Dubai: Microplastics, tiny plastic particles less than 5 millimeter impairing the oceans’ ability to absorb carbon dioxide, which will quietly intensifying another global climate crisis, a new study revealed.
A new scientific review reveals that microplastics (MPs) are not just passive pollutants but active players in Earth’s climate system.
By interfering with oceanic carbon cycles, releasing greenhouse gases, and altering ecosystems from the deep sea to the Arctic, microplastics may be contributing to global warming in ways that have so far received little public attention.
The study, published in the ‘Journal of Hazardous Materials: Plastics’, said microplastics disrupt a process called biological carbon pumping.
Microplastics “interfere with this process by reducing phytoplankton photosynthesis and impairing zooplankton metabolism,” it says. These are two key agents of carbon cycling.
They also emit greenhouse gases when degrading and interfere with the “plastisphere,” which it described as “an assembly of microbes in aquatic settings that form biofilms on surfaces.”
The plastisphere, it says, “is home to a variety of microorganisms, the majority of which are involved in biological processes like the nitrogen and carbon cycles.”
Dr Ihsanullah Obaidullah, an Associate Professor of Integrated Water Processing Technologies at the University of Sharjah and the study’s corresponding author, was quoted by the university’s website as saying microplastics are widely known as pollutants but their impact on climate change has received limited attention to date.
“Our study shows they also interfere with the oceans’ ability to absorb carbon dioxide, a process critical for regulating Earth’s temperature,” he said.
“Microplastics disrupt marine life, weaken the biological carbon pump, and even release greenhouse gases as they degrade. Over time, these changes could lead to ocean warming, acidification, and biodiversity loss, threatening food security and coastal communities worldwide.”
Dr Obaidullah said the study was a collaborative work involving scientists from China, Hong Kong, Pakistan and the United Arab Emirates.
A diagram of oceans’ carbon sink function (from the study; ‘MP’ is for microplastics)
Oceans play a crucial role in regulating the planet’s climate by absorbing vast amounts of carbon dioxide (CO₂) from the atmosphere. Central to this process is the biological carbon pump, driven by microscopic organisms such as phytoplankton and zooplankton. Phytoplankton absorb CO₂ through photosynthesis, and when they die, carbon-rich material sinks to the ocean floor, locking carbon away for centuries.
The review finds that microplastics interfere with this system at multiple levels. Phytoplankton exposed to MPs can experience reduced growth and photosynthetic efficiency, while zooplankton may ingest plastic particles instead of nutritious food. Weathered microplastics can also slow the sinking of “marine snow” organic particles that transport carbon to the deep ocean, reducing the ocean’s capacity to store carbon.
The Plastisphere: A Hidden Source of Greenhouse Gases:-
Microplastics quickly become coated with microbial communities known as the plastisphere. These microbes are not harmless hitchhikers. According to the study, they can actively produce climate-relevant gases such as carbon dioxide, methane, and ethylene as plastics degrade under sunlight and biological activity.
This process not only adds greenhouse gases to the atmosphere but also contributes to ocean acidification, as CO₂ dissolves into seawater. Acidification disrupts marine ecosystems and further alters microbial communities, creating feedback loops that may worsen climate impacts.
The influence of microplastics is not limited to the oceans. Atmospheric MPs may act as cloud condensation nuclei, potentially altering cloud formation and rainfall patterns. On land, plastic residues from agriculture, where over 12 million tonnes of plastic were used globally in 2019—accumulate in soils, affecting water retention, soil structure, and crop productivity, especially during extreme weather events.
In polar regions, microplastics trapped in snow, sea ice, and glaciers reduce surface reflectivity (albedo), causing more sunlight to be absorbed. This accelerates ice melt and warming in already vulnerable Arctic ecosystems. As permafrost thaws, stored MPs may be released into soils and waterways, further disrupting carbon and nutrient cycles.
A Threat to Sustainable Development and Human Rights:-
The study frames microplastic pollution not only as an environmental issue but also as a barrier to achieving the United Nations Sustainable Development Goals (SDGs).
Microplastics threaten food security, clean water, public health, climate action, and ecosystem protection. They may also undermine human rights, particularly the right to a healthy environment, by disproportionately affecting vulnerable communities reliant on marine and agricultural ecosystems.
Researchers emphasize that plastic pollution and climate change cannot be tackled separately. Plastics generate greenhouse gases throughout their life cycle from production and recycling to degradation in nature while climate change accelerates plastic breakdown and spread.
The review calls for holistic, integrated strategies that address plastic production, waste management, climate mitigation, and ecosystem protection together. Without coordinated action, microplastics may continue to amplify climate change while simultaneously weakening the planet’s natural defenses against it.
As the study makes clear, when it comes to microplastics, small does not mean insignificant. Their climate footprint may be far larger than previously imagined.
