A world with fewer people would emit less greenhouse gases?

A world with fewer people would emit less greenhouse gases

read the economist article here

Combating environmental greenhouse issues via the availability of contraception to women - it is indeed a very refreshing proposition.
There is, however, in my opinion, a Catch-22 here.
Let me put this into perspective.
The article seem to suggest that the population boom in the coming years would be contributed mainly from the developing countries,
and therefore contraception should be made available to the women in those countries. 7bucks spent on providing family planning as opposed to 32bucks spent on green technologies, seems like a pretty good deal? But I doubt this will ever work out, and definitely not as cheap as 7bucks. The people firstly need to have sex education to truly understand the benefits of contraceptive. You can't force something upon them.
The implementation of education + supply of contraceptives = 7bucks per family? they think what, people only have sex 5 times a year?
And therein lies the irony of it all- the fact that the ones responsible for the bulk of global carbon emission are the G8 countries.