Take it from us, weather forecasting can be a tricky business. Even after rummaging through all the analyses available to derive our inferences daily, there’s always a chance that things will still go differently than predicted.

And now, even though we’re still getting used to the indecisive whims of meteorological phenomena, weather forecasters have started adding another factor to their daily forecasts: plastic rain.

In 2022, a study made quite the news splash after it confirmed that a colossal amount of microplastics were sprinkling down on New Zealand and the US. We’ve already been aware that these plastic contaminants can make their way inside our bodies, potentially leading to cancer risk and other health and reproductive problems.

While we don’t know for certain if someone modified the rain dance to somehow add plastic, there is no doubt that this dangerous phenomenon is prevalent worldwide now. And thus, Paris has begun taking steps to tackle the potential risks associated with it.

The French capital will experience billions of microplastic rain during the five-day plastic treaty international discussion on Monday (May 29), their first-ever plastic pollution weather forecast predicts.

According to the report, the city will experience about 40-48 kilograms of free-floating plastic bits daily. Scientists warn that this number could skyrocket — even tenfold! — if the rain becomes heavy.

Most of these microplastics have originated from nylon and polyester, the researchers reckon. Clothing and tyre bits are the most likely suspects. On an especially windy day, these can make their way inside our bodies through inhalation or ingestion.

“In our bodies, the plastics we need to be most worried about are probably those between 10 nanometers and 1 micrometre,” notes Christos Symeonides, a researcher at Murdoch Children’s Research Hospital. “They’re the ones most likely to get through our biological membranes into tissues, including the blood-brain barrier,” he told AFP.

For reference, human hair is only about 80 microns across, meaning most microplastics of concern are stuff we won’t even be able to spot, hiding in plain sight.

Furthermore, the plastic forecast only covers plastics significantly outside this danger range — over 50 microns in length. The microplastics that were detected in human blood were around 700 nanometres, or 0.7 micrometres, in length.

While such forecasting practices are a great initial step, we clearly need to cover many such research gaps. Additionally, the report has been developed based on a 2015 research on Paris from samples collected from multiple locations year-round, meaning we probably won’t be looking at this section to grace our weather sections daily.

“This should sharpen the focus of negotiators,” said Marcus Gover, head of plastics research at the Minderoo Foundation. “Plastic particles break down into the environment, and this toxic cocktail ends up in our bodies, where it does unimaginable damage to our health.”

“We’re just now pulling our heads out of the sand when it comes to the health hazards of microplastics,” Symeonides laments.