133020406080100120JRC BAU
JRC INDCs
JRC 2 °C PathPBL
BAUGlobal Emission(Gt CO−eq) 2a
Business As Usual
RCP 8.5
RCP 4.5
RCP 2.6
Observation
Our Projection1990 2000 2010 2020 2030 2040 2050 2060
051015202530Per−Capita Emission(t CO−eq ppy) 2c
US China India
Annex I* Non−Annex I*051015202530Emission by Group(Gt CO−eq) 2b
US
China
India
Annex I*
Non−Annex I*Fig. 3.8 Future GHG projections, Business as Usual (BAU). (a) Our projection of global emission
of CO 2 FF + CO 2 LUC + CH 4 + N 2 O, expressed as CO 2 -eq, for a BAU approach; shaded region repre-
sents uncertainty based on various population pathways (grey). Global emissions of CO 2 FF +
CO 2 LUC + CH 4 + N 2 O from RCP 2.6, 4.5, and 8.5, as indicated. Four projections of global emissions
for the Kyoto basket of GHGs from JRC (Kitous and Keramidas 2015 ) are shown: BAU, their
analysis of the INDCs, and their estimate of the pathway needed to achieve the Paris upper limit of
2 °C warming. The INDC projections of JRC are for unconditional only (upper orange curve) and
unconditional plus conditional (lower orange curve). Finally, the global GHG emission BAU pro-
jection for 2030 from PBL (Admiraal et al. 2015 ) is shown. (b) Our projection of contributions to
CO 2 FF + CO 2 LUC + CH 4 + N 2 O from the US, China, India, Annex I, and non-Annex I, all for
BAU. (c) Per-capita emission of CO 2 FF + CO 2 LUC + CH 4 + N 2 O from the five groups, based on our
projections in panel (b). See Methods for further information
sions follow the submitted INDC, for the 117 nations that have submitted uncondi-
tional INDCs to UNFCCC at the time of writing, that include specific quantifiable
reductions in GHG emissions. For a few nations, which shall remain unnamed, our
best interpretation of their INDC leads to emissions that are larger than we have
forecast under BAU. In these instances, the INDC-based forecast is used. Most of the
3.3 Future Emissions