English: This graph shows projected emissions of carbon dioxide produced from fossil and other industrial sources between 2000-2100. The projections are based on emissions scenarios described in Clarke et al. (2007, p.20). The emissions scenarios shown were produced using the MiniCAM model of the Joint Global Change Research Institute, which is a partnership between the Pacific Northwest National Laboratory (USA) and the University of Maryland (USA) (Clarke et al. , 2007, p.8). The red line plotted on the graph shows emissions in a "reference" scenario. In the reference scenario, it is assumed that no future efforts are made to limit greenhouse gas (GHG) emissions (Clarke et al. , 2007, p.8). The other four lines plotted show emissions in "stabilization" scenarios. In the stabilization scenarios, GHG emissions are limited so as to stabilize the radiative forcing (i.e., the warming effect) of GHGs on the Earth's climate system. In the "MiniCAM Level 1" stabilization scenario, the radiative forcing of GHGs is stabilized at 3.4 watts per square metre (W/m ² ), relative to the pre-industrial forcing (Clarke et al. , 2007, p.9). Non-CO ₂ gases contribute approximately 0.8 W/m ² to this, while CO ₂ contributes approximately 2.6 W/m ² . The corresponding atmospheric CO ₂ concentration is 450 parts-per-million by volume (ppmv). For the other stabilization scenarios (levels 2, 3, and 4), total GHG radiative forcing is 4.7, 5.8, and 6.7 W/m ² respectively; with approximately 1.0, 1.3 and 1.4 W/m ² from non-CO ₂ gases; approximately 3.7, 4.5, and 5.3 W/m ² from CO ₂ ; with corresponding CO ₂ concentrations of 550, 650 and 750 ppmv, respectively. References: Clarke, L., et al. , 2007: Scenarios of Greenhouse Gas Emissions and Atmospheric Concentrations. Sub-report 2.1A of Synthesis and Assessment Product 2.1 by the U.S. Climate Change Science Program and the Subcommittee on Global Change Research. Department of Energy, Office of Biological & Environmental Research, Washington, DC., USA.