How long will human impacts last? – David Biello

How long will human impacts last? – David Biello


Imagine aliens land on the planet
a million years from now and look into the geologic record. What will these curious
searchers find of us? They will find what geologists,
scientists, and other experts are increasingly calling
the Anthropocene, or new age of mankind. The impacts that we humans make
have become so pervasive, profound, and permanent that some geologists argue
we merit our own epoch. That would be a new unit
in the geologic time scale that stretches back
more than 4.5 billion years, or ever since the Earth took shape. Modern humans may be on par
with the glaciers behind various ice ages or the asteroid that doomed
most of the dinosaurs. What is an epoch? Most simply, it’s a unit of geologic time. There’s the Pleistocene, an icy epoch that saw the evolution
of modern humans. Or there’s the Eocene,
more than 34 million years ago, a hothouse time during which the continents drifted
into their present configuration. Changes in climate or fossils
found in the rock record help distinguish these epochs
and help geologists tell deep time. So what will be the record
of modern people’s impact on the planet? It doesn’t rely on the things
that may seem most obvious to us today, like sprawling cities. Even New York or Shanghai
may prove hard to find buried in the rocks
a million years from now. But humans have put new things
into the world that never existed on Earth before, like plutonium and plastics. In fact, the geologists
known as stratigraphers who determine the geologic timescale, have proposed a start date
for the Anthropocene around 1950. That’s when people started blowing up
nuclear bombs all around the world and scattering novel elements
to the winds. Those elements will last
in the rock record, even in our bones and teeth
for millions of years. And in just 50 years,
we’ve made enough plastic, at least 8 billion metric tons, to cover the whole world in a thin film. People’s farming, fishing, and forestry
will also show up as a before and after in any such strata because it’s those kinds of activities that are causing unique species
of plants and animals to die out. This die-off started perhaps more than
40,000 years ago as humanity spread out of Africa and reached places like Australia, kicking off the disappearance
of big, likable, and edible animals. This is true of Europe and Asia,
think woolly mammoth, as well as North and South America, too. For a species that has only roamed the planet for
a few hundred thousand years, Homo sapiens has had a big impact
on the future fossil record. That also means that even if people
were to disappear tomorrow, evolution would be driven
by our choices to date. We’re making a new homogenous world
of certain favored plants and animals, like corn and rats. But it’s a world that’s not as resilient
as the one it replaces. As the fossil record shows, it’s a diversity of plants and animals that allows unique pairings
of flora and fauna to respond to environmental challenges,
and even thrive after an apocalypse. That goes for people, too. If the microscopic plants
of the ocean suffer as a result of too much
carbon dioxide, say, we’ll lose the source of as much as half
of the oxygen we need to breathe. Then there’s the smudge in future rocks. People’s penchant for burning coal,
oil, and natural gas has spread tiny bits of soot
all over the planet. That smudge corresponds
with a meteoric rise in the amount
of carbon dioxide in the air, now beyond 400 parts per million, or higher than any other Homo sapiens
has ever breathed. Similar soot can still
be found in ancient rocks from volcanic fires
of 66 million years ago, a record of the cataclysm touched off
by an asteroid at the end of the late Cretaceous epoch. So odds are our soot will still be here
66 million years from now, easy enough to find for any aliens
who care to look. Of course, there’s an important
difference between us and an asteroid. A space rock has no choice
but to follow gravity. We can choose to do differently. And if we do, there might still be
some kind of human civilization thousands or even millions of years from now. Not a bad record to hope for.

99 thoughts on “How long will human impacts last? – David Biello

  1. A whole video once again tainted by poor pronunciation. I accept that American-English and English-English are different, but come on… epic? That's insane!!

  2. Yes, the cost of our progress is high for this planet. However, things are getting better every year, we can remain hopeful.

  3. I don't quite understand why they chose that quote at the beginning. Surely we're not exaggerating when we try and point out how much damage we're doing to the planet? If anything, we're not saying it enough

  4. Can you please make a video in what humans can do to reverse the predicament we have gotten ourselves into? Even if is not very probable considering the politics of the world.

  5. shame there wasn't the mention of the geological impact concrete has, as that never existed until we made it too, or is it that things with half lives matter?

  6. 174 antiscience cuckservatives who don't believe in finite oil reserves or in Anthropogenic Global Warming (AGW) or evolution voted this down.

  7. I always imagine millions of years after we disappear, to be some sort of blissful wasteland. Like a war that, inevitably, nature won.

  8. Aww… I was hoping to make more of an impact than that… 😭
    Everyone, please watch my little nature videos. There is no talking in them. Shhh!

  9. Even if we go extinct, the internet will always exist. If they can find it, then all your comments shall be discovered.

  10. Unlike the asteroid, we have the power of choice? That doesn't jive well with all the "Big Think" videos that say free will is an illusion.

  11. Humans didn't kill off the woolly mammoth, it's a misnomer, so I question about the extinction of other long gone species too, put at our feet.

  12. Actually I'm from the future. I was(will be) born In 3086, and by 3100, we humanbeings will finally be able to travel through time, and I'm sent back to the 21st century. I know this sounds crazy, but it is true.There are also some people being sent back to 13th century. I am not allowed to do anything that can change the future, but I am still leaving this comment becsuse I know no one believes me.

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  14. Just take the nature for example:
    it's the fight between animals to gain respect from other species, then us humans shown up as the "Arena Closer", killing off any animals who bother us and eventually, after all animals died, we'll self-destruct.

  15. Thank you. "Man is organic with the world. His inner life molds the environment and is itself deeply affected by it. The one acts upon the other and every abiding change in the life of man is the result of these mutual reactions." ~ Baha'i Faith

  16. So basically we humans get our own kind of rock named a fancy way that aliens will find 1 million years ago, right?

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