Abstract The observed inter‐annual variability of Global Dust Events (GDE) occurrence on Mars remains challenging to understand and therefore to predict. Several hypotheses have been investigated so far, but a central aspect seems to be missing: How the heterogeneity of the surface dust cover and regolith particle size distributions relate to regional discrepancies in dust emission. We set up a framework based on saltation theory and surface wind stress scenarios to perform simulations of the vertical dust emission flux at a low computational cost. By implementing a relationship between the Dust Cover Index and dust particle mobilization thresholds and emission efficiencies, our work shows that the geographic heterogeneity of surface dust particle sizes may constitute a key feature to better understand the explosive growth of GDEs and their inter‐annual variability.