Welcome to the Greenhouse Gas Value Calculator! To start using the calculator, click start below. See below for a brief introduction to using the calculator and interpreting its results.
About Greenhouse Gas Value
"Greenhouse Gas Value" (GHGV) is a measure of the total greenhouse gas benefit of maintaining an ecosystem - or, conversely, the greenhouse gas cost of clearing it. GHGV provides a comprehensive method of calculating the change in greenhouse gas emissions - and therefore climate - that results from changes in land use.
GHGV is expressed in units of CO2-equivalents; that is, it compares the climate effect of clearing the ecosystem with the effect of releasing one ton of CO2 to the atmosphere. This allows easy comparison of the long-term effects of clearing a forest, for example, to the costs of other greenhouse gas emissions.
For more information about GHGV, see this news story and the links at the bottom of this page.
About the Greenhouse Gas Value Calculator
The Greenhouse Gas Value Calculator is an online tool for calculating the greenhouse gas value of terrestrial ecosystems. You may calculate GHGV for different types of ecosystems using default parameters, input your own parameters, or test the sensitivity of GHGV to any paramenter. Results are summarized graphically, and files detailing the results are available for download.
Interpreting Results
The figure to the right is sample output from the GHGV calculator (when used to compare different types of ecosystems). The three panels represent:
- Contribution to GHGV from initial storage of organic material. If the ecosystem is cleared, carbon stored in vegetation, non-living organic material, and soil will be released to the atmosphere as CO2. If fire is used to clear the ecosystem, other GHGs will also be released (e.g., CH4, N2O).
- Contribution to GHGV from displaced from ongoing exchange of GHGs between the ecosystem and the atmosphere. Every year, ecosystems exchange GHGs with the atmosphere. For example, many natural ecosystems take up CO2 from the atmosphere, and croplands release N2O as a byproduct of nitrogen fertilization. If the ecosystem is cleared, such GHG exchanges will be displaced. Displaced GHG exchange is counted over the time period of interest (50 years in this case.)
- Total GHGV. GHGV is the sum of the contributions from storage and flux. In some cases, the probable effects of disturbance may also be included.
Results are presented in units of CO2-equivalents per hectare over the selected number of years (50 in this case); in other words, GHGV quantifies how many (metric) tons of CO2 would have the same climate effect, if released to the atmosphere, as clearing one hectare of the ecosystem (and measuring the impacts over the selected time frame).
We caution that outputs of the GHGV calculator - when run using default parameters - should not be used as off-the-shelf estimates of GHGV for any particular ecosystem. Ecosystem categories presented here are quite broad and default values, which are based on global data sets, may not be appropriate for a specific location. Influential variables such as organic matter storage, cattle density (pastures), and crop management practices can vary by orders of magnitude within some of the GHGV Calculator's ecosystem categories. We encourage users to critically evaluate the assumptions implicit in the use of default parameters, and to customize parameters as appropriate.
News story about GHGV:
Scientific Background
Related Academic Articles:
- Kristina J. Anderson-Teixeira, Peter K. Snyder, Evan H. DeLucia. Do biofuels lifecycle analyses accurately quantify the climate impacts of biofuels related land use change? Illinois Law Review, 2011.
Questions or Comments? Please contact us:
- Evan DeLucia: delucia@globalchangesolutionsllc.com
- Kristina Anderson-Teixeira: krista@globalchangesolutionsllc.com
- Site Comments: bug_reports@globalchangesolutionsllc.com
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