Ozone harms East Asian crops, costing $63 billion a year, scientists say
By Gloria Dickie
(Reuters) – Fossil fuel emissions are not only driving climate change and deteriorating air quality, they are also damaging crop yields enough to cause some $63 billion in annual losses in East Asia, according to scientists.
With high levels of ozone pollution, China, South Korea and Japan are seeing declining wheat, rice and corn yields, according to a study published Monday in the journal Nature Food.
China alone loses a third of its potential wheat production and nearly a quarter of rice yields because ozone disrupts plant growth. This has worrying implications beyond the region, with Asia providing the majority of the world’s rice supply.
“East Asia is one of the biggest breadbaskets and rice bowls in the world,” said lead author Zhaozhong Feng, an environmental researcher at the University of Science and Technology. information from Nanjing.
Asia is also a hotspot for ozone, formed when sunlight interacts with greenhouse gases such as nitrous oxide, carbon monoxide and volatile organic compounds that are released by the burning of fossil fuels.
In the stratosphere, an ozone layer protects the planet from ultraviolet rays. 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 that crop damage cost about $63 billion. Previous research on the subject has used computer simulations to assess the economic impact of ozone pollution on crops.
Ozone “directly harms food security in China for all three cultures,” Feng said.
This is a concern for China, which is already worried about the degradation of the quality of its land. The country has to feed a fifth of the world’s population with only 7% of its agricultural land.
As industry, energy and urban sprawl have competed for scarce land resources, China lost some 6% of its arable land – or 7.5 million hectares – from 2009 to 2019, according to a report. land survey published in August last year. While Beijing has since drawn a “red line” to protect existing farmland, experts still predict the total will drop further by 2030.
“In some parts of the world, ozone pollution is comparable or even worse for crops than the other major stressors of heat, drought and pests,” said Katrina Sharps, space data analyst at the UK Center for Ecology and Hydrology. In a 2018 study, she and other researchers estimated that global wheat yield losses due to ozone pollution amounted to $24.2 billion per year between 2010 and 2012.
“It’s an under-recognized problem,” Sharps said.
Ozone levels have declined in America and Europe over the past two decades, with the introduction of stricter air quality measures. But the pollutant is increasing in Asia.
While the gases that contribute to ozone pollution are largely emitted by cities, the impact is worse in rural areas where ozone forms.
Scientists have said the best way to reduce ozone levels is to limit the use of fossil fuels – the same action needed to reduce the greenhouse gas emissions that cause climate change.
Without tighter emission controls in Asia, Sharps said, “things are going to get worse.”
(Reporting by Gloria Dickie; Additional reporting by David Stanway; Editing by Katy Daigle and Toby Chopra)