Ooh, I just came up with another: Norman Borlaug and others spearheading the global Green Revolution in agriculture, effectively rendering Malthusian concerns largely addressed and saving over a billion people. Countries like India and Mexico wouldn't be as populated as they are now if not for that.
Matthew DownhourI like this brainstorm: greatest achievements since 1969. Number one for me: eradicating smallpox What else?