How to convert mol m-2 s-1 CO2 emission to Megaton day-1 (MtCO2 per day)?
Do the calculation for 1 mol of CO$_2$
1 mol of CO$_2$ weighs 49 grammes = 0.0049 kg
86400 seconds in a day, so 864000 * 0.0049 = 423.36 kg/day/m$^2$
The surface area of the globe is 5.1 x 10$^{14}$ m$^2$ - so 423.6 * 5.1 x 10$^{14}$ = 2.16 x 10$^{17}$ kg/day
Convert from kg to Megatons, 10$^9$ kg in a Megaton  - so we get 1 mol CO$_2$/m$^2$/second = 2.16 x 10$^8$ Megatons/day
This assumes, as farrenthorpe commented, that the molar emission rate represents a rate evenly distributed over the globe - if, for instance it only represented terrestrial emissions, or emissions in a particular region the calculation would need to take that into account.