https://phys.org/news/2016-08-anthropoc ... tists.html...after seven years of deliberation, the 35-strong Working Group has unanimously recognised the Anthropocene as a reality, and voted 30-to-three (with two abstentions) for the transition to be officially registered.
"Our working model is that the optimal boundary is the mid-20th century," said Jan Zalasiewicz, a geologist at the University of Leicester.
"If adopted—and we're a long way from that—the Holocene would finish and the Anthropocene would formally be held to have begun."
Scientists refer to the period starting from 1950 as the "Great Acceleration", and a glance at graphs tracking a number of chemical and socio-economic changes make it obvious why.
Concentrations in the air of carbon dioxide, methane and stratospheric ozone; surface temperatures, ocean acidification, marine fish harvesting, and tropical forest loss; population growth, construction of large dams, international tourism—all of them take off from about mid-century.
One of the main culprits is global warming driven by the burning of fossil fuels.
A telltale surge in the spread of invasive plant and animal species is also a legacy of our species.
Clearly many serious scientists (not just "amateur/blogger/advocates") consider the Anthropocene to be a valid term, though, given the geological rate
at which established scientific bodies as the International Commission on Stratigraphy nor the International Union of Geological Sciences move, it is not surprising that they have not yet officially endorsed the terminology to date.
And indeed, the notion that humans are too insignificant to have a lasting effect on the living and geological planet is in fact a standard denialist meme:
https://www.skepticalscience.com/Are-hu ... limate.htmOn the broader issue T raised at the beginning of the thread that we are now essentially entering the mid-Miocene, a recent comment at RealClimate lends support:
#346 MA Rodger says:
30 Oct 2017 at 5:34 AM
...
The mid-Pliocene Warm Period (mPWP) 3 million years ago is certainly an interesting lesson for us. Yet I’m not sure we tackle it properly. One tiff such discussion can generate (and one that can raise passions) is how much CO2 was there during the mPWP? And a missing piece of discussion seems to be the mechanisms that raised CO2 levels causing the mPWP and why temperatures were then reduced ending the mPWP.
On CO2 levels, we get the likes of Hayward et al (2016) saying “atmospheric CO2 concentration is estimated to have ranged between 350 and 450 p.p.m.v.” citing a list of rather old references. (This is pretty much repeating IPCC AR5 which timidly gives credence to each and every data point of every study shown in AR5 fig 5.2a) So what was it? 350ppm? 400? 450?
Myself, I am more inclined towards the idea that CO2 was likely not above 400ppm, as set out in Zhang et al (2013) (not cited by Haywood et al) which shows only error bars topping 400ppm.
We have to go all the way back to 14 million years ago to find a central point topping 400ppm...
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