How do you argue with the younger generations that we need to heed our ecological footprint now to avoid inevitable disasters on our planet?
Darius the Great of Persia and his irrigation policies are a very apt cautionary tale with regards to our present ecological footprint. Darius, after ascending to the throne in 522 BCE, instituted vast irrigation projects of both pipelines and canals which made the desert flower. Unfortunately, bringing groundwater to the surface where it is subject to evaporation leads to eventual deposition of salts precipitated out of the water, especially in hot climates. This evaporative salt deposition results in increasing salinity of the soil and eventual inability to grow crops. Some authors have speculated that this was one of the reasons for the failure of the Persian empire, allowing Alexander to decisively beat them in 331 BCE. (Huge victory, worth reading about) So what's the take home lesson for us and our future ...
The irrigation policies of Darius the Great provide a lesson in unforeseen results. Soil salinity increases from evaporation of ground water irrigation may have contributed to the fall of the Persian Empire. We are treading a similar path in California, the midwest, and in regions of central Asia. Heeding the lessons from the Persian experience could be useful for present day policy decisions.