sábado, novembro 08, 2008

Questão de nomenclatura: Antropoceno ou Holoceno?

Are we now living in the Anthropocene?
GSA Today: v. 18, no. 2, doi: 10.1130/GSAT01802A.1

ABSTRACT

The term Anthropocene, proposed and increasingly employed to denote the current interval of anthropogenic global environmental change, may be discussed on stratigraphic grounds. A case can be made for its consideration as a formal epoch in that, since the start of the Industrial Revolution, Earth has endured changes sufficient to leave a global stratigraphic signature distinct from that of the Holocene or of previous Pleistocene interglacial phases, encompassing novel biotic, sedimentary, and geochemical change. These changes, although likely only in their initial phases, are sufficiently distinct and robustly established for suggestions of a Holocene–Anthropocene boundary in the recent historical past to be geologically reasonable.

The boundary may be defined either via Global Stratigraphic Section and Point (“golden spike”) locations or by adopting a numerical date. Formal adoption of this term in the near future will largely depend on its utility, particularly to earth scientists working on late Holocene successions. This datum, from the perspective of the far future, will most probably approximate a distinctive stratigraphic boundary.

INTRODUCTION

In 2002, Paul Crutzen, the Nobel Prize–winning chemist, suggested that we had left the Holocene and had entered a new Epoch—the Anthropocene—because of the global environmental effects of increased human population and economic development. The term has entered the geological literature informally (e.g., Steffen et al., 2004; Syvitski et al., 2005; Crossland, 2005; Andersson et al., 2005) to denote the contemporary global environment dominated by human activity. Here, members of the Stratigraphy Commission of the Geological Society of London amplify and extend the discussion of the effects referred to by Crutzen and then apply the same criteria used to set up new epochs to ask whether there really is justification or need for a new term, and if so, where and how its boundary might be placed.

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