A temperature increase of 2oC above pre-industrial levels is the
maximum target range established by the scientific community
for stabilizing carbon concentrations at a level that prevents dangerous interference in the climate system. This corresponds to a target greenhouse gas concentration (in terms of carbon dioxide equivalents (CO2e)) of between 350 and 450 parts per million (ppm) and to global emission reductions of the order of 50-80 per cent over 1990 levels, by 2050. These targets cannot be met without a major transformation in the way energy is produced and consumed. The energy sector, broadly defined, accounts for 60 per cent of global emissions and a stable climate will require reduction in the rate of energy intensity and improvement in carbon intensity by a factor of between 2 and 3 with respect to their historical levels.