气候绩效指数Climate Performance Index

Climate change is the greatest public challenge facing humanity in the 21st century, and it is also a comprehensive yardstick for testing a country's development model and sense of responsibility. Internationally prevailing climate rankings often treat "achieved emissions reductions" as the sole criterion, which easily overlooks the ongoing, large-scale transformation of the energy mix—especially the "incremental contribution" marked by large-scale additions of clean-energy capacity.

This index does not directly reproduce the ranks of any existing list, but instead follows CPPPS's own evaluation algorithm, using underlying public data (carbon emission intensity, share of renewable energy, installed clean-energy capacity, annual new installations, and carbon emission reductions) to comprehensively evaluate about 30 major economies worldwide across four dimensions: Scale, Quality, Innovation, and Contribution. Among them, the "Contribution" dimension is a CPPPS signature: it looks not only at stock emission reductions, but places greater weight on future-oriented incremental contributions represented by annual new clean-energy installations and new emission reductions.

Results: China, the United States, Brazil, Germany, and Canada rank in the top five. Overall, large economies with massive economic scale, leading clean-energy manufacturing and capacity additions, and rapidly cleaning energy structures rank ahead; Nordic countries with highly clean energy structures also rank prominently on the strength of "Quality"; economies with high emission intensity and sluggish energy transition rank lower. All data in this ranking are approximations of public knowledge, marked "subject to official figures", permanently free and public, for research and reference only.

The evaluation of climate performance involves four layers: "responsibility, capability, action, and effectiveness". Ranking solely by "achieved emission-reduction magnitude" would understate the true contributions of two types of actors: first, emerging major economies that have enormous economic scale and high historical and total emissions but are now deploying clean energy at an unprecedented scale; and second, developed economies that have long been powered by low-carbon structures such as hydro, wind, and nuclear and thus naturally have low stock emission intensity. This algorithm therefore decomposes the evaluation into four orthogonal dimensions, balancing "stock effectiveness" and "incremental contribution".

Each indicator is first mapped to [0,1] through min-max normalization; large-span scale indicators (GDP, emissions, installed capacity, new installations) take the natural logarithm to avoid head monopoly, and are then weighted hierarchically:

In the formulas, (′) denotes the [0,1] value after min-max normalization; carbon-intensity and emission-intensity indicators are inverted (higher values receive lower scores); scale and capacity indicators are log-transformed before normalization, so that differences among median economies are not swallowed by a few top massive actors.

The logic of the weight design: Quality (0.30) carries the highest weight because emission intensity and energy structure are the most essential "efficiency face" of climate performance; Innovation and Contribution (0.25 each) are tied next, highlighting technological capability and incremental action; Scale (0.20) has the lowest weight, serving only as the baseline of "weight/responsibility" to avoid large economies enjoying an automatic advantage from sheer size. Within the Contribution dimension, "new installations" dominate (0.6), reflecting emission-reduction contributions to the future rather than a reckoning with history.

Economic scale (nominal GDP), total carbon emissions, the share of renewable energy, installed clean-energy capacity, and annual new installations all use approximations of public data from the International Energy Agency (IEA), the International Renewable Energy Agency (IRENA), the World Bank, and national statistical agencies, marked "subject to official figures"; carbon emission intensity is derived from the ratio of total emissions to GDP. Affected by differences in statistical scope (territorial vs. consumption emissions, and whether hydro is included in installed capacity), the approximations carry some error; this model does not involve indicators such as carbon prices, carbon border taxes, or climate finance that are hard to unify in scope, and the ranking is for research and reference only.