The anthropocene extinction event, anthropocene mass extinction or sixth mass extinction are terms used to describe the current and projected near-future mass extinction event by various commentators. Causes The major drivers behind the current extinction event are habitat destruction (particularly deforestation) and in future, global warming and associated ocean acidification. Alternate descriptions The extinction events described are well-documented, , but the nomenclature used varies. The term Anthropocene is widely used, although not yet formally defined, which incorporates both the earlier Quaternary extinction event and the later Anthropocene extinction event. The Holocene-Anthropocene boundary is contested, with some commentators asserting significant human influence on climate for much of what is normally regarded as the Holocene Epoch. Other commentators place the Holocene-Anthropocene boundary at the industrial revolution.<ref name=Zalasiewicz />