brewbooks/flickr

Fertilizer is fouling the air in California: Study

Due to heavy fertilizer use, California's Central Valley is behind up to 41 percent of the state's emissions of nitrogen oxide—an air pollutant and climate-warming gas

A large proportion of California's nitrogen oxide—which can cause harmful ozone and a variety of health impacts—comes from heavy fertilizer use in the state's Central Valley, according to a new study.


University of California, Davis, researchers reported today that as much as 41 percent of smog-causing nitrogen oxide emissions are coming from the state's Central Valley region, which grows more than half of US vegetables, fruits and nuts.

"The effect of large soil NOx emissions on air quality and human health remain unclear, but the magnitude of the flux alone raises concern about its potential impact, particularly in rural California," the authors wrote in the study published today in Science Advances journal.

Nitrogen oxides, a "family of air-polluting compounds," according to the study, are also pumped into the air via burning fossil fuels and car exhaust.

The pollutants spur ground level ozone, have been linked to asthma, other breathing problems and heart disease, and are a potent greenhouse gas. One pound of nitrous oxide—a common component of nitrogen oxide—has 300 times more climate warming impact than a pound of carbon dioxide, according to the U.S. Environmental Protection Agency.

The scientists collected data from flights over the farming region and analyzed it along with computer models.

They estimated between 25 percent and 41 percent of the state nitrogen oxide emissions come from farm soils that received nitrogen-based fertilizers.


Credit: UC Davis

The fertilizers simulate soil microbes that can convert nitrogen, an essential plant nutrient, to nitrogen oxide.

About half of nitrogen-based fertilizers put on crops are actually absorbed by plants.

The study built upon 2012 research from the university that reported, since 1750, nitrous oxide levels have increased 20 percent, largely due to heavy fertilizer use over the past 50 years.

The authors didn't vilify fertilizers. "We need to increase the food we're making," said lead author Maya Almaraz, a postdoctoral fellow at UC Davis, in a statement. "We need to do it on the land we have. But we need to do it using improved techniques."

Almaraz and colleagues pointed to potential solutions, including slow-release fertilizers that reduce emissions, healthy soil efforts to bolster crops' uptake and retention of nutrients, and precision agriculture, which would mean more discriminate fertilizer application.

"It's critical that new policies focus on incentives to bring the latest nutrient management technologies to farms so that growers can produce food more efficiently, increasing their bottom line and improving rural health," said senior author Ben Houlton, a professor with the UC Davis Department of Land, Air and Water Resources, and director of the John Muir Institute of the Environment, in a statement.

Local impacts of wildfire smoke connected to rise in recent deaths, researchers say

California deaths due to wildfire smoke on the rise, as most of the state was exposed to heavy concentrations of dangerous chemicals during massive wildfires.

Get our Good News newsletter

Get the best positive, solutions-oriented stories we've seen on the intersection of our health and environment, FREE every Tuesday in your inbox. Subscribe here today. Keep the change tomorrow.

www.ctvnews.ca

Some polar bears are getting short-term benefit from thinning ice: study

New research shows that a small subpopulation of polar bears that used to live on thick, multiyear sea ice are getting a short-term benefit from the ice thinning as temperatures warm.
www.theguardian.com

What is carbon capture, usage and storage - and can it trap emissions?

Technology that can keep carbon dioxide emissions from entering the atmosphere and stoking global heating will be essential to tackle the growing climate crisis, experts say. But how does it work, and why will it make a difference in fighting climate breakdown?

MAP: See the toxic sites near you that are threatened by climate change

New Jersey has the most Superfund sites facing climate threats, followed by Florida, California and Pennsylvania.
Photo by Kouji Tsuru on Unsplash

Carney backs call for climate risk to be baked into company financial accounts

United Nations climate envoy Mark Carney on Thursday threw his weight behind a growing push by investors for companies to more accurately reflect climate-related risks in their financial accounts.
www.climatechangenews.com

Trudeau promises green jobs for Canada as his leadership hangs in the balance

Justin Trudeau promised to make climate action a "cornerstone" of Canada's coronavirus recovery plan, but has yet to win the backing he needs in parliament.

www.upi.com

Spots of shade may help butterflies cope with climate change

Butterfly species vary widely in their ability to regulate body temperature, according to a new survey in Britain. The research, published this week in the Journal of Animal Ecology, suggests species that rely on shade to cool down are most vulnerable to climate change.