The pollution of the planet by microplastics is significantly cutting food supplies by damaging the ability of plants to photosynthesise, according to a new assessment.
The analysis estimates that between 4% and 14% of the world’s staple crops of wheat, rice and maize is being lost due to the pervasive particles. It could get even worse, the scientists said, as more microplastics pour into the environment.
About 700 million people were affected by hunger in 2022. The researchers estimated that microplastic pollution could increase the number at risk of starvation by another 400 million in the next two decades, calling that an “alarming scenario” for global food security.
Other scientists called the research useful and timely but cautioned that this first attempt to quantify the impact of microplastics on food production would need to be confirmed and refined by further data-gathering and research.
The annual crop losses caused by microplastics could be of a similar scale to those caused by the climate crisis in recent decades, the researchers behind the new research said. The world is already facing a challenge to produce sufficient food sustainably, with the global population expected to rise to 10 billion by around 2058.
Microplastics are broken down from the vast quantities of waste dumped into the environment. They hinder plants from harnessing sunlight to grow in multiple ways, from damaging soils to carrying toxic chemicals. The particles have infiltrated the entire planet, from the summit of Mount Everest to the deepest oceans.
“Humanity has been striving to increase food production to feed an ever-growing population [but] these ongoing efforts are now being jeopardised by plastic pollution,” said the researchers, led by Prof Huan Zhong, at Nanjing University in China. “The findings underscore the urgency [of cutting pollution] to safeguard global food supplies in the face of the growing plastic crisis.”
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The new study, published in the journal Proceedings of the National Academy of Sciences, combined more than 3,000 observations of the impact of microplastics on plants, taken from 157 studies.
Previous research has indicated that microplastics can damage plants in multiple ways. The polluting particles can block sunlight reaching leaves and damage the soils on which the plants depend. When taken up by plants, microplastics can block nutrient and water channels, induce unstable molecules that harm cells and release toxic chemicals, which can reduce the level of the photosynthetic pigment chlorophyll.
The researchers estimated that microplastics reduced the photosynthesis of terrestrial plants by about 12% and by about 7% in marine algae, which are at the base of the ocean food web. They then extrapolated this data to calculate the reduction in the growth of wheat, rice and maize and in the production of fish and seafood.
Asia was hardest hit by estimated crop losses, with reductions in all three of between 54m and 177m tonnes a year, about half the global losses. Wheat in Europe was also hit hard as was maize in the United States. Other regions, such as South America and Africa, grow less of these crops but have much less data on microplastic contamination.
In the oceans, where microplastics can coat algae, the loss of fish and seafood was estimated at between 1m and 24m tonnes a year, about 7% of the total and enough protein to feed tens of millions of people.