Microplastics hamper crop photosynthesis, threatening global food security, warns study

Microplastics can hinder photosynthesis in staple crops and marine algae by up to 14%, impacting global food security, a team of international researchers has warned. 

The study notes that this reduction causes an annual loss of 109.73–360.87 million metric tons for crop production, including key crops like wheat, maize, and rice, and 1.05–24.33 metric tons for seafood production.

Photosynthesis is the process through which plants convert energy from sunlight into water and CO2 into oxygen and glucose, which helps growth.

Studies from the Wageningen University and Research indicate that a higher rate of photosynthesis causes plants to grow larger and bear flowers more abundantly. In contrast, previous research has established that microplastics can damage plants by blocking sunlight from reaching leaves and worsening soil quality.

Quantifying crops lost to microplastics

The scientists, led by professor Huan Zhong of Nanjing University in China, analyzed an extensive dataset comprising 3,286 records to quantify the reductions caused by microplastics across various ecosystems. The study is published in the Proceedings of the National Academy of Sciences.

The findings suggest that Asia was the worst hit by the estimated crop losses, with reductions accounting for 54 million and 177 million metric tons annually. In Europe, wheat showed a substantial decline as did maize in the US. The paper notes that regions in South America and Africa do not grow these crops at the same scale, but data on microplastic contamination is also missing.

According to the researchers, lowering current environmental microplastic by 13% could mitigate production losses by 14.26 to 46.91 metric tons in crops and 0.14 to 3.16 metric tons in seafood.

The team notes that these findings emphasize the urgency for effective plastic mitigation strategies and provide data for policymakers and researchers to secure global food supplies in the age of plastic pollution.

Microplastics have long plagued the food and beverage industry. According to a 2019 report by the UN’s Food and Agriculture Organization, global agricultural production consumed at least 12.5 million metric tons of plastics annually, accounting for over 3.5% of total plastic production worldwide.

Civil society organizations have repeatedly urged governments to address the issue comprehensively.

“It is urgent to denounce once more the overuse of plastic within the food sector, from the production to the distribution. Its presence is detrimental to the environment, animals, and human health,” says Edie Mukiibi, president of Slow Food, a global movement that works to ensure good, clean, and fair food globally.

“There are alternatives to this massive use of plastic, [some] solutions already adopted and put in place. We urgently call on politicians and lobbies to adopt a wider and wiser vision, put aside personal economic interests, and look at the future of the world — to our future.”