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Anthropocene
Anthropocene
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Anthropocene
0.000073 – 0 Ma
The invention of electric lights has allowed massive human population centers to be seen from low Earth orbit, demonstrating how humanity's impacts are visible at a global scale.
Chronology
1940 —
1950 —
1960 —
1970 —
1980 —
1990 —
2000 —
2010 —
2020 —
Cenozoic
 
 
 
Subdivision of the Anthropocene according to the Anthropocene Working Group, as of 2024.
Vertical axis scale: Gregorian years
Usage information
Celestial bodyEarth
Regional usageProposed but rejected subdivision of the Quaternary Period
Time scale(s) usedICS Time Scale
Definition
Chronological unitEpoch
Stratigraphic unitSeries
First proposed byAnthropocene Working Group
Lower boundary definitionMinimum atmospheric methane concentration
Lower boundary GSSPCrawford Lake, Ontario, Canada
43°28′05″N 79°56′55″W / 43.46806°N 79.94861°W / 43.46806; -79.94861[1]
Upper boundary definitionPresent day
Upper boundary GSSPN/A
N/A
Upper GSSP ratifiedN/A

Anthropocene is a term that has been used to refer to the period of time during which humanity has become a planetary force of change. It appears in scientific and social discourse, especially with respect to accelerating geophysical and biochemical changes that characterize the 20th and 21st centuries on Earth. Originally a proposal for a new geological epoch following the Holocene, it was rejected as such in 2024 by the International Commission on Stratigraphy (ICS) and the International Union of Geological Sciences (IUGS).[2][3][4]

The term has been used in research relating to Earth's water, geology, geomorphology, landscape, limnology, hydrology, ecosystems and climate.[5][6] The effects of human activities on Earth can be seen, for example, in regards to biodiversity loss, and climate change. Various start dates for the Anthropocene have been proposed, ranging from the beginning of the Neolithic Revolution (12,000–15,000 years ago), to as recently as the 1960s. The biologist Eugene F. Stoermer is credited with first coining and using the term anthropocene informally in the 1980s; Paul J. Crutzen re-invented and popularized the term.[7]

The Anthropocene Working Group (AWG) of the Subcommission on Quaternary Stratigraphy (SQS) of the ICS voted in 2016 to proceed towards a formal golden spike (GSSP) proposal to define an Anthropocene epoch in the geologic time scale. Later that year, the group presented the proposal to the International Geological Congress.[8]

In 2019, the AWG voted in favour of submitting a formal proposal to the ICS by 2021.[9] The proposal located potential stratigraphic markers to the mid-20th century.[10][9][11] This time period coincides with the start of the Great Acceleration, a post-World War II time period during which global population growth, economic growth, pollution and exploitation of natural resources have all increased at a dramatic rate.[12] The Atomic Age also started around the mid-20th century, when the risks of nuclear wars, nuclear terrorism, and nuclear accidents increased.

Twelve candidate sites were selected for the GSSP; the sediments of Crawford Lake (Halton Region), Canada were finally proposed, in 2023, to mark the lower boundary of the Anthropocene, starting with the Crawfordian stage/age in 1950.[13][14]

In 2024, after 15 years of deliberation, the Anthropocene Epoch proposal of the AWG was voted down by a wide margin by the SQS, owing largely to its shallow sedimentary record and extremely recent proposed start date.[15][16] The ICS and the IUGS later formally confirmed, by a near unanimous vote, the rejection of the AWG's Anthropocene Epoch proposal for inclusion in the Geologic Time Scale.[2][3][4] The IUGS statement on the rejection concluded: "Despite its rejection as a formal unit of the Geologic Time Scale, Anthropocene will nevertheless continue to be used not only by Earth and environmental scientists, but also by social scientists, politicians and economists, as well as by the public at large. It will remain an invaluable descriptor of human impact on the Earth system."[4]

Development of the concept

[edit]

As early as 1873, the Italian geologist Antonio Stoppani acknowledged the increasing power and effect of humanity on the Earth's systems and referred to an 'anthropozoic era'.[17] From 1877 onward, the term 'Psychozoic' was used by geologists such as Joseph LeConte and Johannes Herman Frederik Umbgrove.[18][19]

The Anthropocene is characterized by human impacts on their environment, with ramifications for variables such as climate change, biodiversity loss, and global food insecurity.[20]

An early concept for the Anthropocene was the Noosphere by Vladimir Vernadsky, who in 1938 wrote of "scientific thought as a geological force".[21] Scientists in the Soviet Union appear to have used the term Anthropocene as early as the 1960s to refer to the Quaternary, the most recent geological period.[22] Ecologist Eugene F. Stoermer subsequently used Anthropocene with a different sense in the 1980s[23][24] and the term was widely popularised in 2000 by atmospheric chemist Paul J. Crutzen,[7][25] who regarded the influence of human behavior on Earth's atmosphere in recent centuries as so significant as to constitute a new geological epoch.[26]: 21 [27]

The pressures we exert on the planet have become so great that scientists are considering whether the Earth has entered an entirely new geological epoch: the Anthropocene, or the age of humans. It means that we are the first people to live in an age defined by human choice, in which the dominant risk to our survival is ourselves.

Achim Steiner, UNDP Administrator[28]

The term Anthropocene is informally used in scientific contexts.[29] The Geological Society of America entitled its 2011 annual meeting: Archean to Anthropocene: The past is the key to the future.[30] The new epoch has no agreed start-date, but one proposal, based on atmospheric evidence, is to fix the start with the Industrial Revolution c.1780, with the invention of the steam engine.[31][32] Other scientists link the new term to earlier events, such as the rise of agriculture and the Neolithic Revolution (around 12,000 years BP).

Evidence of relative human impact – such as the growing human influence on land use, ecosystems, biodiversity, and species extinction – is substantial; scientists think that human impact has significantly changed (or halted) the growth of biodiversity.[33][34][35][36] Those arguing for earlier dates posit that the proposed Anthropocene may have begun as early as 14,000–15,000 years BP, based on geologic evidence; this has led other scientists to suggest that "the onset of the Anthropocene should be extended back many thousand years";[37]: 1  this would make the Anthropocene essentially synonymous with the current term, Holocene.

Anthropocene Working Group

[edit]

In 2008, the Stratigraphy Commission of the Geological Society of London considered a proposal to make the Anthropocene a formal unit of geological epoch divisions.[6][31] A majority of the commission decided the proposal had merit and should be examined further. Independent working groups of scientists from various geological societies began to determine whether the Anthropocene will be formally accepted into the Geological Time Scale.[38]

The Trinity test in July 1945 has been proposed as the start of the Anthropocene.

In January 2015, 26 of the 38 members of the International Anthropocene Working Group published a paper suggesting the Trinity test on 16 July 1945 as the starting point of the proposed new epoch.[39] However, a significant minority supported one of several alternative dates.[39] A March 2015 report suggested either 1610 or 1964 as the beginning of the Anthropocene.[40] Other scholars pointed to the diachronous character of the physical strata of the Anthropocene, arguing that onset and impact are spread out over time, not reducible to a single instant or date of start.[41]

A January 2016 report on the climatic, biological, and geochemical signatures of human activity in sediments and ice cores suggested the era since the mid-20th century should be recognised as a geological epoch distinct from the Holocene.[42]

The Anthropocene Working Group met in April 2016 to consolidate evidence supporting the argument for the Anthropocene as a true geologic epoch.[43] Evidence was evaluated and the group voted to recommend Anthropocene as the new geological epoch in August 2016.[8]

In April 2019, the Anthropocene Working Group (AWG) announced that they would vote on a formal proposal to the International Commission on Stratigraphy, to continue the process started at the 2016 meeting.[11] In May 2019, 29 members of the 34 person AWG panel voted in favour of an official proposal to be made by 2021. The AWG also voted with 29 votes in favour of a starting date in the mid 20th century. Ten candidate sites for a Global boundary Stratotype Section and Point have been identified, one of which will be chosen to be included in the final proposal.[9][10] Possible markers include microplastics, heavy metals, or radioactive nuclei left by tests from thermonuclear weapons.[44]

In November 2021, an alternative proposal that the Anthropocene is a geological event, not an epoch, was published[45][46] and later expanded in 2022.[47] This challenged the assumption underlying the case for the Anthropocene epoch – the idea that it is possible to accurately assign a precise date of start to highly diachronous processes of human-influenced Earth system change. The argument indicated that finding a single GSSP would be impractical, given human-induced changes in the Earth system occurred at different periods, in different places, and spread under different rates. Under this model, the Anthropocene would have many events marking human-induced impacts on the planet, including the mass extinction of large vertebrates, the development of early farming, land clearance in the Americas, global-scale industrial transformation during the Industrial Revolution, and the start of the Atomic Age. The authors are members of the AWG who had voted against the official proposal of a starting date in the mid-20th century, and sought to reconcile some of the previous models (including Ruddiman and Maslin proposals). They cited Crutzen's original concept,[48] arguing that the Anthropocene is much better and more usefully conceived of as an unfolding geological event, like other major transformations in Earth's history such as the Great Oxidation Event.

In July 2023, the AWG chose Crawford Lake in Ontario, Canada as a site representing the beginning of the proposed new epoch. The sediment in that lake shows a spike in levels of plutonium from hydrogen bomb tests, a key marker the group chose to place the start of the Anthropocene in the 1950s, along with other elevated markers including carbon particles and nitrates from the burning of fossil fuels and widespread application of chemical fertilizers respectively. Had it been approved, the official declaration of the new Anthropocene epoch would have taken place in August 2024,[49] and its first age may have been named Crawfordian after the lake.[50]

Rejection in 2024 vote by IUGS

[edit]

In March 2024, an internal vote was held by the IUGS: After nearly 15 years of debate, the proposal to ratify the Anthropocene had been defeated by a 12-to-4 margin, with 2 abstentions.[16] These results were not out of a dismissal of human impact on the planet, but rather an inability to constrain the Anthropocene in a geological context. This is because the widely-adopted 1950 start date was found to be prone to recency bias. It also overshadowed earlier examples of human impacts, many of which happened in different parts of the world at different times. Although the proposal could be raised again, this would require the entire process of debate to start from the beginning.[15] The results of the vote were officially confirmed by the IUGS and upheld as definitive later that month.[16]

Proposed starting point

[edit]

Industrial Revolution

[edit]

Crutzen proposed the Industrial Revolution as the start of Anthropocene.[17] Lovelock proposes that the Anthropocene began with the first application of the Newcomen steam engine in 1712.[51] The Intergovernmental Panel on Climate Change takes the pre-industrial era (chosen as the year 1750) as the baseline related to changes in long-lived, well mixed greenhouse gases.[52] Although it is apparent that the Industrial Revolution ushered in an unprecedented global human impact on the planet,[53] much of Earth's landscape already had been profoundly modified by human activities.[54] The human impact on Earth has grown progressively, with few substantial slowdowns. A 2024 scientific perspective paper authored by a group of scientists led by William J. Ripple proposed the start of the Anthropocene around 1850, stating it is a "compelling choice ... from a population, fossil fuel, greenhouse gasses, temperature, and land use perspective."[55]

Mid 20th century (Great Acceleration)

[edit]

In May 2019 the twenty-nine members of the Anthropocene Working Group (AWG) proposed a start date for the Epoch in the mid-20th century, as that period saw "a rapidly rising human population accelerated the pace of industrial production, the use of agricultural chemicals and other human activities. At the same time, the first atomic-bomb blasts littered the globe with radioactive debris that became embedded in sediments and glacial ice, becoming part of the geologic record." The official start-dates, according to the panel, would coincide with either the radionuclides released into the atmosphere from bomb detonations in 1945, or with the Limited Nuclear Test Ban Treaty of 1963.[9]

First atomic bomb (1945)

[edit]

The peak in radionuclides fallout consequential to atomic bomb testing during the 1950s is another possible date for the beginning of the Anthropocene (the detonation of the first atomic bomb in 1945 or the Partial Nuclear Test Ban Treaty in 1963).[9]

Minimum atmospheric methane concentration

[edit]

On June 19, 2025, Vincent Gauci proposed that Anthropocene began in 1592. Ice core records had shown a minimum atmospheric methane concentration at that time.[56]

Etymology

[edit]

The name Anthropocene is a combination of anthropo- from the Ancient Greek ἄνθρωπος (ánthropos) meaning 'human' and -cene from καινός (kainós) meaning 'new' or 'recent'.[57][58]

Nature of human effects

[edit]

Biodiversity loss

[edit]

The human impact on biodiversity forms one of the primary attributes of the Anthropocene.[59] Humankind has entered what is sometimes called the Earth's sixth major extinction.[60][61][62][63][64] Most experts agree that human activities have accelerated the rate of species extinction.[35][65] The exact rate remains controversial – perhaps 100 to 1000 times the normal background rate of extinction.[66][67]

Anthropogenic extinctions started as humans migrated out of Africa over 60,000 years ago.[68] Increases in global rates of extinction have been elevated above background rates since at least 1500, and appear to have accelerated in the 19th century and further since.[5] Rapid economic growth is considered a primary driver of the contemporary displacement and eradication of other species.[69]

According to the 2021 Economics of Biodiversity review, written by Partha Dasgupta and published by the UK government, "biodiversity is declining faster than at any time in human history."[70][71] A 2022 scientific review published in Biological Reviews confirms that an anthropogenic sixth mass extinction event is currently underway.[72][73] A 2022 study published in Frontiers in Ecology and the Environment, which surveyed more than 3,000 experts, states that the extinction crisis could be worse than previously thought, and estimates that roughly 30% of species "have been globally threatened or driven extinct since the year 1500."[74][75] According to a 2023 study published in Biological Reviews some 48% of 70,000 monitored species are experiencing population declines from human activity, whereas only 3% have increasing populations.[76][77][78]

Summary of major environmental-change categories that cause biodiversity loss. The data is expressed as a percentage of human-driven change (in red) relative to baseline (blue), as of 2021. Red indicates the percentage of the category that is damaged, lost, or otherwise affected, whereas blue indicates the percentage that is intact, remaining, or otherwise unaffected.[79]

Biodiversity loss happens when plant or animal species disappear completely from Earth (extinction) or when there is a decrease or disappearance of species in a specific area. Biodiversity loss means that there is a reduction in biological diversity in a given area. The decrease can be temporary or permanent. It is temporary if the damage that led to the loss is reversible in time, for example through ecological restoration. If this is not possible, then the decrease is permanent. The cause of most of the biodiversity loss is, generally speaking, human activities that push the planetary boundaries too far.[79][80][81] These activities include habitat destruction[82] (for example deforestation) and land use intensification (for example monoculture farming).[83][84] Further problem areas are air and water pollution (including nutrient pollution), over-exploitation, invasive species[85] and climate change.[82]

Many scientists, along with the Global Assessment Report on Biodiversity and Ecosystem Services, say that the main reason for biodiversity loss is a growing human population because this leads to human overpopulation and excessive consumption.[86][87][88][89][90] Others disagree, saying that loss of habitat is caused mainly by "the growth of commodities for export" and that population has very little to do with overall consumption. More important are wealth disparities between and within countries.[91] In any case, all contemporary biodiversity loss has been attributed to human activities.[92]

Climate change is another threat to global biodiversity.[93][94] For example, coral reefs—which are biodiversity hotspots—will be lost by the year 2100 if global warming continues at the current rate.[95][96] Still, it is the general habitat destruction (often for expansion of agriculture), not climate change, that is currently the bigger driver of biodiversity loss.[97][98] Invasive species and other disturbances have become more common in forests in the last several decades. These tend to be directly or indirectly connected to climate change and can cause a deterioration of forest ecosystems.[99][100]

Biogeography and nocturnality

[edit]

Studies of urban evolution give an indication of how species may respond to stressors such as temperature change and toxicity. Species display varying abilities to respond to altered environments through both phenotypic plasticity and genetic evolution.[101][102][103] Researchers have documented the movement of many species into regions formerly too cold for them, often at rates faster than initially expected.[104]

Permanent changes in the distribution of organisms from human influence will become identifiable in the geologic record. This has occurred in part as a result of changing climate, but also in response to farming and fishing, and to the accidental introduction of non-native species to new areas through global travel.[5] The ecosystem of the entire Black Sea may have changed during the last 2000 years as a result of nutrient and silica input from eroding deforested lands along the Danube River.[105][106]

Researchers have found that the growth of the human population and expansion of human activity has resulted in many species of animals that are normally active during the day, such as elephants, tigers and boars, becoming nocturnal to avoid contact with humans, who are largely diurnal.[107][106]

Climate change

[edit]

One geological symptom resulting from human activity is increasing atmospheric carbon dioxide (CO2) content. This signal in the Earth's climate system is especially significant because it is occurring much faster,[108] and to a greater extent, than previously. Most of this increase is due to the combustion of fossil fuels such as coal, oil, and gas.

Atmospheric CO2 concentration measured at Mauna Loa Observatory in Hawaii from 1958 to 2023 (also called the Keeling Curve). The rise in CO2 over that time period is clearly visible. The concentration is expressed as μmole per mole, or ppm.
In the atmosphere of Earth, carbon dioxide is a trace gas that plays an integral part in the greenhouse effect, carbon cycle, photosynthesis, and oceanic carbon cycle. It is one of three main greenhouse gases in the atmosphere of Earth. The concentration of carbon dioxide (CO2) in the atmosphere reached 427 ppm (0.0427%) on a molar basis in 2024, representing 3341 gigatonnes of CO2.[109] This is an increase of 50% since the start of the Industrial Revolution, up from 280 ppm during the 10,000 years prior to the mid-18th century.[110][111][112] The increase is due to human activity.[113]


Effects of climate change are well documented and growing for Earth's natural environment and human societies. Changes to the climate system include an overall warming trend, changes to precipitation patterns, and more extreme weather. As the climate changes it impacts the natural environment with effects such as more intense forest fires, thawing permafrost, and desertification. These changes impact ecosystems and societies, and can become irreversible once tipping points are crossed. Climate activists are engaged in a range of activities around the world that seek to ameliorate these issues or prevent them from happening.[114]

The effects of climate change vary in timing and location. Up until now the Arctic has warmed faster than most other regions due to climate change feedbacks.[115] Surface air temperatures over land have also increased at about twice the rate they do over the ocean, causing intense heat waves. These temperatures would stabilize if greenhouse gas emissions were brought under control. Ice sheets and oceans absorb the vast majority of excess heat in the atmosphere, delaying effects there but causing them to accelerate and then continue after surface temperatures stabilize. Sea level rise is a particular long term concern as a result. The effects of ocean warming also include marine heatwaves, ocean stratification, deoxygenation, and changes to ocean currents.[116]: 10  The ocean is also acidifying as it absorbs carbon dioxide from the atmosphere.[117]
Thick orange-brown smoke blocks half a blue sky, with conifers in the foreground
A few grey fish swim over grey coral with white spikes
Desert sand half covers a village of small flat-roofed houses with scattered green trees
large areas of still water behind riverside buildings
Some climate change effects: wildfire caused by heat and dryness, bleached coral caused by ocean acidification and heating, environmental migration caused by desertification, and coastal flooding caused by storms and sea level rise.

Geomorphology

[edit]

Changes in drainage patterns traceable to human activity will persist over geologic time in large parts of the continents where the geologic regime is erosional. This involves, for example, the paths of roads and highways defined by their grading and drainage control. Direct changes to the form of the Earth's surface by human activities (quarrying and landscaping, for example) also record human impacts.

It has been suggested[by whom?] that the deposition of calthemite formations exemplify a natural process which has not previously occurred prior to the human modification of the Earth's surface, and which therefore represents a unique process of the Anthropocene.[118] Calthemite is a secondary deposit, derived from concrete, lime, mortar or other calcareous material outside the cave environment.[119] Calthemites grow on or under man-made structures (including mines and tunnels) and mimic the shapes and forms of cave speleothems, such as stalactites, stalagmites, flowstone etc.

Stratigraphy

[edit]

Sedimentological record

[edit]

Human activities, including deforestation and road construction, are believed to have elevated average total sediment fluxes across the Earth's surface.[5] However, construction of dams on many rivers around the world means the rates of sediment deposition in any given place do not always appear to increase in the Anthropocene. For instance, many river deltas around the world are actually currently starved of sediment by such dams, and are subsiding and failing to keep up with sea level rise, rather than growing.[5][120]

Fossil record

[edit]

Increases in erosion due to farming and other operations will be reflected by changes in sediment composition and increases in deposition rates elsewhere. In land areas with a depositional regime, engineered structures will tend to be buried and preserved, along with litter and debris. Litter and debris thrown from boats or carried by rivers and creeks will accumulate in the marine environment, particularly in coastal areas, but also in mid-ocean garbage patches. Such human-created artifacts preserved in stratigraphy are known as technofossils.[5][121]

Twentieth-century technofossils in inundated landfill deposits at East Tilbury on the River Thames estuary

Changes in biodiversity will also be reflected in the fossil record, as will species introductions. An example cited is the domestic chicken, originally the red junglefowl Gallus gallus, native to south-east Asia but has since become the world's most common bird through human breeding and consumption, with over 60 billion consumed annually and whose bones would become fossilised in landfill sites.[122] Hence, landfills are important resources to find "technofossils".[123]

Trace elements

[edit]

In terms of trace elements, there are a range of distinct signatures left by modern societies. For example, in the Upper Fremont Glacier in Wyoming, there is a layer of chlorine present in ice cores from 1960's atomic weapon testing programs, as well as a layer of mercury associated with coal plants in the 1980s.[124][125][126]

From the late 1940s, nuclear tests have led to local nuclear fallout and severe contamination of test sites both on land and in the surrounding marine environment. Some of the radionuclides that were released during the tests are 137Cs, 90Sr, 239Pu, 240Pu, 241Am, and 131I. These have been found to have had significant impact on the environment and on human beings. In particular, 137Cs and 90Sr have been found to have been released into the marine environment and led to bioaccumulation over a period through food chain cycles. The carbon isotope 14C, commonly released during nuclear tests, has also been found to be integrated into the atmospheric CO2, and infiltrating the biosphere, through ocean-atmosphere gas exchange. Increase in thyroid cancer rates around the world is also surmised to be correlated with increasing proportions of the 131I radionuclide.[127]

The highest global concentration of radionuclides was estimated to have been in 1965, one of the dates which has been proposed as a possible benchmark for the start of the formally defined Anthropocene.[128]

Human burning of fossil fuels has also left distinctly elevated concentrations of black carbon, inorganic ash, and spherical carbonaceous particles in recent sediments across the world. Concentrations of these components increases markedly and almost simultaneously around the world beginning around 1950.[5]

Anthropocene markers

[edit]

A marker that accounts for a substantial global impact of humans on the total environment, comparable in scale to those associated with significant perturbations of the geological past, is needed in place of minor changes in atmosphere composition.[129][130] A range of markers characterizing the period have been identified, such as silicone or aluminium, but most prominently plastic, with plastic, reminiscent of archaeological ages like the Iron Age, marking an archaeological plastic age or the anthropocene even as a geological plastic epoch.[131]

A useful candidate for holding markers in the geologic time record is the pedosphere. Soils retain information about their climatic and geochemical history with features lasting for centuries or millennia.[132] Human activity is now firmly established as the sixth factor of soil formation.[133] Humanity affects pedogenesis directly by, for example, land levelling, trenching and embankment building, landscape-scale control of fire by early humans, organic matter enrichment from additions of manure or other waste, organic matter impoverishment due to continued cultivation and compaction from overgrazing. Human activity also affects pedogenesis indirectly by drift of eroded materials or pollutants. Anthropogenic soils are those markedly affected by human activities, such as repeated ploughing, the addition of fertilisers, contamination, sealing, or enrichment with artefacts (in the World Reference Base for Soil Resources they are classified as Anthrosols and Technosols). An example from archaeology would be dark earth phenomena when long-term human habitation enriches[134] the soil with black carbon.

Anthropogenic soils are recalcitrant repositories of artefacts and properties that testify to the dominance of the human impact, and hence appear to be reliable markers for the Anthropocene. Some anthropogenic soils may be viewed as the 'golden spikes' of geologists (Global Boundary Stratotype Section and Point), which are locations where there are strata successions with clear evidences of a worldwide event, including the appearance of distinctive fossils.[135] Drilling for fossil fuels has also created holes and tubes which are expected to be detectable for millions of years.[136] The astrobiologist David Grinspoon has proposed that the site of the Apollo 11 Lunar landing, with the disturbances and artifacts that are so uniquely characteristic of our species' technological activity and which will survive over geological time spans could be considered as the 'golden spike' of the Anthropocene.[137]

An October 2020 study coordinated by University of Colorado at Boulder found that distinct physical, chemical and biological changes to Earth's rock layers began around the year 1950. The research revealed that since about 1950, humans have doubled the amount of fixed nitrogen on the planet through industrial production for agriculture, created a hole in the ozone layer through the industrial scale release of chlorofluorocarbons (CFCs), released enough greenhouse gasses from fossil fuels to cause planetary level climate change, created tens of thousands of synthetic mineral-like compounds that do not naturally occur on Earth, and caused almost one-fifth of river sediment worldwide to no longer reach the ocean due to dams, reservoirs and diversions. Humans have produced so many millions of tons of plastic each year since the early 1950s that microplastics are "forming a near-ubiquitous and unambiguous marker of Anthropocene".[138][139] The study highlights a strong correlation between global human population size and growth, global productivity and global energy use and that the "extraordinary outburst of consumption and productivity demonstrates how the Earth System has departed from its Holocene state since c. 1950 CE, forcing abrupt physical, chemical and biological changes to the Earth's stratigraphic record that can be used to justify the proposal for naming a new epoch—the Anthropocene."[139]

A December 2020 study published in Nature found that the total anthropogenic mass, or human-made materials, outweighs all the biomass on earth, and highlighted that "this quantification of the human enterprise gives a mass-based quantitative and symbolic characterization of the human-induced epoch of the Anthropocene."[140][141]

Debates

[edit]
"While we often think of ecological damage as a modern problem our impacts date back millennia to the times in which humans lived as hunter-gatherers. Our history with wild animals has been a zero-sum game: either we hunted them to extinction, or we destroyed their habitats with agricultural land." – Hannah Ritchie for Our World in Data.[142]

Although the validity of Anthropocene as a scientific term remains disputed, its underlying premise, i.e., that humans have become a geological force, or rather, the dominant force shaping the Earth's climate, has found traction among academics and the public. In an opinion piece for Philosophical Transactions of the Royal Society B, Rodolfo Dirzo, Gerardo Ceballos, and Paul R. Ehrlich write that the term is "increasingly penetrating the lexicon of not only the academic socio-sphere, but also society more generally", and is now included as an entry in the Oxford English Dictionary.[143] The University of Cambridge, as another example, offers a degree in Anthropocene Studies.[144] In the public sphere, the term Anthropocene has become increasingly ubiquitous in activist, pundit, and political discourses. Some who are critical of the term Anthropocene nevertheless concede that "For all its problems, [it] carries power."[145] The popularity and currency of the word has led scholars to label the term a "charismatic meta-category"[146] or "charismatic mega-concept."[147] The term, regardless, has been subject to a variety of criticisms from social scientists, philosophers, Indigenous scholars, and others.

The anthropologist John Hartigan has argued that due to its status as a charismatic meta-category, the term Anthropocene marginalizes competing, but less visible, concepts such as that of "multispecies."[148] The more salient charge is that the ready acceptance of Anthropocene is due to its conceptual proximity to the status quo – that is, to notions of human individuality and centrality.

Other scholars appreciate the way in which the term Anthropocene recognizes humanity as a geological force, but take issue with the indiscriminate way in which it does. Not all humans are equally responsible for the climate crisis. To that end, scholars such as the feminist theorist Donna Haraway and sociologist Jason Moore, have suggested naming the Epoch instead as the Capitalocene.[149][150][151] Such implies capitalism as the fundamental reason for the ecological crisis, rather than just humans in general.[152][153][154] However, according to philosopher Steven Best, humans have created "hierarchical and growth-addicted societies" and have demonstrated "ecocidal proclivities" long before the emergence of capitalism.[155] Hartigan, Bould, and Haraway all critique what Anthropocene does as a term; however, Hartigan and Bould differ from Haraway in that they criticize the utility or validity of a geological framing of the climate crisis, whereas Haraway embraces it.

In addition to "Capitalocene," other terms have also been proposed by scholars to trace the roots of the Epoch to causes other than the human species broadly. Janae Davis, for example, has suggested the "Plantationocene" as a more appropriate term to call attention to the role that plantation agriculture has played in the formation of the Epoch, alongside Kathryn Yusoff's argument that racism as a whole is foundational to the Epoch. The Plantationocene concept traces "the ways that plantation logics organize modern economies, environments, bodies, and social relations."[156][157][158][159] In a similar vein, environmental humanities scholars like Heather Davis and Indigenous studies scholars such as Métis geographer Zoe Todd have argued that the Epoch must be dated back to the colonization of the Americas, as this "names the problem of colonialism as responsible for contemporary environmental crisis."[160] Potawatomi philosopher Kyle Powys Whyte has further argued that the Anthropocene has been apparent to Indigenous peoples in the Americas since the inception of colonialism because of "colonialism's role in environmental change."[161][162][163]

Other critiques of Anthropocene have focused on the genealogy of the concept. Todd also provides a phenomenological account, which draws on the work of the philosopher Sara Ahmed, writing: "When discourses and responses to the Anthropocene are being generated within institutions and disciplines which are embedded in broader systems that act as de facto 'white public space,' the academy and its power dynamics must be challenged."[164] Other aspects which constitute current understandings of the concept of the Anthropocene such as the ontological split between nature and society, the assumption of the centrality and individuality of the human, and the framing of environmental discourse in largely scientific terms have been criticized by scholars as concepts rooted in colonialism and which reinforce systems of postcolonial domination.[165] To that end, Todd makes the case that the concept of Anthropocene must be indigenized and decolonized if it is to become a vehicle of justice as opposed to white thought and domination.

Eco-philosopher David Abram, in a book chapter titled 'Interbreathing in the Humilocene', has proposed adoption of the term 'Humilocene' (the Epoch of Humility), which emphasizes an ethical imperative and ecocultural direction that human societies should take. The term plays with the etymological roots of the term 'human', thus connecting it back with terms such as humility, humus (the soil), and even a corrective sense of humiliation that some human societies should feel given their collective destructive impact on the earth.[166]

"Early anthropocene" model

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William Ruddiman has argued that the Anthropocene began approximately 8,000 years ago with the development of farming and sedentary cultures.[167] At that point, humans were dispersed across all continents except Antarctica, and the Neolithic Revolution was ongoing. During this period, humans developed agriculture and animal husbandry to supplement or replace hunter-gatherer subsistence.[168] Such innovations were followed by a wave of extinctions, beginning with large mammals and terrestrial birds. This wave was driven by both the direct activity of humans (e.g. hunting) and the indirect consequences of land-use change for agriculture. Landscape-scale burning by prehistoric hunter-gathers may have been an additional early source of anthropogenic atmospheric carbon.[169] Ruddiman also claims that the greenhouse gas emissions in-part responsible for the Anthropocene began 8,000 years ago when ancient farmers cleared forests to grow crops.[170][171][172]

Ruddiman's work has been challenged with data from an earlier interglaciation ("Stage 11", approximately 400,000 years ago) which suggests that 16,000 more years must elapse before the current Holocene interglaciation comes to an end, and thus the early anthropogenic hypothesis is invalid.[173] Also, the argument that "something" is needed to explain the differences in the Holocene is challenged by more recent research showing that all interglacials are different.[174]

Homogenocene

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Homogenocene (from old Greek: homo-, same; geno-, kind; kainos-, new;) is a more specific term used to define our current epoch, in which biodiversity is diminishing and biogeography and ecosystems around the globe seem more and more similar to one another mainly due to invasive species that have been introduced around the globe either on purpose (crops, livestock) or inadvertently. This is due to the newfound globalism that humans participate in, as species traveling across the world to another region was not as easily possible in any point of time in history as it is today.[175]

The term Homogenocene was first used by Michael Samways in his editorial article in the Journal of Insect Conservation from 1999 titled "Translocating fauna to foreign lands: Here comes the Homogenocene."[176]

The term was used again by John L. Curnutt in the year 2000 in Ecology, in a short list titled "A Guide to the Homogenocene",[177] which reviewed Alien species in North America and Hawaii: impacts on natural ecosystems by George Cox. Charles C. Mann, in his acclaimed book 1493: Uncovering the New World Columbus Created, gives a bird's-eye view of the mechanisms and ongoing implications of the homogenocene.[178]

Society and culture

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Humanities

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The concept of the Anthropocene has also been approached via humanities such as philosophy, literature and art. In the scholarly world, it has been the subject of increasing attention through special journals,[179] conferences,[180][181] and disciplinary reports.[182] The Anthropocene, its attendant timescale, and ecological implications prompt questions about death and the end of civilisation,[183] memory and archives,[184] the scope and methods of humanistic inquiry,[185] and emotional responses to the "end of nature".[186] Some scholars have posited that the realities of the Anthropocene, including "human-induced biodiversity loss, exponential increases in per-capita resource consumption, and global climate change," have made the goal of environmental sustainability largely unattainable and obsolete.[187]

Historians have actively engaged the Anthropocene. In 2000, the same year that Paul Crutzen coined the term, world historian John McNeill published Something New Under the Sun,[188] tracing the rise of human societies' unprecedented impact on the planet in the twentieth century.[188] In 2001, historian of science Naomi Oreskes revealed the systematic efforts to undermine trust in climate change science and went on to detail the corporate interests delaying action on the environmental challenge.[189][190] Both McNeill and Oreskes became members of the Anthropocene Working Group because of their work correlating human activities and planetary transformation.

Bridie Lonie has reflected that the Anthropocene has been a theme for art in New Zealand since the 1970s. Often working outside the art institutions as societally challenging intervention art also "Interrupting the Automatism" in the activation, decision making and ultimate control of especially urban public space[191]

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  • In 2019, the English musician Nick Mulvey released a music video on YouTube named "In the Anthropocene".[192] In cooperation with Sharp's Brewery, the song was recorded on 105 vinyl records made of washed-up plastic from the Cornish coast.[193]
  • The Anthropocene Reviewed is a podcast and book by author John Green, where he "reviews different facets of the human-centered planet on a five-star scale".[194]
  • Photographer Edward Burtynsky created "The Anthropocene Project" with Jennifer Baichwal and Nicholas de Pencier, which is a collection of photographs, exhibitions, a film, and a book. His photographs focus on landscape photography that captures the effects human beings have had on the earth.[195][196]
  • In 2015, the American death metal band Cattle Decapitation released its seventh studio album titled The Anthropocene Extinction.[197]
  • In 2020, Canadian musician Grimes released her fifth studio album titled Miss Anthropocene. The name is also a pun on the feminine title "Miss" and the words "misanthrope" and "Anthropocene."[198]

See also

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
The Anthropocene is a proposed designation for the current phase of Earth's history in which human activities have emerged as the primary agent of geological and , surpassing natural variability in their influence on planetary systems. The term, derived from Greek roots meaning "human" and "new," was popularized by atmospheric chemist Paul Crutzen and limnologist Eugene Stoermer in 2000 to underscore the scale of anthropogenic impacts observable in sediment layers, atmospheric composition, and biotic records. Despite its widespread adoption in scientific discourse to frame discussions on climate alteration, biodiversity decline, and technofossil proliferation, the Anthropocene has not been formally ratified as a geological epoch by the (ICS). In March 2024, the ICS rejected a proposal to define it as commencing around 1950, citing insufficient stratigraphic distinction from the ongoing epoch and debates over its precise temporal boundaries, which alternatives place at the or earlier agricultural revolutions. Proponents argue for markers such as spikes from mid-20th-century nuclear tests, , and fertilizer-derived isotopes as globally synchronous signals of human dominance. The concept encapsulates empirical evidence of causal human drivers in phenomena including accelerated carbon dioxide accumulation—rising from pre-industrial ~280 ppm to over 420 ppm by 2023—and vertebrate biomass reduction by approximately 85% since the rise of , reflecting intensified and resource extraction. These transformations, while debated in scope relative to past geological events like the Paleocene-Eocene Thermal Maximum, affirm humanity's role in etching a novel stratigraphic signature through industrial emissions, habitat conversion, and synthetic materials persistence.

Definition and Geological Context

Distinction from Holocene

The Holocene epoch began approximately 11,700 years ago, marking the end of the Pleistocene glaciation and ushering in a period of relative climatic stability characterized by interglacial conditions, with temperature and sea-level variations primarily driven by Milankovitch orbital cycles, , and volcanic activity. This stability facilitated the around 9,000 to 5,000 years , followed by the Neoglaciation with gradual cooling until the pre-industrial era, during which human populations grew and early agriculture emerged, exerting localized influences such as deforestation in regions like the and . However, these Holocene anthropogenic effects remained regionally heterogeneous and did not produce globally synchronous stratigraphic signals overriding natural baselines. In distinction, the Anthropocene proposal identifies a fundamental shift where human activities have become the primary driver of planetary change, with rates and magnitudes exceeding precedents; for instance, atmospheric CO2 concentrations have risen from pre-industrial levels of about 280 ppm to over 420 ppm by 2023, surpassing any peaks and decoupling from orbital forcings. in the Anthropocene, including a 68% average decline in populations since 1970, contrasts with the slower, extinction-filtered faunal turnovers of the , where megafaunal declines were tied to early human hunting but lacked the current scale of habitat homogenization and dominance. Similarly, and cycles have been altered by synthetic fertilizers at rates 100 to 170 times background deposition, leading to signals in sediments worldwide. Stratigraphically, the Holocene lacks the composite markers defining the proposed Anthropocene base, such as the mid-20th-century spike in from (peaking 1963–1964), , from fossil fuel combustion, and fly ash, which form a globally correlatable layer distinct from Holocene or biogenic deposits. These signals, accelerating during the "Great Acceleration" post-1950, overprint prior Holocene patterns, including those from early anthropogenic episodes like the or , rendering the transition functionally and geologically abrupt on epochal timescales. While some Holocene human impacts, such as rice paddy around 3,000 years ago, are detectable regionally, they do not exhibit the synchronicity or persistence of Anthropocene technofossils like and aluminum alloys.

Formal Recognition Status

The (AWG), established in 2009 under the Subcommission on (SQS), developed a formal proposal to designate the Anthropocene as a new within the Geological Time Scale, with its base defined at approximately 1952 CE, coinciding with the global peak in and -240 fallout from atmospheric . The proposed Global Stratotype Section and Point (GSSP) was identified at Crawford Lake in , , where varved sediments preserve a sharp stratigraphic marker of this plutonium signal, supplemented by auxiliary sites exhibiting synchronous anthropogenic signatures such as , fly ash, and biotic shifts. In February 2024, the SQS initiated a formal vote on the AWG's proposal, resulting in 4 votes in favor, 12 against, and 3 abstentions, leading to its rejection on March 4, 2024. The (ICS) and (IUGS) ratified this decision on March 26, 2024, affirming that the Anthropocene does not qualify as a formal chronostratigraphic unit and that the current interval remains part of the Epoch's Age. Key reasons cited for the rejection include the proposed epoch's exceptionally brief duration—spanning only about 70 years—which contrasts with typical epochs lasting tens of thousands to millions of years, rendering it stratigraphically insignificant on geological timescales. Additionally, dissenters argued that profound human-induced changes, such as , , and early industrialization, commenced millennia earlier, diluting the sharpness and of the mid-20th-century boundary as a global marker; the signal, while detectable, is transient and overlaid on longer-term anthropogenic strata. As of October 2025, the Anthropocene lacks formal recognition in the official Geological Time Scale, with no subsequent proposals advancing to override the decision; however, the term persists in as an informal descriptor for the era of accelerated human planetary influence, independent of stratigraphic formalization. Proponents maintain that the rejection prioritizes rigid chronostratigraphic conventions over of unprecedented perturbation, though critics emphasize adherence to established criteria to avoid diluting the precision of geological divisions.

Etymology and Conceptual Origins

Coining of the Term

The term "Anthropocene" was first informally coined and employed by American limnologist Eugene F. Stoermer in the early 1980s to denote the geological characterized by profound human influence on Earth's systems, drawing from observations of anthropogenic alterations to aquatic and terrestrial environments. Stoermer, a researcher at the , used the term in lectures and writings without formal publication during that decade, reflecting his assessment that human activities had eclipsed natural processes in shaping . The term gained prominence through Dutch atmospheric chemist , who, during a February 2000 meeting of the International Geosphere-Biosphere Programme's (IGBP) scientific committee in , , interrupted a presentation on climate dynamics to assert that humanity had initiated a new epoch, the Anthropocene. , a Nobel for his work on stratospheric , argued that the Industrial Revolution's onset around 1784 marked the boundary, citing rapid increases in , land use changes, and as evidence of human dominance over geological forces. This spontaneous declaration, prompted by frustration with outdated references to the , catalyzed broader scientific discourse. In May 2000, Crutzen and Stoermer formalized their proposal in a article titled "The 'Anthropocene'", published by the IGBP, which outlined stratigraphic markers such as elevated carbon isotope ratios from combustion and widespread extinctions as indicators of the proposed . The piece emphasized that population growth—from approximately 1 billion in 1800 to over 6 billion by 2000—had amplified these effects, rendering natural variability subordinate to anthropogenic drivers. While Stoermer's earlier usage provided the linguistic foundation, Crutzen's intervention and their joint publication established the term's within , influencing subsequent geological and environmental debates.

Early Influences and Precursors

One of the earliest systematic recognitions of profound human alteration to Earth's surface came from American diplomat and scholar George Perkins Marsh in his 1864 book Man and Nature; or, Physical Geography as Modified by Human Action. Marsh documented how civilizations, particularly in the Mediterranean, had deforested landscapes, eroded soils, and disrupted hydrological cycles, leading to desertification and loss of fertility, arguing that "not all the winds, and storms, and earthquakes, and seas, and seasons of the world, have done so much to revolutionize the earth as MAN". He emphasized that human agency rivaled natural geological forces in reshaping the planet's crust, atmosphere, and biota, though he stopped short of proposing a formal new epoch. Building on such observations, Italian geologist Antonio Stoppani explicitly advanced the idea of a human-dominated geological period in his 1873 treatise Corso di Geologia. Stoppani designated this as the "Anthropozoic era," marking it as the seventh epoch in Earth's history, characterized by humanity's introduction of a "new telluric force" through , , , and technological interventions that left indelible stratigraphic signatures. He contended that human creations, from canals to artificial soils, constituted geological agents comparable to volcanic activity or , predicting the era's ongoing expansion without foreseeable end. Stoppani's framework, rooted in empirical surveys of Italian landscapes altered by centuries of human labor, prefigured modern stratigraphic debates by highlighting anthropogenic strata as diagnostic markers. In the early 20th century, Russian-Ukrainian geochemist Vladimir Vernadsky extended these notions through his conceptualization of the biosphere as a dynamic, life-driven geochemical system, detailed in his 1926 monograph The Biosphere. Vernadsky posited that human intellect and technology were evolving the biosphere into a "noosphere"—a sphere of reason—wherein collective human cognition would amplify geological transformations on planetary scales, including biogeochemical cycles altered by industry and agriculture. He quantified human biomass manipulation and fossil fuel combustion as emerging forces capable of rivaling natural processes, such as in accelerating carbon fluxes, though his optimistic view framed this as progressive rather than primarily destructive. Vernadsky's work, grounded in thermodynamic and empirical data from geochemical cycles, influenced later proposals by integrating human agency into global Earth system dynamics. These precursors, emerging amid industrialization's visible impacts, laid intellectual groundwork for viewing humanity as a geological , though they lacked the mid-20th-century empirical markers like radionuclides that would later define boundary strata debates. Their ideas persisted in relative obscurity until revived in discussions of human-induced planetary change, underscoring a causal chain from localized observations to global-scale propositions.

Development of the Proposal

Anthropocene Working Group Activities

The (AWG) was established in 2009 by the Subcommission on Quaternary Stratigraphy (SQS), a body under the (ICS), on the initiative of then-SQS chair Phil Gibbard, to evaluate the Anthropocene as a potential chronostratigraphic unit within the Geological Time Scale. Initially chaired by geologist Jan Zalasiewicz of the , the interdisciplinary group included approximately 35 members from fields such as , , and , tasked with assessing geological evidence of human-driven changes distinct from the Epoch. Key activities encompassed systematic review of stratigraphic markers, including radionuclides from mid-20th-century nuclear testing, persistent organic pollutants, , and homogenizing biotic assemblages, to determine if they constituted a synchronous global signal warranting formal recognition. The group published multiple syntheses, such as a overview in Earth-Science Reviews detailing the Anthropocene's stratigraphic basis, emphasizing post-1950 signals tied to the "Great Acceleration" in human activity. Internal deliberations addressed boundary options, rejecting earlier starts like the Industrial Revolution or agriculture in favor of mid-20th-century markers for their sharp, widespread detectability in sediments, ice cores, and corals. In August 2016, during the 35th International Geological Congress in , the AWG conducted a preliminary vote, approving by 30 to 3 (with 2 abstentions) the designation of the Anthropocene as a formal at the series/ rank, initiating preparations for a Global boundary Stratotype Section and Point (GSSP). This was followed by a binding vote on , 2019, where 29 of 33 members (88%) affirmed the Anthropocene's formal status and selected a mid-20th-century base, exceeding the required 60% ; the same margin supported stratotype sites reflecting peaks around 1952 CE. The group proposed Crawford Lake in , , as the primary GSSP due to its varved sediments preserving a clear plutonium-239/240 spike from 1963 atmospheric tests, supplemented by auxiliary sites in , , and . By 2023, under chair Colin Waters, the AWG finalized its recommendation for the Epoch with a basal "Crawfordian" Age at 1952 CE, submitting the formal proposal to the SQS on October 31, 2023, after 14 years of evidence compilation and debate. Activities highlighted stratigraphic rigor but faced internal challenges, including resignations from members like Erle Ellis in July 2023, who argued the narrow post-1950 boundary overlooked longer-term human influences and risked politicizing geological classification. The group's work underscored causal human dominance in recent system perturbations, though debates persisted on whether such signals justified epochal status over informal usage.

Key Proposals and Boundary Debates

The Anthropocene Working Group (AWG) advanced a primary proposal for the epoch's base at 1952 CE, aligning with the mid-20th-century Great Acceleration in human population growth, industrialization, and resource use. This boundary is defined by the abrupt global spike in plutonium-239 from thermonuclear weapons testing, providing a precise, synchronous stratigraphic marker preserved in sediments, ice cores, and peat. The AWG nominated Crawford Lake in Ontario, Canada, as the Global Stratotype Section and Point (GSSP), citing its annually laminated varves that record this signal alongside secondary markers like microplastics and spheroidal fly ash particles. Complementary Standard Auxiliary Boundary Stratotypes include Beppu Bay in Japan, Sihailongwan Maar Lake in China, and Śnieżka peatland in Poland, ensuring multi-continental correlation. In a 2019 ballot, 29 of 33 AWG members endorsed the as a formal chronostratigraphic unit with this mid-20th-century onset, emphasizing the era's unprecedented convergence of anthropogenic signals, including , homogenized lead isotopes, and escalated nutrient fluxes from fertilizers. Proponents argue this timing captures the transition to a planetary state dominated by human-caused transformations, with radionuclides offering an unambiguous primary marker absent in earlier records due to their novel atomic origin and global dispersal post-1945 testing. Competing proposals favor earlier starts to encompass longer histories of human environmental modification. Atmospheric chemist Paul Crutzen proposed circa 1784, coinciding with the Industrial Revolution's coal-driven CO2 rise following James Watt's steam engine refinements. Other suggestions include an "Early Anthropocene" around 8,000 years ago, linked to Neolithic farming's initiation of sustained deforestation, rice paddy methane emissions, and biomass burning, as hypothesized by William Ruddiman. A 2015 analysis in Scientific Reports advocated 1610 CE, based on early colonial pollution signatures in Greenland ice cores marking the "Orleans flysch" or dirted sediments from global land clearance. Boundary debates hinge on stratigraphic rigor versus broader system dynamics. Mid-20th-century advocates prioritize a clear, globally correlatable primary signal meeting International Chronostratigraphic Chart criteria, dismissing pre-1950 changes as diachronous or secondary—such as regionally variable industrial emissions lacking uniform lithospheric imprint. Opponents counter that this recency ignores causal precursors like agricultural and fossil fuel ignition, which already deviated trajectories, and question the epoch's validity given its ~70-year span contravenes typical geological unit durations exceeding . Critics, including some stratigraphers, favor informal usage or reclassification as an "event" to reflect gradual human ascendancy without forcing a late breakpoint, arguing the proposal risks politicizing by overemphasizing recent escalations amid evident earlier anthropogenic forcings.

2024 Rejection and Post-2024 Developments

In March 2024, the Subcommission on Stratigraphy (SQS), tasked with evaluating proposals for the period, voted against formalizing the Anthropocene as a new geological , with 12 members opposing, 4 in favor, and 2 abstentions. The proposal, advanced by the after over a decade of deliberation, had advocated for a 1952 boundary marked by fallout from as a global stratigraphic marker. Opponents argued that the proposed epoch's brevity—spanning only about 75 years—contradicted the typical multimillion-year durations of geological epochs, rendering it incompatible with the hierarchical structure of the . Additional concerns included the boundary's failure to encompass earlier human impacts, such as or industrialization, and perceptions of undue political influence in prioritizing mid-20th-century markers over longer-term anthropogenic signals. The (ICS) endorsed the SQS decision without requiring a broader vote, effectively halting formal recognition. Proponents, including AWG chair Colin Waters, expressed disappointment, viewing the rejection as a missed opportunity to codify humanity's dominant geological role through empirical stratigraphic evidence like persistent radionuclides and . Critics of the decision, however, maintained that the Anthropocene's conceptual value persisted independently of formal status, emphasizing its utility in interdisciplinary discussions of human-induced planetary change without necessitating epochal designation. Following the rejection, the term Anthropocene continued in widespread scientific and public usage as an informal descriptor of the current era of intensified human influence, appearing in peer-reviewed literature on Earth system dynamics and . In March 2025, the (IUGS) reaffirmed the ICS stance, prompting calls from some stratigraphers for alternative classifications, such as an Anthropocene "event" or "stage" within the , to better align with observed sedimentary records while avoiding epochal timescales. Publications in 2025 explored cross-disciplinary tools for delineating human impacts, including isotopic and biotic proxies, without pursuing formal ratification, reflecting a shift toward pragmatic application over terminological precision. Debates persisted on whether the rejection undervalued causal evidence of anthropogenic dominance—evident in metrics like accelerated and atmospheric composition shifts—or appropriately prioritized geological orthodoxy over advocacy-driven . No subsequent proposals for formal status advanced by October 2025, with focus turning to integrating Anthropocene concepts into broader chronostratigraphic frameworks.

Proposed Chronological Boundaries

Pre-Industrial or Early Anthropocene Views

Proponents of pre-industrial or early Anthropocene boundaries contend that significant human modifications to Earth's systems commenced during the epoch, particularly with the advent of and associated land-use changes, rather than awaiting the . These views posit that the , beginning approximately 12,000 to 10,000 years ago with the domestication of plants and animals in regions such as the , initiated sustained alterations in atmospheric composition, vegetation patterns, and biogeochemical cycles. Evidence includes pollen records indicating widespread for farming, which reduced and contributed to early carbon releases, though the scale remained regionally variable and debated in magnitude relative to later industrial emissions. A prominent formulation is the Early Anthropogenic Hypothesis advanced by paleoclimatologist William Ruddiman in 2003, which attributes anomalous late-Holocene increases in atmospheric (CO2) and (CH4) to prehistoric human activities. Ruddiman argued that CO2 levels began deviating upward around 8,000 years ago due to intensified clearance for agriculture in and , releasing stored carbon and preventing the expected orbital-driven cooling toward glaciation. Similarly, CH4 concentrations rose sharply about 5,000 years ago, linked to wetland rice cultivation in and expanded practices, which enhanced anaerobic decomposition in paddies. These inferences draw from ice-core data, such as Vostok and records, showing trends inconsistent with alone, implying human causation on a global scale sufficient to alter climate trajectories over millennia. Supporting geographic evidence includes archaeological and paleoenvironmental data from Eurasian sites, where early farming expanded by an estimated 5-10% of ice-free continental area by 5,000 years ago, fostering technofossils like layers and domesticated in sediments. Proponents like Ruddiman update the to incorporate rice paddy emissions accounting for up to 40% of pre-industrial CH4 anomalies, with contributing 20-50 ppm to CO2 rises by 1850 CE. These early impacts are framed as causal drivers of the Climatic Optimum's persistence, averting a natural decline. Critics of these views, while acknowledging cumulative human footprints, argue that pre-industrial changes lack the stratigraphic synchronicity and novelty required for epochal boundaries, as natural forcings like volcanic activity or solar variability could explain portions of the gas anomalies, and early signals are obscured by over 8,000 years versus the sharp post-1950 spikes. Nonetheless, early Anthropocene advocates emphasize causal realism in attributing deviations—such as a 10-20 ppm CO2 excess—to empirically reconstructed and land conversion rates, positioning human agency as the dominant factor in environmental stability.

Mid-20th Century Great Acceleration

The Great Acceleration refers to the sharp escalation in human socio-economic activity and its corresponding impacts on 's systems beginning around , marking a phase of unprecedented planetary change. This period aligns with post-World War II economic booms, rapid from approximately 2.5 billion in to over 6 billion by 2000, and intensified resource extraction and technological deployment. Indicators compiled by the International Geosphere-Biosphere Programme (IGBP) demonstrate this through 24 metrics—12 socio-economic and 12 Earth system-related—revealing near-synchronous "hockey-stick" trajectories post-, including a tripling of global GDP , a 10-fold increase in consumption, and the construction of over 45,000 large dams by 2010. Earth system responses, such as a rise in atmospheric CO2 concentrations from 310 ppm in to 390 ppm by 2010 and a 50% decline in wild vertebrate biomass since then, exhibit similar abrupt shifts, distinguishing this era from prior gradual trends. Proponents of a mid-20th century Anthropocene boundary, including members of the (AWG), argue that the Great Acceleration provides the optimal stratigraphic signal due to its global synchroneity and novelty. Unlike earlier human influences, which were regionally variable and reversible, post-1950 changes reflect a systemic reconfiguration of the Earth system, with novel markers like from appearing synchronously in sediments worldwide starting in the early 1950s. Atmospheric nuclear tests, peaking between 1959 and 1963 with over 500 detonations, deposited radionuclides such as Pu-239/240 at detectable levels (typically 0.1-10 Bq/kg in soils and sediments), offering a precise, anthropogenically unique horizon uncorrelated with natural processes. Additional synchronous signatures include spheroidal fly ash from combustion, , and aluminum particles from industrial processes, all emerging prominently after 1950 and persisting in stratigraphic records. This boundary proposal favors circa 1950 over earlier candidates like the , as pre-1950 human impacts lack the uniform global imprint required for geological epoch delineation; for instance, while CO2 rose during the , the rate accelerated dramatically post-1950, and losses were episodic rather than systemic until then. Sites like Crawford Lake in , , preserve varved sediments capturing the 1950 plutonium spike alongside biotic shifts (e.g., algal community changes from ) and chemical anomalies, supporting its nomination as a Global Boundary Stratotype Section and Point (GSSP). Critics, however, note that some acceleration precursors trace to the early , though empirical data confirm the mid-century threshold as the point of irreversible, planet-wide dominance by human drivers.
CategoryKey Indicators of Great Acceleration (Post-1950 Trends)
Socio-economicPopulation growth (2.5B to 7B+ by 2010); Urban population (0.75B to 3.5B); GDP tripling; International air travel (from negligible to millions annually); Fertilizer use (10x increase).
Earth SystemCO2 emissions (from ~6 GtC/yr to 9 GtC/yr); Dams (from ~5,000 to 45,000+); Freshwater use doubling; Nitrogen fixation (tripling); Wild mammal biomass decline (~50%).

Atomic Bomb Fallout and Other Markers

The atomic bomb fallout from atmospheric nuclear weapons testing serves as a primary stratigraphic marker for the proposed mid-20th century boundary of the Anthropocene, particularly the onset around 1950 coinciding with the "Great Acceleration" in human activity. Between 1945 and 1980, over 500 atmospheric nuclear tests released anthropogenic radionuclides, including plutonium-239 (Pu-239) and plutonium-240 (Pu-240), into the global atmosphere, resulting in widespread deposition preserved in sediments, ice cores, and biological archives. The global first appearance of excess Pu-239 in sedimentary sequences aligns with the early 1950s, providing a sharp, synchronous signal absent in pre-1950 layers due to the absence of large-scale testing prior to that period. This plutonium anomaly is advocated as a potential "golden spike" for the Anthropocene base because of its unambiguous anthropogenic origin, global distribution via , and stratigraphic utility in high-resolution archives like annually laminated lake sediments at Crawford , where the Pu signal delineates the 1950s onset. Nuclear testing injected approximately 6 kilograms of Pu-239 into the environment, with peak fallout concentrations in the mid-1960s following intensified tests by the and , yet the initial rise post-1950 offers precise chronostratigraphic correlation across hemispheres. Complementary bomb-produced (¹⁴C) exhibits a similar spike, peaking in tree rings and atmospheric records around 1963-1964, reinforcing the mid-century marker through independent isotopic evidence. Other concurrent markers bolster the atomic fallout signal, including spheroidal fly ash particles from high-temperature combustion, which appear globally in sediments from the onward, and elevated levels of persistent organic pollutants like , whose production surged post-World War II. Heavy metal enrichments, such as lead from leaded gasoline, and also emerge sharply in this interval, though less uniformly distributed than radionuclides. These multi-proxy signals in peat bogs, ocean cores, and corals—such as Pu onset dated to 1955-1956 in specimens—collectively indicate a rapid, human-driven perturbation detectable at sub-decadal resolution, distinguishing the mid-20th century from earlier variability.

Recent Alternative Proposals

In response to the 2024 rejection of the mid-20th-century boundary proposal by the Subcommission on Quaternary , several scientists have advocated for alternative conceptualizations of anthropogenic geological change that emphasize diachronous, time-transgressive impacts rather than a synchronous global stratigraphic marker. This approach posits that influences on systems began accumulating variably across regions and intensified gradually, rendering a single "" inappropriate for formal epochal definition. For instance, a 2024 analysis argues that the Anthropocene should be understood as an ongoing geomorphic process with roots in pre-industrial activities, such as land clearance and early , which produced detectable environmental signals like altered records and patterns dating back millennia, rather than confining it to the post-1950 "Great Acceleration." The Palaeoanthropocene concept, formalized in 2013 but revisited in subsequent geological discussions, proposes recognizing anthropogenic environmental modifications from the early onward, including megafaunal extinctions around 50,000–10,000 years ago and the onset of circa 8,000 years before present, which initiated widespread , from rice paddies, and carbon perturbations evidenced in ice cores and sediment layers. Proponents contend this framework better captures humans as an integral system component, with empirical traces like increased deposition and shifts predating industrial use, challenging the recency of the standard proposal. This view aligns with stratigraphic of regional asynchrony, such as Eurasian land-use changes by 6,000 years ago, contrasting with the uniform plutonium spike favored by the . Post-rejection syntheses in 2024–2025 have further proposed treating the Anthropocene as an informal "event" or intensifying perturbation within the , extending potentially into the future based on projected trajectories of human dominance, such as projected exceeding 50% of by 2050 under current trends. These alternatives prioritize causal chains of cumulative human forcing—e.g., from 1 billion in to 8 billion by driving habitat conversion—over rigid chronostratigraphic boundaries, arguing that formal rejection underscores the limitations of applying Phanerozoic-scale criteria to recent, ongoing transformations. Critics of the mid-20th-century marker note its failure to account for earlier baselines, like the 20–30% reduction in global wild biomass since the Pleistocene, attributable to and farming rather than atomic testing. Such proposals maintain the term's utility for interdisciplinary analysis while avoiding the stratigraphic rigidity that doomed the formal bid.

Empirical Evidence of Human Influence

Stratigraphic and Sedimentological Records

Stratigraphic records document human impacts through synchronous global markers and diachronous alterations in sedimentary architecture. A prominent chemostratigraphic signal is the sharp rise in and isotopes from thermonuclear weapons testing, initiating around and peaking circa 1963, detectable in sediments worldwide including lakes, peat bogs, and ocean floors. This radionuclide spike provides a precise, anthropogenically unique boundary layer, proposed at approximately 1952 CE to align with the onset of the mid-20th-century Great Acceleration in human activity. In varved lake sediments, such as those from Crawford Lake in , —proposed as the Global Stratotype Section and Point (GSSP)—annual laminae reveal this plutonium increase starting in 1951, concurrent with spikes in spheroidal fly ash particles from combustion, , and like lead and mercury. These layers contrast sharply with baselines, showing novel combinations of synthetic pollutants absent in pre-1950 deposits. Supporting auxiliary sites, including Beppu Bay in and Śnieżka peatland in , corroborate the global synchroneity of these signals. Sedimentological evidence includes accelerated from and , with human actions increasing global fluvial flux by about 215% relative to pre-industrial levels, though impoundment in over 1 million reservoirs has reduced delivery to coastal and marine sinks by similar magnitudes. "Legacy sediments"—alluvial deposits from post-colonial —blanket bottoms in regions like the eastern U.S., forming distinctive stratigraphic units up to several meters thick with homogenized, anthropogenically enriched compositions. In marine settings, industrial has resuspended and homogenized sediments across roughly 7% of continental shelves, incorporating modern artifacts and altering benthic . Lithostratigraphic signatures feature technofossils such as persistent plastics, aluminum particles, and fragments, embedded in urban fills and landfills that rival geological formations in volume and durability. These records, while globally pervasive, exhibit some diachrony; for instance, polycyclic aromatic hydrocarbons from early industrialization appear in 19th-century sediments, but the integrated post-1950 assemblage defines a distinct anthropogenic event horizon.

Trace Elements and Isotopic Signatures

Trace elements such as , , and exhibit elevated concentrations in mid-20th-century sediments, ice cores, and peat bogs worldwide, reflecting industrial emissions, mining, and . These metals often exceed pre-industrial baselines by factors of 2 to 10, with Pb levels in European lake sediments rising sharply from the onward due to and burning, peaking around 1970 before declining with controls. enrichment in coastal sediments, such as those in the Nakdong Estuary, has doubled modern levels compared to pre-industrial times, driven primarily by anthropogenic inputs rather than natural variability. , a tracer for heavy oil , shows synchronous global spikes in the post-1950 stratigraphic record, distinguishing human-sourced from geological background. Isotopic ratios of stable elements provide distinct anthropogenic fingerprints, enabling source attribution in geological archives. Lead isotopes, particularly the ratio of 206Pb/207Pb, reveal a global signal from additives in , which dominated emissions from the 1920s to the 1980s; sediments from remote lakes in and record this alkyl-lead signature peaking in the 1970s, with ratios shifting toward less radiogenic values (e.g., 1.20) compared to pre-industrial ores. isotopes (δ34S) in ice cores and sediments trace sulfate aerosols from sulfur, with depleted values indicating large-scale combustion since the , though mid-20th-century acceleration aligns with the Great Acceleration. isotopes (δ15N) in lake sediments reflect use, showing progressive enrichment from ammonium-based post-1940s, altering global biogeochemical cycles. Radioactive isotopes from thermonuclear testing offer precise, synchronous stratigraphic markers for the mid-20th century. Plutonium isotopes 239Pu and 240Pu, with atomic ratios of ~0.18 from bomb fallout, first appear in global sediments around 1954, peaking in 1963-1964 following the Partial Test Ban Treaty, and persist due to 239Pu's 24,110-year ; this signal is detectable in marine corals, , and ice, providing a clear boundary horizon absent in pre-1950 records. Cesium-137 (137Cs), another fallout product with a 30-year , corroborates this, with activity peaks in 1963 sediments from widespread testing (over 500 megatons ). These , uniformly distributed via stratospheric injection, override local variability and confirm human dominance over natural radionuclide fluxes like 210Pb. While these signatures demonstrate unprecedented human perturbation, their diachroneity—e.g., lead pollution initiating earlier in industrialized regions—complicates a single global boundary, though mid-century spikes provide the most coherent stratigraphic utility. Heavy metal remobilization in soils and oceans can blur signals, but isotopic specificity mitigates this, as seen in Pb ratios persisting in post-ban sediments from legacy emissions. Peer-reviewed analyses emphasize that such markers, verified across hemispheres, empirically delineate the scale of technofossil deposition and geochemical flux changes.

Fossil and Biotic Records

The fossil and biotic records of the Anthropocene exhibit distinct signatures of human influence, including accelerated rates, proliferation of domesticated , and biotic homogenization, diverging from patterns. Terrestrial mammal assemblages show a marked shift, with human-associated dominating potential inputs; for instance, fossils of humans and domestic animals such as dogs, , and chickens are projected to comprise the majority of mammalian remains in strata post-dating widespread and industrialization. This cosmopolitan reflects global transport and , contrasting with the regionally diverse, wild-dominated assemblages of prior epochs. Extinction and defaunation patterns provide stratigraphic markers, with current rates estimated at 100 to 1,000 times the pre-human background level, driven by habitat loss, , and , though debates persist on whether this constitutes a full comparable to deep-time events. The biomass of wild mammals has declined by approximately 83% since the advent of around 12,000 years ago, with further intensification in the mid-20th century "Great Acceleration," evidenced by reduced abundances of large herbivores and carnivores in sedimentary records. Non-native invasions, facilitated by human-mediated dispersal, contribute to biotic homogenization, as seen in North American mammalian communities where beta-diversity decreased following megafaunal s and subsequent human introductions around 10,000 years , accelerating globally post-1500 CE with European colonization. Pollen and microfossil records capture anthropogenic vegetation shifts, revealing widespread deforestation and agricultural expansion; for example, North American lacustrine sediments document macroscale declines in forest pollen diversity since the late Pleistocene, with sharp increases in grass and crop indicators correlating to human land clearance. In tropical regions, pollen assemblages indicate non-uniform responses to post-Columbian exchanges, including afforestation in some areas from invasive species but overall homogenization through selective weeding and monoculture promotion. Domesticated avian species, particularly broiler chickens (Gallus gallus domesticus), emerge as emblematic biotic markers, with their genetically modified skeletons—characterized by rapid growth and high meat yield—preserved in vast quantities from intensive farming since the 1950s, exceeding the combined biomass of all wild birds. Marine biotic records similarly reflect human impacts, with altering assemblage compositions and homogenizing coastal and deep-sea faunas, though fossilization biases from and acidification complicate direct stratigraphic signals. Overall, these palaeontological changes form a globally synchronous signal, distinct from natural variability, supporting mid-20th century boundaries via spikes in introduced taxa and functional trait losses.

Atmospheric and Oceanic Changes

Atmospheric concentrations of carbon dioxide (CO₂) have risen from approximately 280 parts per million (ppm) in the pre-industrial era to 425.48 ppm as measured at Mauna Loa Observatory in August 2025, with a seasonal peak of 430.2 ppm in May 2025. This increase, accelerating since the mid-20th century, correlates with global fossil fuel combustion and deforestation, supported by declining δ¹³C isotopic ratios in atmospheric CO₂ that distinguish fossil fuel-derived carbon from natural sources. Methane (CH₄) levels have more than doubled to over 150% of pre-industrial values, and nitrous oxide (N₂O) has increased by about 20%, primarily from agricultural practices and industrial processes. These trends, documented through ice core records and continuous monitoring since 1958, mark a departure from millennial-scale stability observed in paleoclimate proxies. Stratospheric ozone depletion, evident from the ozone hole first observed in , resulted from anthropogenic chlorofluorocarbons (CFCs) released post-World War II, with recovery underway following the 1987 bans. Aerosol loading from industrial emissions has altered atmospheric clarity, contributing to regional dimming until recent clean air regulations reduced sulfate particles. Oceans have absorbed roughly 25-30% of anthropogenic CO₂ emissions since the , driving a decline of about 0.1 units from 8.2 to 8.1, equivalent to a 30% increase in acidity as measured in surface waters. This acidification, corroborated by repeated hydrographic surveys, impairs in marine organisms like corals and , with empirical data from benthic showing reduced carbonate saturation states. Ocean warming has sequestered over 90% of excess heat from forcing since the 1950s, with upper rising by approximately 0.4 watts per square meter, leading to and . Dissolved oxygen levels have declined by 1-2% globally since 1960, accelerating in oxygen minimum zones due to stratification and reduced ventilation, as evidenced by float and shipboard measurements. Global mean has risen 21-24 cm since 1880, with the rate doubling to 4.6 mm per year since 1993, attributable largely to anthropogenic and melt post-1970. These changes, quantified through satellite altimetry and networks, reflect human forcing overriding natural variability in post-industrial records.

Scale and Nature of Human Impacts

Geomorphological Alterations

Human activities dominate contemporary geomorphological processes, mobilizing and reshaping landforms at rates that exceed agents such as rivers, glaciers, , and waves. Annual human-induced earth-moving totals approximately 45 billion metric tons globally, a volume that surpasses the aggregate transport by all abiotic processes. More recent assessments quantify this disparity as humans displacing 24 times more material than geomorphic forces combined. Agricultural practices, including plowing, , and , have intensified , elevating global rates far beyond pre-industrial baselines. For instance, human acceleration of fluvial delivery through added 2.3 ± 0.6 billion metric tons per year to river transport worldwide, though trapping has concurrently reduced downstream deposition by an equivalent amount. This imbalance manifests in delta , such as the Mississippi Delta's retreat at rates up to 20 meters per year due to starvation post-dam construction beginning in the early . Urbanization and infrastructure development flatten terrains, fill valleys, and excavate hillsides, creating artificial landforms like spoil heaps and leveled expanses that cover millions of square kilometers. operations alone redistribute billions of tons annually, forming open pits deeper than natural canyons and waste piles that alter drainage patterns and . material transfer has risen tenfold since the mid-20th century, correlating with the Great Acceleration phase after 1950. Fluvial systems bear extensive modifications from channelization and dam-building, with over 60,000 large dams worldwide by fragmenting rivers and homogenizing flow regimes. These interventions stabilize banks but induce migration and bed incision downstream, as observed in the below , where entrenchment exceeded 100 meters since 1935. Coastal geomorphology shifts through and port , with human sediment extraction amplifying on 70% of deltas globally. Collectively, these alterations have transformed over 50% of Earth's ice-free land surface, embedding anthropogenic signatures in evolving landforms that reflect accelerated and deposition patterns. Anthropogenic sediment production surged 467% from 1950 to 2010, underscoring the epochal scale of human dominance in geomorphic work.

Biodiversity and Ecosystem Shifts

![Decline of the world's wild mammals][float-right] Human activities since the mid-20th century have driven unprecedented declines in , with monitored populations averaging a 73% reduction between 1970 and 2020, according to the WWF based on over 35,000 populations of 5,230 . Freshwater populations have experienced the steepest drops at 85%, followed by terrestrial at 69% and marine at 56%, primarily due to habitat degradation from , , and infrastructure expansion during the Great Acceleration. These trends reflect causal drivers like land-use change, which has converted more land to cropland in the decades post-1950 than in the prior 150 years combined. Extinction rates have accelerated markedly, with current anthropogenic losses estimated at 100 to 1,000 times the pre-human background rate of approximately one per million per year, based on record analyses and modern observations. The assesses 46,337 as threatened with as of 2024, out of 166,061 evaluated, including over one-third of worldwide, underscoring selective pressures from , , and introductions amplified by global trade post-World War II. populations, critical to and food webs, show annual abundance declines of 1-2% in many regions, linked to use, , and shifts. Ecosystem shifts manifest as biotic homogenization and regime changes, where human pressures reduce local diversity and favor generalist species across terrestrial, freshwater, and marine realms. Approximately 75% of terrestrial and 66% of marine environments have been severely altered by 2020, with coral reef coverage halving since 1950 due to ocean warming, acidification, and direct exploitation. Lake ecosystems exhibit increasing abrupt shifts since the 1950s, driven by synergistic eutrophication, warming, and hydrological alterations, disrupting native assemblages and promoting algal dominance. These transformations erode ecosystem services like carbon sequestration and fisheries yields, with empirical data indicating cascading effects such as trophic downgrading from large vertebrate losses. ![A few grey fish swim over grey coral with white spikes][center] Defaunation disproportionately affects and apex predators, leading to altered structures; for instance, global wild biomass has plummeted, with human and dominance now comprising 96% of mammalian versus 4% for wild . Such shifts, empirically tied to post-1950 intensification of and , parallel historical precedents but occur at rates exceeding natural variability, as evidenced by stratigraphic biotic records showing assemblages. Conservation responses, including protected areas established since the 1970s, have mitigated some local declines but fail to counter global drivers without addressing underlying consumption patterns.

Climate Variability and Human Forcing

Natural climate variability arises from internal atmospheric and oceanic processes, such as the El Niño-Southern Oscillation (ENSO) on interannual timescales and the Atlantic Multidecadal Oscillation (AMO) on decadal to multidecadal scales, alongside external factors including variations and volcanic aerosol injections. These mechanisms have driven fluctuations throughout Earth's history, including warm and cool periods like the Medieval Climate Anomaly (circa 950–1250 CE) and the (circa 1450–1850 CE), with global temperature variations typically under 1°C. Orbital forcings via operate on millennial timescales, pacing cycles but yielding gradual changes, such as the ~5°C rise from the to the optimum over approximately 5,000–7,000 years, at rates of about 0.07–0.1°C per century. Anthropogenic forcings, dominated by greenhouse gas emissions from fossil fuel combustion, deforestation, and industrial activities, have introduced rapid perturbations absent in prior natural variability. Atmospheric CO₂ concentrations remained stable at 260–280 ppm throughout most of the , with a modest ~20 ppm rise from 6,000 BCE to the pre-industrial era around 1750 CE. In contrast, levels surged to 417 ppm by March 2021 and continue rising at ~2–3 ppm annually, marking a 50% increase over pre-industrial baselines and exceeding any values by over 100 ppm. This escalation correlates with a global mean surface temperature (GMST) rise of ~1.1°C since pre-industrial times, occurring at rates of ~0.2°C per decade since 1980—tenfold faster than typical deglacial warming. Attribution studies quantify human forcing's dominance: from 1880 to 2017, greenhouse gases accounted for ~70% of multi-decadal GMST changes, with internal variability (e.g., AMO, ) modulating but not driving the net warming trend. Post-1950 observations show anthropogenic influences responsible for virtually all detected warming, as natural forcings alone (solar and volcanic) would have produced slight cooling. In the Anthropocene context, this human-induced forcing overrides natural variability's amplitude, imprinting a sustained positive trend evident in hydroclimate shifts, intensified extremes, and amplified daily variability by ~1.2% per globally. Such changes exceed precedents, where variability lacked comparable directional persistence or rapidity. Peer-reviewed syntheses affirm >99.9% agreement among studies that anthropogenic emissions are the primary cause of recent alterations.

Quantitative Assessments of Dominance

Quantitative assessments underscore human dominance over Earth's and through metrics such as distribution, land surface modification, and perturbations. In terms of , humans and domesticated animals comprise the majority of mass; accounts for approximately 62% of global , humans 34%, and wild s only 4%, reflecting a profound shift from pre-industrial conditions where wild predominated. This dominance extends to total , with human activities having reduced wild terrestrial to about 20 million tonnes of carbon (Mt C), compared to at 100 Mt C and humans at 60 Mt C. Land surface transformation provides another metric of dominance, with humans altering over 75% of ice-free land through , , and . Specifically, occupies roughly half of habitable land (ice- and desert-free), including 37% for and the remainder for crops, leaving only about 20% of ice-free land with minimal human influence. Biogeochemical cycles further quantify this influence. Human activities have more than doubled global reactive (Nr) inputs, with anthropogenic fixation reaching 170-190 Tg N per year, exceeding natural terrestrial biological fixation of around 140 Tg N per year and contributing to widespread and atmospheric pollution. Similarly, in the , human withdrawals constitute about 70% of global freshwater use for , significantly altering river flows and levels, though total appropriation of renewable freshwater resources remains below 10% globally due to inefficiencies and regional variations. These metrics, derived from empirical censuses and satellite data, illustrate the scale at which human actions now override natural processes across multiple systems.

Scientific Debates and Criticisms

Arguments Against Epoch Status

In March 2024, the Subcommission on Quaternary Stratigraphy voted against formalizing the Anthropocene as a geological epoch, with 12 members opposing the proposal, 4 in favor, and 2 abstentions, effectively halting its ratification by the International Union of Geological Sciences. The rejected proposal, advanced by the Anthropocene Working Group (AWG), sought to define the epoch's base at 1952 CE using a plutonium isotope spike from nuclear weapons testing preserved in Crawford Lake sediments, Ontario, as the global stratotype section and point (GSSP). Critics contended that this boundary fails stratigraphic standards requiring a durable, synchronous global signal etched into rock records, as plutonium-239/240 peaks decay rapidly (half-life ~24,000 years) and vary regionally in detectability. A primary objection centers on the proposed duration: at approximately 72 years by 2024, it dwarfs typical epoch lengths of hundreds of thousands to millions of years, such as the Holocene's 11,700 years, rendering it geologically insignificant for long-term classification and lacking sufficient stratigraphic thickness for future identification. Human-induced alterations, including agriculture's emergence around 10,000 years ago, widespread , and biotic homogenization via , predate the mid-20th century by millennia and exhibit comparable or greater stratigraphic footprints in records, layers, and shifts. Proponents of an earlier onset, such as geographer Erle Ellis, argue that these Holocene-era transformations already signal anthropogenic dominance, making the 1952 marker an arbitrary late snapshot rather than a foundational boundary. Stratigraphic heterogeneity further undermines the case: unlike abrupt events like the Paleocene-Eocene Thermal Maximum with uniform layers, Anthropocene signals—such as , , and biotic invasions—manifest unevenly across continents, oceans, and ice cores, often overlaid by natural variability and lacking persistence if anthropogenic forcings diminish. Geologists emphasize that formal epochs demand empirical, non-prognostic evidence from physical strata, not projected futures or cultural narratives; the AWG's focus on recent "Great Acceleration" metrics risks conflating transient industrial surges with enduring geological units. This rejection preserves the Geologic Time Scale's rigor, viewing pronounced human effects as an informal "event" series within the , akin to the , rather than warranting epochal subdivision.

Conceptual and Definitional Challenges

The formal geological definition of the Anthropocene as a distinct requires a globally synchronous stratigraphic boundary identifiable in rock records, akin to other units in the , yet proposed markers like from mid-20th-century nuclear tests fail to meet this criterion due to their patchy distribution and rapid decay relative to epochal timescales typically spanning millions of years. In March 2024, the Subcommission on voted 12-4 against formalizing the Anthropocene, with four abstentions, citing its brevity—roughly 75 years since the proposed 1950 start—and lack of clear demarcation from preceding conditions, a decision later ratified by the . This rejection underscores that while human-induced signals (e.g., , isotopes) are evident, they do not constitute a uniform "" for global correlation, as required by chronostratigraphic standards. Debates over the onset further complicate definition: proponents of a mid-20th-century "Great Acceleration" boundary emphasize post-World War II surges in population, industrialization, and atmospheric radionuclides, but critics argue this ignores earlier anthropogenic strata, such as deforestation-linked sediments from ~8,000 years ago or megafaunal extinctions tied to around 50,000 years ago. Alternative datings, including the onset of agriculture (~11,700 years ago) or the (~1800 CE), highlight asynchronous regional impacts—e.g., European colonization's biotic homogenization via the predating global nuclear signatures—rendering a single boundary arbitrary and non-stratigraphically robust. Conceptually, the Anthropocene's framing as a human-dominated risks conflating causal agency with stratigraphic preservation, as geological epochs are defined by enduring lithological, mineralogical, or paleontological signals rather than inferred processes like anthropogenic forcing. This leads to tensions with non-geological usages in or social sciences, where the term denotes broad planetary influence without stratigraphic rigor, potentially diluting its precision; for instance, philosophical critiques note that attributing all changes to "Anthropos" overlooks uneven culpability—disproportionate Western emissions versus global effects—and implies a monolithic essence, echoing speciesist assumptions rather than dissecting historical contingencies like or technology. Moreover, equating impacts with epochal novelty ignores Earth's dynamic baseline, where natural forcings (e.g., orbital cycles) have driven comparable biotic turnovers, challenging claims of unprecedented dominance without quantifying relative magnitudes across . Such ambiguities suggest the concept functions better as a for interdisciplinary dialogue than a formal unit, avoiding the pitfalls of retrofitting causal narratives onto empirical strata.

Overemphasis on Recent vs. Long-Term Human Effects

Critics of the conventional Anthropocene framing, which often anchors the epoch's onset to mid-20th-century markers like and plastic proliferation, argue that this approach disproportionately highlights abrupt recent accelerations while marginalizing millennia of prior human-driven modifications to Earth's systems. Human activities during the early , particularly the advent of around 10,000 years ago, initiated widespread land clearance and biotic alterations that left detectable stratigraphic signatures, such as shifts in pollen assemblages and increased from anthropogenic fires. These changes, including the of megafauna coinciding with human dispersal—such as the disappearance of over 100 genera of large mammals between 50,000 and 10,000 years ago, primarily linked to pressure rather than alone—demonstrate that human dominance over ecosystems predates industrial-era spikes by orders of magnitude. A prominent example is the "early anthropogenic hypothesis" proposed by geologist William Ruddiman in 2003, positing that anomalies emerged thousands of years before industrialization due to farming practices. records reveal a CO₂ rise from approximately 260 ppm to 284 ppm between 8,000 and 1,000 years ago, attributed to for releasing stored carbon, alongside a increase from natural levels of about 450 ppb to 704 ppb starting around 5,000 years ago, largely from wetland rice irrigation in . These perturbations, estimated to have warmed the planet by roughly 0.75°C globally (amplified to 2°C at high latitudes), forestalled a natural cooling trend and potential growth that models predict would have occurred absent human intervention. Further evidence of pre-industrial fingerprints includes atmospheric from colonial-era , with South American ice cores showing elevated lead, , and other metals from Peruvian and Bolivian operations beginning around A.D. 1540—over two centuries before the —due to silver extraction techniques like mercury amalgamation. Such long-term impacts, including cumulative , river damming, and biotic homogenization from selective , argue for viewing the Anthropocene as a intensification within the rather than a novel post-1950 rupture, as early transformations already reshaped up to 60% more by the late through intensified practices. This perspective challenges the recency bias in epoch proposals, emphasizing that forcing's causal chain originates in deep historical processes, with recent effects representing acceleration atop established dominance rather than its genesis.

Alternative Frameworks

Anthropocene as Event Rather Than Epoch

Some geologists propose conceptualizing the Anthropocene as a rather than a formal to accommodate its spatial and temporal heterogeneity, which does not align with the strict criteria for stratigraphic subdivision. Geological epochs require a globally synchronous boundary defined by stratigraphic markers persisting for millions of years, whereas events encompass diverse, non-uniform processes over shorter durations without necessitating a precise global stratotype section and point (GSSP). This distinction allows the Anthropocene to be recognized for its causal role in planetary changes—such as accelerated , extinctions, and atmospheric alterations—initiated variably across regions, from early around 8,000 years ago to industrial intensification post-1800. The formal rejection of the Anthropocene as an epoch by the Subcommission on in March 2024, via a 12-4 vote with 10 abstentions, underscored these definitional challenges, as the proposed 1950 start date (marked by and plastic proliferation) spanned only about 75 years—far shorter than typical epochs like the Holocene's 11,700 years. Critics argued that such brevity undermines geological permanence, as human-induced signals like radionuclides may decay within millennia, failing to meet the International Chronostratigraphic Chart's standards for long-term preservation. Framing it as an event sidesteps these issues by emphasizing process over chronology, linking human activities to stratigraphic records without imposing a singular boundary, thus facilitating interdisciplinary analysis of technofossils, biogeochemical shifts, and transformations. This event-based perspective also highlights causal realism in human dominance, attributing changes to scalable drivers like population growth (from 1 billion in 1800 to 8 billion by 2022) and fossil fuel combustion (emitting over 500 gigatons of carbon since 1750), rather than inflating recent decades as epoch-defining. Proponents, including stratigraphers, contend it better captures diachronous onsets—e.g., deforestation in Eurasia millennia before mid-20th-century globalization—avoiding the pitfalls of overemphasizing post-1950 "Great Acceleration" metrics like nitrogen fixation (tripled since 1900) at the expense of earlier anthropogenic forcings. By rejecting epoch status, this framework preserves stratigraphic integrity while acknowledging the Anthropocene's role as a transient phase of intensified biosphere engineering, potentially reversible through technological adaptation rather than an irreversible geological fixture. The term Homogenocene refers to an era characterized by the increasing uniformity of Earth's biota due to human activities, particularly the global spread of non-native , selective extinctions of endemic taxa, and modifications that favor cosmopolitan generalists. Coined by entomologist Michael Samways in 1999, it highlights the erosion of regional biotic distinctiveness, contrasting with the broader human geological imprint emphasized in the Anthropocene concept. This framework posits that post-Columbian exchanges initiated in marked the onset, accelerating with industrialization and to produce more similar ecological communities worldwide. Biotic homogenization, the core process underlying the Homogenocene, involves declining (turnover between sites) as proliferate and unique local species decline. Mechanisms include anthropogenic dispersal via trade, agriculture, and urbanization, which introduce propagules across barriers, alongside that disadvantages specialists. For instance, a of 100 studies across taxa found that land-use intensification correlates with 10-20% reductions in taxonomic dissimilarity among assemblages over decades. Empirical evidence spans ecosystems: in North American birds, compositional similarity between regions rose by 12% from 1968 to 2006 due to declining native diversity in modified landscapes. Similarly, communities in exhibit functional homogenization, with convergent traits like tolerance to dominating post-1950. Related concepts extend this theme to specific dimensions of uniformity. Functional homogenization describes convergence in ecological roles, where species assemblages lose variability in traits such as foraging strategy or resilience, often measured via trait dispersion indices declining under or warming. Genetic homogenization occurs through from domesticated or invasive populations, as seen in crop wild relatives hybridizing with cultivars, reducing allelic diversity by up to 30% in some agroecosystems. These processes intersect with Anthropocene dynamics but emphasize ecological sameness over stratigraphic novelty, critiquing overly anthropocentric views by underscoring biodiversity's qualitative loss—e.g., the replacement of 85% of wild mammal biomass by since . Proponents argue this lens better captures causal human drivers like over alone, though debates persist on whether homogenization metrics overstate uniformity amid novel local diversities.

Natural Variability and Holocene Comparisons

The epoch, spanning approximately 11,700 years to the present, exhibited significant natural climate variability driven primarily by orbital forcings, fluctuations, and volcanic activity, with global mean surface temperatures fluctuating by about 1–2°C over millennial timescales. Reconstructions from multi-proxy data, including ice cores, tree rings, pollen records, and lake sediments, indicate an early thermal maximum around 9,000–6,000 years (), characterized by warmer-than-present conditions in many mid-to-high latitude regions due to peak summer insolation from Earth's cycle. Subsequent cooling trends, including the Neoglacial period after ~4,000 and shorter oscillations like the Medieval Climate Anomaly (roughly 950–1250 CE, with temperatures ~0.5–1°C above the subsequent baseline in some hemispheres), demonstrate the Holocene's dynamic nature rather than uniform stability. Comparisons to recent changes attributed to the Anthropocene reveal both alignments and divergences from this natural variability. Instrumental records show global temperatures rising ~1.1°C since the late , with rates of ~0.2°C per decade in recent decades, exceeding many multi-centennial trends but comparable in magnitude to rapid shifts like the ~4.2 ka BP event or the transition out of the ~11,700 BP. Proxy-based global mean surface temperature reconstructions suggest current levels may surpass mid- averages by ~0.5–1°C, yet some hemispheric and regional data indicate early warmth equaled or exceeded modern values in the extratropics, challenging claims of global unprecedentedness. Atmospheric CO₂ concentrations, stable at 260–280 ppm throughout the until the industrial era, have risen to over 420 ppm, a rate without clear analog in records, though temperature responses in models and proxies highlight that orbital-driven insolation changes produced similar equilibrium shifts over longer periods. Critics of Anthropocene epochal designation argue that emphasizing recent human forcings overlooks precedents, where natural drivers induced shifts, sea-level variations of several meters, and responses without anthropogenic dominance. For instance, sea-level rise post-glacial maximum averaged ~1–2 mm/year initially, decelerating to near stability by ~6,000 BP, paralleling modern rates of ~3–4 mm/year but within a context of ongoing isostatic adjustments. This perspective posits that while human activities have accelerated certain parameters, the 's inherent variability—evidenced by high-frequency events like Bond cycles—undermines delineations of a novel epoch, as causal attribution remains entangled with unforced internal dynamics like ocean-atmosphere oscillations (e.g., AMO, PDO). Peer-reviewed syntheses caution against overinterpreting proxy uncertainties, such as errors or seasonal biases in records, which can inflate perceived anomalies in recent warming relative to paleoclimate baselines. In essence, Holocene comparisons highlight that Earth's systems have undergone comparable perturbations naturally, suggesting the Anthropocene's proposed boundary may reflect amplified but not categorically distinct forcing rather than a rupture from norms. Empirical data from diverse proxies underscore the need for rigorous signal detection amid noise, with some reconstructions indicating modern conditions align more closely with early states than with the cooler late- baseline preceding industrialization. This framework prioritizes long-term context over short-term trends, informing debates on whether human effects constitute a geological or merely a perturbation within ongoing variability.

Societal and Intellectual Implications

Scientific and Policy Uses

In , the Anthropocene concept serves as a framework for analyzing the scale and synchronicity of human-induced changes across , such as atmospheric composition, integrity, and land-system change, enabling quantitative assessments of tipping points and resilience. Researchers apply it to model interactions between human activities—like combustion and —and geophysical processes, facilitating predictions of future trajectories in and biogeochemical cycles. This approach integrates data from ice cores, sediment records, and satellite observations to trace causal links, such as the post-1950 spike in radiogenic isotopes from nuclear testing as a global stratigraphic signal. ![Mauna Loa CO2 monthly mean concentration.svg.png][center] Stratigraphically, despite the International Commission on Stratigraphy's rejection of the Anthropocene as a formal in March 2024 due to its brevity and diachronous onset, the term persists in geological studies to denote informal chronostratigraphic units marked by anthropogenic "technofossils" like and , aiding correlations in sedimentary archives. It supports multidisciplinary research in and by highlighting novel sedimentary signatures absent in prior strata, such as homogenized pollen profiles from global agriculture. In policy domains, the Anthropocene frames by emphasizing human agency in planetary stewardship, influencing frameworks like the (SDGs), where it underscores as limits to development, prioritizing actions on climate mitigation and biodiversity conservation over unprioritized . IPCC assessments invoke it to justify integrated responses to coupled human-environmental s, arguing that adaptation and mitigation can co-benefit if aligned with empirical thresholds, such as limiting warming to 1.5°C to avoid irreversible shifts. This conceptual lens has spurred proposals for "earth system law," reorienting international treaties toward holistic regulation of feedbacks like nitrogen cycles and , though critics note its occasional rhetorical overreach in non-peer-reviewed advocacy. Applications include assessments for and , promoting policies that decouple resource use from economic expansion via technological innovation.

Critiques from Humanities and Ideology

Scholars in the humanities have critiqued the Anthropocene concept for homogenizing human agency and responsibility, attributing planetary-scale changes equally to all humans despite evidence that such transformations originated disproportionately from European industrialization, capitalism, and colonialism beginning in the 16th century. This perspective argues that the term obscures socioeconomic inequalities, as the majority of historical emissions and resource extraction stem from a minority of affluent populations in the Global North, while vulnerable groups in the Global South bear disproportionate consequences. In response, environmental historian Jason W. Moore proposed the "Capitalocene" as an alternative framework, positing that the epoch's dynamics reflect not generic human activity but the expansive logic of , which commodified nature and intensified ecological crises from the long onward. Similarly, feminist scholar , alongside , advanced the "Plantationocene" to emphasize plantation agriculture and colonial slavery as pivotal drivers of and atmospheric alterations, starting around 1610 with the "Orbis Spike" in carbon isotopes linked to land clearance. Haraway further critiqued the Anthropocene for reinforcing anthropocentric narratives that prioritize human , advocating instead for the "Chthulucene," a multispecies era focused on symbiotic kin-making and response-ability across human and non-human entities to avoid defeatist predictions of inevitable collapse. Political theorist Jeremy Baskin characterized the Anthropocene as " dressed as ," arguing it functions more as an ideological construct than a neutral geological descriptor, embedding assumptions of planetary and managerial control that justify geoengineering and accelerate technological interventions without confronting biophysical limits. This view posits that the concept's proponents, often from , promote a hubristic where are reimagined as a unified geological force, potentially enabling neoliberal governance models that prioritize through markets over systemic restraint. Critics in and echo this by highlighting how the narrative marginalizes non-Western ontologies and overemphasizes autonomous subjects, sidelining relational and indigenous perspectives on . These humanities-based objections often reflect disciplinary tendencies toward emphasizing historical contingency, power asymmetries, and cultural narratives, which can introduce interpretive biases favoring socioeconomic explanations over empirical stratigraphic markers of recent global homogenization, such as ubiquity and since 1950. While valid in underscoring unequal culpability—e.g., the Global North's emissions exceeding those of the by factors of 10 or more since 1850—the critiques risk understating the post-1945 "Great Acceleration" in which developing nations have contributed substantially to aggregate impacts through and industrialization.

Potential for Human Adaptation and Innovation

Humans have demonstrated resilience to environmental disturbances throughout history, with archaeological evidence from the past 10,000 years indicating that frequent climate variability and societal collapses fostered adaptive innovations, such as diversified and fortified settlements, which enhanced long-term societal stability in regions like the Mediterranean and . In the Anthropocene, this capacity persists through engineered solutions; for instance, the in , completed in 1982, has prevented flooding during over 200 storm surges by dynamically adjusting to tidal patterns, protecting 125 square kilometers of urban area and demonstrating scalable for rising sea levels. Technological advancements offer further potential for mitigating anthropogenic impacts, including techniques like , which scaled to capture 4,000 tons of CO2 annually by 2023 at facilities such as ' Orca plant in , integrating with basaltic rock storage for permanent sequestration. transitions, exemplified by solar photovoltaic costs declining 89% from 2010 to 2020, have enabled widespread deployment, with global capacity reaching 1,052 gigawatts by 2022, reducing reliance on fuels and curbing emissions growth in sectors like . Genetic modifications in , such as drought-resistant varieties adopted in since 2010, have boosted yields by up to 30% under water-stressed conditions, supporting amid shifting patterns. Geoengineering proposals, including to reflect sunlight, represent high-risk pathways, with modeling studies from 2014 suggesting potential to limit warming to 1.5°C but warning of side effects like altered patterns affecting 2 billion people. Urban strategies, such as in Singapore's ABC Waters program initiated in 2006, have integrated 7,800 hectares of bioretention systems to manage and urban , reducing risks by 40% in test sites. These interventions underscore human agency in planetary stewardship, though their efficacy depends on coordinated to avoid unintended ecological disruptions, as evidenced by historical delta where adaptive stabilized 7000-year human settlements against and . Overall, while no single resolves Anthropocene challenges, integrated approaches leveraging empirical data on past position humanity to sustain prosperity amid altered Earth systems.

References

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