Wetlands, which play a crucial role in climate regulation by storing carbon, face a new threat from plastic pollution that could transform them from carbon sinks into significant emission sources. Research published in Frontiers of Environmental Science & Engineering demonstrates that nanoplastics—plastic particles smaller than 100 nanometers—substantially intensify emissions of two powerful greenhouse gases, methane and nitrous oxide, in plant–soil systems.
The study, conducted by researchers from Tsinghua University and collaborating institutions, reveals that nanoplastics interfere with plant growth, photosynthesis, and root function, reshaping the chemical and biological conditions of wetland soils. These changes stimulate microbial processes that favor greenhouse gas production, creating an overlooked pathway through which plastic pollution may accelerate climate change. The full findings are available in the journal article published online on August 10, 2025, accessible via DOI: 10.1007/s11783-025-2066-8.
Using simulated wetlands planted with reeds, researchers introduced increasing concentrations of polystyrene nanoplastics to the soil and monitored greenhouse gas emissions over time. They found that nanoplastics increased methane emissions by 20% to nearly 100%, while nitrous oxide emissions approximately doubled under higher concentrations. These effects became more pronounced as plants matured and environmental temperatures rose.
Mechanistic analyses revealed that nanoplastics inhibited plant growth, reduced chlorophyll content, and weakened antioxidant defenses, impairing photosynthesis and stress resistance. Crucially, nanoplastics reduced oxygen release from plant roots, creating more anaerobic conditions in the rhizosphere that favored methane-producing microorganisms and enhanced denitrification processes responsible for nitrous oxide formation.
Metagenomic analyses showed increased abundance of genes involved in acetoclastic methanogenesis and denitrification pathways, particularly in rhizosphere soils. Simultaneously, nanoplastics altered root exudate composition, sharply increasing the release of L-phenylalanine—a compound that can be converted into substrates fueling methane production. Although some methane-oxidizing and nitrous oxide–consuming microbes also increased, their activity was insufficient to offset the elevated greenhouse gas generation.
The findings suggest that plastic pollution may contribute to climate change in ways not currently accounted for in greenhouse gas models. Wetlands are widely recognized as nature-based solutions for carbon sequestration, yet nanoplastic contamination could undermine their climate-mitigation potential. Incorporating nanoplastics into environmental risk assessments and greenhouse gas inventories may therefore be essential for accurate climate modeling and policy development.
More broadly, the study underscores the urgency of controlling plastic pollution at its source, as continued accumulation of nanoplastics could amplify greenhouse gas emissions across sensitive ecosystems worldwide. For business and technology leaders, this research highlights emerging environmental risks that could affect corporate sustainability strategies, regulatory compliance, and investment in plastic alternatives. The intersection of plastic pollution and climate change represents a critical area for innovation in materials science, waste management technologies, and environmental monitoring systems.
