Greenhouse gas (GHG) emission estimates from signatories of the American College and University Presidents' Climate Commitment (ACUPCC) were compared across Carnegie institutional classifications. Average annual emissions from all institutional classifications are 52,434 metric tons carbon dioxide equivalent (MTCO2E), with emissions from purchased electricity, stationary combustion, and commuting accounting for approximately 88% of total emissions. Average annual emission intensity from all institutional classifications is 19.39 MTCO2E per 1000 gross square feet (GSF) and 7.67 MTCO2E per full-time equivalent (FTE) student. In 2005, U.S. institutions of higher education accounted for approximately 121 million MTCO2E, or nearly 2% of total annual U.S. GHG emissions. For reference, these emissions are comparable to approximately one-quarter of those from the state of California. Because ACUPCC signatories represent over 30% of U.S. higher education enrollment, their long-term commitments to carbon neutrality can result in a measurable reduction (approximately 0.6%) of total annual U.S. GHG emissions.