Clouds form when water vapor sticks to tiny floating particles, such as dust, and turns into liquid water droplets or ice crystals. In a newly published study, scientists show that microplastic particles can have the same effects, producing ice crystals at temperatures 5 to 10 degrees Celsius (9 to 18 degrees Fahrenheit) warmer than droplets without microplastics.
- This suggests that microplastics in the air may affect weather and climate by producing clouds in conditions where they would not form otherwise.
Key facts
- Clouds in the atmosphere can be made up of liquid water droplets, ice particles or a mixture of the two.
- In clouds in the mid- to upper atmosphere where temperatures are between 32 and minus 36 F (0 to minus 38 C), ice crystals normally form around mineral dust particles from dry soils or biological particles, such as pollen or bacteria.
- Microplastics are less than 5 millimeters wide – about the size of a pencil eraser. Some are microscopic. Scientists have found them in Antarctic deep seas, the summit of Mount Everest and fresh Antarctic snow.
- Because these fragments are so small, they can be easily transported in the air.
- Clouds also affect weather and climate in several ways. They reflect incoming sunlight away from Earth’s surface, which has a cooling effect. Clouds also absorb some radiation that is emitted from Earth’s surface, which has a warming effect.
- The amount of sunlight reflected depends on how much liquid water vs. ice a cloud contains. If microplastics increase the presence of ice particles in clouds compared with liquid water droplets, this shifting ratio could change clouds’ effect on Earth’s energy balance.
(Source: The Conversation)
