Reproducibility package for Satellite-Based Measures For Tracking Atmospheric Co₂ And Ch₄ At National, Subnational And Urban Scales

A scalable method for estimating local greenhouse gas emission changes from satellite-based atmospheric composition measures is developed and applied in this paper. Large panels of spatially-referenced, time-stamped atmospheric CO₂ observations from NASA’s OCO-2 and CH₄ observations from ESA’s Sentinel-5P were employed to compute monthly mean concentration anomalies, defined as deviations from global trends. Long- and short-term trend regressions were estimated for cells of high-resolution global grids, and cell-specific results meeting the classical significance test (p ≤ 0.05) were identified as positive or negative trends. These high-resolution findings were aggregated to generate performance scores for geographic areas of arbitrary scale.
The global scalability of the approach was demonstrated with performance assessments for 242 countries and disputed areas, 3,242 provinces, 36,563 sub-provinces, 6,672 Functional Urban Areas, and 670 offshore oil and gas production zones. Regional illustrations were provided for 11 Southeast Asian countries, alongside a global overview organized by World Bank regions and income groups. Findings indicated that long-term CO₂ decreases outnumbered increases, but recent changes (2024–2025) revealed a reversal. By contrast, CH₄ displayed large net decreases in both long- and short-term measures.
Results highlighted substantial variation across regions and income groups. Low-income countries showed the strongest movement toward reductions, yet their contributions remain overshadowed by high-income economies, where performance has been mixed. It is hoped that this methodology will inform global policy dialogue by enabling transparent and comparable emissions assessments. The approach also provides a practical tool for identifying emissions hotspots, supporting policymakers at national and subnational levels in developing targeted mitigation strategies aligned with global climate objectives.