Bridging the climate-corporate gap: utilizing GWP* with GWP100 for livestock companies’ greenhouse gas inventories

Abstract

Corporations must follow established standards when developing their emission accounting frameworks and reports. This standard necessitates that the various greenhouse gas (GHG) species are reported on a carbon dioxide (CO 2 ) equivalence (CO 2 -e) basis using the global warming potential (GWP) metric on a 100-year timeframe (GWP100). However, GWP100 was developed to evaluate the warming contributions of a pulse or one-off emissions compared with an equivalent pulse emission of CO 2 . Accordingly, the GWP100 metric does not account for scenarios of changing emission rates, which is an important factor for determining the warming effects of short-term climate pollutants. More recently, the GWP-star (GWP*) metric has been developed to address this issue by evaluating the short-term climate pollutants’ impact on global surface temperature change over time. With the emergence of GWP* there has been increasing interest in adopting this metric into corporate reporting. However, the 20-year baseline data required to calculate GWP* has limited companies’ ability to incorporate GWP* into their current GHG reporting inventories. To bridge the gap between GWP* and corporate accounting we developed a straightforward methodology to enable companies to dual report GWP* and GWP100 based on current GHG reporting inventories. Specifically, the methodology developed a “shadow company” technique that will allow GWP* to be calculated from a specified baseline reporting year and onwards. To realistically model a multi-national corporate GHG inventory, we developed a mock company, titled the Global Beef Company that operated in Brazil, Australia, and the United States. The GHG inventory was modeled and calculated using the same procedures currently employed by meat packers and retailers for estimating their scope 3 livestock GHG emissions. Emission reduction and growth scenarios were modeled over an 80-year time scale to demonstrate the long-term effects on warming. To evaluate the cumulative effect of warming over time, absolute GHG emissions were modeled using the cumulative sums of GWP* and GWP100 values. With many companies reporting GHG on an intensity basis, a new indicator was formulated entitled Cumulative Intensity where GWP* and GWP100 were both reported on intensity basis. Overall, the current analysis developed a step-by-step template for dual reporting GWP* and GWP100 on an absolute and intensity basis for GHG accounting at the corporate level.