Atmospheric Microplastics Identified as Net Warming Agents

An international team used electron energy-loss spectroscopy (EELS) to measure optical properties of individual micro- and nanoplastic particles and incorporated the results into global climate models. The models indicate a net warming effect, with average radiative forcing about 16 % of that of atmospheric black carbon (soot).

Microplastics could be making the world warmer

Microplastics have been found in mountains, urban air and protected areas worldwide (e.g., Thompson et al. 2024; Allen et al. 2019; Brahney et al. 2020). Prior work documented long-range transport and inclusion in fine particulate matter (PM2.5), but their radiative impact remained unknown. These findings extend earlier observations of plastic deposition in remote mountain catchments and protected areas.

Nature

• Drew Shindell (Duke University) and Hongbo Fu (Fudan University) highlighted the knowledge gap and led the EELS measurements.

Microplastics could be making the world warmer

• Gilberto Binda, University of Insubria, wrote the News & Views commentary.

Microplastics could be making the world warmer

• An unnamed international consortium supplied the climate-modeling framework.

Nature

• Radiative forcing: microplastic warming ? 16 % of black-carbon warming; dark particles (black, yellow, blue, red) absorb more sunlight than white, and polymer type affects absorption.

Microplastics could be making the world warmer

• Measurements span micro-(µm) to nanoplastic (sub-µm) sizes, adding to aerosol (PM2.5).

Microplastics could be making the world warmer

Drew Shindell noted that the analysis shows almost all airborne microplastic particles produce a net warming effect. Gilberto Binda warned that increasing plastic production makes understanding atmospheric microplastics increasingly urgent.

Microplastics could be making the world warmerNature

The modeling shows net warming, yet earlier aerosol studies emphasized scattering by other particles (e.g., brown carbon, black carbon). No direct atmospheric concentration measurements of plastics were provided, leaving a gap between optical property data and real-world loading. Scientists also note that the atmospheric load of microplastics remains poorly quantified, limiting confidence in the climate impact estimate.

Microplastics could be making the world warmer

• “Our lab is uniquely equipped to perform such detailed optical measurements,” — Hongbo Fu, aerosol researcher, Fudan University

Microplastics could be making the world warmer

• “The process of calculating optical properties from EELS spectra is a complex challenge, but fortunately, we have successfully solved this problem,” — Hongbo Fu

Microplastics could be making the world warmer

• “these findings suggest that airborne microplastics and nanoplastics are not just an environmental contamination issue, but potentially an emerging climate factor,” — Gilberto Binda, University of Insubria

Microplastics could be making the world warmer

• “In fact, the researchers’ climate simulations showed that, on average, the warming caused by microplastics was about 16% of that from atmospheric black carbon—essentially, soot.” — Research team, as reported in C&EN

Microplastics could be making the world warmer

Future work must quantify atmospheric plastic loads through systematic sampling and remote sensing, integrate size-resolved optical data into Earth system models, and evaluate mitigation pathways as global plastic production rises.

Nature