Assessing the applicability of the ICAO carbon emissions calculator at a Chinese plateau airport using operational data

Abstract The International Civil Aviation Organization (ICAO) Carbon Emissions Calculator (ICEC) is widely recognized as an authoritative tool for estimating aviation carbon footprints. However, its globally averaged static assumptions have not been systematically tested in regionally specific operational environments. This study takes Kunming Changshui International Airport (ZPPP)—a high-altitude hub in southwestern China—as a case study and empirically evaluates ICEC’s mapping mechanisms in a regional context using full‑year 2023 operational data from 113,937 flights. The results show that ICEC’s static distance correction does not capture the pronounced directional asymmetry and seasonal variation driven by the mid‑latitude westerly jet and its seasonal intensification. In summer, severe convective weather further induces high daily dispersion in flight times. Regarding emission allocation, passenger load factors exhibit directional asymmetry and seasonal patterns. The average body weight of Chinese adult passengers is approximately 30% lower than ICEC’s default value, and the increased proportion of children during holiday periods further reduces the average passenger mass. Cargo loads show extreme directional imbalance and significant heterogeneity across airlines. These multi‑level biases interact and accumulate, leading to systematic deviations in per‑passenger emission estimates depending on season, route, and airline. This study demonstrates that ICEC’s static assumptions, built upon globally averaged parameters, may produce multidimensional systematic biases when applied to the complex operational environment of a high-altitude airport in China. We recommend that future improvements to international carbon accounting tools introduce direction‑dependent distance corrections, dynamic load parameters, and region-specific passenger mass factors to enhance the fairness and scientific accuracy of emission calculations.