Microplastic pollution may be weakening the oceans’ ability to absorb carbon dioxide (CO₂), threatening a crucial natural system that helps regulate Earth’s climate, according to a new study.
Disrupting the ocean’s carbon pump
Oceans function as one of the planet’s largest carbon sinks through a process known as biological carbon pumping, which transfers carbon from the atmosphere into deep ocean layers. The study found that widespread microplastic contamination is interfering with this mechanism by harming marine organisms essential to the process.
Impact on marine life and climate regulation
“Microplastics interfere with this process by reducing phytoplankton photosynthesis and impairing zooplankton metabolism,” the authors noted. These organisms play a key role in capturing and transferring carbon, and their disruption could weaken the oceans’ capacity to moderate global temperatures.
Findings from a global review
The research, published in the Journal of Hazardous Materials: Plastics, reviewed 89 studies conducted between 2010 and 2025. It analysed peer-reviewed research and reports from international organisations to assess links between microplastic pollution, ocean health and climate change.
Plastic pollution and climate change are interconnected
Highlighting the broader implications, Ihsanullah Obaidullah, associate professor of integrated water processing technologies at the University of Sharjah, said oceans are Earth’s largest carbon sink and microplastics are undermining this natural shield against climate change.
Scale of the plastic problem
The study noted that more than 8.3 billion tonnes of plastic have been produced globally, with nearly 80 per cent ending up in landfills or the environment and only about nine per cent being recycled. Microplastics—plastic fragments smaller than five millimetres—have now been detected from deep oceans to the human body.
Call for integrated action
Researchers stressed that microplastic pollution and climate change cannot be addressed separately. They called for coordinated governance frameworks that tackle plastic pollution alongside climate challenges such as ocean warming and acidification, while recommending reduced single-use plastics and improved waste management to protect ocean health and preserve its carbon-absorbing capacity.
