Cutting Air Pollution Could Help Us Feed The World More Easily

Planting additional crops isn't the sole option for feeding an expanding population. According to recent study, reducing air pollution might help increase food yield while saving land and money.

Winter crops may yield 28 percent more in China and up to 10% more in other regions of the world if the world cut emissions of just one type of air pollution in half.

The pollutants in concern are nitrogen oxides, a group of invisible, deadly gases created by automobile exhaust and industrial emissions, including nitrogen dioxide.

Nitrogen oxide emissions are among the most widely dispersed air pollutants on the planet, and it's thought that if plants are exposed to increased amounts of these gasses, their leaves would be harmed and their development slowed, but specialists aren't sure how.

Nitrogen oxides are also precursors to the development of ozone and small particles in the atmosphere, which can affect agricultural yield by dimming sunlight.

Reduced ozone, particulate matter, nitrogen dioxide, and sulfur dioxide prompted a 20 percent boost in corn and soybean yields in the United States between 1999 and 2019, according to research published last year by some of the same scientists.

By decreasing only four types of air pollutants, almost $5 billion worth of crops may be saved each year.

Nitrogen dioxide is one of the more straightforward contaminants to detect at a regional level and compare to crop growth. Nitrogen dioxide reacts with ultraviolet light in such a manner that satellites can detect it when it is released into the atmosphere.

"Nitrogen oxides are invisible to humans, but new satellites have been able to map them with incredibly high precision," says Stanford University agricultural ecologist David Lobell.

"Since we can also measure crop production from space, this opened up the chance to rapidly improve our knowledge of how these gasses affect agriculture in different regions." 

The researchers discovered a consistent negative relationship between nitrogen dioxide emissions and agricultural greenness in many parts of the world.

Greenery loss was particularly visible in China, as well as for winter crops such as wheat. Using this relationship, researchers predict that decreasing nitrogen dioxide emissions by half would boost winter crop yields in China by about 28%. Yields might increase by 16 percent in the summer.

In India, experts estimate that lowering nitrogen dioxide levels might boost agricultural yields by up to 8% in the winter and 6% in the summer. Meanwhile, yields for summer and winter crops in Western Europe might climb by 10%.

When yield rates change by a percentage point per year, the impact of reducing air pollution in some regions of the world might be enormous. 

"The main take-home from this study is that the agricultural benefits of these actions could be really substantial, enough to help ease the challenge of feeding a growing population," says Jennifer Burney, an environmental scientist at the University of California, San Diego.

Although we don't yet understand how nitrogen oxides affect plant development directly, the significant link discovered in this study shows that air pollution is a factor in crop loss throughout the world.