Microplastics undermine soil health on every continent, infiltrating farm fields via sewage‑sludge fertilizers, tire dust, and weathered litter; once embedded, they change soil texture, clog pore spaces, and disrupt nutrient‑cycling microbes that plants rely on for growth and disease resistance. Recent studies show declines in microbial diversity and enzymatic activity, alongside measurable drops in crop productivity and earthworm fitness where concentrations exceed a few tenths of a percent by weight.

In the oceans, these particles interfere with the planet’s largest natural carbon sink—the biological pump—by shading phytoplankton, inhibiting photosynthesis, and physically adsorbing “marine snow” so that less organic matter sinks to the deep sea. Research published in 2025 warns that plastics also leach labile carbon compounds that bacteria consume while scavenging vital nutrients like nitrogen and phosphorus, a diversion that further weakens the ocean’s capacity to lock away CO₂. Scientists now question whether the ocean can continue sequestering roughly a quarter of human‑generated carbon emissions if plastic pollution keeps rising.

Microplastics exacerbate climate change and pollution on land as well. Wastewater‑treatment plants capture tons of them in sludge, yet when that sludge is stored or spread on fields it fragments further, releasing greenhouse gases such as methane and ethylene during ultraviolet weathering and microbe‑driven degradation. Life‑cycle assessments estimate that current sludge practices emit the equivalent of millions of tons of CO₂ annually while creating a feedback loop of plastic contamination that is costly—sometimes impossible—to remediate.

Because these particles are virtually indestructible and easily wind‑borne, they now blanket alpine snowpacks, Arctic ice, desert soils, and deep‑sea trenches, seeding foreign polymers into ecosystems that evolved without them. Their physical presence alters habitat structure, smothers coral and seagrass, and transports invasive microbes and toxic chemicals across biomes, undermining ecosystem resilience at a planetary scale. Scientists caution that without aggressive reductions in plastic production and better filtration at every stage of the waste stream, microplastics will continue to erode the Earth’s capacity to regulate climate, cycle nutrients, and sustain biodiversity.