RESUMO
Although the world understands the possible threat of the future of climate changes, there remain serious barriers to be resolved in terms of policy decisions. The scientific and the societal uncertainties in the climate change policies must be the large part of this barrier. Following the Paris Agreement, the world comes to the next stage to decide the next actions. Without a view of risk management, any decision will be "based on neglecting alternatives" behavior. The Ministry of the Environment, Japan has established an inter-disciplinary research project, called Integrated Climate Assessment-Risks, Uncertainties, and Society (ICA-RUS) conducted by Dr. Seita Emori, National Institute for Environmental Studies. ICA-RUS consists of five research themes, i.e., (1) synthesis of global climate risks, (2) optimization of land, water, and ecosystem for climate risks, (3) analysis of critical climate risks, (4) evaluation of climate risk management options, and (5) interactions between scientific and social rationalities. We participated in the fourth theme to provide the quantitative assessment of technology options and policy measures by integrating assessment model simulations. We employ the multi-model approach to deal with the complex relationships among various fields such as technology, economics, and land use changes. Four different types of integrated assessment models, i.e., MARIA-14 (Mori), EMEDA (Washida), GRAPE (Kurosawa), and AIM (Masui), participate in the fourth research theme. These models contribute to the ICA-RUS by providing two information categories. First, these models provide common simulation results based on shared socioeconomic pathway scenarios and the shared climate policy cases given by the first theme of ICA-RUS to see the ranges of the evaluation. Second, each model also provides model-specific outcomes to answer special topics, e.g., geoengineering, sectoral trade, adaptation, and decision making under uncertainties. The purpose of this paper is to describe the outline and the main outcomes of the multi-model inter-comparison among the four models with a focus upon the first and to present the main outcomes. Furthermore, in this study, we introduce a statistical meta-analysis of the multi-model simulation results to see whether the differently structured models provide the inter-consistent findings. The major findings of our activities are as follows: First, in the stringent climate target, the regional economic losses among models tend to diverge, whereas global total economic loss does not. Second, both carbon capture and storage (CCS) as well as BECCS are essential for providing the feasibility of stringent climate targets even if the deployment potential varies among models. Third, the models show small changes in the crop production in world total, whereas large differences appear between regions. Fourth, the statistical meta-analysis of the multi-model simulation results suggests that the models would have an implicit but common relationship between gross domestic product losses and mitigation options even if their structures and simulation results are different. Since this study is no more than a preliminary exercise of the statistical meta-analysis, it is expected that more sophisticated methods such as data mining or machine learning could be applicable to the simulation database to extract the implicit information behind the models.
RESUMO
We estimate the economic value of the natural environment damaged in the Seto Inland Sea after the introduction of the Law on Temporary Measures for the Environmental Conservation of the Seto Inland Sea (Setouchi Law) and the value of the natural environment that survived, using a Contingent Valuation (CV) survey on an Internet web site. The CV survey contains three plans. Plan 1 is to restore 4 ha of reclaimed land. By estimating the Willingness To Pay (WTP) for plan 1, we can appraise the value of the natural environment that was damaged as a result of the original reclamation. Plan 2 is to transplant Zostera (eel-grass) into an area of 10 ha offshore. Plan 3 is to preserve the shore area, a natural habitat for rare animal species, under the National Trust Program. From the WTP for plans 2 and 3, we can estimate the value of the shore area and the areas a little farther offshore. The value of the natural environment damaged in the Seto Inland Sea as a result of reclaiming projects after the introduction of the Setouchi Law and the value of the existing natural environment of the Seto Inland Sea from the WTP for the plans were estimated to about 172 trillion yen (1.46 trillion dollars) and about 424 trillion yen (3.60 trillion dollars), respectively. The results indicate that in the 25 years since the introduction of the Setouchi Law, we have degraded every year about 6.88 trillion yen (58.5 billion dollars) worth of the natural environment by reclaiming. Some seaweed farms and natural shore areas, natural habitats to rare marine life-forms like the horseshoe crab and the fiddler crab have survived, but their value amounts to about 80% of Japan's GDP.
