We were too conservative in our estimates and other accelerating factors, like loss of the reflectivity of our arctic regions, have entered the game.
This stuff doesn’t go away on any human perceived timeframe even if we stopped entirely. Our beloved capitalists will be able protect themselves for a couple more decades beyond us peasants, but their luxury bunkers with ironically self-sustaining agricultural sections will effectively become the tombs of the families most responsible.
We were just smart enough to make technologies that helped us today and doomed us tomorrow, and still too bone dead stupid not to stop/drastically reduce using them upon discovering the consequences of their use.