Although farmers often see themselves as part of the solution to Canada’s environmental challenges, Environment Canada says agriculture is a major contributor to the greenhouse gas problem.
Canada’s greenhouse gas emissions are beginning to fall slightly in some sectors, led by reductions in industrial processes and residential emissions, but agricultural emissions have had among the sharpest increases since 1990.
The sector now contributes 8.5 percent of Canada’s greenhouse gas emissions, the annual equivalent of 62 million tonnes (megatonnes) of carbon dioxide. It represents a 25 percent increase since 1990.
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“The major factor is the increase in the livestock herd and emissions from manure management,” said Art Jaques, director of the department’s greenhouse gas division.
The livestock sector contributes more than half of agriculture’s greenhouse gas emissions through methane emitted by livestock, as well as methane and nitrous oxide released from manure stored or spread on fields.
Nitrous oxide emitted because of fertilizer use makes up most of the remainder.
“Emissions from soils have been relatively stable,” Jaques said. “So the increase really is on the livestock side.”
The emission numbers are gross calculations that do not take into account offsetting greenhouse gas reductions through carbon sequestration in the soil, which the environment department thinks was 1.4 to 9.6 megatonnes from 1990 to 2006. The government will be seeking credits for those reductions in international greenhouse gas negotiations.
“In accordance with accounting provisions under the Kyoto Protocol (on climate change), Canada has elected to offset emissions from agricultural sources by electing crop land management as a category to ensure Canada is credited for good land management practices,” Environment Canada officials said in an e-mail about agriculture’s contribution to the greenhouse gas problem.
“This in effect will allow Canada to net out its sinks from its sources during the Kyoto Protocol commitment period 2008 to 2012.”
As well, many farmers have reduced their emissions through changes in tillage practices and reductions in the amount of fertilizer used.
The department estimates that between 1990 and 2000, net carbon dioxide emissions from soil fell from 7.3 megatonnes to a small net positive in soil carbon storage compared to soil emissions. It credits increased use of conservation tillage and reduced use of summerfallow on the Prairies.
“Certainly there is a move to less tillage and other management practices that mitigate emissions,” Jaques said. “Having the knowledge of which sectors contribute makes it possible to target specific mitigation policies that will help alleviate the problem.”
The environmental file within Agriculture Canada’s Growing Forward policy framework, including funding for environmental farm plans, is one of the government’s main attempts to change farm practices that contribute to global warming.
Still, in 2000, the Prairies were responsible for more than 62 percent of Canada’s agricultural greenhouse gas emissions. While net carbon emissions are under control, nitrous oxide emissions from fertilizer use are rising.
As well, the agricultural number does not include emissions from farm use of fuel that would be reported separately under transportation. As a heavy user of fossil fuel to power vehicles and machines, including fuel use would add significantly to agriculture’s carbon footprint, but those numbers are not broken out of the transportation total.
The 62-megatonne greenhouse gas output that was reported to the United Nations this year under the provisions of the decade-old Kyoto agreement is not just an estimate, Jaques said.
“This is considered the actual volume of emissions and not some notional number or estimate.”
To come up with the number it reports to the UN, the government, in co-operation with universities and research centres, uses internationally developed “good practice guidelines” and considers the amount of land being farmed, farming methods, the number of animals and other factors.
“We believe this is the best number we can come up with,” Jaques said. “We believe it is accurate.”
