Ag inefficient with carbon emissions: study

New research suggests the farming and agri-food industry could do more to better use carbon from the atmosphere

New research says the Canadian agriculture industry is emitting lots of unused carbon, so much so that it’s underperforming in efficiency when compared to the petroleum sector.

The recently released Canadian Energy Systems Analysis Research (CESAR) study from the University of Calgary found the country’s agricultural crops are pulling in massive amounts of carbon from the atmosphere, but only a small portion ends up in value-added products.

The majority of the carbon, the study said, ends up back in the atmosphere.

“This is the first study to quantify the energy and carbon flows of the agri-food system of Canada,” said CESAR researcher and PhD candidate Adekunbi Adetona, who led the study published in the peer-reviewed journal Anthropocene.

“It’s about highlighting the magnitude of this carbon flow and the opportunity that lies for agriculture. If there is a way we can better utilize this carbon by not just letting it go back into the atmosphere, agriculture could play a bigger role in greenhouse gas management.”

Through the research, Adetona found that from 2010-13, Canada’s farm crops pulled in 141 million tonnes of elemental carbon each year to build biomass.

She said the figure equals about 71 percent of the country’s total greenhouse gas emissions, and is almost the same amount of carbon (144 million tonnes of carbon per year) in all of the crude oil that was extracted over the same study period.

What sets agriculture and crude oil extraction apart, however, is their efficiency rates.

Adetona said even though agriculture overall has fewer emissions than oil and gas, only 14 percent of the carbon that is pulled from the atmosphere ends up in value-added products. The remaining 86 percent returns to the atmosphere.

In comparison, she said, the petroleum industry manages to turn 91 percent of its pulled carbon into products. The remaining nine percent is lost during the conversion process.

Agriculture’s low carbon efficiency rate is due to several factors, she said, which include unused crop residues that are either burned or decomposed.

Therefore, the agri-food industry could take some notes from the oil and gas sector.

“While the production of refined petroleum products is different than the production of food products, the agri-food sector could take some lessons from the oil sector when it comes to conversion efficiency,” she said.

Canada has made strides in converting byproducts, like straw and manure, into usable resources, like biofuels, but the research suggests more could be done to improve agriculture’s carbon efficiency.

For instance, Adetona said it’s possible these byproducts could be converted to what’s called biochar, a specialized form of charcoal that can help build soil.

Not only would biochar improve carbon efficiency, she said, but it could also ensure farmers grow better crops with fewer inputs, potentially saving them money.

“Solutions need to be convenient and profitable,” she said. “Farmers don’t want to lose money while adopting it. It has to make sense financially and governments need to make some incentives.”

In fact, the research found about 55 million tonnes of elemental carbon per year could be used, ensuring much of it isn’t returned to the atmosphere while also reducing fossil fuel demand.

As well, the study suggests several other actions to improve agriculture’s carbon efficiency:

  • Diverting residual carbon, like crop residues, into producing energy that would reduce demand for fossil fuels.
  • Reducing the production and consumption of food products characterized by low conversion efficiencies, like ruminant production of meat and milk.
  • Increasing the production and consumption crops and foods, like legumes and grain crops, that have lower fuel and electricity input requirements along the value chain.
  • Rethinking the optimal use of agricultural land to balance the need of feeding the world’s growing population and contributing to the local economy with minimizing adverse climate and biodiversity impacts.

To get their results, the researchers gathered data from Statistics Canada and Agriculture Canada. They compiled food supply, disposition, crop processing, animal production and crop/pasture production numbers, converting the data into units of energy and carbon to figure out the efficiency.

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