{"id":11497,"date":"2024-03-28T10:00:00","date_gmt":"2024-03-28T10:00:00","guid":{"rendered":"https:\/\/modernsciences.org\/staging\/4414\/?p=11497"},"modified":"2024-03-15T04:51:27","modified_gmt":"2024-03-15T04:51:27","slug":"what-the-anthropocenes-critics-overlook-and-why-it-really-should-be-a-new-geological-epoch","status":"publish","type":"post","link":"https:\/\/modernsciences.org\/staging\/4414\/what-the-anthropocenes-critics-overlook-and-why-it-really-should-be-a-new-geological-epoch\/","title":{"rendered":"What the Anthropocene\u2019s critics overlook \u2013 and why it really should be a new geological epoch"},"content":{"rendered":"\nSimon Turner<\/a>, UCL<\/a><\/em>; Colin Waters<\/a>, University of Leicester<\/a><\/em>; Jan Zalasiewicz<\/a>, University of Leicester<\/a><\/em>, and Martin J. Head<\/a>, Brock University<\/a><\/em><\/span>\n\n

Geologists on an international subcommission recently voted down a proposal<\/a> to formally recognise that we have entered the Anthropocene, a new geological epoch representing the time when massive, unrelenting human impacts began to overwhelm the Earth\u2019s regulatory systems. <\/p>\n\n

A new epoch needs a start date. The geologists were therefore asked to vote on a proposal to mark the beginning of the Anthropocene using a sharp increase in plutonium traces found in sediment at the bottom of an unusually undisturbed lake in Canada<\/a>, which aligned with many other markers of human impacts. <\/p>\n\n

The entire process was controversial<\/a> and the two us who are on the subcommission (chair Jan Zalasiewicz and vice-chair Martin Head) even refused to cast a vote<\/a> as we did not want to legitimise it. In any case, the proposal ran into opposition from longstanding members.<\/p>\n\n

Why this opposition? Many geologists, used to working with millions of years, find it hard to accept an epoch just seven decades long \u2013 that\u2019s just one human lifetime. Yet the evidence suggests that the Anthropocene is very real. <\/p>\n\n

Environmental scientist Erle Ellis was one critic who welcomed the decision, stating in The Conversation<\/a>: \u201cIf there is one main reason why geologists rejected this proposal, it is because its recent date and shallow depth are too narrow to encompass the deeper evidence of human-caused planetary change.\u201d<\/p>\n\n

It\u2019s an oft-repeated argument. But it completely misses the point. When Paul Crutzen first proposed the term Anthropocene in a moment of insight at a scientific meeting in 2000, it was not from realisation that humans have been altering the functioning and geological record of the Earth, or to capture all their impacts under one umbrella term. He and his colleagues were perfectly aware that humans had been doing that for millennia. That\u2019s nothing new.<\/p>\n\n

Crutzen\u2019s insight<\/a> was wholly different. He said that the Earth system \u2013 that is, the really fundamental things like atmospheric composition, climate, all ecosystems \u2013 had recently sharply departed from the stability that they had shown for thousands of years during the Holocene epoch, a stability which allowed human civilisation to grow and flourish. <\/p>\n\n

\n \"Huge<\/a>\n
\n Humans have destabilised the Earth system in many ways.<\/span>\n mykhailo pavlenko \/ shutterstock<\/span><\/span>\n <\/figcaption>\n <\/figure>\n\n

It makes no sense, Crutzen said, to use the Holocene for present time. He conceived the Anthropocene as the time when human impacts intensified, suddenly, dramatically, enough to push the Earth into a new state. The science journalist Andrew Revkin (who thought up the name \u201cAnthrocene\u201d even before Crutzen\u2019s inspiration) aptly called it the \u201cbig zoom<\/a>\u201d.<\/p>\n\n

Flesh on bones<\/h2>\n\n

We\u2019re part of the Anthropocene Working Group (AWG)<\/a> that has been gathering evidence to put geological flesh on the bones of Crutzen\u2019s concept. The AWG had a mandate: to assess the Anthropocene as a potential geological time unit during which \u201chuman modification of natural systems has become predominant\u201d. Thus, not just any impact but a decisive one. <\/p>\n\n

There\u2019s now no doubt about this decisive change \u2013 nor that it has left sufficient marks in recent geological layers<\/a> to justify the description of the Anthropocene as a geological time unit (for such a unit must be able to be read in layers of rock millions of years from now, and not just sensed as a change in conditions). These layers abound in fallout from nuclear bomb tests, microplastics, pesticides, fly ash<\/a>, the shells of invasive species and much else.<\/p>\n\n\n\n

But how can one show the difference between Crutzen\u2019s idea and the \u201cage of humans\u201d Ellis wrote about, which he, with others, has proposed to call an \u201cAnthropocene event<\/a>\u201d extending over 50,000 years or more? We can use the very diagram they used:<\/p>\n\n

\n \"\"<\/a>\n
\n How various human activities have affected the planet over the millennia.<\/span>\n Philip Gibbard, et al., 2022<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

It\u2019s a nicely laid out, easy-to-understand picture that summarises the changes caused by human activity over the last million years. All these things certainly happened. But what is lost here is any sense of the quantified rate and magnitude of change, other than by a little shading. Looking at it, you\u2019d wonder what the fuss was all about.<\/p>\n\n

That\u2019s because there\u2019s no Y-axis (the vertical one). It only has the X-axis, that of time. The Y-axis is what scientists use to show the magnitude of measurements such as temperature and mass. It\u2019s absolutely crucial to get an objective, number-based understanding of what really is happening<\/a>.<\/p>\n\n

Now let\u2019s see how things look when a Y-axis is added. This just shows the last 30,000 years, that includes all the Holocene, but doesn\u2019t use a logarithmic scale (that is, it doesn\u2019t squash up the big numbers) so it more clearly shows how things relate to time.<\/p>\n\n

\n \"Graphs<\/a>\n
\n Global atmospheric concentrations from ice core records of greenhouse gases (carbon dioxide, methane and nitrous oxide) and global temperature over the past 30,000 years. There is a sharp, unprecedented uptick in values in the Anthropocene.<\/span>\n Adapted from Zalasiewicz et al al (2024)<\/a>, CC BY-SA<\/a><\/span>\n <\/figcaption>\n <\/figure>\n\n

The speed and magnitude of recent change jumps out at you. The sharp upturns are essentially Crutzen\u2019s Anthropocene, representing the last 72 years of what has been called the \u201cgreat acceleration<\/a>\u201d of population, consumption, industrialisation, technical innovation and globalisation (a more detailed way of expressing the \u201cbig zoom\u201d). <\/p>\n\n

Similar graphs can be drawn for species extinction and invasion rates, or the production and spread of fly ash, concrete, plastics, and a host of other things. They show that Crutzen\u2019s Anthropocene is real, evidence based, and represents an epoch-scale change (at least). The significance for us all, of course, is that the near-vertical recent trends in these graphs are still, for the most part, rising, zooming us into a new kind of planet. The repercussions cannot fail to last for many thousands of years \u2013 and some will change the Earth for ever.<\/p>\n\n

Epoch vs event<\/h2>\n\n

So the Anthropocene as an epoch is very different from the \u201cevent\u201d of Erle Ellis and others, which encapsulates all human influence on the planet (and so is about a thousand times longer than the epoch, and differs in many other ways). They\u2019re both valid concepts of course, and have some overlap, just like a mouse in some ways overlaps with a blue whale (they\u2019re both mammals, and share a good deal of their genetic code). But they\u2019re different. <\/p>\n\n

It\u2019s absurd, therefore, to give them the same name: to take Crutzen\u2019s term and appropriate it for a wholly different purpose, and in doing so obscuring the real meaning of his insight and its significance. Under a different name (the Anthropolithic, perhaps?), it could perfectly well complement an Anthropocene epoch.<\/p>\n\n

Humans have had a long and complex impact on the planet, true. For almost all that time, they left their marks on Earth \u2013 but did not utterly overwhelm it. Less than a century ago, processes that began during the Industrial Revolution swung into overdrive. That\u2019s the Anthropocene as an epoch. It\u2019s real, it\u2019s already made geology, and it won\u2019t go away. Best to acknowledge it, to help us cope with its consequences. <\/p>\n\n

\n\n
\n \"Imagine\n
\n <\/span>\n \n <\/figcaption>\n <\/figure>\n\n

Don\u2019t have time to read about climate change as much as you\u2019d like?<\/em><\/strong>\n
Get a weekly roundup in your inbox instead.<\/a> Every Wednesday, The Conversation\u2019s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 30,000+ readers who\u2019ve subscribed so far.<\/a><\/em>\"The<\/p>\n\n

\n\n

Simon Turner<\/a>, Senior Research Fellow in Geography, UCL<\/a><\/em>; Colin Waters<\/a>, Honorary Professor, Department of Geology, University of Leicester<\/a><\/em>; Jan Zalasiewicz<\/a>, Professor of Palaeobiology, University of Leicester<\/a><\/em>, and Martin J. Head<\/a>, Professor of Earth Sciences, Brock University<\/a><\/em><\/span><\/p>\n\n

This article is republished from The Conversation<\/a> under a Creative Commons license. Read the original article<\/a>.<\/p>\n\n","protected":false},"excerpt":{"rendered":"Simon Turner, UCL; Colin Waters, University of Leicester; Jan Zalasiewicz, University of Leicester, and Martin J. Head, Brock…\n","protected":false},"author":767,"featured_media":11475,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"nf_dc_page":"","fifu_image_url":"","fifu_image_alt":"","footnotes":""},"categories":[13,18],"tags":[875,234,474],"class_list":{"0":"post-11497","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-earth","8":"category-history","9":"tag-anthropocene","10":"tag-geology","11":"tag-the-conversation","12":"cs-entry","13":"cs-video-wrap"},"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11497","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/users\/767"}],"replies":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/comments?post=11497"}],"version-history":[{"count":1,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11497\/revisions"}],"predecessor-version":[{"id":11498,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/posts\/11497\/revisions\/11498"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media\/11475"}],"wp:attachment":[{"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/media?parent=11497"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/categories?post=11497"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/modernsciences.org\/staging\/4414\/wp-json\/wp\/v2\/tags?post=11497"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}