2030-
Warfare advanced to the point where anyone with a gun, was no longer safe on the Earth's surface. Terrorism had to start being hidden underground instead of among the population. The UN were only a few months from irradiating terror threats. Subsurface bombs were being designed. Ever drop caused a small earthquake within a twenty mile radius from the epicentre, causing the collapse of entire cave systems, some of which are centuries old.
2100-
The UN haven't existed for half a century. Every country now fights each other, blaming them for the loss of trade and treaties. No politician wants to deal with international politicians. Britain is now trying to reopress it's old empire, the USA have torn away into separate states under devolved governments and war is now fought on Mobile bases in the sea and sky. Scientists were given permission to begin human testing of new drugs and implants. They tried several. Most were terminal. 3 worked. One caused a massive bloodlust, similar to that of alcoholism. The second caused undwindling strength from the moon. The final was described as "The key that unlocks the imagination".
2300-
Humans have wiped out most of themselves. Predatory animals are now dominant in most of the landmass. Safe Havens exist, but they are few and far between. Scientists have factionised survivors and now govern the Earth...