“Air is a much more dynamic medium than water,” says co-author Dr Melanie Bergmann from the AWI. “As a result, micro- and nanoplastic can much more quickly penetrate those regions of our planet that are most remote and still largely untouched.” Once there, the particles could affect the surface climate and the health of local ecosystems. For example, when these darker particles are deposited on snow and ice, they affect the ice-albedo feedback, reducing their ability to reflect sunlight and promoting melting. Similarly, darker patches of seawater absorb more solar energy, further warming the ocean. And in the atmosphere, microplastic particles can serve as condensation nuclei for water vapour, producing effects on cloud formation and, in the long term, the climate.
How do plastic particles get into the atmosphere?
First of all, through human activities. Particles produced by tyres and brakes in road traffic, or by the exhaust gases from industrial processes, rise into the atmosphere, where they are transported by winds. However, according to the overview study, there is also evidence suggesting that a substantial number of these particles are transported by the marine environment. Initial analyses indicate that microplastic from the coastal zone also finds its way into the ocean through eroded beach sand. The combination of sea spray, wind and waves forms air bubbles in the water containing microplastic. When the bubbles burst, the particles find their way into the atmosphere. As such, transport to remote and even polar regions could be due to the combination of atmospheric and marine transport.