Greenhouse Gas Emissions

Environment Canada defines climate change as “changes in long-term weather patterns caused by natural phenomena and human activity that alter the chemical composition of the atmosphere through the build-up of Greenhouse Gases (GHGs)” (Environment Canada, 2008).

Earth’s average temperature has been increasing in recent decades at a faster rate than can be explained by natural climatic cycles alone. Greenhouse Gas emissions, such as Carbon Dioxide, are released from burning of fossil fuels. According to Natural Resources Canada, Greenhouse Gas “absorbs and radiates heat in the lower atmosphere that otherwise would be lost into space. The resulting Greenhouse Effect is essential for life on this planet, since it keeps average global temperatures high enough to support plant and animal growth” (Natural Resources Canada, 2008). The main Greenhouse Gases that are monitored by Canada’s National Greenhouse Gas Inventory are: Carbon Dioxide (CO2), Methane (CH4), Nitrous Oxide (N2O), Sulphur Hexafluoride (SF6), Perfluorocarbons (PFCs), and Hydrofluorocarbons (HFCs). Carbon Dioxide is by far the most abundant greenhouse gas, accounting for approximately 78% of all greenhouse gas emissions in 2006 (Environment Canada, 2008).

"...the construction and operation of buildings consumes over a third of the world’s energy and 40% of all the mined resources..."

According to Environment Canada’s National Inventory Report: Greenhouse Gas Sources and Sinks in Canada (1990-2006) Canada produced about 721 Mt of CO2e in 2006. On a global scale, this equals about 2% towards total global GHG emissions in 2006. Figure 7, produced by the National Round Table on the Environment and Economy, ranks Canada as number seven in the world in terms of the top ten GHG emitting countries for the year 2005.

Figure 7: Top 10 Greenhouse Gas Emitters Globally (2005) (National Round Table on the Environment and the Economy, 2009).

In Canada, one of the single largest contributors to CO2 emissions is the building industry. In fact, the construction and operation of buildings consumes over a third of the world’s energy and 40% of all the mined resources (Straube, 2006). Examining the total GHG emissions for secondary energy sectors in Canada for the year 2006, the trends are similar to those of secondary energy use. Figure 8 presents the GHG emission profile for the five secondary energy sectors in Canada. Transportation and Industrial sectors are the two largest contributors of GHG emissions at 36% and 34% respectively. Following that, the Building sector (Residential + Commercial/Institutional) is responsible for nearly 27% of the Secondary Energy GHG emissions.

Figure 8: Total Greenhouse Gas Emissions for Secondary Energy Sectors in Canada (2006) (Natural Resources Canada, Office of Energy Efficiency, 2006).

In Figure 9, it’s evident that similar to energy use, space conditioning (space heating + space cooling) dominates at nearly 56% of the GHG emissions for Commercial/Institutional buildings. Auxiliary equipment and lighting are the next largest contributors of GHG at 16.6% and 10.8% respectively. Water heating and auxiliary motors account for the remaining 8.6% and 8.3% of GHG emissions for Commercial/Institutional type buildings in Canada.

Figure 9: Total Commercial/Institutional Secondary Energy Use Greenhouse Gas Emissions by End Use in Canada (2006) (Natural Resources Canada, Office of Energy Efficiency, 2006).

In Figure 10, statistics have been subdivided by Activity Type. Similar to the trends in energy consumption of Commercial/Institutional buildings subdivided by Activity Type, Office buildings lead the way at 35% in terms of GHG emissions. Retail buildings produce the next highest amount of GHG emissions at roughly 16%. Educational Services buildings are responsible for about 14% of GHG emissions in this category, followed by Health Care and Social Services buildings at 10%. Various other types of Commercial/Institutional buildings complete the GHG emission profile as illustrated in Figure 10.

Figure 10: Total Commercial/Institutional Secondary Energy Use Greenhouse Gas Emissions by Activity Type in Canada (2006) (Natural Resources Canada, Office of Energy Efficiency, 2006).