Ozone damages East Asian crops and costs $63 billion a year, scientists say

Fossil fuel emissions are not only driving climate change and worsening air quality, but also hurting crop yields to the tune of $63 billion in annual losses in East Asia, scientists say.

With high levels of ozone pollution, China, South Korea and Japan are experiencing declining yields of wheat, rice and corn, according to a study published Monday in the journal Nature Food.

China is losing a third of its potential wheat production and nearly a quarter of rice yields due to ozone disrupting plant growth. That has worrying implications beyond the region, as Asia provides the bulk of the world’s rice supply.

Asia is also a hotspot for ozone, which forms when sunlight interacts with greenhouse gases such as nitrous oxide, carbon monoxide and volatile organic compounds released by burning fossil fuels.

In the stratosphere, an ozone layer protects the planet from ultraviolet radiation. But closer to the Earth’s surface, ozone can harm plants and animals, including humans.

Feng and his colleagues used ozone monitoring data to estimate crop damage at about $63 billion per year. Previous research on the topic has used computer simulations to assess the economic impact of ozone pollution on crops.

Ozone “directly harms food security in China for all three crops,” Feng said.

This is a problem for China, which is already dealing with the declining quality of its land. The country has to feed a fifth of the world’s population with only 7% of its farmland.

As industry, energy and urban sprawl have competed for limited land resources, China lost about 6% of its arable land, or 7.5 million hectares, between 2009 and 2019, according to a state study published in August.

While Beijing has since drawn a “red line” to protect existing farmland, experts still expect the total to drop further by 2030.

While the gases that contribute to ozone pollution are largely emitted from cities, the impact is worse in rural areas where ozone is formed.

Scientists said the best way to reduce ozone levels is to curb the use of fossil fuels, the same action needed to reduce greenhouse gas emissions that cause climate change.

Without tighter emissions controls in Asia, Sharps said, “things are going to get worse.”