Researchers at Fudan University found that colored microplastics contribute to global warming at a level equivalent to 16.2% of the warming caused by black carbon.
Study co-author Hongbo Fu said the study revealed a “long-overlooked link” between microplastics and global warming. Previous studies have suggested that microplastics have minimal impact on climate change, but these studies were conducted on transparent plastics, even though most plastics are colored with pigments.
“Our study suggests that climate models need to be updated,” Hu said. “The Intergovernmental Panel on Climate Change (IPCC) should take note.”
Microplastics exist in every environment
Microplastics come from a variety of sources, including textiles and tire wear, and are prevalent on land, sea, and air. Twenty times more microplastic particles are released into the atmosphere from land than from the ocean.
Although the actual number of microplastics on Earth is more difficult to calculate, they are found in almost every region, especially in urban environments.
Up to 1,300 microplastic particles per square meter per day have been recorded in urban areas, and another study found that 94% of airborne microplastics were less than 10 micrometers, large enough to reach the deepest parts of the lungs.
Mimic real-world plastic aging to more accurately measure environmental impact
This study measured the optical properties of a variety of plastics of different sizes and colors, focusing on how the materials age in the environment. When exposed to UV light, clear, bright plastics turn yellow and dark plastics bleach.
They then simulated these findings on a global scale using atmospheric climate models and found that the warming effects of dark-colored microplastics (which absorb heat) far exceeded the cooling properties of light-colored plastics (which are more likely to reflect heat).
Co-author Drew Schindel of Duke University told USA Today that the study shows that “the net effect of microplastics in the atmosphere on the climate is to cause further warming…Our study shows that these particles absorb about five times as much sunlight as they reflect, making the planet hotter on net, which was not previously apparent.”
This raises concerns that plastics not only act as environmental pollutants, but, as Fu warned, “they may also act as heating agents in the atmosphere.”
The study was published in the journal Nature Climate Change and led by Yu Liu and Hongbo Fu.
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