We describe three fire shifts-that we propose drive changes in fire suppression of biomass between 140 and 50 Ma. These shifts are informed by the key evolutionary changes and innovations listed in each box that are used to determine the fire suppression ratio in the COPSE model (see Fig. 3a). Specific events are marked by labelled red lines. This information is set against the abundance of inertinite (fossil charcoal) found in coals (black line) (data from ref. 47) and changes in angiosperm leaf vein density (grey line) (data from ref. 54) is shown highlighting the transition to plants with high transpiration capabilities.