Colored microplastics could be making global warming worse
Microplastics and nanoplastics (MNPs) generally come from the slow decomposition of large plastic products and synthetic fibers and range in size from billionths of a meter (nanoplastics) to up to a few millimeters (microplastics) in diameter. They have been found in every part of the planet, including drinking water, the guts of marine animals, and in Antarctic snow.
[...]
Previous studies into microplastics in the atmosphere underestimated their impact on the climate because they often ignored the effect that different colored particles might have on heat absorption. The color of an object affects how much sunlight it absorbs or reflects, which in turn influences how it traps or radiates heat into the atmosphere.
[...]
Scientists from China and the U.S. measured the optical properties of a range of individual colored plastics and found that colored microplastics and nanoplastics absorb much more sunlight than previously estimated. While white particles mostly scatter light, darker shades like blue, red, and black can absorb up to 74.8 times more sunlight than uncolored plastic. The problem with this is that the particles then convert that energy into heat in the air around them.
[...]
The study revealed that the global average warming effect (direct radiative forcing, or DRF) from these particles is 0.039 watts per square meter. "Colored MNPs intensify DRF by 15.3-fold compared with non-pigmented particles," write the paper's authors. In some parts of the world, such as the North Pacific Subtropical Gyre circulation, their warming effect was found to be nearly five times that of local soot.