Scientists say we are in a new epoch.

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The Romulan Republic
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Scientists say we are in a new epoch.

Post by The Romulan Republic »

www.cbc.ca/news/technology/anthropocene-paper-1.3393823
We're living through one of the most extraordinary events in Earth's history — the start of a new geological epoch, an international group of scientists says.

Welcome to the Anthropocene, everyone.

Geological epochs are long periods of time — typically lasting around two million years — separated by major, global changes to the planet, such as the massive exploding meteor that ended the Late Cretaceous and wiped out the dinosaurs.

'They've left a permanent record in our sediments and our soils and our glacial ice that's going to be detectable for millennia.'
- Colin Waters, Anthropocene Working Group
Modern humans arose during the Pleistocene epoch, and since the sudden warming that ended the last ice age about 12,000 years ago, we had been living in the Holocene epoch.

But modern human technology has had such a profound effect on our planet that we're now in a new epoch that started during the mid-20th century — the Anthropocene, argues an international group of researchers in a new paper published today in the journal Science.

Alex Wolfe
University of Alberta researcher Alexander Wolfe studies the remains of lake microorganisms in layers of sediments deposited over decades and centuries, and says he has personally observed enormous changes marking the past 50 years. (University of Alberta)

The boundary between two epochs is visible to geologists as some kind of "marker" between layers of rock, soil or ice that are deposited all over the Earth over time. For example, the Late Cretaceous-ending meteor left a distinct layer of iridium.

In the case of the Anthropocene, scientists note that humans have produced unusual materials like radioactive fallout from nuclear tests in the 1950s and 1960s.

"They've left a permanent record in our sediments and our soils and our glacial ice that's going to be detectable for millennia," said Colin Waters, a geologist with the British Geological Survey and secretary of the Anthropocene Working Group, whose members authored the new report.

"Geologists in millions of years time will look back at and say, 'Something quite incredible happened at this time' and be quite precise about when it happened."

In their paper, the researchers added, "Not only would this represent the first instance of a new epoch having been witnessed firsthand by advanced human societies, it would be one stemming from the consequences of their own doing."

CHINA-PROPERTY/PRICES
Concrete is among the unusual materials - and a type of rock - that humans have spread all over the Earth in a distinct layer. A wide range of such materials is listed in the new paper. (John Woo/Reuters)

Nobel Prize-winning scientist Paul Crutzen first proposed in 2002 that a new geological epoch called the Anthropocene be assigned to the present to describe the profound changes that humans have made to the planet.

That eventually led the International Commission on Stratigraphy, the scientific body that officially decides when epochs begin and end, to ask a group of geologists, paleontologists and other scientists to look into whether there was enough science to back up that proposal. The Anthropocene Working Group has been working on the question since 2009.

Many markers

In the new paper summarizing their findings, they list a large number of "markers" that humans have left in rock, soil and ice around the world. In addition to the radioactive fallout, they make a note of:

Pottery
Glass
Bricks
Concrete
Copper alloys
Elemental aluminum (only found as an ore in nature).
Plastics
Black carbon and other particles from fossil fuel combustion.
High levels of nitrogen and phosphorus from fertilizers and pesticides.
The start of new epochs is often accompanied by climate change and mass extinctions, both of which humans are causing now.

"Humans now control several of the fundamental dials or knobs on the planetary system," said Alexander Wolfe, an adjunct professor of paelobiology at the University of Alberta who is a member of the working group and a co-author of the paper.

Wolfe studies the remains of lake microorganisms in sediments deposited over decades and centuries, and says he has personally observed enormous changes marking the past 50 years.

Making new rocks

Nevertheless, he acknowledged that the group has faced some criticism from people who feel the Earth hasn't had enough time to make enough rock to really define a new geological epoch.

"The reality is we've done some calculations and there's the equivalent of one kilogram of concrete produced by humans for every square metre of the planet," he said.

hi-bc-111129-bottles-recycling-cp
Plastics are also among man-made materials that will be found in ice and sediments from the past 50 years. (CP)

The new epoch isn't official yet. The Anthropocene Working Group still needs to:

Decide exactly when the Anthropocene began.
Decide what formal marker they'll use to define it and then choose a location in which to drive a "golden spike" into the rock at that marker at a place on Earth where the marker is very distinct.
Formally present its arguments to the International Commission of Stratigraphy and have them accepted.
For now, the group suggests making the start 1950 — when humans started having a really major effect on the planet — and the marker of nuclear fallout from Cold War nuclear tests.

"It's an absolutely bomber marker that fits right in the middle of this transition," Wolfe said.
Huh. So... Anthropocene era has commenced, apparently. And it took us 65 years, give or take, to figure it out.
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SpottedKitty
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Re: Scientists say we are in a new epoch.

Post by SpottedKitty »

Interesting, but I wonder how new the idea actually is. I've seen the name mentioned here and there for at least the last few years; maybe five, maybe a bit more.
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Re: Scientists say we are in a new epoch.

Post by Ziggy Stardust »

There's nothing particularly new about this. Scientists have been arguing for over a decade now about when the official "start" date of the Anthropocene epoch was. Almost nobody has argued that we aren't currently in that epoch, but only when you would consider it officially to have begun. Last year I remember a paper being published that put the start date at 1610, with the beginning of the Columbian exchange. Others have proposed the Industrial Revolution, or even as far back as the development of agriculture. This is just the most recent of a long string of proposals; and here they are using the development of atomic technology as the cut-off point.

The only reason the Anthropocene isn't "official" is because nobody has been able to decide when it started. To my knowledge, no prominent scientists (or at least very few) have argued that we AREN'T in the Anthropocene.

And besides, it STILL isn't official, yet. The Working Group only finished writing up its proposal, which will be considered by International Commission on Stratigraphy later this year, and thereafter it will have to be considered by the International Union of Geologic Sciences.
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Re: Scientists say we are in a new epoch.

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The thing about the whole "Anthropocene" thing is that there are arguments being put forth that human deforestation created a minor global warming that prevented the earth from going back into the ice age. Under that argument, the "anthropocene" extends back through most of the holocene.

If you were to dimiss these arguments and/or only put it down to nuclear testing, I'm not sure a since 1610 or 1945 are really long enough to put the "epoch" label on it. In the case of this definition, it's not as if nuclear tests are even happening anymore (for the main part), and they haven't had a massive impact on the planet itself.
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xthetenth
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Re: Scientists say we are in a new epoch.

Post by xthetenth »

jwl wrote: If you were to dimiss these arguments and/or only put it down to nuclear testing, I'm not sure a since 1610 or 1945 are really long enough to put the "epoch" label on it. In the case of this definition, it's not as if nuclear tests are even happening anymore (for the main part), and they haven't had a massive impact on the planet itself.
It's a handy one because it's very obvious which side of the event things fall on, and the general assumption is that the changes are big enough that if we all just leave they'll still be there and the epoch will continue.
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Re: Scientists say we are in a new epoch.

Post by Ziggy Stardust »

jwl wrote: If you were to dimiss these arguments and/or only put it down to nuclear testing, I'm not sure a since 1610 or 1945 are really long enough to put the "epoch" label on it.
That doesn't make any sense. That's like saying we can't call the 21st century a century because it hasn't 100 years long, yet. The entire point of defining it as an epoch is to say that the changes wrought are such that the world is irrevocably changed from its general biological and ecological profile in the previous epoch. The definition isn't supposed to be with reference to right NOW.
jwl wrote: In the case of this definition, it's not as if nuclear tests are even happening anymore (for the main part), and they haven't had a massive impact on the planet itself.
Nobody said that the nuclear tests themselves had a massive impact on the planet, but rather that the development of atomic energy marked a significant technological threshold that simply and clearly delineates the world before vs the world after.

That said, I'm not a huge fan of this particular cut-off. I think that the development of agriculture or the beginning of the Columbian exchange are more momentous; they changed the planet in an EVOLUTIONARY sense. Both of those events completely changed the evolutionary "trajectories" (so to speak) of millions of species in a way that no other single development has.
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Re: Scientists say we are in a new epoch.

Post by jwl »

Ziggy Stardust wrote:
jwl wrote: If you were to dimiss these arguments and/or only put it down to nuclear testing, I'm not sure a since 1610 or 1945 are really long enough to put the "epoch" label on it.
That doesn't make any sense. That's like saying we can't call the 21st century a century because it hasn't 100 years long, yet. The entire point of defining it as an epoch is to say that the changes wrought are such that the world is irrevocably changed from its general biological and ecological profile in the previous epoch. The definition isn't supposed to be with reference to right NOW.
But how do we know that is is irrecoverably changed if there hasn't been enough time yet to put it to the test.

jwl wrote: In the case of this definition, it's not as if nuclear tests are even happening anymore (for the main part), and they haven't had a massive impact on the planet itself.
Nobody said that the nuclear tests themselves had a massive impact on the planet, but rather that the development of atomic energy marked a significant technological threshold that simply and clearly delineates the world before vs the world after.
But if you look at other changes between epochs, the layer of rock between the epochs is actually relevant to the event that makes the changes. In this case it isn't, any changes man has made to the planet are completely independent of nuclear testing during the cold war. And actually, going on the extended abstract of their paper, the segment on cold war testing seems to me to be rather dodgy. They talk about nuclear fallout producing large amounts of 14C and 239Pu, but neglect to mention that both of these have half-lives of mere thousands or tens of thousands of years, meaning that during the next epoch in 2 million years or whatever, the majority of those isotopes will have decayed away. So I don't think it will represent a geological marker in the way that they say it will.
That said, I'm not a huge fan of this particular cut-off. I think that the development of agriculture or the beginning of the Columbian exchange are more momentous; they changed the planet in an EVOLUTIONARY sense. Both of those events completely changed the evolutionary "trajectories" (so to speak) of millions of species in a way that no other single development has.
The thing about the development of agriculture is that happened at the beginning of the Holocene. So why even bother going around calling it the Anthropocene when you could just go on calling it the Holocene like before.
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