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So what is a carbon footprint and why is Vanderbilt calculating one?

Posted by on Friday, March 6, 2009 in GHG, News.

So what is a carbon footprint and why is Vanderbilt calculating one?

On February 23, Vanderbilt announced that a carbon footprint, or greenhouse gas inventory, would be created for the first time. This article is the first in a series discussing Vanderbilt’s carbon footprint. The terms “carbon footprint” and “greenhouse gas” are used a lot in the news and on TV, but what do they really mean?

A carbon footprint is a standard that people and organizations are using to quantify the impact they have on the environment, particularly as their behaviors relate to climate change.

To start calculating a carbon footprint, the first thing that must be determined is how much of six specific “greenhouse gases” are being emitted by the person’s or organization’s behavior and operations.

The gases included in a carbon footprint, or greenhouse gas inventory, are the following:
•    Carbon Dioxide (CO2)
•    Methane (CH4)
•    Nitrous Oxide (N2O),
•    Hydroflurocarbons (HFCs)
•    Perflurocarbons (PFCs)
•    Sulfur hexafluoride (SF6)

Once the amount of emissions of each gas is determined, it is converted to a standard unit of measure, or carbon dioxide equivalents (CO2E). The sum of all CO2E emitted by that person or organization is the carbon footprint, usually reported in metric tons as MTCO2E.

Examples of how greenhouse gases are produced:

Carbon Dioxide
Naturally produced: During the carbon cycle (see graphic to the left)
Human generated: Burning fossil fuels (oil, coal, natural gas)

Naturally produced: wetlands, oceans and wildfires
Human generated: landfill decay, natural gas and coal systems, raising cows and coal mining

Nitrous Oxide
Naturally produced: during bacteria breakdown of nitrogen in the soil and oceans
Human generated: burning fossil fuels, fertilizer use, anesthetic gas, motor racing oxidizer

Human generated: used in refrigeration and fire suppression

Human generated: primarily used in refrigeration units, byproduct of aluminum production, used medically in eye surgeries and MRIs

Sulfur Hexafluoride
Human generated: used in electric system circuit breakers and in ultrasound imaging

Vanderbilt emits many of these greenhouse gases through its daily operations, such as energy consumption in campus buildings, burning of coal and natural gas at the Power Plant, use of fuel to power campus fleet vehicles, and the disposal of waste generated on campus.  Thus, the VU Greenhouse Gas Emissions Inventory to be published on Earth Day, April 22, will establish a baseline of VU’s average annual carbon footprint so that the VU community can better understand our impact to the environment.

Vanderbilt’s energy consumption is the largest contributing factor in our greenhouse gas emissions.  If you would like more information how to conserve energy at Vanderbilt, visit the ThinkOne Web site at

To read more about Vanderbilt’s greenhouse gas emissions and to follow progress of the development of the carbon footprint, please visit


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