Snowballing Impact of Spontaneously Degrading Microplastics on Atmospheric Ice Nucleation

Microplastics (MPs), originating from human activities, represent an escalating threat to the global environment and ecosystems. Here, we demonstrate that persistent MPs in the environment profoundly enhance ice nucleation and alter precipitation patterns, which may disrupt air quality, atmospheric chemistry, and climate. Degradation of MPs leads to micronization, nanoporosification, and surface functionalization, significantly boosting their ice-nucleating activity. By integrating global airborne MP data with ice-nucleation assessments, we find that micronization alone can increase cloud-ice-crystal concentrations by up to an order of magnitude. This effect is further amplified when coupled with nanoporosification or surface functionalization with the potential to trigger extreme precipitation events and contribute to climate anomalies. Our research highlights the far more severe consequences of MPs for the future climate than previously imagined, with profound implications for atmospheric science, environmental chemistry, and climate dynamics.