Spheroidal carbonaceous particles are a defining stratigraphic marker for the Anthropocene

Abstract

There has been recent debate over stratigraphic markers used to demarcate the Anthropocene from the Holocene Epoch. However, many of the proposed markers are found only in limited areas of the world or do not reflect human impacts on the environment. Here we show that spheroidal carbonaceous particles (SCPs), a distinct form of black carbon produced from burning fossil fuels in energy production and heavy industry, provide unambiguous stratigraphic markers of the human activities that have rapidly changed planet Earth over the last century. SCPs are found in terrestrial and marine sediments or ice cores in every continent, including remote areas such as the high Arctic and Antarctica. The rapid increase in SCPs mostly occurs in the mid-twentieth century and is contemporaneous with the ‘Great Acceleration’. It therefore reflects the intensification of fossil fuel usage and can be traced across the globe. We integrate global records of SCPs and propose that the global rapid increase in SCPs in sedimentary records can be used to inform a Global Standard Stratigraphic Age for the Anthropocene. A high-resolution SCP sequence from a lake or peatland may provide the much-needed ‘Golden Spike’ (Global Boundary Stratotype Section and Point).

Response to: Comment on “Peatland carbon stocks and burn history: Blanket bog peat core evidence highlights charcoal impacts on peat physical properties and long‐term carbon storage” by Evans et al. (Geo: Geography and Environment 2019; e00075)

“…Importantly, a more recent date is also supported by a publication (poster) using 1976 as the SCP peak with Evans listed as a co-author (Collier et al, 2016). Therefore, the selection of 1975 as the peak age, which sits comfortably with the 1977 ± 5 estimate given by Swindles et al (2015), probably had very little impact on the findings of our study. Figure 1 clearly shows that the peak shape is very similar for all three sites.…”

“…Therefore, the selection of 1975 as the peak age, which sits comfortably with the 1977 ± 5 estimate given by Swindles et al (2015), probably had very little impact on the findings of our study. SCP counts shown in Swindles et al, 2015). However, we agree that our study would have benefited from additional dating methods, which we stated within the paper.…”

“…We provided all the relevant information regarding SCP dating. Secondly, Swindles et al (2015) state a peak age of 1977 ± 5 for a blanket bog at Malham Tarn in the Yorkshire Dales, which is very close to all three of our peatland sites. Firstly, Swindles (2010) identified the peak as 1979 but with a considerable tendency towards a younger age (i.e., the shape of the curve is flatter towards a younger age).…”

Anthropogenic- and natural sources of dust in peatland during the Anthropocene

“…3). This is linked with the appearance of other chronomarkers, e.g., spheroidal carbonaceous particles (SCP), whose numbers have rapidly increased everywhere after the second world war19. SAP are a typical inorganic, glassy component of fly ash generated during industrial coal combustion2122232425 and are found even in regions located far from industrial centres, e.g., Greenland (Summit area)26 and the glaciers of Tianshan27.…”

“…1)141516. Furthermore, no existing studies identify the recently proposed Anthropocene period, the period in which human activity dramatically altered all earth systems171819. Here, we provide a first high-resolution record of dust flux as evidence for geochemical anomalies of both anthropogenic- and natural origin in the Mukhrino peatland in Western Siberia (Fig.…”