Science Snippets: Microplastics Changing Earth's Climate

Draft script:

Microplastics exert tremendous influence over the living planet. I can hardly read a headline at a corporate media outlet without learning more about the enormous influence of microplastics. They’re in our water. They’re in our food. They’re in our blood. They contaminate beaches throughout the world.

From SciTechDaily comes a headline indicating the power of microplastics: Startling New Research Reveals That Microplastics Could Be Changing Earth’s Climate. The article was published on 11 November 2024.

Here’s the lede, followed by another sentence that completes the first paragraph: “Microplastics in the atmosphere may be altering weather and climate by facilitating ice formation in clouds. Penn State research suggests these particles could impact precipitation and climate patterns, though their full effects remain unknown.”

Of course, “their full effects remain unknown.” As Professor and Science Educator Carl Sagan pointed out long ago, “Science is a way of thinking much more than it is a body of knowledge.” We will never know all there is to know about Earth, much less the universe we inhabit. Science is a means of accumulating reliable knowledge through observation and testing. However, complete knowledge is beyond us, as indicated in the next paragraph of the article at SciTechDaily: “Scientists have discovered microplastics—tiny plastic particles less than 5 millimeters in size—in some of the planet’s most untouched places, from the depths of the Mariana Trench to the snow-capped peak of Mt. Everest, and even in clouds over mountains in China and Japan. Microplastics have also been found in human brain tissue, inside sea turtles, and even within plant roots. Now, new research led by Penn State scientists suggests that these airborne microplastics could be influencing weather patterns and impacting the climate.

The study, published in the journal Environmental Science and Technology: Air, demonstrated that microplastics act as ice nucleating particles. These are microscopic aerosols that facilitate the formation of ice crystals in clouds.

This means that microplastics could impact precipitation patterns, weather forecasting, climate modeling and even aviation safety by influencing how atmospheric ice crystals form clouds, explained Miriam Freedman, professor of chemistry at Penn State and senior author on the paper.”

The senior author on the paper is quoted in the article at SciTechDaily: “Throughout the past two decades of research into microplastics, scientists have been finding that they’re everywhere, so this is another piece of that puzzle. It’s now clear that we need to have a better understanding of how they’re interacting with our climate system, because we’ve been able to show that the process of cloud formation can be triggered by microplastics.”

In other words, the formation of clouds can be triggered by microplastics. As with other particles in the atmosphere, microplastics serve as a focus of nucleation. As explained by the senior author on the peer-reviewed paper, “When air patterns are such that a droplet gets lifted into the atmosphere and cools, that’s when microplastics could be affecting weather patterns and forming ice in clouds. In a polluted environment with many more aerosol particles, like microplastics, you are distributing the available water among many more aerosol particles, forming smaller droplets around each of those particles. When you have more droplets, you get less rain, but because droplets only rain once they get large enough, you collect more total water in the cloud before the droplets are large enough to fall and, as a result, you get heavier rainfall when it comes.”

The peer-reviewed paper was written by four scholars and published in Environmental Science and Technology: Air. Published on 7 November 2024, the article is titled Pristine and Aged Microplastics Can Nucleate Ice through Immersion Freezing.

The peer-reviewed article is not open-access. However, the Abstract provides a good overview of the article: “Microplastics are ubiquitous in the environment; their atmospheric relevance is being increasingly recognized. Because of their atmospheric concentrations, there is the question of whether microplastics can act as ice nucleating particles in the atmosphere. This study investigates the immersion freezing activity of lab-prepared microplastics of four different compositions—low density polyethylene, polypropylene, poly(vinyl chloride), and poly(ethylene terephthalate)—using droplet freezing assays. The microplastics are also exposed to ultraviolet light, ozone, sulfuric acid, and ammonium sulfate to mimic environmental aging of the plastics to elucidate the role that these processes play in the ice nucleating activity of microplastics. Results show that all studied microplastics act as immersion nuclei, and aging processes can modify this ice nucleating activity, leading, primarily, to decreases in ice nucleating activity for low density polyethylene, polypropylene, and poly(ethylene terephthalate). The ice nucleating activity of poly(vinyl chloride) generally increased following aging, which we attribute to a cleaning of chemical defects present on the surface of the stock material. Chemical changes were monitored with infrared spectroscopy …, and the growth of a peak at 1650–1800 cm^–1 was associated with a decrease in ice nucleating activity while loss of an existing peak in that region was associated with an increase in ice nucleating activity. The studied microplastics have ice nucleating activities sufficient to be a non-negligible source of ice nucleating particles in the atmosphere if present in sufficiently high concentrations.”

The first sentence of the Abstract provides a terrifying summary of the contemporary situation: “Microplastics are ubiquitous in the environment; their atmospheric relevance is being increasingly recognized.” I’d go a step further in pointing out that the relevance of microplastics is being increasingly recognized well beyond the atmosphere. They’re in our water. They’re in our food. They’re in our blood. They contaminate beaches throughout the world. They are ubiquitous, and not in a good way.

If we had a scoop of ice cream for every scoop of microplastic on Earth, then that would be a good way. However, the ubiquitous nature of toxic microplastics in the environment we inhabit is not a good way.

It seems humans are intent upon self-annihilation as quickly as possible. As I have pointed out in this space, the rate of environmental change in our wake insures we take all life on Earth with us when we depart. I’m not a fan.