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Mexico City in April 2021: Humans leave unmistakable traces on the earth

Photo: Hector Vivas / Getty Images

The Earth has been in the Holocene geological epoch for around 12,000 years.

But humans have changed the earth so much that researchers have been calling for years to declare the age of the Anthropocene, i.e. the age of humans - and thus officially end the Holocene.

This proposal has now been rejected by the International Union of Geological Sciences (IUGS), the highest scientific body in its discipline.

The voting result on Tuesday evening was quite clear: of the 22 members of the commission, 12 voted no, four voted yes, two abstained, and four others did not respond, the New York Times initially reported.

The debate was initiated by Nobel Prize winner in chemistry Paul Crutzen in 2002. At that time, he outlined the concept of the Anthropocene as the successor to the previously ongoing Holocene in the scientific journal “Nature”.

He proposed that the beginning of the human age be placed in the mid-18th century, when the concentration of carbon dioxide in the atmosphere began to rise.

This date also coincides with the invention of the steam engine in 1784, wrote the now deceased Crutzen in the paper.

The core idea behind the proposed new age is the massive influence of humanity on the environment since industrialization, which will still be detectable by geologists in the distant future, for example in rock layers or using fossils.

These include new rocks such as concrete and asphalt, a global extinction of species, the mass distribution of individual species or the radioactive residue from atomic bomb tests and nuclear power plants.

Since Crutzen's initiative, researchers around the world have been discussing the idea.

However, there is no agreement about the beginning of the era.

The International Commission on Stratigraphy (ICS) therefore set up the Anthropocene Working Group (AWG) to discuss the new epoch.

Since then, the AWG has been searching for a point on Earth that marks the beginning of the Anthropocene.

The group examined, among other things, the Baltic Sea, coral reefs off Australia, the ice of the Arctic and peatlands in Poland.

Last summer, researchers chose Lake Crawford in Canada as evidence of a new geological era.

Year after year, sediments are deposited at the bottom, documenting what is happening on earth.

That's why the experts designated the lake as the reference point for a new geological era, the Anthropocene.

Anthropocene and climate change

But the final decision did not lie with the AWG, but with the higher-ranking body IUGS.

After his decision, it remains controversial whether, based on the available data, one can already speak of a new epoch in earth's history that is fundamentally different from the Holocene.

One argument made by many defenders of the new age is climate change.

It will also leave traces that will be recognizable for millions of years.

Future fossils and sediments will retrospectively show how climate zones suddenly shifted and coastlines changed due to sea level rise.

The CO2 content of the atmosphere is also “stored” indirectly via deposits on the seabed or in stalactites.

These sources are already being used to reconstruct climate changes in the history of the earth.

However, according to many researchers, what is special about the current change is the speed.

Natural geological processes usually extend over thousands to millions of years.

Currently, however, they tend to take place in decades to centuries.

For future geologists, the current upheavals will probably be most comparable to the asteroid impact at the end of the Cretaceous period, which also ushered in a new era, namely that of mammals.

Climate researcher Michael Mann commented on the IUGS decision on Platform X: »I think it's more of a storm in a teacup.

Scientists will continue to use the term “Anthropocene” regardless of what this panel decides.”

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