Making A Difference
Steve Davis is a very busy man. As an associate professor of Earth System Science, he naturally has a number of environmental interests. But Steve has become an expert in a number of fields and therefore regularly quoted in worldwide news and magazine articles. And he is a popular guest on such programs as All Things Considered (NPR), Good Morning America (ABC), and The Daily Show (Comedy Central).
His research focuses on understanding the complex interactions of human and natural systems in order to assess the causes and magnitude of current and future environmental damages and disruptions, and to identify possible solutions. Satisfying global demand for energy, food, and goods without emitting CO2 to the atmosphere is a central challenge of the 21st century. His work is aimed at recognizing the scale of that challenge and finding ways to meet it.
A wide variety of topics keep his research team occupied, including food and water systems, human health, impacts of international trade and its effects on the environment, global water use, and energy systems. More information is available on his group web site.
For example, his team has found that the U.S. could supply 80% of its energy with wind and solar, but their article in Science offered a stark reminder that there are still huge parts of the global energy system where we simply don’t have affordable ways of halting greenhouse-gas emissions. Air travel, long-distance transportation and shipping, steel and cement manufacturing, and remaining parts of the power sector account for 27 percent of global emissions from the energy and industrial sectors. Steve says say we need much more research, innovation, and strategic coordination to clean up these sources.
Along the way, Steve has also sparked global attention by publishing articles about how heat and drought could threaten the world’s beer supply, on how airborne particles cause more than three million early deaths a year, and on the economic impacts of COVID-19 lockdowns.
A recent paper in the journal Nature Food has stirred interest within the world of agriculture. Steve’s research team and their collaborators have found that air quality regulations that limit ozone have a significant benefit to farmers. Higher levels of ozone in the air substantially reduce farm harvests, so limiting ozone emissions in the transportation and power generation sectors improves crop production of fruits and nuts in California’s Central Valley. This study is an excellent example of how Steve and his team are making a difference for our planet and its health.
Here is the press release for this article:
California's strict air quality regulations help farmers prosper, UCI-led study finds
Despite reductions, pollution in growing regions persists, pointing to mitigation opportunities
Irvine, Calif., March 16, 2020 – Farmers in California's Central Valley are not known for their love of government regulations, but those same growers have seen a boost in the productivity of their high-value crops – and greater earnings – as a result of the Golden State's strict air pollution controls.
For a study published March 16, 2020 in Nature Food, researchers at the University of California, Irvine and other institutions conducted a statistical analysis of pollution exposure and yields from 1980 to 2015 on a key sector making up about 38 percent of the state's total agricultural output: perennial crops such as almonds, grapes, nectarines, peaches, strawberries, and walnuts. They found that reductions in ground ozone during this 35-year period resulted in $600 million in increased production annually by the early 2010s.
"A lot of California farmers may not appreciate that air quality standards have had such a benefit on their ability to grow crops," said co-author Steven Davis, UCI associate professor of Earth system science. "The irony is that by fighting against certain environmental regulations, these folks may be damaging their own earning capacity."
The researchers also projected yield changes up to 2050 under various scenarios, determining that expected declines in ambient ozone will result in a 5 percent boost in wine grapes, an 8 percent climb in nectarines and a 20 percent jump in table grapes. They discovered, however, that yields of other crops, such as almonds, may suffer comparable decreases due to higher temperatures.
Davis noted that earlier studies on the impact of climate warming and ambient ozone on the state's ability to grow food have focused on high-volume staple crops such as wheat, soy and rice. But he and his colleagues chose to concentrate on perennials because of the long-term investment they represent and the fact that California is a major supplier of this type of produce.
"These aren't the things that are providing the global population with its main source of calories. These are the sweet things in life – fruits, nuts and grapes for wine," Davis said. "Also, monetarily, some of these crops are a lot more valuable than wheat or corn."
Another difference is that some grains can be annually modified to withstand greater heat and even higher ozone levels in the air. But almond trees, for example, remain for decades (to recoup the capital investment in them), and once planted, there's no way to make them more tolerant of changing conditions.
The study demonstrated that the effects of warming have not been statistically significant for many perennial crops to date, but ambient ozone – much of which results from emissions from California's energy production and transportation sectors – substantially reduces harvests of strawberries, grapes, peaches and nectarines – by as much as 22 percent in the case of table grapes.
"If you look at a map of the state, you'll see an overlap in areas such as the San Joaquin Valley where many perennial crops are grown and which have high levels of ozone pollution," said lead author Chaopeng Hong, a UCI postdoctoral scholar in Earth system science. "This co-location indicates that there are opportunities to increase the state's crop production with even a localized reduction in the amount of ambient ozone pollution."
Tropospheric ozone is created when nitrogen oxide, emitted primarily through human activities, reacts with volatile organic compounds in sunlight. When ozone enters plants' leaves via their stomates, it burns plant cells via oxidization, impairing photosynthesis and the energy the plants can dedicate to producing fruit.
Davis said that now that he and his fellow climate scientists know more about the relationship between air pollution and agricultural output, California is in a position to serve as a test bed for different climate change mitigation scenarios.
"We can really look at the state's energy and transportation systems and be quantitative about how those things might help or hurt agriculture," he said. "As we transition away from fossil fuels in favor of solar and wind energy and electric vehicles, there will be big changes in ozone pollution. We can simulate those changes and project the effects on California's most valuable crops."
This project – which involved collaborators from Colorado State University, UC San Diego, Northeastern University, UC Davis and The Ohio State University – was funded jointly by the National Science Foundation and the U.S. Department of Agriculture.
