You've probably heard about the Anthropocene, the geological era of man and machine. Does it exist? Are we in it right now? At the end of this summer, the International Union of Geological Sciences will meet and try to answer these weighty questions. Deciding whether we have entered a new chapter in geological history or not will not be easy. Scientists usually look at the displacement of rock layers, fossils and geochemical data to place a new notch on the geological scale. But the traces of industrial society have not yet drowned in sedimentary strata: they are still around us. We are creating them right now. To find out if humanity has really become a geological force of nature, we need to make sure our footprints remain long after us.
Here are six pieces of evidence that scientists offer.
Techno-fossil
In what in what, and in the production of garbage, modern humanity is succeeding. From CD-ROMs to styrofoam cups, we quickly fill our landfills, our oceans, and even our nearest space with debris that doesn't decompose. These "techno-fossils" are likely to remain on Earth for thousands or millions of years, even if humans do not survive that century.
While the large Pacific garbage patch eloquently hints at our garbage problems, fossil evidence of the future will be in the form of landfills, as a recent article in Antropocene magazine suggests:
“On a geological time scale, landfill plastic can be a ticking time bomb. Some landfills, in the lowlands of tectonically subsiding areas, will simply go deep to petrify, like paleontological kitchen heaps. Where landfills are eroded, they will start releasing their waste, including plastic, into the sedimentary cycle.”
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When alien archaeologists begin to unearth the remains of our society in the distant future, they may assume that beer bottles and bags from the store, and not humans, were the dominant life form on our planet.
Actual fossils
The plastic world aside. The era of the people will also be marked by major changes in the natural records. After all, the human population has grown exponentially since the beginning of the industrial revolution, and a billion people in the 19th century have become seven billion people today. By the end of the century, four billion more people will appear on Earth. And not only people divide and rule: pets, cows, pigs, sheep, cats and dogs grow with us. Geologically speaking, the fossil record will be captured by two-legged and four-legged mammals.
Other species are disappearing in an attempt to counter our space takeoff - scientists confirmed last year that we are on the cusp of a sixth mass extinction. Meanwhile, organisms that are not going to die out reproduce and spread around the planet in new and unusual ways - think about the appearance of cane toads in Australia, zebra mussel in Lake Michigan, rabbits everywhere. Global travel, climate change and urbanization have led to migration across the planet, with some species heading north with warming poles; others move to cities to occupy new niches; still others go by plane or ship to the far reaches of the earth. If the fossil record were a book, the Anthropocene chapter would be regularly raided by scissors, glue, and pencil.
Carbon spoilage
It's no secret that humans are burning fossil fuels and releasing huge amounts of carbon into the air - roughly 10 billion tonnes a year, recent tests show. Carbon dioxide warms the climate and alters the chemistry of the atmosphere. Add to that all the nitrous oxide, sulfur dioxide, chlorofluorocarbons and other industrial pollutants that we do not hesitate to pump into the heavens.
Tens of thousands of years will pass, and the newly formed layers of ice at the north and south poles will trap our modern atmosphere, trap air bubbles and invite geochemists of the future to taste the sky of yesterday. Unless, of course, we burn all the fossil fuels and destroy the evidence.
Nitrogen fertilizers
Agriculture has been changing the shape of our planet over the past ten thousand years, but all previous agricultural advances pale in comparison to the technological advances of the mid-20th century. One of them, the Haber process, completely revolutionized the way our planet and our planet are fed. Developed by German chemists Fritz Haber and Karl Bosch, this process uses high pressure and heat to convert atmospheric nitrogen (the inert gas N2) into ammonia fertilizers; earlier only "nitrogen-fixing" bacteria were capable of this. Fertilizers have become cheap and quickly produced, so farmers have gladly adopted them. The yield has grown.
The most obvious consequence of the Haber process - aside from doubling the human population - is the insidious impact of nitrogen on our biosphere. The saturation with fertilizers doubled the amount of actively cycling nitrogen in our biosphere and some species began to actively develop. For example, when fertilizer seeps into lakes, rivers, and coastal waters, it feeds massively flowering algae and expels other life forms. The sudden acceleration of the nitrogen cycle on Earth will leave an indelible mark on the geochemistry and ecology of the Anthropocene.
Wells
One of the strangest ways humans are changing the planet right now has nothing to do with the Anthropocene - it has to do with geological eras that were before. People dig, drill, break up and blow up the bowels of the crust of our planet, accumulating thousands of meters of precipitation over hundreds or millions of years. No species or natural process has done anything like this before.
These footprints can be the most permanent, and therefore truly geological, scar that people leave. The only way to remove these marks is to drag them up to the surface and let the erosion take its toll, or disappear in a continental collision or other tectonic activity. Be that as it may, it will take tens or hundreds of millions of years.
Nuclear weapon
Scientists are more puzzled not by whether the Anthropocene exists, but when exactly it began. Some suggest the first human-induced shift in atmospheric CO2 as a starting point - when Europeans migrated to the New World and started killing everyone. Huge glades of agricultural land turned into forests again. Others suggest 1964.
This year has become an important year for nuclear weapons testing - so important that it led to a sharp surge in radioactive carbon (carbon-14) in our atmosphere. This excess carbon-14 has entered the food chain and biosphere, from plants to animals, from people to soil. If you lived on Earth in the 60s and 70s, there will inevitably be a trace of the Cold War inside you. Perhaps he became the herald of a new era.
Despite the fact that all the evidence seems to point to a new geological era, scientists still have doubts, for example, whether the Anthropocene began or not. What if the most significant technological changes are yet to come? Maybe we should leave this short and painful period of time on our planet in geological isolation? What if there is still a lot we don't know, especially in context? The experiment is huge: the testing ground is our planet.
In any case, we know that our planet has never seen such a century as the 21st century. This alone makes the present century geologically remarkable.
ILYA KHEL