Perceived feasibility and potential barriers of a net-zero system transition among Japanese experts

Many governments and organizations have committed to net-zero greenhouse gas emissions by 2050, raising questions about the feasibility of these ambitious goals. Existing literature predominantly relies on techno-economic assessments, often overlooking crucial national contexts and sociocultural factors. This study addresses this gap by introducing a novel framework that complements traditional techno-economic approaches. The framework integrates assessments of both perceived feasibility (a probabilistic measure) and multi-dimensional barriers. Applying this framework to Japan, a nation with a relatively slow energy transition, allows for an in-depth analysis of expert perceptions regarding the nation's net-zero pledge. The research questions guiding this study are: (1) How do experts perceive the feasibility and desirability of Japan's net-zero transition, and are there differences across expert groups? (2) What barriers hinder Japan's net-zero transition, and how do experts assess the risks associated with each barrier?

Existing research on the feasibility of net-zero transitions often employs a binary approach, neglecting the probabilistic nature of feasibility. While techno-economic analyses through Integrated Assessment Models (IAMs) offer valuable insights, they often lack the breadth of socio-political considerations necessary for comprehensive assessment. Studies have examined feasibility for specific options (renewable energy expansion, coal phase-out) and at global or regional scales. However, a national-level assessment encompassing diverse perspectives within a shared context remains limited. This study builds upon previous work by incorporating both probabilistic feasibility and desirability, and by explicitly acknowledging the influence of diverse socio-political barriers within a specific national context, addressing the shortcomings of existing approaches.

The researchers developed a framework inspired by political feasibility and future cones, representing feasibility as a probabilistic variable rather than a binary one. A survey instrument was created, incorporating 22 potential barriers to Japan’s net-zero transition, drawn from a literature review, convenience sampling expert interviews and the IPCC’s six-dimensional feasibility assessment framework (geophysical, environmental-ecological, technological, economic, socio-cultural, and institutional). The questionnaire assessed both the probability and impact of each barrier on a Likert scale. The survey, conducted from October 2021 to March 2022, involved over 100 Japanese experts from various fields, recruited from the IPCC author list, Web of Science, and Kakenhi funding database. The response rate was 63.7%. Data analysis involved descriptive statistics and correlation analysis to examine the relationship between perceived feasibility and desirability, as well as the probability and impact of identified barriers. The risk for each barrier was calculated by multiplying perceived probability and impact. The data from survey respondents was anonymized to protect their privacy.

The majority of experts considered a 100% emission reduction by 2050 desirable. However, the perceived feasibility of achieving this goal was centered around 33-66%, with a distribution skewed towards pessimism. Notably, the IPCC/IAM group showed a broader distribution of feasibility assessments compared to other experts. The analysis of barriers revealed that while many barriers showed high potential impacts, the probabilities of occurrence varied considerably. Experts' assessments across disciplines showed substantial agreement, although some nuances were observed (e.g., academics were more optimistic about 33-66% probability for the net-zero goal compared to non-academics). Concerns over nuclear power, lack of national strategies, and insufficient local capacities emerged as high-risk factors (high probability x high impact). The analysis highlighted a weak but positive correlation between perceived feasibility and desirability. The barriers identified reflected Japan's specific circumstances. The most impactful barrier was the concern about adequate clean energy supply, followed by lack of national strategy and limitations in local capacities.

The study's findings underscore the gap between the desirability and perceived feasibility of Japan's net-zero target, emphasizing the need for accelerated action and targeted policy interventions. The identified high-risk barriers—nuclear energy concerns, inadequate national strategy, and limited local capacities—highlight areas needing immediate attention. The discrepancies in feasibility assessments between the IAM/IPCC group and other experts suggest a need for increased dialogue and collaborative research. The unique national context of Japan influences the specific barriers encountered. This framework’s ability to capture such nuances makes it suitable for national-level feasibility assessments in various geographic settings, particularly in data-scarce regions.

This research offers a novel framework for assessing the perceived feasibility and barriers to net-zero transitions, particularly valuable at the national level. The findings highlight the need for more nuanced assessments than those provided by techno-economic approaches alone. Future research could involve longitudinal studies tracking changes in expert perceptions over time, incorporate stakeholder perspectives, and combine quantitative and qualitative methods for a more comprehensive understanding of the complex interplay between feasibility, desirability, and the myriad barriers to net-zero transitions. The framework can be applied to assess feasibility across other sectors and countries, particularly in data-scarce contexts.

The study relies on expert elicitation, which is susceptible to cognitive and motivational biases. While efforts were made to mitigate cognitive biases, the design did not fully address motivational biases. The analysis did not explicitly model interactions between barriers, a limitation given their complexity. The reliance on self-reported data requires careful interpretation.