The accelerating spread of microplastics in marine environments is raising serious concerns among climate scientists, as new research suggests these particles may be undermining the ocean’s capacity to regulate the Earth’s temperature. The findings, led by researchers from the United Arab Emirates, indicate that plastic pollution could weaken one of the planet’s most important natural buffers against climate change.
According to the United Nations, the ocean produces around 50 per cent of the oxygen required for life on Earth, absorbs approximately 30 per cent of global carbon dioxide emissions and captures more than 90 per cent of the excess heat generated by human activity. This makes it the world’s largest carbon sink and a critical stabilising force in the global climate system.
However, scientists warn that the growing presence of microplastics is beginning to interfere with these essential processes.
A neglected link between plastic pollution and climate stability
A recent scientific review published in Journal of Hazardous Materials: Plastic draws attention to what researchers describe as a long-overlooked connection between microplastic pollution and the ocean’s climate-regulating functions. The study was conducted by a research team from the University of Sharjah, which analysed 89 peer-reviewed studies to critically assess current knowledge on microplastics and ocean health.
The researchers concluded that microplastics not only disrupt marine ecosystems but may also reduce the ocean’s ability to absorb greenhouse gases and excess heat from the atmosphere.
Disruption of marine life and carbon absorption
The review highlights several mechanisms through which microplastics may interfere with the ocean’s natural carbon cycle. One of the most significant is their impact on the biological carbon pump, a process through which carbon dioxide is transferred from the atmosphere to the deep ocean via marine organisms.
Microplastics were found to impair the photosynthetic activity of phytoplankton, microscopic organisms responsible for converting sunlight, water and carbon dioxide into energy while releasing oxygen. The study also identified negative effects on zooplankton metabolism, including species such as krill that play a central role in marine food webs and carbon transfer.
Scientific literature published in journals such as Nature Climate Change and Global Biogeochemical Cycles has previously shown that even small disruptions to plankton communities can have far-reaching consequences for carbon sequestration and ocean temperature regulation.
Potential consequences for climate and biodiversity
Researchers warn that prolonged interference with these biological processes could lead to rising ocean temperatures, increased acidification and accelerating biodiversity loss. Such changes would threaten global food security and the livelihoods of coastal communities worldwide.
The study’s corresponding author, Associate Professor Ihsanullah Obaidullah, cautioned that if the ocean’s capacity to absorb carbon dioxide and heat continues to decline, it could eventually shift from acting as a carbon sink to becoming a net source of emissions. Similar transitions have already been observed in major tropical forest regions in South America, Southeast Asia and Africa.
A critical moment for climate thresholds
The findings emerge at a time when climate scientists project that 2026 may become the fourth recorded year in which global average temperatures reach 1.4°C above pre-industrial levels, edging dangerously close to the 1.5°C limit set by the Paris Agreement.
Experts warn that weakening the ocean’s buffering capacity could accelerate progress towards this threshold, making climate targets significantly harder to achieve.
Calls for an integrated global response
A 2025 United Nations report estimates that annual global plastic production now exceeds 400 million tonnes, with around half designed for single-use. Without intervention, plastic production could triple by 2060. While plastics remain essential for certain sectors, including aviation, electronics and medical devices, researchers stress that unchecked consumption poses serious environmental and public health risks.
The study argues that microplastic pollution and climate change must be addressed together, rather than as separate challenges. An integrated policy approach, the authors suggest, could reduce climate impacts by slowing the production and environmental release of microplastics.
Professor Obaidullah noted that the research team’s next phase will focus on quantifying the direct climate impact of microplastics and developing practical, integrated solutions to mitigate their effects.
As evidence continues to mount, scientists emphasise that reducing plastic pollution may be not only an environmental priority but also a crucial component of global climate protection strategies.