Q799. What are the global warming potentials (GWPs) used in publication of GHGRP data?

A799. Effective reporting year 2013, the GHGRP updated many of the GWP values used to calculate reporters’ emissions in carbon dioxide equivalent (CO2e). These GWP values were updated from values provided in Intergovernmental Panel on Climate Change’s (IPCC) Second Assessment Report (SAR) to those in the Fourth Assessment Report (AR-4). See Table A-1 for the complete list of gases and their updated GWPs. To present a consistent time-series, EPA has provided re-calculated prior year GHG totals, which were calculated using SAR values, using the revised AR4 GWP values. The raw data submitted by facilities for reporting years prior to 2013 remains as submitted using SAR GWPs.