An emissions inventory that identifies and quantifies a country’s primary anthropogenic sources and sinks of greenhouse gases is essential for addressing climate change. This inventory adheres to both (1) a comprehensive and detailed set of methodologies for estimating sources and sinks of anthropogenic greenhouse gases, and (2) a common and consistent format that enables Parties to the United Nations Framework Convention on Climate Change (UNFCCC) to compare the relative contribution of different emission sources and greenhouse gases to climate change.
In 1992, the United States signed and ratified the UNFCCC. As stated in Article 2 of the UNFCCC, The ultimate objective of this Convention and any related legal instruments that the Conference of the Parties may adopt is to achieve, in accordance with the relevant provisions of the Convention, stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time-frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened and to enable economic development to proceed in a sustainable manner.
Parties to the Convention, by ratifying, shall develop, periodically update, publish and make availableâ€¦national inventories of anthropogenic emissions by sources and removals by sinks of all greenhouse gases not controlled by the Montreal Protocol, using comparable methodologies. The United States views this report as an opportunity to fulfill these commitments.
This chapter summarizes the latest information on U.S. anthropogenic greenhouse gas emission trends from 1990 through 2016. To ensure that the U.S. emissions inventory is comparable to those of other UNFCCC Parties, the estimates presented here were calculated using methodologies consistent with those recommended in the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for National Greenhouse Gas Inventories.
- In 2016, total gross U.S. greenhouse gas emissions were 6,546.2 million metric tons (MMT) of CO2 equivalent.
- Since 1990, the largest source of U.S. greenhouse gas emissions is CO2 from fossil fuel combustion has accounted for approximately 77 percent of GWP-weighted emissions.
- Total U.S. emissions have increased by 2.8 percent from 1990 to 2016, and emissions decreased from 2015 to 2016 by 2.0 percent (131.1 MMT CO2 equivalent), the recent decrease driven in large part by a decrease in CO2 emissions from fossil fuel combustion.