Toward a low-carbon economy: Insights from low- carbon complexity index

Low-carbon production capability is crucial for national low-carbon development. However, mainstream metrics used to assess national low-carbon development levels, such as carbon emission intensity, carbon productivity and composite environmental indices, fail to quantify this capability. These metrics offer limited utility in forecasting and directing low-carbon development. Therefore, using a sample of 43 countries from the EXIOBASE database, this study develops the low-carbon complexity index (LCCI) and analyzes its effectiveness in evaluating, predicting and guiding national low-carbon development. The results show that the LCCI value range has narrowed from [0.087, 2.031] in 1997 to [0.068, 1.891] in 2022. The LCCI rankings among the top 10 and bottom 10 countries have remained relatively stable over the past 20 years, revealing a carbon lock-in effect. Furthermore, low-carbon complexity significantly influences carbon emission intensity and its decline rate, demonstrating that the LCCI is an effective tool in depicting and forecasting national carbon emission performance. Countries with higher LCCI exhibit lower carbon emission intensity and tend to achieve greater reductions in carbon emission intensity. Based on the relatedness-complexity diagram, industrial support targets and investment prioritization to promote low-carbon transition can be identified.