Toshinori Ariga

Co-design of national-scale future scenarios in Japan to predict and assess natural capital and ecosystem services

Although the Intergovernmental Platform on Biodiversity and Ecosystem Services has revealed that the development of scenarios is crucial for helping decision makers identify the potential impact of different policy options, there is a lack of reported scenario approach studies in Asia. A new 5-year research project (PANCES) has been developed for predicting and assessing the natural capital and ecosystem services in Japan using an integrated social–ecological system approach via the participation of 15 research institutions and more than 100 researchers. PANCES conducts the development of national-scale future scenarios for exploring potential changes in natural capital and ecosystem services, as well as human well-being, up to 2050 using key direct and indirect drivers including climate change, depopulation, and super-aging, as well as globalization and technological innovation. The Delphi method is employed to generate key drivers that determine different future pathways. Based on the two drivers for scenario axes identified by the Delphi survey and extensive discussion with project members and policy makers, four future scenarios are created, “Natural capital-based compact society”, “Natural capital-based dispersed society”, “Produced capital-based compact society”, and “Produced capital-based dispersed society”, respectively, in addition to the business-as-usual scenario. This study describes a novel approach for collectively designing national-scale future scenarios with qualitative storylines and a visual illustration of the developed scenarios in Japan.

Sensitivities of Simulated Source Contributions and Health Impacts of PM2.5 to Aerosol Models

Chemical transport models are useful tools for evaluating source contributions and health impacts of PM2.5 in the atmosphere. We recently found that concentrations of PM2.5 compounds over Japan were much better reproduced by a volatility basis set model with an enhanced dry deposition velocity of HNO3 and NH3 compared with a two-product yield model. In this study, we evaluated the sensitivities to organic aerosol models of the simulated source contributions to PM2.5 concentrations and of PM2.5-related mortality. Overall, the simulated source contributions to PM2.5 were similar between the two models. However, because of the improvements associated with the volatility basis set model, the contributions of ammonia sources decreased, particularly in winter and spring, and contributions of biogenic and stationary evaporative sources increased in spring and summer. The improved model estimated that emission sources in Japan contributed 35%-48% of the PM2.5-related mortality in Japan. These values were higher than the domestic contributions to average PM2.5 concentrations in Japan (26%-33%) because the domestic contributions were higher in higher population areas. These results indicate that control of both domestic and foreign emissions is necessary to reduce health impacts due to PM2.5 in Japan.