Transboundary impacts of microplastics within planetary boundaries: Regulation and responses of soil-plant systems...

Microplastics pollution and climate change are two critical environmental concerns today, with land serving as the primary source and significant reservoir of microplastics. According to the latest estimates, by 2050,12 billion tons of plastics will be dumped into landfills and natural environments. Microplastics, defined as particles smaller than 5 mm in diameter, pose an even greater threat when they break down into nanoparticles less than 0.1 μm, entering the environment and harming ecosystems. This study explores the interactions between climate change and microplastics pollution within soil-plant systems and their impact on planetary boundary frameworks. The research indicates that climate change exacerbates the fragmentation, migration, and ecological toxicity of microplastics through increased temperatures, altered rainfall patterns, enhanced wind strength, and rising ozone levels. Higher temperatures accelerate plastics degradation, promoting the penetration of microplastics into deeper soils and groundwater; heavy rainfall and strong winds expand the horizontal and vertical spread of microplastics; ozone increases the chemical activity on the surface of microplastics through oxidation, releasing toxic additives. These processes collectively disrupt soil structure, microbial communities, and nutrient cycles, inhibit plant growth, and threaten human health via the food chain. From a planetary boundary perspective, microplastics, as a "new entity," cross the boundaries of chemical pollution and simultaneously threaten the "biological integrity" and "land system change," creating a transboundary synergistic effect.