If the tax is small enough to be affordable by these Nigerians, it won't have the required effect on climate.
If the tax is large enough to prevent 400m Nigerians from obtaining a better standard of living that they rightly desire, then they won't agree to it - and there's no way to force them to comply (not that it would be right to force them IMHO) other than a bloody war.
Billions of people in developing countries have justifiable, understandable, fair interests in a reasonable standard of living, achieving which unavoidably (at least in short term) involves increasing emissions, not decreasing them.
If the tax is small enough to be affordable by these Nigerians, it won't have the required effect on climate.
If the tax is large enough to prevent 400m Nigerians from obtaining a better standard of living that they rightly desire, then they won't agree to it - and there's no way to force them to comply (not that it would be right to force them IMHO) other than a bloody war.
Billions of people in developing countries have justifiable, understandable, fair interests in a reasonable standard of living, achieving which unavoidably (at least in short term) involves increasing emissions, not decreasing them.