A farmer walks past his dried-up wheat cropland at Liuhe village in Tongzhou district in Beijing, China, on Sunday, February 8, 2009. CREDIT: AP PHOTO/COLOR CHINA PHOTO
Right now, in China’s Henan and Inner Mongolia regions, more than 300,000 people are without drinking water. Approximately 1 million hectares of farmland are too dry to work with, and more than 900,000 hectares of crops are unusable.
The reason for this increased lack of food and water is extreme heat and drought — the worst drought in 40 years, according to China’s state news agency Xinhua. Mainstay crops such as soybeans, barley, and rice have been impacted. And it’s not just in China, either.
According to two new studies published in the journals Nature Climate Change and Global Change Biology, rising global temperatures are increasingly harming crop yields in certain areas of the world — a phenomenon that could eventually lead to more famine. Warming combined with worsening air quality from ground level ozone pollution could exacerbate the problem even further, the study in Nature showed.
“Future food production is highly vulnerable to both climate change and air pollution with implications for global food security,” the Nature study, published Sunday by researchers at MIT, reads. “Little is known about how climate and ozone pollution interact to affect agriculture, nor the relative effectiveness of these two strategies for different crops and regions.”
Ground level ozone pollution is the main component of smog, primarily formed by burning fossil fuels. It’s long been known that both higher temperatures and ozone pollution can, on their own, impact food production by damaging crop yields. But until the MIT study, how they work together had not been determined.
One way they work together, as noted by MIT News writer David Chandler, is that warmer temperatures actually cause more ozone pollution to be produced. This is because of the chemical interaction that forms ozone — the combination of volatile organic compounds plus nitrogen oxide under sunlight. That interaction yields more ozone pollution when temperatures are higher, the study showed.
Because of that interaction, the study found that 46% of soybean crop damage — such as the type happening in China — was actually caused by increased pollution, and not by heat as had been previously believed. But that pollution causing damage to the crops can also be exacerbated by heat.
Scientists have found excessively high levels of air pollution in many Chinese cities,which has caused myriad health problems, marred cityscapes, and even gave an 8-year-old girl lung cancer. Much of the pollution has been linked to fossil fuel production, most notably burning coal.
“An important finding … is that controls on air-pollution levels can improve agricultural yields and partially offset adverse impacts of climate change on yields,” Princeton University professor Denise L. Mauzerall told Chandler. “Thus, the increased use of clean energy sources that do not emit either greenhouse gases or conventional air pollutants, such as wind and solar energy, would be doubly beneficial to global food security, as they do not contribute to either climate change or increased surface-ozone concentrations.”
The MIT study also predicted that, even without ozone pollution, climate change is likely to reduce crop yields at least 10% by 2050 from 2000 levels. The authors noted this is especially problematic because food demand is expected to increase substantially by 2050 as the world population increases.
And not all foods will be impacted equally by heat or pollution, the study noted. Effects will vary considerably, as Chandler said — wheat is more sensitive to ozone exposure, while corn is more sensitive to heat.
However, another study published this month in Global Change Biology found that wheat crops, especially in India, are more sensitive to rising temperatures than previously believed. That’s largely because of increased heat at night, the study showed, and warmth during the plant’s reproductive and ripening periods.
“Our findings highlight the vulnerability of India’s wheat production system to temperature rise,” Dr. Jadu Dash at the University of Southampton told Climate News Network. “We are sounding an early warning to the problem, which could have serious implications in the future and so needs further investigation.”
The researchers recommended Indian farmers consider switching to more heat-tolerant wheat varieties — especially because of the hunger problem already impacting the country. Wheat is India’s main crop, but already 60 million children in India are underweight, with 21% of the general population malnourished, according to the International Food Policy Research Institute.
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