Microplastics affect cloud-formation and could be altering weather patterns, according to new research.
Scientists showed that microplastics can have the same effects on cloud-formation as dust particles, which help water droplets form ice crystals in the atmosphere at warmer temperatures. Microplastics can allow ice crystals to form at temperatures between 5 and 10 degrees Celsius warmer than warmer droplets without them.
The scientists tested a variety of different types of microplastic particle, suspending them in water and then cooling the droplets to observe when they froze. They also looked at the molecular structure of the microplastics to observe how it affected ice formation.
As one of the study authors explains, “For most of the plastics we studied, 50 percent of the droplets were frozen by the time they cooled to minus 8° F (minus 22° C). These results parallel those from another recent study by Canadian scientists, who also found that some types of microplastics nucleate ice at warmer temperatures than droplets without microplastics.”
At this stage, the consequences of the discovery aren’t clear, since the experiments took place in a lab, but it’s possible that growing microplastic pollution, if it does affect cloud-formation on a large scale, could have significant effects on weather patterns.
Clouds affect the weather and climate in a variety of ways. Clouds reflect incoming sunlight from the earth’s surface, which has a cooling effect, and they also absorb radiation from the earth’s surface, which has a warming effect.
The amount of sunlight a cloud reflects depends on the concentration of ice within it. If there are more microplastics present in clouds, and therefore more ice, more sunlight could be reflected, altering the earth’s energy balance.
The presence of microplastics could also increase rain and snowfall.
More than nine billion tons of plastic are estimated to have been produced between 1950 and 2017, with over half of that total having been produced since 2004. The vast majority of plastic ends up in the environment in one form or another, where it breaks down, through weathering, exposure to UV light and organisms of all kinds, into smaller and smaller pieces—microplastics and then nanoplastics.
Microplastics produced in this way are called “secondary” microplastics, because they start off big and end up small, but there’s a whole class of “primary” microplastics which are small by design, like so-called “microbeads” used in cosmetics.
Within our homes, microplastics are mainly produced when synthetic fibres from clothes, furnishings and carpets are shed. They accumulate in large quantities in dust and float around in the air, which we then inhale.
Microplastics are being linked to a wide variety of environmental and health problems, including serious reproductive issues in animals and humans.
Microplastics were recently discovered in brain tissue, in a study that suggested concentrations in the brain may have increased by as much as 50% in the last eight years.
The researchers behind the new study now want to focus on measuring concentrations of microplastics at the altitude where clouds form, and concentrations of other substances that affect cloud-formation, so they can start to model the effects of microplastics on clouds and weather in detail.
If you’re interested in learning more about microplastics and how to protect yourself and your family from them, read our exclusive primer on the subject.