Microplastics Could Form Clouds and Severely Affect Weather, Climate

A new study reveals that microplastics, tiny plastic particles less than 5 millimeters in size, may influence cloud formation and potentially affect weather and climate.

Researchers discovered that these microplastic particles can cause ice crystals to form in clouds at temperatures 5 to 10 degrees Celsius (9 to 18 degrees Fahrenheit) warmer than usual.

The finding suggests that microplastics could play a role in cloud formation in areas where clouds would not typically form.

Clouds are made up of water droplets or ice crystals that form when water vapor in the atmosphere sticks to particles such as dust. These particles serve as a surface for the formation of ice crystals, a process known as nucleation.

While clouds usually form around mineral dust or biological particles, like pollen, microplastics can also act as nuclei for ice crystals. This discovery has important implications for understanding how clouds form and how they impact weather, according to The Conversation.

Microplastics in Clouds Could Alter Earth's Climate

The researchers tested four common types of plastics - low-density polyethylene, polypropylene, polyvinyl chloride, and polyethylene terephthalate - by suspending them in water droplets and cooling the droplets to observe when they froze.

They found that microplastics caused 50% of the droplets to freeze at temperatures as low as minus 8°F (minus 22°C), much warmer than the typical freezing point of water. The study also revealed that ultraviolet light, ozone, and acids, which are present in the atmosphere, affected the microplastics' ability to nucleate ice.

Understanding the role of microplastics in cloud formation is crucial because clouds affect Earth's climate in various ways. Clouds reflect sunlight away from the Earth's surface, cooling the planet, while also absorbing radiation, which can lead to warming. If microplastics cause clouds to form more ice particles than liquid droplets, this could change how clouds interact with Earth's energy balance.