In the graph below, we have plotted literacy in India against fertility by state.
We need to do some proper calculations of the deviations, but it looks very much like a very high inverse correlation between fertility rates and literacy rates.
Therefore one of the following is true:
1. Higher literacy rates cause lower birthrates;
2. Lower birthrates cause higher literacy rates (highly unlikely);
3. Something else causes lower birthrates, and higher literacy rates as well.
Our next step is to find out if #1 is true.
It has been suggested that lowering birthrate is probably the most effective method of reducing global warming. (See http://www.optimumpopulation.org/reducingemissions.pdf)
Therefore if we can lower birthrate cheaply by making people literate, we can reduce global warming by making people literate.
To see a full-size version of the graph, please click here.