• 2023.12.18 ｜

  Paper

  Masahiro Sugiyama, Professor

A research paper from Prof. Masahiro Sugiyama’s group published at “Communications Earth & Environment”

The research group from The University of Tokyo, Waseda University, and Nagoya University have published a paper entitled “Perceived feasibility and potential barriers of a net-zero system transition among Japanese experts.”

This paper provides a scientific approach to investigate an emerging concern in Japan: whether a transition to net-zero greenhouse gas emissions would be feasible.

This concern about decarbonization has been discussed mostly based on techno-economic assessments but with broader contextual considerations such as national conditions and local sociocultural characteristics nearly absent. After taking these into account and conducting a survey of 100+ experts using a novel assessment framework, the authors found that most of the experts supported the desirability of the net-zero goal but chose a probability of 33-66% for its feasibility (Fig.1). The distribution of feasibility assessments differs between groups of integrated assessment modelers and authors on the IPCC report compared to more general experts, suggesting opportunities for further exploration within and between research communities. The key barriers reflecting the unique national condition of Japan are also identified, including the limitations of national strategies and clean energy supply (Fig.2).

Fig. 1: Perceived feasibility of achieving long-term national climate goals.

The results are presented according to the goal (columns; 80%, 90%, 100%, and 110% emission reduction, from left to right) and type of respondents (rows; all respondents, IPCC or IAM-related respondents, and others, from top to bottom).

Fig. 2: Risks of all the 22 potential barriers.

Each risk is a multiplication of the perceived impact by the perceived probability. The jittered points represent individual answers whereas the boxplots reveal the summary distributions. Each box represents the 25 percentile, 50 percentile (median) (vertical line in the box), and 75 percentile of risk for each potential barrier. The lines can extend to 1.5 times the interquartile range beyond either the 25 percentile or 75th percentile values. The color of the box represents our own assessment of the relative difficulty of including each factor in quantitative modeling assessments.