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

3.2.2 Emissions

There is still a large span of CO2 emissions across baseline scenarios in the literature, with emissions in 2100 ranging from 10 GtCO2 to around 250 GtCO2. The wide range of future emissions is a result of the uncertainties in the main driving forces, such as population growth, economic development, and energy production, conversion, and end use, as described in the previous section.