Observationally constrained global NOx and CO emissions variability reveals sources which contribute significantly to CO2 emissions

Abstract

Global high-resolution emission inventories of trace gases require refinement to align with ground-based observations, especially for extreme events and changing sources. This study utilizes two satellites to globally quantify NO₂ and CO concentrations on daily to weekly scales and estimate emissions with uncertainty bounds, grid-by-grid, for regions with significant variability in 2010. These emissions demonstrate overall increased emissions and identify missing sources compared with various inventories. The NO_x and CO emissions are 5.76 × 10⁵–6.25 × 10⁶ Mt/yr and 1.06 × 10⁷–2.78 × 10⁷ Mt/yr, representing a mean 200% and 130% increase. Significant emissions originate from typical and atypical sources, exhibiting short-to-medium-term variability, primarily driven by biomass burning and anthropogenic activities, with substantial redistribution and compression due to long-range transport. The extra CO emissions chemically decay into CO₂, resulting in an increase in CO₂ mass equivalent to 3.5% of CO₂ emissions from Central Africa and 6.1% from Amazon, reflecting the importance of addressing CO from biomass burning.