THE METHODOLOGY

How Was the Inventory Conducted? Get the Facts

Greenhouse Gas Inventories are a new tool. Consequently, variations in methodology are widespread throughout the academic, government and corporate sectors, depending on data availability and analysis depth. Also, the very tools that are used to calculate the emissions change from one year to another as methodology becomes more clear and complete. Harvard recently abandoned the Clean Air Cool Planet Inventory tool and created its own GHG calculator (due to the complexities of Harvard's campus, it was simpler to create a Harvard-specific calculator than to use a pre-packaged tool from a third party). Harvard now makes an effort to comply with the WRI/WBCSD Greenhouse Gas Protocol, which is the most standardized and internationally accepted methodology.

Over time, the inventories will become more uniform in quality and approach to enable cross-institutional comparisons. Before this happens, it is essential to thoroughly document the inventory methodology used, including all associated data sets, assumptions and coefficients.  This will allow for adjustments, improvements, and comparisons to occur over time.

Continuous Improvement

Because greenhouse gas inventories are a relatively new exercise, it is important for the HGCI to keep abreast of improvements in greenhouse gas inventory methodologies. Harvard recently abandoned Clean Air Cool Planet's greenhouse gas inventory tool and adopted the Greenhouse Gas Protocol created by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD). The Greenhouse Gas Protocol is the product of a decade of collaboration between WRI; WBCSD; and businesses, governments, and other stakeholders. It is internationally recognized as the gold standard in greenhouse gas inventory methodologies. The Chicago Climate Exchange, the Regional Greenhouse Gas Initiative (RGGI), and the Climate Trust all ask that greenhouse gas inventories be conducting in accordance with WRI/WBCSD Greenhouse Gas Protocol.

Harvard has used other methodologies in the past, but this is not problematic as long as we carefully restate past data years using our new methodology. As we continue to update our inventory to keep up with changes, our emissions totals will change. It is important to understand that greenhouse gas inventories are inherently uncertain, and are only an estimation of an organization's emissions. GHG emission totals should never be thought of as absolute, unchanging figures. This said, HGCI will continue to strive for consistency and reliability in its greenhouse gas inventory and will update its methodology as new developments arise.

For a more detailed explanation of Harvard's methodology, including conversion factor selection, please read our Overview presentation of Harvard's Greenhouse Gas Inventory. Also, a template of Harvard's customized GHG Inventory calculator can be found here.