With something like this it is impossible to really estimate, even if you are looking only at direct effects (starvation. etc.)

First when you have a chain of necessary companents: (Scientific Invention > development of agricultural techniques > NGO Deploying of techniques > Rich guy funding the deployment > ex politician who convinced the rich guy) , each one can claim full credit for the process.

Then you have to guess what would have happened if this guy didn't do it? Would Mexicans still be farming like 1824?