Earlier quoted context omitted.
How much ∘C of change in global temperature does this translate to?
On the order of 0. From what I read, we can expect a 1 degree increase if we release somewhere in the ballpark of 100 billion tons of CO2. Using those figures, 3.93 megatons is 0.0000393 degrees. As a point of comparison, humans release roughly 40 gigatons of CO2 per year; 3.93 megatons is 0.0098% of that. As another point of comparison, around 550 gigatons of CO2 is released (and absorbed) by the planet "naturally".…
So we are currently within 20% of what the planet does naturally, which seems not that bad actually.