High-resolution mapping of combustion processes and implications for CO₂ emissions

Abstract. High-resolution mapping of fuel combustion and CO₂ emission provides valuable information for modeling pollutant transport, developing mitigation policy, and for inverse modeling of CO₂ fluxes. Previous global emission maps included only few fuel types, and emissions were estimated on a grid by distributing national fuel data on an equal per capita basis, using population density maps. This process distorts the geographical distribution of emissions within countries. In this study, a sub-national disaggregation method (SDM) of fuel data is applied to establish a global 0.1° × 0.1° geo-referenced inventory of fuel combustion (PKU-FUEL) and corresponding CO₂ emissions (PKU-CO₂) based upon 64 fuel sub-types for the year 2007. Uncertainties of the emission maps are evaluated using a Monte Carlo method. It is estimated that CO₂ emission from combustion sources including fossil fuel, biomass, and solid wastes in 2007 was 11.2 Pg C yr⁻¹ (9.1 Pg C yr⁻¹ and 13.3 Pg C yr⁻¹ as 5th and 95th percentiles). Of this, emission from fossil fuel combustion is 7.83 Pg C yr⁻¹, which is very close to the estimate of the International Energy Agency (7.87 Pg C yr⁻¹). By replacing national data disaggregation with sub-national data in this study, the average 95th minus 5th percentile ranges of CO₂ emission for all grid points can be reduced from 417 to 68.2 Mg km⁻² yr⁻¹. The spread is reduced because the uneven distribution of per capita fuel consumptions within countries is better taken into account by using sub-national fuel consumption data directly. Significant difference in per capita CO₂ emissions between urban and rural areas was found in developing countries (2.08 vs. 0.598 Mg C/(cap. × yr)), but not in developed countries (3.55 vs. 3.41 Mg C/(cap. × yr)). This implies that rapid urbanization of developing countries is very likely to drive up their emissions in the future.