The Early Anthropocene Hypothesis (sometimes referred to as 'Early Anthropogenic' or 'Ruddiman Hypothesis') is a stance concerning the beginning of the Anthropocene first proposed by William Ruddiman in 2003. [1] It posits that the Anthropocene, a proposed geological epoch coinciding with the most recent period in Earth's history when the activities of the human race first began to have a significant global impact on Earth's climate and ecosystems, dates back to 8,000 years ago, triggered by intense farming activities after agriculture became widespread. It was at that time that atmospheric greenhouse gas concentrations stopped following the periodic pattern of rises and falls that had accurately characterized their past long-term behavior, a pattern that is explained by natural variations in Earth's orbit known as Milankovitch cycles. Ruddiman's proposed start-date has been met with criticism from scholars in a variety of fields.
The Early Anthropocene Hypothesis asserts that the Anthropocene did not begin during European colonization of the Americas, as numerous scholars posit, [2] [3] [4] nor the eighteenth century with advent of coal-burning factories and power plants of the industrial era, as originally argued by Paul Crutzen (who popularized the word 'Anthropocene' in 2000), nor in the 1950s as claimed by the Anthropocene Working Group (a geological research program working on the Anthropocene as a geological time unit).
In his overdue-glaciation hypothesis, Ruddiman claims that an incipient ice age would have begun several thousand years ago, but that scheduled ice age was forestalled by intense farming and deforestation by early farmers that began raising the level of greenhouse gases eight thousand years ago.
The overdue-glaciation hypothesis has been challenged on the grounds that comparison with an earlier interglaciation (MIS 11, 400,000 years ago) suggest that 16,000 more years must elapse before the current Holocene interglaciation comes to an end. Data from even earlier ice-cores going as far back as 800,000 years ago suggest probable cyclicity of interglacial length and an inverse correlation with the maximum temperature of each interglacial, but Ruddiman argues that this results from a false alignment of recent insolation maxima with insolation minima from the past, among other irregularities that invalidate the criticism. [5]
The Neolithic Revolution, or agricultural revolution, was a wide-scale demographic transition in the Neolithic. Historically verifiable, many human cultures changed from hunter-gatherers to agriculture and settlement that supported an increase in population. [6] Archaeological data indicates that various forms of plants and animal domestication evolved in separate locations worldwide, starting in the geological epoch of the Holocene [7] around 12,000 14C years ago (12,000–7,000 BP). [8]
A group of geographers led by Jan Zalasiewicz and Will Steffen argued that the Neolithic Revolution does not show the wide-scale environmental change necessary for epochal designation that other starting points, such as the Anthropocene Working Group's 1950 marker, does. [9]
Other criticism of the Early Anthropocene Hypothesis stems from its representation of American Indian societies. Humanities scholar Elizabeth DeLoughrey has posited that while the Early Anthropocene Hypothesis "traces out an eight-thousand-year history of deforestation," it "never contextualizes the histories of human violence. Consequently, in explaining those eras in which CO2 did not rise due to a significant drop in the production of agriculture caused by death, [Ruddiman] likens the plague in Medieval Europe to the decimation of 90 percent of the Indigenous peoples of the Americas, referring to it simply as a 'pandemic' rather than genocide. Accordingly, the unprecedented drop in CO2 levels from 1550 to 1800—due to a population collapse of more than fifty million people with causal links to colonization, slavery, war, displacement, containment, and outright ethnic cleansing—is attributed to smallpox." [10]
Environmental scholars have also argued that while the Early Anthropocene Hypothesis accounts for land change and rising greenhouse gas production resulting from changing farming practices in Europe and Asia during the Neolithic revolution, it does not account for relational agriculture practiced in the Americas during the same period. Once Native American agriculture is studied alongside the Early Anthropocene Hypothesis, it becomes clear that such land change and greenhouse gas emissions take place in the Americas only after European colonization. Thus, colonialism should be seen as the main driver of environmental change responsible for the Anthropocene rather than agriculture. [11]
Scholars have also disputed Ruddiman's claim that the land change and greenhouse gas emissions caused by Neolithic farming practices account for a large enough systems change to denote new epochal designation. [12] These scholars claim that an early date for the proposed Anthropocene term does not account for a substantial human footprint on Earth. [13] [14] Others have argued that the Early Anthropocene Hypothesis only provides a cursory view of Native American farming practices prior to European colonization, which did not result in the same land change or greenhouse gas emissions as European and Asian agriculture of the same period. They argue that if precolonial Native American farming was studied in relation to European and Asian agriculture of the same period, the European colonization of the Americas would be seen as the epoch's starting point. [11] [15]
The Holocene is the current geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing glacial cycles of the Quaternary, and is equivalent to Marine Isotope Stage 1.
The Holocene extinction, or Anthropocene extinction, is the ongoing extinction event caused by humans during the Holocene epoch. These extinctions span numerous families of plants and animals, including mammals, birds, reptiles, amphibians, fish, and invertebrates, and affecting not just terrestrial species but also large sectors of marine life. With widespread degradation of biodiversity hotspots, such as coral reefs and rainforests, as well as other areas, the vast majority of these extinctions are thought to be undocumented, as the species are undiscovered at the time of their extinction, which goes unrecorded. The current rate of extinction of species is estimated at 100 to 1,000 times higher than natural background extinction rates and is increasing. During the past 100–200 years, biodiversity loss and species extinction have accelerated, to the point that most conservation biologists now believe that human activity has either produced a period of mass extinction, or is on the cusp of doing so. As such, after the "Big Five" mass extinctions, the Holocene extinction event has also been referred to as the sixth mass extinction or sixth extinction; given the recent recognition of the Capitanian mass extinction, the term seventh mass extinction has also been proposed for the Holocene extinction event.
The Quaternary is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene and the Holocene ; a proposed third epoch, the Anthropocene, was rejected in 2024 by IUGS, the governing body of the ICS.
Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. Climate change may refer to any time in Earth's history, but the term is now commonly used to describe contemporary climate change, often popularly referred to as global warming. Since the Industrial Revolution, the climate has increasingly been affected by human activities.
The Anthropocene was a rejected proposal for a geological epoch following the Holocene, dating from the commencement of significant human impact on Earth up to the present day. This impact affects Earth's oceans, geology, geomorphology, landscape, limnology, hydrology, ecosystems and climate. The effects of human activities on Earth can be seen for example in biodiversity loss and climate change. Various start dates for the Anthropocene have been proposed, ranging from the beginning of the Neolithic Revolution, 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. However, in 2024 the International Commission on Stratigraphy (ICS) and the International Union of Geological Sciences (IUGS) rejected the Anthropocene Epoch proposal for inclusion in the Geologic Time Scale sparking significant disagreement from scientists working in the field.
The Neolithic Revolution, also known as the First Agricultural Revolution, was the wide-scale transition of many human cultures during the Neolithic period in Afro-Eurasia from a lifestyle of hunting and gathering to one of agriculture and settlement, making an increasingly large population possible. These settled communities permitted humans to observe and experiment with plants, learning how they grew and developed. This new knowledge led to the domestication of plants into crops.
The Black Sea deluge is the best known of three hypothetical flood scenarios proposed for the Late Quaternary history of the Black Sea. One other flood scenario proposes a rapid, even catastrophic, rise in sea level of the Black Sea.
The Flandrian interglacial or stage is the regional name given by geologists and archaeologists in the British Isles to the period from around 12,000 years ago, at the end of the last glacial period, to the present day. As such, it is in practice identical in span to the Holocene.
The faint young Sun paradox or faint young Sun problem describes the apparent contradiction between observations of liquid water early in Earth's history and the astrophysical expectation that the Sun's output would be only 70 percent as intense during that epoch as it is during the modern epoch. The paradox is this: with the young Sun's output at only 70 percent of its current output, early Earth would be expected to be completely frozen, but early Earth seems to have had liquid water and supported life.
William F. Ruddiman is a palaeoclimatologist and Professor Emeritus at the University of Virginia. Ruddiman earned an undergraduate degree in geology in 1964 at Williams College, and a Ph.D. in marine geology from Columbia University in 1969. Ruddiman worked at the US Naval Oceanographic Office from 1969 to 1976, and at Columbia's Lamont–Doherty Earth Observatory from 1976 to 1991. He moved to Virginia in 1991, serving as a professor in Environmental Sciences. Ruddiman's research interests center on climate change over several time scales. He is a Fellow of both the Geological Society of America and the American Geophysical Union. Ruddiman has participated in 15 oceanographic cruises, and was co-chief of two deep-sea drilling cruises.
Plows, Plagues and Petroleum: How Humans Took Control of Climate is a 2005 book published by Princeton University Press and written by William Ruddiman, a paleoclimatologist and Professor Emeritus at the University of Virginia. He has authored and co-authored several books and academic papers on the subject of climate change. Scientists often refer to this period as the "Anthropocene" and define it as the era in which humans first began to alter the Earth's climate and ecosystems. Ruddiman contends that human induced climate change began as a result of the advent of agriculture thousands of years ago and resulted in warmer temperatures that could have possibly averted another ice age; this is the early anthropocene hypothesis.
Throughout Earth's climate history (Paleoclimate) its climate has fluctuated between two primary states: greenhouse and icehouse Earth. Both climate states last for millions of years and should not be confused with the much smaller glacial and interglacial periods, which occur as alternating phases within an icehouse period and tend to last less than 1 million years. There are five known icehouse periods in Earth's climate history, namely the Huronian, Cryogenian, Andean-Saharan, Late Paleozoic and Late Cenozoic glaciations.
The Subatlantic is the current climatic age of the Holocene epoch. It started about 2,500 years BP and is still ongoing. Its average temperatures are slightly lower than during the preceding Subboreal and Atlantic. During its course, the temperature underwent several oscillations, which had a strong influence on fauna and flora and thus indirectly on the evolution of human civilizations. With intensifying industrialisation, human society started to stress the natural climatic cycles with increased greenhouse gas emissions.
Planetary boundaries are a framework to describe limits to the impacts of human activities on the Earth system. Beyond these limits, the environment may not be able to self-regulate anymore. This would mean the Earth system would leave the period of stability of the Holocene, in which human society developed. The framework is based on scientific evidence that human actions, especially those of industrialized societies since the Industrial Revolution, have become the main driver of global environmental change. According to the framework, "transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental-scale to planetary-scale systems."
Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum, the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases.
John E. Kutzbach was an American climate scientist who pioneered the use of climate models to investigate the causes and effects of large changes of climate of the past.
The Late Cenozoic Ice Age, or Antarctic Glaciation, began 34 million years ago at the Eocene-Oligocene Boundary and is ongoing. It is Earth's current ice age or icehouse period. Its beginning is marked by the formation of the Antarctic ice sheets.
The means by which agriculture expanded into the Philippines is argued by many different anthropologists and an exact date of its origin is unknown. However, there are proxy indicators and other pieces of evidence that allow anthropologists to get an idea of when different crops reached the Philippines and how they may have gotten there. Rice is an important agricultural crop today in the Philippines and many countries throughout the world import rice and other products from the Philippines.
The Anthropocene Working Group (AWG) is an interdisciplinary research group dedicated to the study of the Anthropocene as a geological time unit. It was established in 2009 as part of the Subcommission on Quaternary Stratigraphy (SQS), a constituent body of the International Commission on Stratigraphy (ICS). As of 2021, the research group features 37 members, with the physical geographer Simon Turner as Secretary and the geologist Colin Neil Waters as chair of the group. The late Nobel Prize-winning Paul Crutzen, who popularized the word 'Anthropocene' in 2000, had also been a member of the group until he died on January 28, 2021. The main goal of the AWG is providing scientific evidence robust enough for the Anthropocene to be formally ratified by the International Union of Geological Sciences (IUGS) as an epoch within the Geologic time scale.
The Grindelwald Fluctuation is a period when glaciers in Grindelwald, Switzerland, expanded significantly. Temperatures were 1-2 degrees Celsius lower than twentieth-century averages during this period, which is thought to have lasted from the 1560s to the 1630s.
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