Global energy system to maintain atmospheric CO2 concentration at 550 ppm

Technical measures for reducing CO2 emissions are assessed with a global energy model on the basis of the SRES baseline scenarios. The model study suggests some insights regarding the question as to what combination of measures would be the cost-minimal technological responses to the global warming issue. While considerable uncertainties remain about the various assumptions made for the model analyses, the following items are identified. (1) Our energy system would still be dependent on fossil fuels over the next century, even with the regulation of CO2 concentration. (2) A cautious assessment of the results would conclude that the CO2 problem cannot be easily settled by any single technological option considered here. However, the energy model indicates that if all types of technological options are reasonably integrated with one another, a significant CO2 emission reduction potential exists to limit atmospheric CO2 concentration to 550ppm by the end of the 21st century. (3) The optimal CO2 emission trajectory to stabilize atmospheric CO2 concentration indicates that relatively modest abatement actions are expected, especially in the near future, allowing global CO2 emissions to continue to rise until around the middle of the 21st century. This is not to say that nothing needs to be done for the time being to reduce CO2 emissions. Rather, we must prepare for the future by investing sufficiently in the development of future energy technologies.