Microplastics have long been everywhere – including in the atmosphere. But there the tiny plastic particles have a hitherto largely ignored climate effect: they absorb radiation and thus contribute to global warming. Worldwide, this heating effect of nano and microplastics is already around 0.039 watts per square meter – this corresponds to around 16 percent of global warming caused by soot particles in the atmosphere, as researchers report in “Nature Climate Change”.
Nano and microplastics are plastic particles with a diameter of less than 500 micrometers or less than one millimeter. These tiny plastic particles create larger plastic waste when they break down, but also when plastic products are used and manufactured. Analyzes show that micro- and nanoplastics can now be detected everywhere in the environment – from oceans and waterways to soil and food to our own bodies. Plastic particles are now also present in the air around the world.
How do floating plastic particles affect the radiation balance?
But the ubiquitous presence of atmospheric nano- and microplastics not only has consequences for the environment, but also for the climate. “These particles are increasingly recognized as causing non-negligible radiative forcing,” explain Yu Liu from Fudan University in Shanghai and his colleagues. Radiative forcing refers to the influence on the earth’s radiation balance and thus the warming or cooling effect of an object or substance. This effect has so far hardly been investigated for microplastics floating in the air.
That’s why Liu and his colleagues have now examined in more detail for the first time how plastic particles of different sizes, colors and ages affect the radiation balance of the atmosphere. To do this, they first analyzed in the laboratory how nano- and microplastics absorb or scatter light of different wavelengths using high-resolution electron spectroscopy.
Microplastics create radiative forcing
The result: “All particles show substantial absorption in the wave range from UV to near-infrared,” reports the team. This radiation absorption is largely independent of the type of plastic. The color of the plastic particles plays an important role: the darker the particles are, the more light they absorb. For example, colored plastic particles absorb around 75 times more green light than colorless ones, as Liu and his colleagues determined. With microplastics, this effect is more evenly distributed across almost the entire light spectrum; the smaller nanoplastics, on the other hand, primarily absorb radiation in the UV range and short-wave visible light.
The plastic particles floating in the atmosphere absorb incident solar radiation and then release this energy into their surroundings as heat. “Given their substantial radiation effects and their atmospheric concentration, nano- and microplastics contribute direct radiative forcing that has so far been overlooked in climate models,” the researchers write. In the next step, they determined how large this climate effect actually is using data on regional microplastic concentrations and a global atmospheric model.
Warming effect even on a global scale
These analyzes confirmed that the nano- and microplastics floating in the air also generate measurable radiation forcing on a global scale – they heat up the atmosphere. “The simulations revealed a global direct radiative forcing for nano- and microplastics of an average of 0.039 watts per square meter,” report Liu and his team. This effect corresponds to around 16.2 percent of the heating effect of soot particles, which are released by forest fires and industrial emissions, among other things. “Such a contribution is substantial, especially when one considers that microplastics and nanoplastics represent a class of air pollutants that have not yet been systematically recorded in climate assessments,” comments researcher Gilberto Binda from the University of Insubria in Lombardy, who was not involved in the study.
In addition, the climate impact of plastic in some regions is significantly higher than the global average. The model showed that nano- and microplastics can even achieve a radiation forcing of 0.282 watts per square meter above the large garbage whirlpools in the oceans. “This exceeds the global average by a factor of 7.31 and contrasts sharply with the normally low radiative forcing over the open ocean,” the team writes.
Dual role in climate change
According to the research team, this proves that nano- and microplastics play a previously underestimated, dual role in the Earth’s climate: On the one hand, plastic production releases considerable amounts of the greenhouse gas CO2, and on the other hand, the plastic particles released into the air also directly heat up the atmosphere. “This dual mechanism positions nano- and microplastics as previously unrecognized amplifiers of anthropogenic climate change,” they write. “Therefore, coordinated action is now needed to address both plastic pollution and the associated emission pathways.”
Source: Yu Liu (Fudan University, Shanghai) et al., Nature Climate Change, 2026; doi: 10.1038/s41558-026-02620-1