics in clouds. Hiroshi Okochi, a study author, anticipated finding airborne microplastics in Mount Fuji’s clouds, considering previous findings of these particles in atmospheric fallout, including rainwater. Researchers surmised that if these particles existed in rainwater, they likely existed in cloudwater as well.
Sampling cloud water at the Mount Fuji Research Station posed challenges but provided unobstructed access for collection. Analyzing these samples revealed materials akin to those used in various plastic products like food wraps, shopping bags, and detergent bottles. Backward trajectory analysis suggested that these particles originated mainly from the ocean, and dispersed into the atmosphere by waves splashing into the air.
Moreover, a recent paper in Nature Geoscience highlights the role of particle shape in their atmospheric travel. Contrary to past assumptions of spherical particles, researchers from Cornell University propose that many microplastics may adopt a ribbon-like shape, enabling them to traverse vast distances in the atmosphere. This flat structure allows them to remain airborne considerably longer than spherical particles.
The implications of microplastics in clouds on the climate remain somewhat elusive. However, theories suggest that degraded plastic may provide a surface for water adherence, potentially altering cloud formation and dissipation, thereby affecting temperature and rainfall patterns.
Additional research published in Nature Geoscience speculates on the potential impact of airborne microplastics on climate. These particles, transported to high altitudes, could influence cloud formation by acting as nuclei for droplet or ice crystal formation. This alteration in cloud behaviour plays a crucial role in reflecting sunlight, thereby affecting Earth’s energy balance.
Furthermore, the degradation of floating plastic particles in the upper atmosphere under intense ultraviolet radiation may release greenhouse gases like methane and carbon dioxide, contributing to Earth’s warming. While current microplastic concentrations in clouds might not significantly affect temperature or rainfall, experts caution that addressing this issue is imperative.
