Читать книгу Risks and the Anthropocene - Julien Rebotier - Страница 16

Geological time is marked by changes in the state of the Earth. Between the end of the Pleistocene (11,700 years ago) and the 1960s, several events are strong candidates as anthropogenic signatures of geologic epoch change. Lewis and Maslin (2015) explore several hypotheses and select two.

The great fires associated with the Pleistocene mass extinctions are discarded, their traces not being explicitly global enough. The stratigraphic evidence of the beginnings of agriculture and the upheavals of the Neolithic are not considered sufficiently synchronous. The process of industrialization and then the industrial revolution bequeath diverse and temporally dispersed markers. On the other hand, 1610 and 1964 are favored by authors as potential starting points of the Anthropocene.

For 1610, the consequences of the discovery of the Americas by the Europeans at the very end of the 15th century led to the global dissemination of pollens of many species and to the massive sequestration of carbon. In a few decades, the genocidal impact of the bacteriological shock on the Amerindian populations led to the death of 90% of the indigenous population and the rewilding of 50 million hectares of forest, wooded savannahs and grasslands, for lack of manpower to work them. Considerable amounts of CO₂ were captured, removed from the atmosphere, as indicated by the ice cores that report the date of 1610 (Lewis and Maslin 2015, p. 175). For 1964, in the context of the “Great Acceleration,” it is a spike in the concentration of ¹⁴C (a radioactive isotope of carbon) in ice and trees that wins favor with Steffen et al. (2015). The ¹⁴C spike evidenced in the stratigraphic material was linked to a frequency of nuclear explosions on the Earth’s surface unmatched by any other time period.

Each hypothesis reflects an image of societies and their relationship to the environment. The date of 1610 emphasizes the domination and exploitation of resources. The 1964 date points to the concord of an international governance capable of banishing – or at least reducing significantly – the use of nuclear weapons. The fact remains that there is no consensus on the stratigraphic evidence and, above all, that it is only a matter of conforming to the requirements of geology. As such, the axiological controversies surrounding the Anthropocene carry more meaning – and are of greater interest – to the social sciences than the debates on the stratigraphic classification that presides over its identification from the Earth sciences.