Junichiro Oda

Global emission reductions through a sectoral intensity target scheme

If dangerous climatic change is to be avoided, all countries will need to contribute to reductions in greenhouse gas emissions on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. This article discusses the gap between the past (ideal) model analysis for emission reductions and realistic policies. A key requirement for successful policies is their acceptance by as many countries as possible and their ease of practical implementation. The sectoral intensity approach has been proposed for its focus on tangible, practical actions; however, its emission reduction effects have been said to be ambiguous and difficult to evaluate quantitatively. The effects of global emission reduction based upon a sectoral approach to energy and carbon intensity targets are evaluated using an energy systems model with a high regional resolution and a detailed description of technology. This analysis found that deep emission cuts can be achieved by a sectoral approach, provided that developed and developing countries collaborate towards emission cuts under the proposed framework. This framework has a higher potential for agreement by both developed and developing countries.

Estimating option values of solar radiation management assuming that climate sensitivity is uncertain

Significance Stratospheric sulfur injection is an unprecedented manipulation of climate systems to rapidly decrease the global mean temperature and could entail environmental risk as well as confront ethical and governance challenges. Nonetheless, most studies have only evaluated impacts of solar radiation management (SRM) on the premise of its deployment. This paper presents one possible methodology for estimating option values of SRM assuming a fairly moderate scenario on SRM’s use compared with preceding literature, which would be helpful to examine realistic values of SRM for the society where social acceptability of SRM’s actual deployment is not high. Our results emphasize the near- to mid-term role of retaining SRM as a later risk-hedging option in the face of the uncertainty about climate sensitivity. Although solar radiation management (SRM) might play a role as an emergency geoengineering measure, its potential risks remain uncertain, and hence there are ethical and governance issues in the face of SRM’s actual deployment. By using an integrated assessment model, we first present one possible methodology for evaluating the value arising from retaining an SRM option given the uncertainty of climate sensitivity, and also examine sensitivities of the option value to SRM’s side effects (damages). Reflecting the governance challenges on immediate SRM deployment, we assume scenarios in which SRM could only be deployed with a limited degree of cooling (0.5 °C) only after 2050, when climate sensitivity uncertainty is assumed to be resolved and only when the sensitivity is found to be high (T2x = 4 °C). We conduct a cost-effectiveness analysis with constraining temperature rise as the objective. The SRM option value is originated from its rapid cooling capability that would alleviate the mitigation requirement under climate sensitivity uncertainty and thereby reduce mitigation costs. According to our estimates, the option value during 1990–2049 for a +2.4 °C target (the lowest temperature target level for which there were feasible solutions in this model study) relative to preindustrial levels were in the range between

Effect of Power Generation Mix and Carbon Emissions Tax on Investment Timing

2.5 and

Diffusion of energy efficient technologies and CO2 emission reductions in iron and steel sector

5.9 trillion, taking into account the maximum level of side effects shown in the existing literature. The result indicates that lower limits of the option values for temperature targets below +2.4 °C would be greater than

Estimates of GHG emission reduction potential by country, sector, and cost

2.5 trillion.

International comparisons of energy efficiency in power, steel, and cement industries

Electricity production accounts for around 40% of global energy-related CO2 emissions and it is expected that the electricity demand increases to twice the current level in 2050. Therefore it is necessary to invest in low-carbon thermal power plants, nuclear and renewable energy for realizing low-carbon economy. These policies may require a large amount of investment costs, and additionally, the uncertainty increases in a situation surrounding power generation projects and their investments. On the other hand, environmental policy for encouraging use of low carbon emission generation power includes an internalization of the externality for CO2 emissions such as carbon-emissions tax. In this study, we develop a real option model of power generation investments allowing for two uncertainties of the market risk and the introduction of the policy. We analyze the effect of the uncertainties on the power generation mix and the investment timing.