Basic Glossary of GHG Emissions Terms

  • Sectors: major subcategories of emissions.  The tracker includes residential, commercial, industrial, agriculture, and forestry (with electricity allocated to individual sectors), plus electricity as a separate sector.
    • Agriculture sector: An energy-consuming sector that includes all facilities and equipment engaged in growing crops and raising animals (source). 
    • Commercial sector: Common uses of energy included in this sector include space heating, water heating, air conditioning, lighting, refrigeration, cooking, and running a wide variety of other equipment in commercial facilities.  Commercial facilities include all buildings not in the industrial sector.
    • Electricity sector: A including electricity generation or electricity consumption.  In the Main tracker screen electricity consumption is distributed and included in the separate end-use sectors.  In the Electricity Emissions screen electricity is treated as a separate sector.  In the Electricity Generation screen the locations of power plants generating electricity is shown.
    • Industrial sector: An energy-consuming sector that includes all facilities and equipment used for producing, processing, or assembling goods. (source) 
    • Residential sector: An energy-consuming sector that consists of electricity used in living quarters of private households. (source) 
    • Transportation sector: An energy-consuming sector that consists of all vehicles whose primary purpose is transporting people and/or goods from one physical location to another.
    • Forestry sector: Carbon uptake or sequestration from forests and urban trees.  In the tracker uptake is represented as negative numbers.

  • Afforestation: The planting of new forests on lands where the preceding vegetation or land did not contain forests. (source)

  • Per 1,000 People: this method of displaying the amount of GHG emissions allows you to meaningfully compare emissions between counties with different sized populations. For example, Fulton County (where Atlanta is) has many more people than any other county in Georgia, especially rural counties. By looking at emissions per 1,000 people instead of total emissions, you can see how much emissions a county has relative to its population. 
  • Greenhouse gases (GHGs): The main greenhouse gases are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Water vapor is the most plentiful in Earth’s atmosphere at about one percent. The next most plentiful is carbon dioxide at about 0.04 percent. The effect of human activity on global water vapor concentrations is too small to be important. The effects of human activity on the other greenhouse gases, however, is large and very important. These gases are increasing faster than they are removed from the atmosphere, causing global climate change (also known as global warming). (source) 

  • Emissions: Emissions are substances released into the air and are measured by their concentrations, or parts per million, in the atmosphere. (source) 

  • Carbon Dioxide / CO2: Carbon dioxide is the gas that accounts for about 84 percent of total U.S. greenhouse gas emissions. In the U.S. the largest source of carbon dioxide (98 percent) emissions is combustion of fossil fuels. Combustion can be from mobile (vehicles) or stationary sources (power plants). As energy use increases, so do carbon dioxide emissions. (source) 

  • Metric Tons (represented as “mt” throughout the dashboard): a common international measurement for the quantity of greenhouse gas emissions. A metric ton is equal to 2,205 lbs 
  • Metric tons of carbon dioxide equivalent: A metric measure used to compare the emissions from different greenhouse gases based upon their global warming potential (GWP). The carbon dioxide equivalent for a gas is derived by multiplying the tons of the gas by its associated GWP. (source)  
  • Kilowatt Hours: Electricity usage is most often calculated in kilowatt-hours. A kilowatt-hour is 1,000 watts used for one hour. As an example, a common 100-watt light bulb operating for ten hours would use one kilowatt-hour. 
  • Watt Hours: One Watt hour is equal to one Watt of average power flow over an hour (example: One Watt over four hours = four Watt Hours of power). 
  • Gigawatt hours (represented as “GWh”): Gigawatt hours is a measure of electricity equivalent to one million (1,000,000) kilowatt hours, or one billion (1,000,000,000) watt hours. It makes the most sense to display energy consumption at this scale for counties and states because of the large amount of electricity used. 
  • Large facility GHG emissions: facilities that emit more than 25,000 metric tons of CO2 and CO2 equivalent emissions. Note: power plants are not included in “large facilities.” 

  • Uptake / Sequestration / Sinks: CO2 that is absorbed by grasses, plants, and trees, and stored as biomass.  In the tracker GHG uptake is represented as negative numbers.
  • Net emissions: the result of subtracting GHG uptake from GHG emissions

  • Net zero emissions: Achieving net zero carbon dioxide emissions through the balance of residual carbon dioxide emissions with the same amount of carbon dioxide removal. (source)