Abstract
At the ultimate level of human knowledge, the disciplinary boundaries tend to disappear and it transpires borrowing of ideas, concepts, theories, and even terminologies from one discipline to another. Anthropology has very largely benefitted by borrowing ideas from other disciplines. The accumulated knowledge of the universe that we have today is the product of millions and millions of years, obtained by our ancestors ever since their appearance on earth and transferred by them from one generation to another. At the threshold of the 21st century, it is hoped that we are entering, or we have already entered, a new age, namely, Anthropocene. The archeologists have their own terminologies to classify archeological periods, such as Paleolithic Period, Mesolithic Period, Neolithic Period, etc., based upon tool typology and technology. Geologists have their own terminologies to explain geological timescale, such as geological eras and epochs, based upon the study of different strata of earth. Currently, geologists have proposed Anthropocene as a geological epoch dating from the commencement of significant human impact on earth’s geology and ecosystem. The debate still continues among the scientists that exactly what point of time could be considered as the beginning of Anthropocene. Which event could be precisely considered to have kicked off Anthropocene? An attempt has been made in this editorial to suggest that the discipline of Anthropology can perhaps help geologists to determine the beginning of the New Epoch, after Holocene.
Humanity has had a profound impact on every aspect of our planet. Each step along the biological and social evolution of humans; like discovery of fire, first mass migration of Homo sapiens out of Africa, domestication of plants and animals, industrial and scientific revolution, etc., has in turn led to climate change, global warming, species invasions, and mass extinction of species. In recent years, there has been a general consensus among scientific community that humans have now so much altered the terrestrial and climatic conditions of earth that we may as well be living in Anthropocene or the Epoch of Humans—a brand new epoch in Earth’s geological timescale. However, two substantial hurdles have been identified in efforts to get the current epoch recognized as Anthropocene.
Firstly is the impact of humans big enough to have caused changes to geologic deposits on earth? And secondly, if yes, then when exactly this change happened? To answer the first question, the International Commission on Stratigraphy (ICS) set up an Anthropocene Working Group (AWG) to find stratigraphic markers that could scientifically differentiate Anthropocene from Holocene (the epoch we are currently living in). To establish events in geological timescale, a scientist studies different strata of sedimentary rocks. Sedimentary rocks are formed by accumulation of deposits and the subsequent cementation of mineral and organic particles on the earth’s surface. Because these rocks are formed by deposition of layer after layer of particles, they are found in the form of distinct layers or strata. Dead plants, animals, and minerals get buried under these layers and over millions of years become fossils.
By studying fossils and minerals, and their geographic distribution, we can find out the terrestrial, climatic, and biological features of earth over any given period. For example, thin layers of silver to black iron oxide found in sedimentary rocks have been dated to 2.4 to 1.8 billion years old. Sudden emergence of iron oxide reveals that around this time, oxygen became abundant in the atmosphere and eventually led to evolution of all plants and animals, as we know today. However, sudden emergence of Oxygen in this specific period of earth’s history also means that almost all existing unicellular life forms of the time had evolved to live in Oxygen-less environment and therefore died out. This event is sometimes called the first mass extinction on earth, and the sudden spike in Oxygen of that period is termed as Great Oxygenation Event or Oxygen Revolution! Similarly, we find that about 65 million years ago, another mass extinction event occurred when 17percent of all families, 50percent of all genera, and 75percent of all species became extinct (Raup & Sepkoski, 1982). This event, more commonly known for the disappearance of dinosaurs and appearance on earth of mammals and birds, is a major landmark that forms the boundary between Cretaceous Period of Mesozoic (middle life) Era and the Paleogene Period of Cenozoic (new life) Era.
However, today we are living through possibly another mass extinction, which is caused by human actions. Some studies suggest that 7percent of all species may already be lost (Régnier et al., 2015), and according to a report by Inter-governmental Science Policy Platform on Biodiversity and Ecosystem Services, by the end of next century, up to 25percent of surviving species could become extinct because of human actions. Also, industrial activities have generated and deposited new types of particles on rocks like elemental aluminum, spherical carbonaceous particles released from burning of fossil fuels, inorganic ash, and plastics. At the same time, soil nitrogen and phosphorous have almost doubled in last few years because of excessive use of fertilizers for agriculture. Taken together, all these were enough for the Working Group on Anthropocene to recommend, in May 2019, the declaration of a new Epoch of Anthropocene that recognizes the increasing role humans have played in changing and shaping the present face of earth. However, Anthropocene has still not formally been adopted because of the problem in identifying a single event or year when it could be proven to have started.
The problem with identifying an epoch on the basis of human actions is the difficulty in reconciling different ideas of time. In Geology, the smallest unit used to measure time is an Age, but a Geological Age is still measured in millions of years. On the other hand, modern humans did not begin impacting the ecosystem in a substantial manner before the emergence of behavioral modernity some 50,000 years ago. Thus, in geological terms, modern humans with advanced behavioral and cognitive traits emerged during the end of Pleistocene Epoch (2.58 million years ago to 12,000 years ago) and spread out to almost all parts of earth by the beginning of Holocene Epoch (some 12,000 years ago). During this time, major events that altered biodiversity and climate of earth include Agricultural Revolution (10,000 years ago), mixing of Old World and New World species (500 years ago), Industrial Revolution (250 years ago), and Atomic Age (75 years ago). The challenge is to recognize one of these events to have caused such large-scale changes so as to justify a new epoch of humans.
In our opinion, as this period coincides with archaeology and recorded human history, and is too small for finding geological markers, an event to recognize Anthropocene can be better understood from the perspective of Social Science in general and Cultural Anthropology in particular. For example, we can think of Leslie White’s Law on cultural evolution to find how human societies become advanced enough to substantially alter ecosystems. Leslie White, in his book Evolution of Culture (1959) writes, “Culture evolves as the amount of energy harnessed and put to use per capita per year is increased, or in other words as the efficiency of the instrumental means of putting energy to work is increased.” For thousands of years, only viable sources of energy for humans were solar energy and fire. However, According to White, in 1776, James Watt modified Newcomen’s atmospheric engine to form his steam engine. Steam engine allowed humans to harness energy as never before giving rise to the age of machines and industries. A particular event like Watt’s invention of steam engine, or a period of history like Industrial Revolution, can be taken as a marker when human beings left their dependence on sun and fire for their energy needs and thus, could be regarded as the start of Anthropocene.
This is of course just one of the options. However, we can safely say that to understand the impact humans have had on the planet, we need to understand the aspects of human culture that enables us to alter global ecology in unprecedented ways all by ourselves. A careful study of history and anthropology can thus provide better understanding as to how and when humans became such a strong agent of change that the planet as a whole entered into Anthropocene or the Epoch of Humanity.