Greenhouse Gas Emissions from Canadian Agriculture: Estimates and Measurements

Greenhouse gases (GHGs) cause the warming of the planet’s surface. Although this warming is vital for life on Earth, accelerated surface temperature rises due to increased GHGs in the atmosphere result in increasing atmospheric energy and rates of evaporation, causing unpredictable weather patterns and more intense weather events. The main GHGs are carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Of the 729 Megatonnes (Mt) of CO2 equivalent (CO2 eq) emitted by GHGs in Canada in 2018, 59 Mt were emitted by the agricultural sector in the form of CO2, N2O and CH4. The largest GHG emissions come from CH4 through enteric fermentation of beef and dairy cattle. Most N2O emissions come from agricultural soils through direct and indirect releases into the atmosphere. Carbon dioxide was also emitted after lime and urea applications as well as with the use of fossil fuel combustion machinery. Field techniques and empirical and process models have been developed to estimate and validate GHG emissions for different farm scenarios. These models aim to simulate every component of a farming system, whether a large beef cattle operation or a small animal and crop farm. Consequently, the models are constantly being assessed and revised as more data are available and methodologies are improved. As we gain better understanding of agricultural GHG emission estimates for different farm scenarios, the next step is to target emission sources and find ways to decrease emissions while maintaining or improving the financial sustainability of the farm and production system