Quantitative impacts and patterns of greenhouse gas emission trends: implications for global change and policy

The Conference of the Parties (COP) prioritises global greenhouse gas (GHG) emission mitigation, yet rising temperatures and intensifying climate impacts highlight persistent implementation gaps. This study quantifies global patterns and drivers of GHG emissions across major emitting regions from 1990 to 2020, including CO₂, CH₄, N₂O, and fluorinated gases (HFCs, PFCs, SF₆, and NF₃). PCA and LMDI decomposition were applied to assess national climate pledges and projected CO₂-equivalent pathways to 2100, using gas-specific Global Warming Potentials (GWPs). Coefficient of variation and Pearson correlation analyses reveal a strong positive relationship between emissions and GDP, indicating that economic growth remains closely tied to GHG pathways. Results indicate that CO₂ remains the dominant contributor in 2020, followed by CH₄ and N₂O, whose higher GWPs increase long-term warming impacts, with China, the United States, and India emerging as leading emitters. The LMDI analysis reveals that the decline in COVID-19-related emissions from 2019 to 2020 was transient, with marginal shifts in energy and carbon intensity, consistent with the rapid rebound in 2022. Long-term pledge projections to 2100 indicate a persistent implementation deficit; despite widespread net-zero targets, projected emissions remain approximately 20–30% above 1.5 °C consistent pathway levels. Sensitivity analysis reveals that robust effects on GDP are achieved under uncertain perturbations, reinforcing the persistence of the growth-emissions nexus and the importance of collaborative, data-driven global efforts to mitigate climate impacts.