Browsing by Subject "CARBON-CYCLE"

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Open Access
Making the case for a formal Anthropocene Epoch: An analysis of ongoing critiques
(Newsletters on Stratigraphy, 2017-01-01) Zalasiewicz, J; Waters, CN; Wolfe, AP; Barnosky, AD; Cearreta, A; Edgeworth, M; Ellis, EC; Fairchild, IJ; Gradstein, FM; Grinevald, J; Haff, P; Head, MJ; do Sul, JAI; Jeandel, C; Leinfelder, R; McNeill, JR; Oreskes, N; Poirier, C; Revkin, A; Richter, DDB; Steffen, W; Summerhayes, C; Syvitski, JPM; Vidas, D; Wagreich, M; Wing, S; Williams, M
© 2017 The Authors. A range of published arguments against formalizing the Anthropocene as a geological time unit have variously suggested that it is a misleading term of non-stratigraphic origin and usage, is based on insignificant temporal and material stratigraphic content unlike that used to define older geological time units, is focused on observation of human history or speculation about the future rather than geologically significant events, and is driven more by politics than science. In response, we contend that the Anthropocene is a functional term that has firm geological grounding in a well-characterized stratigraphic record. This record, although often lithologically thin, is laterally extensive, rich in detail and already reflects substantial elapsed (and in part irreversible) change to the Earth System that is comparable to or greater in magnitude than that of previous epoch-scale transitions. The Anthropocene differs from previously defined epochs in reflecting contemporary geological change, which in turn also leads to the term's use over a wide range of social and political discourse. Nevertheless, that use remains entirely distinct from its demonstrable stratigraphic underpinning. Here we respond to the arguments opposing the geological validity and utility of the Anthropocene, and submit that a strong case may be made for the Anthropocene to be treated as a formal chronostratigraphic unit and added to the Geological Time Scale.
Open Access
The Anthropocene: A conspicuous stratigraphical signal of anthropogenic changes in production and consumption across the biosphere
(Earth's Future, 2016-03-01) Williams, M; Zalasiewicz, J; Waters, CN; Edgeworth, M; Bennett, C; Barnosky, AD; Ellis, EC; Ellis, MA; Cearreta, A; Haff, PK; Ivar Do Sul, JA; Leinfelder, R; McNeill, JR; Odada, E; Oreskes, N; Revkin, A; Richter, DDB; Steffen, W; Summerhayes, C; Syvitski, JP; Vidas, D; Wagreich, M; Wing, SL; Wolfe, AP; Zhisheng, A
© 2016 The Authors. Biospheric relationships between production and consumption of biomass have been resilient to changes in the Earth system over billions of years. This relationship has increased in its complexity, from localized ecosystems predicated on anaerobic microbial production and consumption to a global biosphere founded on primary production from oxygenic photoautotrophs, through the evolution of Eukarya, metazoans, and the complexly networked ecosystems of microbes, animals, fungi, and plants that characterize the Phanerozoic Eon (the last 541 million years of Earth history). At present, one species, Homo sapiens, is refashioning this relationship between consumption and production in the biosphere with unknown consequences. This has left a distinctive stratigraphy of the production and consumption of biomass, of natural resources, and of produced goods. This can be traced through stone tool technologies and geochemical signals, later unfolding into a diachronous signal of technofossils and human bioturbation across the planet, leading to stratigraphically almost isochronous signals developing by the mid-20th century. These latter signals may provide an invaluable resource for informing and constraining a formal Anthropocene chronostratigraphy, but are perhaps yet more important as tracers of a biosphere state that is characterized by a geologically unprecedented pattern of global energy flow that is now pervasively influenced and mediated by humans, and which is necessary for maintaining the complexity of modern human societies.