Tire wear particles (TWPs), an emerging anthropogenic micro- and nanoplastic aerosol, are carbon-containing and light-absorbing. Yet the radiative forcing of TWPs has been difficult to assess due to the lack of optical property data. Here, our calculations based on valence electron energy loss spectroscopy (VEELS) and Mie theory reveal that airborne TWPs exhibit pronounced spectral dependence, with enhanced absorption in the visible and predominantly scattering behavior in the infrared band. At the wavelength of 550 nm, their complex refractive index N of ~ 1.35 − 0.28i indicates substantial light absorption (absorption coefficient k ≈ 0.28), lying between the k of strongly (e.g., black carbon BC, soot) and weakly (e.g., brown carbon BrC) absorbing aerosols. Global simulations further show collocated but opposite-signed radiative forcing at the surface and the top of the atmosphere (surface cooling and TOA heating). The strongest forcing arises from the Northern Hemisphere mid-latitudes, particularly east-central North America, west-central Europe, and East Asia. Clouds further amplify the TOA response, yielding a global annual mean direct radiative forcing (DRF) of 0.0847 W m− 2, broadly comparable to that of BrC and ~ 1/4 of that of BC. Together, these results identify TWPs as a previously underappreciated absorbing aerosol class. They have non-negligible impacts on global warming, especially given their substantial radiative efficiency and increasing atmospheric abundance.