Science & Society The ‘Anthropocene’: alea iacta est The proposal of the ‘Anthropocene’ as a new geological epoch has been submitted for formalization Valentí Rull 1,2 ✉ A lmost two and a half decades after its http://quaternary.stratigraphy.org/working- strata that characterize the new unit and first appearance, the term ‘Anthro- groups/anthropocene/), which recently sub- the particular features—the stratigraphic pocene’ is widely used by many mitted a proposal to the ICS Subcommission markers—that differentiate it from the scholars as if it was already a well-defined of Quaternary Stratigraphy (SQS; http:// underlying unit. Then, the base of the formal epoch of the Geological Time Scale quaternary.stratigraphy.org/) for approval, as new unit is dated using geological methods a first step towards formalization. Downloaded from https://www.embopress.org on January 23, 2024 from IP 83.45.80.101. (GTS) but it is still an informal term and its to provide the chronological framework. precise definition remains uncertain. Rigor This body of evidence is known as the is as important in geology as in any other In a nutshell Global Stratotype Section and Point research discipline, and scientific terms and (GSSP), or more popularly the “golden concepts are therefore subjected to a process Twenty-three years ago, the Danish environ- spike”. Without a GSSP, it is not possible to 1234567890();,: of formalization. mental chemist Paul Crutzen and the Amer- measure geological time and the definition ......................................................... ican ecologist Eugene Stoermer coined the of a new chronostratigraphic unit would term ‘Anthropocene’ to emphasize that the therefore make no sense. Like a sand glass Rigor is as important in geology as global consequences of human activities with no sand, time passes but it cannot be in any other research discipline, have surpassed the range of variability of measured. and scientific terms and concepts the Holocene—the epoch since the end of the ......................................................... last glaciation—which would justify the are therefore subjected to a definition of a new geological epoch (Crutzen Without a GSSP, it is not possible process of formalization. and Stoermer, 2000). Notably, the term to to measure geological time and the ......................................................... designate this new unit implicitly suggested definition of a new the rank of an epoch, as the suffix ‘-cene’ is The units of the GTS are represented in reserved for the epochs of the Cenozoic era, chronostratigraphic unit would the International Chronostratigraphic Chart such as Paleocene, Miocene or Pleistocene. therefore make no sense. (ICC). Without the ICC, it would not In 2009, the AWG, led by the British ......................................................... be possible to understand the geological geologists Jan Zalasiewicz (until 2019) history of our planet or the origin and and Colin Waters, was formed to analyze The GSSP for the ‘Anthropocene’ evolution of life. Such a fundamental frame- Crutzen and Stoermer’s proposal. However, remains undefined though. In 2016, the work therefore requires high scientific it has been criticized by influential strati- AWG members voted that the ‘Anthropo- accuracy. Any new unit to be added graphers, including the ICS Secretary cene’ starting should be placed in the has to meet the requirements of the General, the British geologist Philip mid-20th century, coinciding with the Great International Stratigraphic Guide (ISG) Gibbard, and the IUGS Secretary General, Acceleration when many indicators of and must be approved by the International the American geologist Stanley Finney, who Earth’s anthropization experienced an Commission on Stratigraphy (ICS; https:// are directly involved in the approval/ratifi- abrupt increase (Head et al, 2022). The stratigraphy.org/) and ratified by the Inter- cation of the AWG proposal (Finney, 2014; most suitable stratigraphic markers would national Union of Geological Sciences Gibbard and Walker, 2014; Edwards, 2015; be radioactive fallout, mainly plutonium (IUGS; https://www.iugs.org/) (Rull, 2017). Finney and Edwards, 2015). (239Pu) and radiocarbon (14C), which were This process is similar to the addition of a One of the main critiques is that the generated by atomic tests during the 1940s new element to the Periodic Table of AWG uses environmental criteria to define and 1950s (Zalasiewicz et al, 2017). The Elements (PTE), which is overseen by the this new epoch, but a valid chronostrati- AWG defined a specific date and a set of International Union of Pure and Applied graphic unit must be defined on the basis of stratigraphic markers based on environ- Chemistry (IUPAC). The proposition distinct and characteristic rock bodies as mental considerations before identifying to add the ‘Anthropocene’ as a new the only available evidence for measuring the GSSP, which is contrary to ISG rules. geological epoch was evaluated by the geological time. According to the ISG This proposal was questioned, not only Anthropocene Working Group (AWG; criteria, the first step is to locate the rock because of the procedure but also because it 1 Botanic Institute of Barcelona, Spanish National Research Council (CSIC), Pg. del Migdia s/n, 08038 Barcelona, Spain. 2Institut Català de Paleontologia Miquel Crusafont (ICP- CERCA), Universitat Autònoma de Barcelona, c/ Columnes s/n, 08193 Cerdanyola del Vallès, Barcelona, Spain. ✉E-mail: vrull@csic.es; valenti.rull@icp.cat https://doi.org/10.1038/s44319-024-00065-1 | © The Author(s) EMBO reports 1 EMBO reports Valentí Rull dismissed other possible starting points. Combining the better suited archives and would irreversibly eradicate the ‘Anthro- Indeed, in the original proposal, Crutzen stratigraphic markers, a total of 12 localities pocene’ GSSP (Perkins, 2023). However, the and Stoermer postulated that the ‘Athropo- around the world were selected for a more final proposal, still unpublished, proposes cene’ could encompass the last centuries or intensive study as GSSP candidates (Fig. 1). the above quoted Crawford Lake GSSP to the last millennia, even the whole Holocene, Using these criteria, the ‘Anthropocene’ was define the ‘Anthropocene’. which began 11,700 years ago. Numerous tentatively dated between 1945 and 1968, other studies have proposed a wide range of with most dates occurring in the 1950s Further complications dates within this timeframe and have (Table 1). After a detailed site-by-site emphasized the diachronic (nonsynchronic) analysis, the AWG announced in July 2023 A few years ago, a new possibility emerged nature of human impact across the globe that the best GSSP candidate was the that may challenge the progress made by the (Lewis and Maslin, 2015). Another critique Canadian Crawford Lake. The bomb test AWG during the last decade: a group of was that the sedimentary record accumu- signal (239Pu) is clearly visible in the stratigraphers suggested that the ‘Anthro- lated during barely 70 years is insufficient sediments at approximately 15 cm depth, pocene’ could be defined as an event, rather for characterizing a geological epoch. which corresponds to 1950. This boundary than an epoch (Gibbard et al, 2022). This Nonetheless, the AWG decisions were is also marked by an enhanced sediment could affect the formalization process, as Downloaded from https://www.embopress.org on January 23, 2024 from IP 83.45.80.101. confirmed in 2019 and the task group con- supply from the basin caused by the rapid this group includes the most influential ICS/ centrated on identifying the GSSP that would industrialization of the surrounding area, IUGS critics quoted above. represent this time period, that is, a rock body along with an abrupt decline in elm pollen ......................................................... that meets the preestablished conditions. due to a documented widespread disease of this tree (McCarthy et al, 2023). … a group of stratigraphers Latest developments ......................................................... suggested that the ‘Anthropocene’ could be defined as an event, After a thorough review of the available The most suitable stratigraphic rather than an epoch. evidence (Waters et al, 2018), the AWG markers would be radioactive concluded that the most suitable candidates ......................................................... fallout, mainly plutonium (239Pu) for the ‘Anthropocene’ GSSP were paleoarc- hives able to provide high-resolution— and radiocarbon (14C), which were A geological event is a time-transgressive annual or seasonal— records from the generated by atomic tests during concept that does not need to be homo- 20th century, such as annually laminated the 1940s and 1950s. logated using a fixed point in time and (varved) sediments from lakes and anoxic ......................................................... is therefore able to accommodate the marine basins; annual growth rings from spatiotemporal heterogeneity characteristic trees and corals; or accumulation layers Some critics, especially the American of human impact on Earth. An event is from polar ice caps. The most suitable geologist and former ICS member Lucy not a minor geological feature and can markers were proposed to be the previously Edwards, have argued that barely a few imply fundamental global transformations. mentioned radionuclides, fly ash, heavy centimeters of unconsolidated lake sedi- For example, the Great Oxidation Event metals, biotic turnovers and anthropogenic ments can easily be mixed or removed— (GOE) radically changed the course of introductions, among others (Table 1). even the whole lake could dry out— which evolution and enabled the development of Table 1. The localities of Fig. 1, with indications of the type of archive, the date suggested for the beginning of the ‘Anthropocene’ at each site (A-onset), the thickness of the ‘Anthropocene’ sediments (A-thick) in cm, and the stratigraphic markers. Site Map Archive A-onset A-thick Stratigraphic markers 239 241 East Gotland, Baltic Sea EG Anoxic marine basin 1956 ± 4 26.5 LT, Pu, Am th San Francisco, USA SF Estuary Mid-20 230 (?) Unclear 239 Searsville, USA Sv Lake 1948 366 Pu, SCPs, Pb, BTIs Crawford, Canada Cf Lake 1950 15.6 239 Pu, SCPs, δ15N, BTIs Sihailongwang, China Sl Lake 1953 8.8 LT, 239 Pu, I, C, SCPs, PAHs, δ13C 129 14 Flinders, Australia Fl Coral reef 1958 36.9 239 Pu, C, Sr/Ca, δ18O, δ15N 14 14 239 West Flower Garden, USA WF Coral reef 1957 28.4 C, Pu 239 Palmer, Antarctica Pm Ice sheet 1952 3490 Pu, SCPs 14 Ernesto, Italia Er Cave speleothem 1960 ± 3 0.4 C, S Śnieżka, Poland Sk Peatland 1950-1955 39.5-44.5 239 Pu, 14C, BTIs Beppu, Japan Bp Bay 1953 64.6 LT, 239 Pu, 210 Pb, δ15N 239 Vienna, Austria Vn Urban anthropogenic deposits 1945-1959 30 Pu, AAs, HD AAs anthropogenic artifacts, BTIs biotic turnovers/anthropogenic introductions, HD historical documentation, LT lithology, SCPs spheroidal carbonaceous particles (fly ash). Data from Waters et al (2023). 2 EMBO reports © The Author(s) Valentí Rull EMBO reports Downloaded from https://www.embopress.org on January 23, 2024 from IP 83.45.80.101. Figure 1. The 12 localities selected by the AWG to determine the most suitable GSSP for the ‘Anthropocene’. The locality selected by the AWG as the best GSSP candidate (Crawford Lake; Cf) is highlighted in red. Redrawn from Waters et al (2023). multicellular life and the colonization of necessarily be a quick step, as the SQS Zalasiewicz and Head, were reluctant to land. The GOE was not a point in time but should analyze the proposal in detail. If modify the current proposal to downgrade rather a gradual process lasting approxi- approved, the proposal will be submitted for the ‘Anthropocene’ to one more Holocene mately 300 million years (2400–2100 Ma). ratification to the IUGS where Finney, one stage/age, as suggested by Gibbard and According to Gibbard et al (2022), an of the most active critics of the AWG others (Gibbard et al, 2022). They empha- ‘Anthropocene Event’ could incorporate a proposal, is the Secretary General. size that changes associated with the far broader range of transformative dia- According to Waters (pers. comm.), the ‘Anthropocene’ are of greater magnitude chronic anthropogenic practices than an current AWG Chair, none of these steps are than those associated with current subdivi- ‘Anthropocene Epoch’. The AWG replied guaranteed to pass and there is no pre- sions of the Holocene. Zalasiewicz also that such an event would include all kinds liminary feedback from the ICS, as its stated that there is no plan B and that the of human activities that occurred during the Executive prevented the AWG members AWG will remain attached to the ‘Anthro- past 50 millennia and would obscure the from discussing the issue with SQS mem- pocene’ concept. Regarding the possibility recent abrupt planetary change, which is bers. Waters also noted that the SQS is not of the ‘Anthropocene’ to be upgraded to what an epoch wants to emphasize. In in favor of publishing the submitted propo- an era—actually the ‘Anthropozoic’ (Rull, addition, they recall that the suffix ‘-cene’ sal, which will be posted soon in the 2023 2021)—Edwards stated that, curiously, the characterizes Cenozoic epochs and is there- AWG Newsletter. AWG never considered such an option. fore inappropriate for naming an event Gibbard and Edwards also commented on (Head et al, 2023). Expectations the survival of the ‘Anthropocene’ term, regardless of the final outcome, in a cultural The final proposal There is a real possibility that the ‘Anthro- sense to emphasize the human influence pocene’ proposal will not pass, as a on global environmental issues, a topic The AWG proposal was submitted to the number of relevant ICS/IUGS members that is beyond the competence of geological ICS on October 31, 2023 and is now under have repeatedly questioned AWG deci- organisations. consideration. Within the ICS, the first sions. Noteworthy, the AWG always reaf- The general impression is that both instance is the SQS—which is led by two firmed its position without reconsidering proponents and opponents of the current relevant AWG members, Zalasiewicz and the questioned points, which did not help ‘Anthropocene’ proposal remain attached to the Canadian geologist Martin Head—and to change the opponents’ perspective. their own positions and are reluctant to the second instance is the ICS Executive, What are the alternatives to an eventual change their mind. The AWG has crossed where Gibbard is the Secretary General. rejection? its Rubicon and is waiting for the result of In both cases, a minimum of 60% majority When asked about these alternatives the SQS deliberations. This subcommission is needed for approval. This will not (Rull, 2018), the AWG members, including may endorse or reject the proposal but can © The Author(s) EMBO reports 3 EMBO reports Valentí Rull also request modifications. It is important to and correct status of the ‘Anthropocene’ Finney SC, Edwards LE (2015) The ‘Anthropocene’ note that an eventual rejection does not proposal, not only in scientific publications epoch: scientific decision or political statement? imply the refusal of the ‘Anthropocene’ as a but also in the media or via other commu- GSA Today 26:4–10 stratigraphic term and concept but of nication venues. Sowing more confusion Gibbard PL, Walker MJC (2014) The term the current AWG proposal. Therefore, a about the ‘Anthropocene’ by careless or ‘Anthropocene’ in the context of formal new and different proposition would still uninformed scholars and writers will geological classification. In: Waters CN, be possible. According to Waters (pers. neither benefit the geological sciences nor Zalasiewicz J, Williams M, Ellis MA, Shelling comm.), some SQS members have published discussions about the human impact on AM (eds) A Stratigraphic Basis for the strongly in favor of the AWG proposal and planet Earth. Anthropocene. London Geological Society: others strongly against, and the result is ......................................................... London. p 29–37 uncertain, especially if we consider that a Gibbard PL, Bauer AM, Edgeworth M, Ruddiman 60% majority is required. Alea iacta est. Sowing more confusion about the WF, Gill JL, Merritts DJ, Finney SC, Edwards LE, ‘Anthropocene’ by careless or Walker MJC, Maslin M et al (2022) A practical Societal impact uninformed scholars and writers solution: the Anthropocene is a geological event, not a formal epoch. Episodes The ‘Anthropocene’ concept has been will neither benefit the geological Downloaded from https://www.embopress.org on January 23, 2024 from IP 83.45.80.101. 45:349–357 adopted by a wide range of disciplines— sciences nor discussions about the Gibbard P, Walker M, Bauer A, Edgeworth M, philosophy, sociology, politics, environmen- human impact on planet Earth. Edwards LE, Ellis E, Finney S, Gill JL, Maslin M, tal activism and so on—with different ......................................................... Merritts D, Ruddiman W (2022) The meanings, including an expression of mod- Anthropocene as an event, not an Epoch. J Quat ernity, an attack on Earth’s biosphere, a An interesting observation is that, if the Sci 37:395–399 biological imperative inherent to our own current AWG proposal is approved and Head MJ, Steffen W, Fagerlind D, Waters CN, Poirier species, a consequence of global capitalism ratified by the ICS/IUGS, all humans born C, Syvitski J, Zalasiewicz JA, Barnosky AD, or the decoupling between environmental before 1950 will have originated in a past Cearreta A, Jeandel C et al (2022) The Great health and human welfare (Autin, 2016). In geological epoch, the Holocene. This means Acceleration is real and provides a quantitative some extremist sectors, the rejection of the that more than 310 million humans, almost basis for the proposed Anthropocene Series/ ‘Anthropocene’ proposal would be viewed 4% of the total population, could be Epoch. Episodes 45:359–376 as a ‘negationist’ attitude from geological considered as genuine Holocene living Head MJ, Zalasiewicz JA, Waters CN, Turner SD, science. However, as the proposal’s oppo- fossils. Williams M, Barnosky AD, Steffen W, nents clearly emphasized, any decision to ......................................................... Wagreich M, Haff PK, Syvitski J et al (2023) formalize such an epoch or not will neither The Anthropocene is a prospective epoch/ stop nor aggravate the global environmental … if the current AWG proposal is series, not a geological event. Episodes problems caused by humankind. Other approved and ratified by the ICS/ 46:229–238 scientists remain indifferent about formali- IUGS, all humans born before 1950 Lewis SL, Maslin MA (2015) Defining the zation and have already adopted the Anthropocene. Nature 519:171–180 ‘Anthropocene’ as a matter of fact, regard- will have originated in a past McCarthy FMG, Patterson RT, Head MJ, Riddick NL, less of the final decision, perhaps trusting geological epoch, the Holocene. Cumming BF, Hamilton PB, Pisaric MFJ, Gushulak that formalization is only a matter of time. ......................................................... AC, Leavitt PR, Lafond KM et al (2023) The The persistence of all these options creates varved succession of Crawford Lake, Milton, confusion in the general public and among Ontario, Canada as a candidate Global boundary Peer review information scholars, who are perplexed about the Stratotype Section and Point for the ‘Anthropocene’ and whether or not it is a Anthropocene series. Anthropocene Rev A peer review file is available at https:// scientifically valid term and concept. 10:146–176 doi.org/10.1038/s44319-024-00065-1. The media greatly contribute to this mis- Perkins S (2023) Researchers move closer to perception by announcing the arrival of the mdefining the Antropocene. Proc Natl Acad Sci ‘Anthropocene’ every time the AWG References USA 120:e2310613120 announced some progress in their delibera- Autin W (2016) Multiple dichotomies of the Rull V (2017) The “Anthropocene”: neglects, tions. For example, in 2016, when the task Anthropocene. Anthropocene Rev 3:218–230 misconceptions, and possible futures. EMBO Rep group voted about the onset and the strati- Crutzen PJ, Stoermer EF (2000) The ‘Anthropocene’. 18:1056–1060 graphic markers chosen to define the new Global Change Newsl 41:17–18 Rull V (2018) What if the “Anthropocene” is not epoch, and in 2023, when Crawford Lake was Edwards LE (2015) What is the Anthropocene? EOS formalized as a new geological series/epoch? selected as the GSSP, the media ran headlines 96:6–7 Quaternary 1:24 such as ‘welcome to the Anthropocene’ or ‘the Finney SC (2014) The ‘Anthropocene’ as a ratified Rull V (2021) The Anthropozoic era revisited. Lethaia Anthropocene is here’. unit of the ICS International Chronostratigraphic 54:289–299 However, as explained above, the Chart: fundamental issues that must be addressed Waters CN, Turner SD, Zalasiewicz J, Head MJ approval and ratification of the ‘Anthro- by the Task Group. In: Waters CN, Zalasiewicz J, (2023) Candidate sites and other reference pocene’ proposal is not guaranteed. Scholars Williams M, Ellis MA, Shelling AM (eds) A sections for the Global boundary Stratotype who are concerned with scientific rigor Stratigraphic Basis for the Anthropocene. London Section and Point of the Anthropocene series. should therefore clearly explain the current Geological Society: London. 23–28 Anthropocene Rev 10:3–24 4 EMBO reports © The Author(s) Valentí Rull EMBO reports Waters CN, Zalasiewicz J, Summerhayes C, Fairchild Author contributions not included in the article’s Creative Commons IJ, Rose NL, Loader NJ, Shotyk W, Cearreta A, Valentí Rull: Conceptualization; Visualization; licence and your intended use is not permitted by Head MJ, Syvitski JPM et al (2018) Global Writing—original draft. statutory regulation or exceeds the permitted use, Boundary Stratotype Section and Point (GSSP) for you will need to obtain permission directly from the the Anthropocene Series: where and how to look Disclosure and competing copyright holder. To view a copy of this licence, visit for potential candidates. Earth-Sci Rev interests statement http://creativecommons.org/licenses/by/4.0/. 178:379–429 The author declares no competing interests. Creative Commons Public Domain Dedication Zalasiewicz J, Waters CN, Summerhayes CP, Wolfe waiver http://creativecommons.org/publicdo- A, Barnosky AD, Cearreta A, Crutzen P, Ellis E, Open Access This article is licensed under a main/zero/1.0/ applies to the data associated with Fairchild IJ, Gałuszka A et al (2017) The Working Creative Commons Attribution 4.0 International this article, unless otherwise stated in a credit line to Group on the Anthropocene: summary of License, which permits use, sharing, adaptation, the data, but does not extend to the graphical or evidence and interim recommendations. distribution and reproduction in any medium or creative elements of illustrations, charts, or figures. Anthropocene 19:55–60 format, as long as you give appropriate credit to the This waiver removes legal barriers to the re-use and original author(s) and the source, provide a link to mining of research data. According to standard Acknowledgements the Creative Commons licence, and indicate if scholarly practice, it is recommended to provide Downloaded from https://www.embopress.org on January 23, 2024 from IP 83.45.80.101. The author is grateful to AWG members Colin changes were made. The images or other third party appropriate citation and attribution whenever tech- Waters (Chair) and Alejandro Cearreta for their material in this article are included in the article’s nically possible. comments on the current status of the Creative Commons licence, unless indicated ‘Anthropocene’ proposal. otherwise in a credit line to the material. If material is © The Author(s) 2024 © The Author(s) EMBO reports 5