The Paris Agreement requires all signatory countries to make the transition to a carbon neutral society by the early latter half of this century, which calls for fundamental changes in socio-economic systems and activities of all aspects of human life. This paper first examines the implications of the Paris Agreement and SDGs. Then, it reviews global trends of transition to a carbon neutral society as well as issues pertaining to “just transition,” particularly employment impact of phasing out of coal power plant, taking a look at Germany as a case study. The paper then discusses the challenges that the government of Japan is facing, by critically examining “The Long-term Strategy under the Paris Agreement”. Finally, it proposes various policy measures relevant to the transition to a carbon neutral society, in particular, building decentralized and independent locally-based energy systems through the promotion of renewable energy.

The Global Covenant of Mayors for Climate and Energy is the largest network of cities and local governments working towards a carbon neutral society. The signatory cities aim to exceed their NDC's (Nationally Determined Contribution) greenhouse gas emissions reduction targets, adapt to the impacts of climate change, and access safe, affordable and sustainable energy. The member municipalities have clear goals and visions, as well as policy principles such as the Paris Agreement and SDGs.

Region-basis carbon reduction actions are keys for motivating the transition from a high carbon intensive society to a carbon neutral society in Japan. In order to encourage such actions while gaining wider involvement of stakeholders in each region, such as citizens, governments, businesses and NGOs, it is important to develop a common view of the goal—carbon neutral society—and share scenarios on how to reach it. Building a future scenario to reach the goal serves a common ground among stakeholders. Socioeconomic conditions, city designs, lifestyles, energy systems and other factors related to greenhouse gas emissions differ region by region. Future scenarios are not simply miniature versions of the nationwide scenario: a future scenario must be designed for each region. The “regional 2050 pathway calculator (regional 2050 navi)” is a Web- and Excel-based tool for designing future scenarios depicting the active engagement of stakeholders. The tool was developed based on the Asia-Pacific Integrated Assessment Models (AIMs), an integrated assessment model, used for designing the national climate change mitigation action plan in Japan. The tool allows all stakeholders to design future carbon reduction pathways by themselves.

A remarkable trend in the current promotion of public discussion on climate change issues is the introduction of randomly selected citizens' assemblies. In 2019, France and the UK officially announced the launch of citizens' assemblies to discuss the transition to a carbon neutral society, while the Irish government consulted its multipurpose citizens' assembly in 2017 for recommendations on climate policy. This should be regarded as a global trend, rather than merely a local phenomenon, in that it has roots in the development and application of mini-publics techniques over the last few decades around the world, including the World Wide Views project, which has aimed at realizing participatory environmental governance on a global scale. The author's recent trial of a two-day citizen panel on “Decarbonization Transition and the Quality of Life” held in Japan demonstrates that a randomly selected citizens' panel can effectively provide the members of the public with an opportunity to become informed, deliberate on climate change issues, and collectively envision carbon neutral transitions. However, conclusions from a particular citizens' panel may largely depend on its conditions. To take full advantage of this method, it is important to iterate such meetings in different settings and share their results for wider public debates.

In promoting the transition from our current society to a carbon neutral society, sincere dialogue between stakeholders is required. As the younger generation is expected to play an important role in the future, the Next Generation Energy Workshop program was designed to educate and encourage future young leaders. At first, participants share knowledge about climate change and energy issues by reading relevant text books and participating in an interactive lecture. After the lecture, participants are divided into groups of common interest and engage in discussion and in a simulation exercise. After that, the groups are rearranged, and participants discuss issues with other group participants based on established rules. The intensive learning process and discussions often lead to visions related to energy topics that differ from the plan currently developed by the Japanese government. Since the this workshop concept has already been implemented in various occasions, we forecast that this participative workshop style will be conducted by an increasing number of universities, local governments, industries, and NPOs in the future.