The representative concentration pathways: An overview

This paper summarizes the development process and main characteristics of the Representative Concentration Pathways (RCPs), a set of four new pathways developed for the climate modeling community as a basis for long-term and near-term modeling experiments. The four RCPs together span the range of year 2100 radiative forcing values found in the open literature, i.e. from 2.6 to 8.5 W/m2. The RCPs are the product of an innovative collaboration between integrated assessment modelers, climate modelers, terrestrial ecosystem modelers and emission inventory experts. The resulting product forms a comprehensive data set with high spatial and sectoral resolutions for the period extending to 2100. Land use and emissions of air pollutants and greenhouse gases are reported mostly at a 0.5 × 0.5 degree spatial resolution, with air pollutants also provided per sector (for well-mixed gases, a coarser resolution is used). The underlying integrated assessment model outputs for land use, atmospheric emissions and concentration data were harmonized across models and scenarios to ensure consistency with historical observations while preserving individual scenario trends. For most variables, the RCPs cover a wide range of the existing literature. The RCPs are supplemented with extensions (Extended Concentration Pathways, ECPs), which allow climate modeling experiments through the year 2300. The RCPs are an important development in climate research and provide a potential foundation for further research and assessment, including emissions mitigation and impact analysis

Locked into Copenhagen pledges - Implications of short-term emission targets for the cost and feasibility of long-term climate goals

This paper provides an overview of the AMPERE modeling comparison project with focus on the implications of near-term policies for the costs and attainability of long-term climate objectives. Nine modeling teams participated in the project to explore the consequences of global emissions following the proposed policy stringency of the national pledges from the Copenhagen Accord and Cancún Agreements to 2030. Specific features compared to earlier assessments are the explicit consideration of near-term 2030 emission targets as well as the systematic sensitivity analysis for the availability and potential of mitigation technologies. Our estimates show that a 2030 mitigation effort comparable to the pledges would result in a further “lock-in” of the energy system into fossil fuels and thus impede the required energy transformation to reach low greenhouse-gas stabilization levels (450 ppm CO2e). Major implications include significant increases in mitigation costs, increased risk that low stabilization targets become unattainable, and reduced chances of staying below the proposed temperature change target of 2 °C in case of overshoot. With respect to technologies, we find that following the pledge pathways to 2030 would narrow policy choices, and increases the risks that some currently optional technologies, such as carbon capture and storage (CCS) or the large-scale deployment of bioenergy, will become “a must” by 2030

Transformation of Japan's energy system to attain net-zero emission by 2050

This study assesses Japan's emission pathways aimed at net-zero emissions by 2050, as implied by the Paris Agreement's global climate goal of pursuing efforts to limit the temperature rise to 1.5 °C. Based on a scenario analysis performed using AIM/Enduse [Japan], Japan's energy supply sector requires a radical transformation, including reliance on carbon dioxide removal options such as bioenergy with carbon capture and storage (BECCS) to attain net-zero emissions by 2050 without substantial social changes. By contrast, the gap between the 1.5 and 2 °C scenarios is relatively moderate in demand sectors. The building sector may need to be decarbonized even in the 2 °C case, whereas the transportation sector will face additional challenges, such as electrification and penetration of biofuel, in the 1.5 °C case. Reaching net-zero emissions by 2050 is a huge challenge, since the price of carbon in the net-zero emissions case increases by a factor of four or five over that in the 2 °C case. Moreover, the absence of early action as well as limited use of low-carbon energies would considerably add to the burden. Given these challenges and uncertainties, the potential of other mitigation options, such as drastic social change, large-scale afforestation and international emissions trading, merits consideration

This paper attempts to evaluate the economic impacts of the Kyoto Protocol by using AIM model. It is estimated that the GDP losses to Japan, US, EU, and Russia would be 0.42%, 0.56%, 0.44%, and 0.25%, respectively in case the Annex B countries ratify the Kyoto Protocol and reduce their emissions without emissions trading and without accounting carbon sink. On the other hand, the GDP losses to Japan and EU would grow when the United States would not ratify the Kyoto Protocol, and it is estimated to fall by 0.48% and 0.47% relative to the base case scenario, respectively. The GDP loss of Russia would be 0.17%. The GDP of US would increase by 0.01%. These losses would be recovered if Kyoto mechanisms were adopted. When the emissions trading would be introduced, the GDP losses to Japan, US, and EU would be 0.14%, 0.33% and 0.19%, respectively and Russia would gain GDP by 3.5%. When carbon sink is accounted, the economic impacts can be reduced further. Even when the amount of tradable carbon is restricted, the impacts will become much less. In addition to emission trading, effects of CDM, price induced technical change, and boycott movement are examined. The paper also analyzed the climatic impacts of the mitigation scenarios. Three scenarios are examined. First scenario assumes a goal of the Kyoto Protocol will be achieved in 2010. The second assumes that USA will not ratify the Kyoto Protocol. The third scenario assumes that the emission is reduced at the rate of 5% per decade after 2020. It is found that the temperature will increase to 2.15 ºC by the year 2100 even if the Annex B countries follow the Kyoto protocol and other appropriate countermeasures are taken. If we postpone the reduction policies, climate impacts will become worse. The implementation of the Kyoto Protocol is necessary to keep the temperature increase in 2100 below 2 ºC.

This paper attempts to evaluate the economic impacts of the Kyoto Protocol by using AIM model. It is estimated that the GDP losses to Japan, US, EU, and Russia would be 0.42%, 0.56%, 0.44%, and 0.25%, respectively in case the Annex B countries ratify the Kyoto Protocol and reduce their emissions without emissions trading and without accounting carbon sink. On the other hand, the GDP losses to Japan and EU would grow when the United States would not ratify the Kyoto Protocol, and it is estimated to fall by 0.48% and 0.47% relative to the base case scenario, respectively. The GDP loss of Russia would be 0.17%. The GDP of US would increase by 0.01%. These losses would be recovered if Kyoto mechanisms were adopted. When the emissions trading would be introduced, the GDP losses to Japan, US, and EU would be 0.14%, 0.33% and 0.19%, respectively and Russia would gain GDP by 3.5%. When carbon sink is accounted, the economic impacts can be reduced further. Even when the amount of tradable carbon is restricted, the impacts will become much less. In addition to emission trading, effects of CDM, price induced technical change, and boycott movement are examined

Analysis of Post-Kyoto Scenarios: The Asian-Pacific Integrated Model

The AIM/top-down model is a recursive general equilibrium model used to analyze the post-Kyoto scenarios presented by EMF16. Differences among scenarios mainly arise from the setting of emission trading. Japan's marginal cost is the highest among the Annex I countries except New Zealand, where a relatively high emission reduction is necessary, while the highest GDP loss Is observed in the USA in 2010 in the no trading case. The marginal costs are much less in the global trading case. The countries of the former Soviet Union sell emission rights and the USA buys the largest amount of them. Emission reductions by trading will account for a large part of the total emission reductions if there is no restriction on trading. The GDP gain of the former Soviet Union is the largest in 2010 in the trading cases. The GDP change in Middle East Asia is negative, and reaches the highest level in the no trading case. Carbon leakage is particularly observed in the no trading case.

Two-Level Mathematical Programming for Analyzing Subsidy Options to Reduce Greenhouse-Gas Emissions

In this paper we develop the end-use energy model for assessing policy options to reduce greenhouse-gas emissions. This model evaluates the effects of imposing a carbon tax on various carbon-emitting technologies for reducing CO 2 emissions. It also estimates the effect of combining a carbon tax with other countermeasure policies, such as the introduction of subsidies. The problem can be formulated as two-level mathematical programming. Solution methods for the problem are discussed, and an algorithm to solve the subsidy problem is presented. The conditions under which the conservation technologies would be selected are analyzed with the different carbon tax rates and subsidies. The reduction of CO 2 emissions is calculated based on the introduction of these conservation technologies. Finally, we evaluate the effects of combining a carbon tax with subsidies using the recycled revenues from such a tax