Study shows how microplastic pollution is impacting plant growth

LOS ANGELES - Microplastics—tiny fragments of plastic pollution—are now so widespread that they have been found everywhere from Antarctic ice to human organs.

While scientists have studied their effects on animals, new research reveals that they may also be harming plants, with serious consequences for food security and climate change.

A study published in the Proceedings of the National Academy of Sciences USA found that microplastics can reduce photosynthesis by up to 12% on average, affecting everything from farmland crops to marine algae. 

Researchers warn that if plastic pollution continues at current levels, it could lead to significant declines in crop yields and seafood production, further exacerbating global hunger and environmental challenges.

How do microplastics impact plant growth?

The backstory:

Microplastics—defined as plastic particles smaller than five millimeters—have become a growing environmental concern. They accumulate in soil, water, and air, exposing plants to contamination at every stage of growth.

The new study found that microplastics interfere with photosynthesis, the process by which plants convert sunlight into energy. Across different environments, the rate of photosynthesis dropped by:

• 6–18% in staple crops such as corn, rice, and wheat.
• 2–12% in marine plants like seaweed.
• 4–14% in freshwater algae, which form the base of aquatic ecosystems.

This means less energy for plant growth, leading to reduced agricultural yields and disruptions in food production.

What are the long-term risks?

Big picture view:

The effects of microplastics on plant life could have far-reaching consequences beyond agriculture. If staple crops like corn, rice, and wheat continue to decline, farmers may face 4 to 13.5% yield losses annually over the next 25 years, increasing food insecurity worldwide.

FILE - Plastic waste scattered along a beach, highlighting the growing impact of pollution on coastal ecosystems and plant life. (Photo by: Andy Soloman/UCG/Universal Images Group via Getty Images)

Additionally, because photosynthesis removes carbon dioxide from the atmosphere, a widespread decline in plant health could hamper efforts to slow climate change. Many climate models assume that forests, grasslands, and kelp beds will absorb carbon at a steady rate—but if plant growth is impaired by microplastics, this natural carbon capture could weaken.

What can be done to reduce plastic pollution?

What's next:

The study’s authors estimate that reducing plastic waste by just 13% could mitigate 30% of the photosynthesis loss caused by microplastics. However, international efforts to regulate plastic pollution remain stalled.

The United Nations has been negotiating a global treaty on plastics since 2017, but the most recent talks in Busan, South Korea, ended without a resolution. Scientists warn that without decisive action, plastic waste will continue to degrade into microplastics, increasing ecological damage over the next 70 to 100 years.