Greenhouse gases mark the next major frontier in air quality rules for agriculture

(Editor's Note: This is the third article in a three-part series on air quality issues affecting the California almond industry that ran in Western Fruit Grower)

By Gabriele Ludwig

Senior Manager, Global Technical & Regulatory Affairs

Almond Board of California

Sept. 2008

Greenhouse gas emissions will form the basis of significant new air quality regulations in the next few years, affecting every sector of society. Industry is likely to get the brunt of new rules to curb greenhouse gas emissions, and agriculture will be no exception.

Already, the California Air Resources Board in late June released a sweeping plan aimed at reducing greenhouse gas emissions by more than 20 percent within the next decade. The new plan would help the state comply with AB32, a landmark legislation passed in 2006, which obligates the state to reduce greenhouse gases to pre-1990 levels by the year 2020. And experts say a national policy is likely to follow soon.

While transportation and electricity generation account for the vast majority of greenhouse gases, production agriculture is the sixth largest contributor to greenhouse gas emissions in California, largely as emissions of carbon dioxide (CO₂), nitrous oxide (N₂O) and methane (CH₄).

In production agriculture, carbon dioxide is emitted from fossil fuel consumption, burning biomass or tilling the soil (which releases CO₂ as oxygen reacts with organic matter).

Nitrous oxide is 300 times more potent a greenhouse gas than CO₂ and a major source of  greenhouse gas emissions by production agriculture. Much of that comes from nitrogen fertilizer. About 1 to 3 percent of applied nitrogen is converted in soil to nitrous oxide and released into the atmosphere.

Thus, the majority of new greenhouse gas regulations affecting production agriculture will revolve around energy and fertilizer use—in the form of cleaner burning tractors; energy use efficiencies in production and processing; and fertilizer applications.

In addition, retailers are devising “carbon footprint” measures to allow consumer to buy “greener” products.  A “carbon foot print” looks at greenhouse gas emissions from the whole food chain, including farm inputs, outputs, processing, packaging and transportation. Some consumers are also starting to look at “food miles” of the products they eat, on the assumptions that the greater distance the food has travelled the more greenhouse gasses are emitted. The fact is, however, that various means of transport have widely differing CO₂ emissions.

At the same time, agriculture may have a positive role to play in greenhouse gas sequestration. Carbon sequestration is essentially taking carbon dioxide out of the air and putting it somewhere where it does not impact air quality. Perennial crops, such as almonds, utilize CO₂ during photosynthesis and convert that carbon dioxide into carbohydrates for root and tree growth. Practices such as chipping prunings may also sequester by increasing carbon stored in soil organic matter.

Almond grower, huller and processor Dave Phippen said new equipment that can help reduce dust emissions at the hulling plant also significantly increases energy consumption, which in turns leads to more greenhouse gas emissions. These competing mandates create challenges for the industry. (Photo by Marni Katz)

One of the components proposed under the state’s new global warming plan is a carbon emissions cap and trade system. While questions remain about how such a system would be valuated and regulated, a cap and trade system would give businesses credit for voluntarily reduced greenhouse gas emissions that can be traded on carbon exchange markets.

In the case of almonds, growers may be able, for instance, to earn carbon credits for cultural practices such as chipping or for reducing nitrogen or energy use. But first, data is needed on the reductions in emissions before credit can be given.

The Almond Board of California is funding  research to better understand the contributions to greenhouse gases from almond production . To date, there is no data on greenhouse gases in perennial cropping systems.  

At UC Davis, David Smart is developing baseline information on greenhouse gas exchange from almond orchards soils. Fellow UC Davis researchers Ted DeJong and Johan Six are collaborating on developing a growth model for almonds trees that will help quantify data on carbon sequestration in the trees.

While many questions remain about how exactly greenhouse gases will be regulated, these new rules will require an integrated approach by the almond industry that looks at the entire vertical operation from the almond orchard, to the huller/sheller and throughout the distribution channel.

Dave Phippen of Travaille and Phippen Inc., a vertical growing, packing and processing almond operation in Manteca, Calif., said all sectors of the almond industry will need to communicate on how best to manage new greenhouse gas regulations as they develop.

Phippen said that as with all other air quality regulations that have come along in recent years, hullers and shellers will work with growers to come up with solutions that address these emerging environmental concerns.

“As far as our carbon footprint goes, if we are going to comply with these regulations we are going to have to talk to growers. We will need to figure out how to incentivize him and make him interested without losing him as a grower to somebody else,” Phippen said. “I don’t really know yet what all of the implications are going to be, but we will definitely have to be communicating within the industry.”

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