The term is everywhere: from the Anthropocene School in Lyon, to a dedicated IGN atlas1 and even up to two scientific journals2 dedicated, everyone – including scientists – uses the notion of the Anthropocene. This new geological epoch is characterized by a significant and global imprint of humanity on the planet. But the term is not officially recognized. In March 2024, the International Commission on Stratigraphy – the organization responsible for defining the geological time scale – rejected the official addition of a new geological epoch3. We are therefore still officially in the Holocene epoch, and have been for 11,700 years. This decision has not closed the debate within the scientific community.
#1 THE ANTHROPOCENE EXISTS.
True: Part of the scientific community recognizes its existence.
Erle Ellis. The Anthropocene, as defined in dictionaries, exists and is widely used in science to define a time when humans are transforming the planet. However, there is no official epoch in the geological time scale.
Michel Magny. A large part of the international scientific community recognizes itself in this term. When it was proposed for the first time, within our team which works on the reconstruction of past environments in relation to societies, we had the impression that all our work integrated this concept of the Anthropocene! We see the major impact of humanity on ecosystems from the first agricultural societies. Many geologists also recognize the existence of the Anthropocene.
Without disputing the fact that rapid and large-scale climate changes may have occurred in the past, the Anthropocene marks a sudden change in climate regime. While for a million years, climate oscillations were mainly driven by the Earth’s orbital factors, now it is the pace of human greenhouse gas emissions that is causing climate warming of a similar magnitude.
False: The International Committee of Stratigraphy rejected the adoption of the Anthropocene as a geological epoch.
Jan Piotrowski. There is no justification for ending the Holocene [N.D.LR. : l’époque géologique actuelle officielle]. The end of the last ice age – roughly coinciding with the start of the Holocene – was marked by significantly greater environmental changes than those that would have marked the start of the Anthropocene. For example, the temperature increased by 1°C per decade in Wales 15,000 years ago; 11,700 years ago in Greenland, a warming of 7°C occurred in just 50 years; and 14,000 years ago, the sea level rise documented in Barbados was 40 mm/year. The rates of these changes are greater than those our planet has experienced since 1950.
Uncertain: Other alternatives make it possible to characterize humanity’s footprint on the planet.
JP. The only valid alternative to the Anthropocene is to qualify it not as an epoch but as an event. The events are well-established elements in the stratigraphy: we find, for example, the Great Oxidation 2.4 billion years ago, or the Ordovician biological explosion 500 million years ago. An event can absolutely be diachronic, as is the Anthropocene. [N.D.L.R. : Le groupe de travail Anthropocène indique avoir considéré en détail cette possibilité, et conclut qu’elle est incompatible avec les données stratigraphiques4.]
#2: IT IS POSSIBLE TO PRECISELY DEFINE THE ANTHROPOCENE.
True: Scientists have defined a marker for the start of the Anthropocene.
MM. A working group dedicated to the Anthropocene was set up in 2009 at the request of the International Union of Geological Sciences. In 2019, this group proposed retaining the term Anthropocene. In 2023, he even set a golden nail [N.D.L.R : un repère qui permet de définir la limite entre deux étages géologiques] in the sediments of Crawford Lake, Canada. We are indeed observing – and across the entire globe – a rapid increase in the concentrations of two isotopes of plutonium, which correspond to the first terrestrial nuclear tests. The beginning of the Anthropocene would thus be defined in 1952. Apart from the nuclear marker, many other indicators record an abrupt change at this time: the greenhouse gas content increases, biodiversity falls, pollution accumulates, waste produced by humanity (like plastic) accumulates.
Some may have criticized the choice of Lake Crawford to define the golden nail marking the start of the Anthropocene, particularly due to its lack of accessibility. But what can we say about the site officially selected for the golden nail of the early Holocene? This is a survey in the Greenland ice cap, ultimately threatened with disappearance due to ongoing global warming…
False: It is not possible to rigorously define the beginning of the Anthropocene.
JP. There are geological traces of human presence, well before the proposed start of the Anthropocene (beginning of agriculture, settlement of the Americas, industrial revolution, etc.). Among the arguments against recognizing the Anthropocene as a geological epoch, several concern the beginning of the Anthropocene. It cannot be rigorously defined because it began at different times and in different places on Earth. Furthermore, the proposed date (1952) makes no sense since humanity’s impact on Earth is much older. Would the Second World War be pre-Anthropocene?! Finally, the proposed golden nail – Crawford Lake – does not meet the standards of the geological time scale: it is difficult to access and geologically unstable.
EE. It is potentially possible to precisely define a date and marker for the Anthropocene, but there is no obvious scientific utility for it – especially if it is recent. There are better ways to understand the Anthropocene as an ongoing process and event, rather than an abrupt global change that occurred in 1952.
Uncertain: Contradictory positions remain, they are not always based on scientific evidence.
MM. The decision of the International Commission on Stratigraphy to refuse recognition of the Anthropocene may seem surprising: in fact in 2023, the dedicated working group recommended the adoption of the Anthropocene and proposed a golden nail.
But I understand the reluctance of geologists. First of all, we must remember that the Anthropocene epoch was proposed in 2000 by Paul Josef Crutzen. This chemist who works on stratospheric ozone is recognized by the international scientific community, he received the Nobel Prize in Chemistry. But he is not a geologist… When a chemist proposes to revisit the geological time scale can be a source of difficulty. Finally, geological time scales are very long, often millions of years. The change of scale here is radical, with an Anthropocene which would begin in 1952, that is to say only 72 years ago!
#3: WE CAN STILL KEEP TALKING ABOUT THE ANTHROPOCENE.
True: The term unites many scientists.
MM. The international scientific community seized on this term as soon as it was proposed. There are dedicated journals, and major scientific journals like Nature et The Holocene have devoted special issues to the Anthropocene. This term unites scientists from the natural and human sciences, it is a banner with the authorities that govern us and we will continue to use it. For me, the refusal of official recognition sends a negative signal to scientists, but above all to political and economic leaders and to public opinion. I fear that it will serve as an alibi for inaction on climate change. This is a real source of confusion that we can deplore.
EE. I think scientists will continue to discuss the meaning of the “human era” using the term Anthropocene, and probably others. Human societies are not the first or only global change on the planet caused by organisms, but it is the most recent and is different from previous ones in many ways. There is no need to officially define the Anthropocene epoch for the discussion to continue.
Uncertain: Debate is part of the scientific method, and this decision is not irrevocable.
MM. Despite the decision of the International Commission on Stratigraphy, the debate continues. As scientists, we are accustomed to seeing stories and interpretations evolve as data advances, and I believe that as the ecological crisis deepens, the rupture marked by the Anthropocene will become more and more evident. .
JP. There is nothing wrong with using the Anthropocene as a scientific term, but we should rather talk about an event than an epoch. If the Anthropocene began only 70 years ago, then its future impact is based on predictions and not available geological data. Therefore, its recognition should be noted by future generations of geologists.
