The probability of us becoming fossils is low, but we can leave different traces. Here’s what might catch the attention of our explorers in the distant future.
We human beings have always been fascinated by the past. We have unearthed countless fossils from the ground, relics of Earth’s 4.5 billion year history, which give us clues about how ancient species lived long before we existed.
But if we ourselves went extinct and another intelligent species emerged millions of years from now, would this would know we exist or what was our civilization like?
We cannot count on future paleontologists finding our fossils, he says Adam Frankprofessor of astrophysics at the University of Rochester, USA.
“Only a small fraction of life on Earth has fossilized, especially if its civilization was brief”, he explains.
A 2018 article, co-authored by Frank, points out that to date, few almost complete fossils of dinosaurs have been found, which roamed the Earth for 165 million years.
Thus, the article suggests that, given that our species has only existed for around 300 thousand years, we may not leave a very significant mark in the fossil record. But we can leave different traces.
Changing Earth’s chemistry
As part of the planet’s natural geology, rocks are continually deposited into the ground in layers, or strata. The chemical composition of each stratum is related to the conditions on the planet at that time.
According to Frank, rising temperatures and changes in sea levels due to climate change caused by humans will affect what is deposited in rocks — something that will be detectable “probably hundreds of millions of years from now”.
“We would see that there was a difference in oxygen isotopes and carbon isotopes, due to the fact that the Earth’s climate system has changed because of human activity”, says the astrophysicist.
Reshape evolution
Even though our own bones don’t appear much in the fossil record, it’s quite possible that we’ve altered the fossils of other species through the plants and animals we’ve transported around the globe, or the biodiversity we’ve modified.
A 2018 study concluded that 96% of all mammals in the world are humans or our livestockmeasured by biomass. More than two-thirds of the world’s bird biomass came from poultry.
We slaughter more than 75 billion chickens every year, according to the nonprofit publication Our World in Data.
Thus, the fossils of all these almost identical birds, dying in large numbers, may well cause surprise in the future.
“We altered the course of biological evolution”it says Jan Zalasiewiczgeologist, paleontologist and professor emeritus at the University of Leicester, United Kingdom.
“Our explorers in the distant future will ask themselves: ‘What happened? Why did it happen?'”, he suggests. “And they’re going to focus on the layer where this all started — and that’s our layer.”
Our “final legacy”
Em Discarded: How Technofossils Will Be Our Ultimate LegacyZalasiewicz and her colleague at the University of Leicester, Sarah Gabbottargue that it will be everyday objects that persist in the Earth’s geological record.
They call them technofossils — whether it’s an aluminum can, a polyester shirt or an underground parking space.
A 2020 study estimated that we produce 30 gigatons of objects per year. This is equivalent to every person on Earth producing more than their own body weight per week.
In fact, the authors concluded that today There are more “things” made by human beings in the world than living beingswhen comparing their dry weight.
The largest proportion of human products comes from concretewhich may not seem very natural to future discoverers.
“One of the ways we make concrete today is to add fly ash… under the microscope, [esse material] it seems absolutely bizarre,” says Zalasiewicz.
“If the edges of concrete buildings and paving slabs become fossilized forms, [os arqueólogos do futuro] you will see that it is something very different from a natural stratum.”
Many of our materials will remain for a long time.
O plastic “It could probably last not just thousands of years, but potentially millions of years,” says Gabbott. We produce so much of this material that, by 2050, there could be more plastic than fish in the ocean, according to the United Nations. But it’s not just plastic.
“We have rocks four billion years old that contain graphite“, continues Gabbott. “So graphite in the form of a pencil could last four billion years.”
The paleontologist says that fossilized leaves that are hundreds of millions of years old have been found. “THE paper it is made from cellulose, which is the same substance as leaves. And therefore… paper, in the right environment, could probably last hundreds of millions of years,” he speculates.
Changes on a planetary scale
It is quite possible that human beings have already left a huge mark on the Earth’s geology. If another intelligent species will see it one day, long after our disappearance, it is a unknown.
But does it make sense to imagine our legacy millions of years from now? Professor Frank believes so.
“I think it’s vital that we overcome this period of technological immaturity and be able to think about the long-term history of the Earth”, he argues.
“These are changes on a planetary scale that will have consequences for centuries, millennia, tens of millennia”, he states.
