Diagnosing Climate Instability Through Planetary Energy Redistribution: The Planetary Energy Redistribution Index (PEDI)

This study introduces the Planetary Energy Redistribution Index (PEDI), a physically grounded diagnostic metric designed to quantify large-scale energy redistribution dynamics within the Earth’s climate system. While most conventional climate indicators primarily track energy accumulation—such as global temperature trends or ocean heat content— PEDI instead focuses on how excess energy is redistributed across the coupled atmosphere–ocean–land system. The index is derived directly from the planetary energy budget and integrates three physically interpretable energy pathways: planetary radiative imbalance, ocean heat uptake, and land-system energy variability. By combining these components within a thermodynamically consistent framework, PEDI provides an operational measure of the evolving dynamical state of the climate system. Using observational datasets spanning 2003–2024, the analysis shows that PEDI captures shifts in planetary energy redistribution regimes and exhibits temporal lead relationships relative to several indicators of climate variability and instability. These results suggest that PEDI may serve as a physically interpretable large-scale diagnostic tool for monitoring systemic changes in energy redistribution within the Earth system and for investigating emerging instability regimes in the climate system.