To promote the prevention of global warming, GIO is engaged in the development of annual greenhouse gas inventories and the national inventory report, which involves the necessary tasks such as international response, and conducts research that is needed for inventory preparation and utilizes developed inventories.

Under the Kyoto Protocol that Japan ratified in June of 2002, the greenhouse gases subject to the quantified reduction commitments are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆). These quantified reduction commitments have been established for each country. During the first commitment period, from 2008 to 2012, Japan has committed to reducing these greenhouse gases by 6% from the base year’s emissions (1990 for CO₂, CH₄, and N₂O, while 1995 for HFCs, PFCs, and SF₆). Therefore, accurate emissions inventories are more essential than ever. All developed countries have been responsible for the development of the national inventory on emissions and removals of greenhouse gases mentioned above by one year prior to the first commitment period (2007). The greenhouse gas inventories are crucial databases to report the achievement on the reduction commitments under the Kyoto Protocol.