Across much of the world where species are at risk of extinction there is an exploding human population. From Africa with rapidly growing populations in the east west and south, to Asia with growing populations in almost all countries, the biggest threat to the continued survival of wild species is the loss of habitat.
The thing is, that a rapidly growing population is generally an issue in countries which are poor. The reason for this is that they have lower standards of healthcare, and therefore less family planning.
As such, if the government were to set up a project which spend a couple of million educating educators in 50 countries across the third world, and supported the resulting work, the growth of the populations in these countries could slow or even stop and go into reverse. This would allow the standard of living to increase again.
Alongside these benefits, would be lower pressures on the wealth of biodiversity which so much of these countries economy is based around.
Importantly, this would be likely to have far more impact than it would cost.