Name given to the human-caused mass-extinction of a large proportion of baseline life and biodiversity on Old Earth; one of the six great extinction events on Earth (the others being the end Ordovician, Late Devonian, end Permian, end Triassic, and end Cretaceous). Only the end-Permian extinction is considered worse in estimated number of species and groups of organisms that died out.
From relatively small beginnings in the Industrial Age the Great Dying became more serious during the Atomic Age, and reached epidemic proportions during the early and middle Information Age. By the late Information Age, most of the damage was done. Some genetic and other information was salvaged in the Burning Library Project, although some significant fraction of even this data set was lost during the Technocalypse. Attempts at reconstruction of the original biota and ecosystems of both Holocene and earlier Terragen periods have been undertaken on a regular basis since the First Federation era, with varying degrees of success and varying degrees of controversy. It is often claimed that GAIA has resurrected all or most of the species and ecosystems lost during the Great Dying (as well as various Pleistocene biota), to the degree that the Earth now is as it was before the rise of humanity, but such statements are believed by serious analysts to be extremely unlikely, or at best exaggeration. In any case, it is impossible to verify these claims, since GAIA only allows very limited access by scientists and instruments to the Earth's surface.