A new study aims to quantify the social costs of nitrogen fertilizer. San Joaquin Valley residents are likely familiar with nitrates that seep out of agricultural fields and into the water supply. But nitrogen also makes its way into the air and the environment, impacting human health, ecosystems, and the climate. And all those exact costs on society.
Bonnie Keeler is program director of the Natural Capital Project at the University of Minnesota and is lead author on the study. She says, altogether, those costs range wildly from less than a penny per kilogram of nitrogen fertilizer to over $10.
That range, she says, "really comes down to where it’s applied, where it goes, how many people are exposed to the pollution and then how harmful, how severe are those consequences."
The study focuses on agricultural areas in Minnesota. But Keeler says the main finding of the research isn’t the dollar amount, but a mathematical formula.
"And it basically says, if you want to know what the social cost of nitrogen is," she says, "you have to think about where the nitrogen enters the environment, where does it move, what additional forms does it transfer into, who’s exposed, and how’re they affected?"
Keeler says the formula could be used anywhere—including the San Joaquin Valley.