Dysgenics

The worst disaster in history is the ongoing, world-wide loss of our high-IQ population. Forget the Black Death, forget slavery. Forget Tamerlane and the Huns. The loss of the intelligent is the worst because it kills all hope.
Some of the Marxists have simply executed their high-IQ citizens. The liberal-left works tirelessly to decrease births (social security, obeisance to homosexual activists, abortion, feminism). Frequent and massive medical intervention insures that defective genes will be passed on to future generations. Those with high IQs will increasingly be elderly, sickly, and fewer in number
With the intelligent gone we will experience a technology shutdown. Poverty will become general. We will fail to solve the food/energy/water crisis that will soon be upon us. The new diseases that will inevitably pop-up will go uncured.
Moreover, authoritarian rulers will proliferate: mullahs and Marxists both.
The last gift of the technologically-adept will be nuclear weapons - to provide moments of incandescence during the long night.
The Niagara of births from the less intelligent will drown all hope.
Instead of a demi-paradise, a demi-hell.