IPCC Fourth Assessment Report: Climate Change 2007
Climate Change 2007: Working Group III: Mitigation of Climate Change

1.3.2.4 Total GHG emissions

Without additional policies global GHG emissions (including those from deforestation) are projected to increase between 25% and 90% by 2030 relative to 2000 (see Figure 1.7). Fossil fuel dominance is expected to continue up to 2030 and beyond; consequently, CO2 emissions from energy use tend to grow faster than total GHGs, increasing by 1.2–2.5% over that period. Two thirds to three quarters of the increase in CO2 emissions are projected to come from developing countries, although the average per capita CO2 emissions in developing country regions will remain substantially lower (2.8– 5.1 tCO2 per capita) than those in developed country regions (9.6–15.1 tCO2 per capita).

By 2100, the range in the GHG emission projections is much wider from a 40% reduction to an increase of 250% compared to 2000. Scenarios that account for climate policies currently under discussion for implementation also show global emissions rising for many decades. With the atmospheric concentrations of GHGs thus unlikely to stabilize in this century (even for the low SRES scenario) without major policy changes, from an emissions perspective, we are not on track for meeting the objectives of UNFCCC Article 2.