Determining thresholds for mandatory reporting of greenhouse gas emissions

A number of countries are considering implementation of reporting requirements for greenhouse gases. Some reporting systems have been proposed that would require each entity or facility exceeding an annual emissions threshold to report their emissions to a governmental agency. The analysis presented here provides a first approximation of the number of facilities in selected U.S. economic sectors that would report under several different reporting thresholds. Results indicate that thresholds below 10,000 Mg of carbon dioxide equivalent (CO2E) per year may bring in relatively large numbers of facilities while minimally increasing the percentage of reported emissions. None of the reporting thresholds considered in this analysis would account for the majority of greenhouse gas emissions from the U.S. agricultural, transportation, or residential and commercial building sectors. If these sectors, in which large numbers of farms, vehicles, and buildings each emit relatively small amounts of greenhouse gases, are to be included in a reporting framework, additional or alternative approaches to reporting should be considered. Alternative approaches may include creating separate thresholds for individual greenhouse gases instead of using an aggregated CO2E unit, creating separate reporting thresholds for individual sectors, or combining sources of small emissions into a single reporting entity.