What is the 6th extinction, and how does it compare quantitatively to other such events?
The Sixth Extinction is better known as the Holocene Extinction Event, and is the widespread, ongoing mass extinction of species during the modern Holocene epoch. The large number of extinctions span numerous families of plants and animals including mammals, birds, amphibians, reptiles and arthropods; a sizeable fraction of these extinctions are occurring in the rainforests. Five previous extinction events of historical importance have thus far been chronicled in the geological record. Between 1500 and 2006 CE, 784 extinctions have been documented by the International Union for Conservation of Nature and Natural Resources. However, since most extinctions are likely to go undocumented, scientists estimate that during the 20th century, between 20,000 and two million species became extinct, although the precise total cannot be determined more accurately within the limits of present knowledge. Up to 140,000 species per year (based on Species-area theory) may be the present rate of extincti
