Human Activities Leading to Emissions

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Greenhouse gas emissions due to human activities are associated mainly with energy - the engine for the process of industralization as well as for modern society. Energy is consumed from its initial extraction of fossil fuels from the earth to the end use. All of these uses result in a number of waste gases that contribute to the greenhouse gas concentration of the atmosphere, as well as low-level gases that produce city smog.

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The process of energy production involves industries dealing with fossil fuels as well as with power generation. The end use of energy is wide-ranging but is primarily used for vehicle transportation, power supplies for industrial activities, and heating and power supplies for all commercial buildings and residential houses.

Greenhouse gases also result from other human activities, such as land use, agriculture practices, and wastes. Figure 1 shows a profile of human activities as sources of greenhouse gas (GHG) emissions in Canada for the time periods of 1990 to 2020, as well as the percentage of projected increase of GHG emissions for each sector from 1990 to 2010.

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Figure 1. A Profile of Human Activity as Sources of Greenhouse Gas Emissions in Canada

This Module

Indicators for Human Activities

To represent the wide spectrum of human activities contributing to GHG emissions, the usual approach is to use indicators. For the energy sector, indicators are developed to describe, in a numerical term, the key aspects of energy consumption in relation to GHG emissions. One of the most commonly used aggregate indicators is total energy consumption. This aggregate indicator is normally decomposed into lower levels such as frequency and duration in which the energy-based equipment is used, the mix of energy forms or technologies used, and the average energy efficiency of the equipment. These indicators serve as numerical measures for the assessment of potential effects of policy measures. They also provide a means for tracking the progress of actions towards improving fuel efficiency and reducing GHG emissions.

Themes in the Current Module

For this first phase, the module includes fifteen maps addressing one of the major energy end use sectors - transportation. Specifically, the module looks at the light-duty vehicle sales mix and its average fuel efficiency, for the vehicle model year 1990, the projected model year 2010, and the changes over this time period. Included in this module are:

• Three maps showing the average fuel efficiency of new light-duty vehicles
• Twelve maps representing a major determinant of the average fuel efficiency, namely, light-duty vehicle market shares, for six prominent vehicle classes: subcompact cars; Compact cars; Midsize cars; Large cars; Small vans; Small utility vehicles

These maps are represented using census divisions, for both the historical and future time periods.

Light-duty vehicles refers to all cars and light trucks. The average fuel efficiency of light-duty vehicles is measured in miles travelled per gallon. It is defined by averaging the tested fuel efficiency rating for each vehicle's class, weighted by that class' market share. The data are calculated for each census division. The light-duty vehicle size classes, defined by the US Environment Protection Agency, were adopted for the vehicle classification. This classification has 15 classes: six classes for automobiles, six classes for light trucks, and three classes for station wagons. The six prominent classes account for the large majority of light-duty vehicle sales.

Relation of the Themes to GHG Emissions

As shown in Figure 1, transportation is the largest source of GHG emissions, accounting for over 25% of Canada's total GHG emissions in 1997. Light-duty vehicles contribute to approximately half of the transportation emissions (the remainder is due to heavy trucks, aircraft and other transportation modes). New light-duty vehicles, which enter in the vehicle market in each year, is the key target of policy actions for the light-duty vehicle sector. With this target, such actions as improving vehicle fuel efficiency technology and switching to more fuel-efficient vehicles are expected to take effect in order to reduce GHG emissions. In the case of average fuel efficiency, the lower the average fuel efficiency, the higher the emission per vehicle and, consequently, the greater the contribution to greenhouse gases.

The average vehicle fuel efficiency for a census division is determined by the market share of vehicle classes in the census division, and the fuel efficiency of each class of vehicles per se. The maps of the new light-duty vehicle market share, therefore, provide explanations for the variation in average fuel efficiency across Canada, thereby indicating the level of GHG emissions at a more detailed level.

Cautions

This first phase of this module includes a projection of new light vehicle sales mix and the resulting average fuel efficiency for each census division of Canada for the vehicle model year 2010. The verification of the projection of light-duty vehicle market share has shown its likely validity for forecasting shifts in the mix of light-duty vehicle sales for a given model year in a short to medium term. This projection, however, is based on a series of macroeconomic assumptions in Canada's Energy Outlook 1997, which represent a best guess for the possible future if there will be no additional policy interventions. Generally, it is suggested that an econometric projection should serve as a trend forecast rather than a numerical forecast.

Also note that, while conducted within Natural Resources Canada, this projection does not represent an official Natural Resources Canada projection. An official projection for vehicle fuel efficiency and market shares at aggregate levels can be found in Canada's Emissions Outlook: An Update 1999.