The worst of all possible worlds. In all of the planets of all of the galaxies of all of the universes of all of the infinite multiverses spawned by the fact of existence, there is not a single world worse than that one which we are about to enter, thanks to our affinity for coal-fired power plants and CFC-laden hairspray containers. Life on the barren radiation-bombarded unlivable surface of Mercury would be positively enjoyable in comparison to what is in store for us, according to NASA, who should know.
http://gawker.com/we-have-the-worst-of- ... -493120247
In the past history of Earth, levels of life-on-Earth essential plant-and-tree food (CO2 for Fordama) was many times higher than today. I don't recall reading about the surface of the Earth millions of years ago being worse than "radiation-bombarded" Mercury's.