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Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Here we review the historical genesis of the idea and assess anthropogenic signatures in the geological record against the formal requirements for the recognition of a new epoch. The evidence suggests that of the various proposed dates two do appear to conform to the criteria to mark the beginning of the Anthropocene: 1610 and 1964. The formal establishment of an Anthropocene Epoch would mark a fundamental change in the relationship between humans and the Earth system.
Human activity has been a geologically recent, yet profound, influence on the global environment. The magnitude, variety and longevity of human-induced changes, including land surface transformation and changing the composition of the atmosphere, has led to the suggestion that we should refer to the present, not as within the Holocene Epoch (as it is currently formally referred to), but instead as within the Anthropocene Epoch1-4 (Fig. 1). Academic and popular usage of the term has rapidly escalated5,6 following two influential papers published just over a decade ago1,2. Three scientific journals focusing on the topic have launched: The Anthropocene, The Anthropocene Review and Elementa. The case fora newepochappearsreasonable:whatmatters whendividinggeological-scaletimeisglobal-scalechangestoEarth'sstatus, driven by causes as varied as meteor strikes, the movement of continents and sustained volcanic eruptions. Human activityisnowglobal and is the dominantcauseofmostcontemporaryenvironmentalchange.Theimpacts ofhumanactivitywillprobablybeobservableinthegeologicalstratigraphic record for millions of years into the future7, which suggests that a new epoch has begun4.
Nevertheless, some question the types of evidence8,9, because to define a geological time unit, formal criteria must be met10,11. Global-scale changes must berecordedingeological stratigraphicmaterial,such asrock,glacier iceormarinesediments(seeBox1).Atpresent,thereisnoformalagreement on when the Anthropocene began, with proposed dates ranging from before the end of the last glaciation to the 1960s. Such different meanings may lead to misunderstandings and confusion across several disciplines. Furthermore, unlike other geological time unit designations, definitions will probablyhave effects beyondgeology. For example, defining an early startdate may, inpolitical terms,'normalize' globalenvironmental change. Meanwhile, agreeing a later start date related to the Industrial Revolution may, for example, be used to assign historical responsibility for carbon dioxide emissions to particular countries or regions during the industrial era. More broadly, the formal definition of the Anthropocene...