Do you know what the number would be if you included developed countries in the calculation? Or perhaps better worded, how much would the total tab for this be

Do you know what the number would be if you included developed countries in the calculation? Or perhaps better worded, how much would the total tab for this be per year? Of course, it's crazy to think it'll be implemented in every corner of the world but maybe this thing will work so well that the holdouts will end up doing it.