This project has two objectives. The first is to examine the empirical question of why different countries address a common global challenge in different ways. There are a number of factors that must be considered as potential answers to this question: electoral systems, federal/centralized systems, interests, ideas/beliefs, and so on. Among these, in the Abe Fellowship project I focus on actors' beliefs. As case countries, I have selected Japan, the United States and Germany. At present, there is no viable substitute for fossil fuels. This means that placing limits on GHG emissions, particularly of CO2, poses a fundamental challenge to a traditional, basic, common value – economic prosperity – that these societies have pursued since the Industrial Revolution. Therefore, the likelihood of actors in a given country accepting new beliefs and paradigms and acknowledging limits on the earth's capacity to sustain continuous growth in the quantity of goods and services produced, may explain the differences in climate and energy policy changes in three countries. In examining the explanatory power of this factor, I undertake extensive interviews with stakeholders who have long been involved in climate and energy policymaking, based on semi-structured questionnaires. The second objective of this project is more theoretical – to explore what mechanisms paradigmatic policy change ultimately occurs, and what kind of role actors' beliefs play in the process towards paradigm shifts. As is the case in this project, scholars of comparative politics often assume beliefs as one set of variables explaining differences of policies in different countries. In contrast, scholars of policy process theories argue that core beliefs rarely change. Furthering this argument, beliefs should not be the main factor explaining the differences of policies in different countries. Comparing the interview results from three major countries contributes to exploring the role of beliefs, which in turn offers empirical evidence to examine two contradictory streams of political science thought. For Germany and Japan, I already undertook two rounds of interviews in 2006/2007 and in 2012/2013, and acquired Japanese MEXT/JSPS KAKENHI (18K11757; 2018- 2021) to undertake the third round of interviews. In the Abe Fellowship project, I will conduct interviews with US stakeholders, with the view to including the country in longitudinal, periodical series of interviews. With its economic and political power (with the second largest amount of GHG emissions, the largest economy, and third largest population in the world), the US has always played a crucial role in climate and energy politics. The state was one of the veto players in the 1990s and 2000s, reflecting the interests of business, most notably oil titans. The country then took the lead during the Obama administration, in particular with the conclusion and entry into force of the Paris Agreement. Insofar as President Trump's declaration to withdraw from the Paris Agreement has not necessarily been supported by the US economy as a whole, it is worthwhile to undertake a series of extensive interviews with US stakeholders, identify their present ideas, and compare them with the beliefs of their German and Japanese counterparts.