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Japan's long-term CO2 emission reduction scenarios are assessed with a computable general equilibrium model with recursive dynamics, which was modified in order to assess the effects of renewable energy supply. The period of assessment is from 2000 to 2050 and the increase of gross domestic product per capita was assumed to be 2% per year. The following scenarios in which the level of CO2 emissions in 2050 will be 30% of the level in 1990 or less are proposed: (1) if the renewable energy supply in 2050 is less than the actual potential, an energy intensity improvement of 2.6% per year will bring about a CO2 emission level of 81 MtC in 2050; (2) if the electricity from renewable energy in 2050 can be supplied to the physical potential, and instead of solar heat, 50% more biomass energy can be supplied than the physical potential, the CO2 emission level in 2050 will be 86 MtC by achieving a 2.0% per year energy intensity improvement. When the above two scenarios are appropriately combined, the CO2 emission level in 2050 becomes 66 MtC. In addition to energy efficiency improvement and renewable energy supply, changes in economic activity such as lower material input and higher labor productivity are also important to achieve the above target. [ABSTRACT FROM AUTHOR]

The objectives of this study were to carry out a review of mitigation scenarios that have emerged since the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR), to update the current Emissions Scenarios Database with these scenarios, and to analyze emissions and mitigation scenarios. This article first discusses the characterization of mitigation scenarios and systematically classifies mitigation scenarios. Second, quantitative analyses on gross domestic product (GDP), population, carbon intensity, energy intensity, and carbon taxes are conducted at the regional level in the four regional aggregations used by the IPCC Special Report on Emissions Scenarios. Results show that the range of emissions trajectories is extensive and that the maximum potential mitigation of global CO2 emissions from the baseline level by 2100 is around 95%. There is a correlation between GDP growth and energy intensity improvement. The relationship between energy intensity improvement and carbon intensity reduction changes over the 21st century, with energy intensity improvement outweighing carbon intensity reduction in the first half of the century and carbon intensity reduction becoming more dominant in the latter half. Predicted carbon tax levels for 2100 range from around 50 to 1400 US$/t-C, although a uniform level of carbon tax brings about widely varying CO2 mitigation outcomes across different regions. The range of GDP loss, resulting from CO2 emissions mitigation, varies from -10% to 40% in 2100, with GDP losses in developing regions more evident than those in developed regions. [ABSTRACT FROM AUTHOR]

Using a bottom-up model, the effectiveness of carbon tax policy and a policy mix related to a carbon tax in Japan are assessed to reduce CO2 emissions to the targeted level in the first commitment period of the Kyoto Protocol. In this simulation, only existing technologies and practical new technologies are treated. From the results of the bottom-up model, the necessary carbon tax to achieve the target, a 2% reduction of the CO2 emissions in 1990, is found to be 45000 Japanese yen (JPY)/tC. If the tax revenue is used to decrease the CO2 reduction cost as a policy mix related to the carbon tax, the required tax rate is decreased to 3400J PY/tC. In this simulation, the technologies that make the greatest contribution to CO2 emission reduction are highly efficient gasoline vehicles in the transportation sector, and high-performance motors with inverter control and steel industry energy-saving devices in the industrial sector. The CO2 reduction achieved by these technologies accounts for 44% of the CO2 reduction in the final energy-demand sectors. The quantity of CO2 reduction in the residential sector is almost the same as that in the industrial sector. On the other hand, the additional money granted to the industrial sector is less than 30% of that granted to the residential sector, because the price of subsidized technologies in the industrial sector is less than 15000 JPY/tC, whereas 27% of the subsidized technologies in the residential sector are more expensive than 15000 JPY/tC. [ABSTRACT FROM AUTHOR]

We have been developing a policy support tool, AIM/impact[policy], for use in the integrated assessment of global warming control targets including the stabilization of greenhouse gas concentrations, economically efficient emissions paths to realizing these targets, and consequent impacts and risks of these targets. In this study, a quantitative assessment was made of climate changes and global warming impacts, as well as the timing of greenhouse gas reduction policies, under greenhouse gas stabilization constraints. An energy economic model estimating the optimal emissions path for greenhouse gases and an impact assessment model estimating the impacts of global warming in various fields caused by climate changes under this optimal emissions path were used in our assessment. In contrast to the business-as-usual case, our results showed that in order to maintain greenhouse gas concentrations at less than 500 ppm (by volume), reduction volumes must be 3.0 GtCeq/year by 2020 and 12.2 GtCeq/year by 2050, indicating an urgent need for a full-scale reduction system. [ABSTRACT FROM AUTHOR]

Evaluates investment as a robust adaptation strategy in response to projected climate change in China. Modern optimal economic growth theory; Relations between flood prevention infrastructure and flood damage to agricultural and non-agricultural sectors; Marginal adaptation costs to flood damage.

Numerous CO2 emission scenarios have recently been proposed. However, the time ranges of most scenarios are not long enough to allow analysis of their climate implications. An extrapolation method is proposed to link the emission scenarios with atmospheric stabilization targets that take effect centuries after the scenario period. Using this method, emission scenarios proposed previously are extensively applied to 350 to 750 ppmv CO2 targets during the 23rd century, and allowable emission ranges during the 21st century are discussed. [ABSTRACT FROM AUTHOR]

In order to respond to climate change, it is essential to describe possible future greenhouse gas (GHG) emission trajectories in both nonintervention and intervention terms. This paper analyzes long-term GHG mitigation emission scenarios according to alternative development paths in the world and major regions, based on the nonintervention emission scenarios quantified by the Asian-Pacific Integrated Model (AIM). AIM is revised and applied to the quantification of narrative storylines for scenarios of socioeconomic development, and GHG emissions from energy use, land-use change, and industrial production processes are simulated. A wide range of mitigation policies are adopted in this simulation as responses to the climate change. Several target stabilized levels–650, 550 and 450 ppmv–are analyzed. The results show that to achieve stabilization at a different GHG concentration level, a policy package is essential to reach the target concentration level, rather than a single policy. Energy efficiency improvement will be a key contributor to the reduction of GHG emissions as a result of the policy package. The mitigation cost could be at a medium level, without a large loss of economic growth. The developing world could significantly reduce GHG emissions compared with nonmitigation scenarios with sufficient knowledge transfer from developed countries. [ABSTRACT FROM AUTHOR]

Examines the greenhouse gas (GHG) emission scenarios in China. Details of the socioeconomic development and energy activities; Policy implication of GHG emission; Role of Intergovernmental Panel on Climate Change on the study of GHG emission scenarios.