About the Construction Carbon Calculator.
The Construction Carbon Calculator estimates embodied carbon. Embodied carbon is the carbon released when a product is manufactured, shipped to a project site and installed. This calculator looks at an entire project, and takes into account the site disturbance, landscape and ecosystem installation or restoration, building size and base materials of construction. It does this simply, requiring only basic information that is available to a project team very early in the design process.
The calculator provides an estimate that establishes a base number to clarify the carbon implications of the construction process - to be used as tool to address the reduction of that footprint. The results you obtain will be an estimation and approximate - accurate within 25%, plus or minus.
This first version of the carbon landscape model conservatively estimates the potential of the landscape to release and sequester carbon. (Please see the assumptions for more detail.) The Calculator's estimation demonstrates the role of the immediate landscape in the site carbon footprint and how it should be considered in the whole site design.
The value of the building carbon model will also increase through user input and more data sets. The base model takes the overall building square footage and divides it evenly between floors. A higher carbon footprint per square foot has been assumed for stories below grade to account for excavation work and soil removal from the site.
A complete life cycle analysis will provide more precise carbon quantities. There are various cost consultants, environmental consultants and life cycle software programs that will allow an interested party to generate a more accurate estimate of embodied carbon, however, we are not aware of one that will also address landscape impacts.
Why is embodied carbon important?
13-18% of the total embodied carbon footprint of any construction project (UNEP, 2007) and 100% of the total embodied carbon footprint of any landscape project is released the year the project is built or installed.
The remainder of the carbon footprint is the operational carbon released and the landscape carbon sequestered over the life of the project, typically 30 to 80 years.
Air travel represents about 13% of the total global transportation carbon footprint, and about 2% of the total overall global carbon footprint (Tufts, 2006). Embodied carbon in non-residential buildings contributes about 19% of the total overall global carbon footprint in the United Kingdom (BioRegional Development Group BedZed toolkit) making embodied construction carbon a significant percentage of the overall total. Embodied construction carbon is a more significant factor than air travel, and has an equally immediate impact.
Why is landscape significant? The ecoregion and the maintenance of landscaping both have an impact on the quantity of carbon that can be sequestered there. Certain landscapes, like wetlands, have the capacity to store significant amounts of carbon. This carbon is released when the landscape is disturbed or destroyed. Landscape should be considered in conjunction with the building and site design and can be a key element of carbon sequestration. This calculator is the first to allow landscape impacts to be quantified and applied to the full project embodied carbon footprint.
What about operational carbon? Operational carbon is a footprint that increases over the life of a building. Building design and the behavior of building occupants can greatly reduce that operational carbon footprint. The remaining carbon footprint can be addressed through the purchase of green power - power from renewable energy sources. Any carbon footprint not addressed this way can be offset. There are many carbon calculators and offset retailers that address operational carbon.