The Anthropocene in a nutshell

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Anthropocene is a relatively new word, but it’s spreading fast. “Anthropo-” is for humans and “-cene” derives from an old Greek work for “new”. Anthropocene is a great word to sum up what we humans do on and with planet Earth. Formally, it’s the scientific name of a new geological epoch that’s just about to start, an epoch in which humans become the dominant force of change in the planetary metabolism. In addition, Anthropocene is a strong metaphore. It expresses our huge responsibility for the future of life on Earth.

The main person behind this ground-breaking concept is Paul J. Crutzen. Born in 1933 in the Netherlands, Crutzen became an eminent atmospheric chemist. In 1995, he received the Nobel Prize for Chemistry for his role in detecting and banning substances that harm the planet`s ozone layer. Crutzen was deeply impressed by the possibility that humans might have dissolved the ozone sheet that protects us against cosmic radiation. He started analyzing all impacts humans have on the Earth system.

In 2000, he published a short memo in a newsletter together with his US colleague Eugene F. Stoermer in which the case is made for a big leap forward in the way humans perceive and frame their role on Earth. Human impact has become so deep and long-lasting, Crutzen and Stoermer argued, that it should be viewed on the widest scale Earth science can offer: geology. They argued that a new geological epoch has started: the Anthropocene.

Later, Crutzen was the first to officially make the case for re-naming our epoch the Anthropocene in a peer-reviewed journal. On January 3, 2002 he wrote in an article in „Nature“ titled „Geology of mankind“:

„Unless there is a global catastrophe — a meteorite impact, a world war or a pandemic — mankind will remain a major environmental force for many millennia. A daunting task lies ahead for scientists and engineers to guide society towards environmentally sustainable management during the era of the Anthropocene. This will require appropriate human behavior at all scales, and may well involve internationally accepted, large-scale geo-engineering projects, for instance to ‘optimize’ climate. At this stage, however, we are still largely treading on terra incognita.“

With that article, the Nobel laureate challenged the geological community. One of their bodies, the International Commission on Stratigraphy, is in charge of defining, delineating and naming distinct stretches of time in the Earth‘s long past. Scientists in various committees look for clear and global signals in the deep layers of soil that have built up over hundreds of millions of years.

The Jurassic Period, for example, is defined by its limestone relicts, and the Carboniferous by its remnants of oil and coal. Within those large-scale periods, geologists define epochs. An epoch is no small thing. The Pliocene, for example, began 5.3 million years ago and extends over the period in which an early variation of advanced primates, Australopithecus, appeared. The Pleistocene began 2,6 million years ago and saw up to one third of Earth‘s surface iced over as various waves of glaziation occurred. It was also the time when the first members of what is now called the genus Homo had evolved.

So the current epoch, called the Holocene, is a very young one. Geologists set its beginning at the very end of the last ice age, about 11,700 years ago. Translated from its Greek roots, it means „the totally new“, which certainly is correct. The Holocene is marked by a natural trend of global warming that has brought about the rise of human civilization.

Geologists are used to shuffling around millions of years between ages and epochs, but they go about it almost obsessed with being correct. They prefer setting the boundaries in a way that they will not have to be changed after only a few years. To delineate the Holocene from the Pleistocene involved a process of negotiations and intense conferencing that took the geological community from 1833 to 1968. These guys are not in a short-term business.

So it must have come as a huge challenge when a Nobel Laureate asked for the Holocene to be ended right away and replaced by something new, the Anthropocene.

In 2007 Crutzen detailed his proposal in an article co-written with the environmental scientist Will Steffen and the historian John R. McNeill. They described four distinct phases: In the „Pre-Anthropocene“ phase, humans learned to use fire and drove many species to extinction by over-hunting. They then started agriculture and breeding plants and animals according to their own needs. This was the beginning of the global expansion of the human realm, accompanied by long-distance trading and the first use of metals.

The first phase of the Anthropocene then starts in 1800. The Enlightenment turned technical, and engineers kicked off what is known as the Industrial Revolution. The social and ecological consequences were vast. Fossil fuels and later nitrogen fertilizers started their careers as game-changing agents in Earth‘s metabolism.

The second phase sees the beginning of the real Anthropocene, according to Crutzen and his colleagues. It commences in 1945 with the end of World War II and the onset of a global economic boom. A „Great Acceleration“ kicks in, with the rise of industrialized agriculture, automobile systems and fast increases in material turnover and consumption.

„The Great Acceleration took place in an intellectual, cultural, political, and legal context in which the growing impacts upon the Earth System counted for very little in the calculations and decisions made in the world’s ministries, boardrooms, laboratories, farmhouses, village huts, and, for that matter, bedrooms. This context was not new, but it too was a necessary condition for the Great Acceleration.“

The consequences are dire: Mass extinction of plants and animals, global warming, and serious risks for the Earth‘s intricate net of life support systems.

The idea of a dawning age of an epoch of man is not entirely new, as Crutzen points out himself. In the 19th century the renowned Italian geologist Antonio Stoppani described the present as an „anthropozoic era“ in which humans act as a „new telluric force which in power and universality may be compared to the greater forces of Earth“. In the early 20th century, various scientists, like the Russian geochemist Vladimir Ivanovich Vernadsky and the French philosopher Pierre Teilhard de Chardin reasoned about human consciousness as a new force in nature and a new level of evolution that grows out of the human mind. In the 1980s, the later president of the German Max-Planck-Society, Hubert Markl, described how human responsibility grows in the beginning „anthropozoic era“. And in 1992, New York Times environmental journalist Andrew Revkin wrote about a beginning „Anthrocene“.

Yet it was Paul J. Crutzen who presented the Anthropocene idea so poignantly and prominently that a wider audience started to listen and think…

The Anthropocene has only just started. And we are all part of it.

Image: NASA

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