### Main state indicators

###

Total anthropogenic emissions of CO2 Anthropogenic CO2-equivalent emissions (Kyoto gases) | Global concentration of CO2 CO2-equivalent concentration (Kyoto gases)

| #### Total anthropogenic emissions of CO2
| units:Pg C/yr (Petagram of C per year for CO2) dimension: region, anthropogenic category

This indicator presents the total anthropogenic CO2 emissions from fossil fuel combustion, industrial production and CO2 fluxes caused by land use changes (deforestation and regrowing vegetation). CO2 emissions are generated by the TIMER emissions model (TEM) and the terrestrial carbon model (TCM).

| #### Anthropogenic CO2-equivalent emissions (Kyoto gases)
| unit: Pg C/yr (Petagram of C per year) dimension: region, anthropogenic category, contributor

The CO2-equivalent emissions are computed from the CO2-equivalent emissions since 1970 from the radiative forcing by the greenhouse gases that are regulated in the UNFCCC Kyoto Protocol (CO2, CH4, and N2O, and the HFCs, PFCs and SF6). The radiative forcing is calculated from the direct Global Warming Potentials (GWPs) relative to carbon dioxide for a 100-year time horizon. For example, a GWP of 23 is used for CH4, which means that 1 kg of CH4 has the same impact as 23 kg of CO2 for a time horizon of 100 years. The GWP for N2O is 296. GWPs for the other substances cover a wide range of values, up to 22200 for SF6.

The HFCs, PFCs and SF6 emissions are not included in the regional CO2-equivalent emissions, since there is no regional historical emission data available, and the emissions scenarios of Fenhann (2000) are only specified for the four IPCC regions. Therefore the regional CO2-equivalent emissions only consists of the emissions of the three major greenhouse gases: CO2, CH4, and N2O.

| #### Global CO2 concentration
| units:ppmv (parts per million by volume) dimension: none

This indicator presents the global CO2 concentration. The net CO2 flux to the atmosphere is converted to concentration by a fixed conversion factor. The net flux is the balance between emissions from fossil fuel combustion, industrial production and deforestation, and uptake by mature vegetation (CO2 fertilization) and regrowing vegetation and uptake by the oceans. CO2 emissions are generated by the TIMER emissions model (TEM), while CO2 uptake is calculated by the terrestrial carbon model (TCM) and oceanic carbon model (OCM). The CO2 concentration is computed by the atmospheric chemistry model (ACM)

| #### CO2-equivalent concentration (Kyoto gases)
| unit: ppmv (parts per million by volume) dimension: none

The CO2-equivalent concentration combines the radiative forcing of the greenhouse gases that are regulated in the UNFCCC Kyoto Protocol, i.e. the three major greenhouse gases: CO2, CH4, and N2O, and the HFCs, PFCs and SF6.

The forcing of the other greenhouse gases or radiatively active compounds (chlorinated and brominated halocarbons, i.e. CFCs, methyl chloroform, carbon tetrachloride, halons and HCFCs, ozone precursors including tropospheric O3, and SO2 are not included.

The CO2-equivalent concentration is calculated as follows:

with:

CCO2, pre = pre-industrial CO2 concentration (in ppmv)
QGHG= total radiative forcing caused by the changes in concentration of the greenhouse gas (GHG) considered

This indicator is an important climate policy target under the United Nations Framework Convention on Climate Change (UNFCCC) (post-Kyoto) in the context of stabilizing GHG concentrations (UNFCCC, article 2).