Mass extinctions and the future of life on Earth | Michael Benton | TEDxThessaloniki


Translator: Chryssa R. Takahashi
Reviewer: Leonardo Silva My subject is the future of life on Earth. This is a very large and complex topic. It’s the subject of futurology. And in fact, I am a palaeontologist,
I study dinosaurs, and you might wonder why a palaeontologist would have
something to say about the future. However, there are some shared aspects
which I will talk about, and this can provide some evidence
to help us in making decisions. I’m a palaeontologist, as I say. I decided on this career
when I was seven years old. I loved dinosaurs at the age of seven, and I think these days,
young people still do. And I haven’t changed my view since. I love the job, teaching students, going to exotic parts of the world
to dig up dinosaurs, finding new facts
about the history of life. However, this kind of subject,
studying the past, like studying the future, could be said by some
not to be truly scientific. And I want to explore that
a little bit first, how do we do this, before we get to the point of beginning
to establish some facts and figures about life and current threats. And this has been criticised
by other scientists. For example, 100 years ago, Sir Ernest Rutherford, a very famous physicist,
Nobel Prize winner, said, ‘All of science is physics,
and the rest is stamp collecting.’ By which he meant that if you cannot
make it into mathematics or physics, it doesn’t count. That excludes then the natural sciences,
medicine and a lot of other areas. And I think at the far end of the spectrum
would be my subject, palaeontology. I’d like to give you an example though, to show you how
we apply scientific methods to achieve a certain level
of understanding and certainty. And this is something that has been
developing during my career so that when I started, a lot of what we did would be called
a speculation or guesswork, whereas now, a lot of what
we do can be tested and can be called scientific. The example I’m going to take
is the question I asked when I was seven, ‘Could T. rex bite a car in half?’ This is a question about the most
famous dinosaur, Tyrannosaurus Rex, which was huge, five tons in weight,
enormous jaws and teeth. Could it bite a car in half? Well, there were no cars
in the Cretaceous, but let’s forget that for the moment. When I started, you could only
answer that question by guesswork, or you could make some very
simple models of the skull, like levers, and try to calculate things. If you were going
to make a realistic model that had all the properties of the
original bone and flesh of the dinosaur, you could not do it. But now, with the power of computing,
we can do this kind of thing. So the way you calculate
the bite force of T. rex, and the way people have done it, is they scan a skull and make a three-dimensional,
digital model inside the computer. You then divide that model into a mesh, or into a framework of elements or small components. And each of these elements
can be given physical properties so that we know the physical properties
of bone of living animals. These are material properties, like how far can you twist
the bone before it breaks, how much compression can that bone take. And so all of those properties
are mapped into the skull. And then you apply imaginary forces and increase those pressures
until the thing breaks. And so the bite force of T. rex is huge. Let me lead you to the figure. Our bite force is about
800 newtons at most. The biggest bite force of any
living animal is the great white shark, and that is about 5,000 newtons. T. rex, 50,000 newtons, ten times. And that’s equivalent
to five tons of weight, acting. So it could bite a car in half. Why do we believe this method? Because this method is a standard
in design and architecture. Finite element analysis is used
for designing buildings like this one. You don’t simply build it
and hope it doesn’t fall down. The thing is designed in a computer, it is stress-tested using this program
we apply to the dinosaur. I think we can believe it. But let’s move on. That was just a brief word about
how you can actually apply science, I would argue, to questions that are not
happening at our time, in the past, or maybe in the future. And in palaeontology,
we don’t just find fossils. We also care about evolution
and diversification, how groups have become diverse,
how groups go extinct. And at the moment, we are crucially
concerned about extinction. So let’s have a look at that,
let’s explore that. What are the current views? And these views are expressed
not by scientists, but also by very important politicians. So some of you may recall,
a number of years ago, Al Gore, who was then vice president
of the United States – He quoted a figure of 100 species
are going extinct every day. So this is a very high rate of extinction, 100 per day, which is equivalent to 40,000 per year. At the other end, other politicians,
perhaps in President Trump’s camp, would say, ‘Don’t worry about it.
Extinction happens. Look at the dinosaurs. We’ve got nothing to do.’ So how do you connect
between these two positions because of course we have
to think about these points. The first approach that we use
is to look at history. We have recent history
recorded of extinction. So many of you will be familiar
with the extinct bird called the dodo. This lived on the island of Mauritius
in the Indian Ocean. The dodo was a kind of fat,
flightless bird related to pigeons, and a very famous image of the dodo was in the famous children’s book
‘Alice in Wonderland’, where the dodo, who is a wise,
old gentleman with a walking stick organises Alice and all the animals and says to them,
‘We will have a Caucus race.’ And a Caucus race is one
where people start when they like and they finish when they like, and everybody gets a prize. So that was very nice, but unfortunately
the dodo in real life didn’t get a prize. Because some of you may know
the first records of dodos were in 1598 when seamen reported
they had seen this bird. They could go on the island
and catch it very easily and eat it. And within 60 years it was extinct. Another example of recorded
extinction is the great auk. This was a large bird
that lived in the North Atlantic, and the great auk went extinct in 1844. How do we know that? Because collectors sent by a museum
shot the last example. They were concerned that their museum did not have
a stuffed specimen of this bird. They heard it was going extinct, so they thought, ‘We’d better get one
before it dies out.’ So these are two examples
of data about extinction. And indeed through the last 500 years, mankind has killed many species
which are recorded like that. And this is the basis of the figure
that Al Gore gave. Let me explain it. He gave that figure of 100 species
per day going extinct. This was based on the bird data. But we know something like 100 or two
or three hundred species of birds have been killed by human activity
in the last 500 years. And the figures are debated. It’s something like from half a species
to four species each year on average. We don’t know for sure because
of course people didn’t record everything. Now, how do we scale this up
to get a global figure, from birds on the one hand to all of life? And the way it was done was simply to say, ‘We know how many species
or birds there are alive today.’ There are 10,000, and the initial estimate for the diversity
of all of life were 100 million. So you scale from four a day upwards, and that brings you up
to this figure of 100 per day by multiplying up many times; 40,000 lost per year, 100 per day,
based on that extreme high bird figure. At the other end, the lowest estimate
is something like one species per day. This is because we are not sure
about that bird figure, so we could take a lower estimate, and also we are actually not sure
about the diversity of life today either. Some of you will know that you might think
we would have named every species, we would know that – we don’t. You can look at Wikipedia. There are thousands and thousands of pages
describing all the living species, but there are so many living species
that we have never discovered, never described, aren’t there in Wikipedia. So there is that uncertainty. One hundred million?
Ten million? We don’t know. Those are the estimates of numbers
of species going extinct each day. One per day, one hundred per day. Do we worry about that? This is where palaeontology
comes in first, because fossil data allows us to calculate what would be
the normal rate of extinction. Species do go extinct, so this politician over here
was quite right. But was Al Gore right? We don’t know. You know, he was giving that high figure –
maybe somewhere in between. But what is the norm? Is one a day okay?
It doesn’t sound too many. If there are millions and millions
of species, it is far too high. We know that the average duration
of a species is two million years. They originate, they go extinct. Two million years. And that means, as they come and go, on average, we would expect
the extinction of five million species every million years, which is five species per year. So that does contrast remarkably even
at the lowest estimate of human impact – 500 species per year is 100 times
the normal rate of 5 per year. And at the bottom there is the dodo, just in case you weren’t sure
what it looked like. So I want to look
at two other topics briefly. One is risk. And so, one of the questions we would have
estimating the total numbers is one thing. We have learned that we are impacting life
harder than we should be. Human activity is causing extinction. What about risk? It’s easy to say of course,
the dodo was stupid, it lived on one island, it just stood around and allowed itself
to be hit on the head. To an extent. We worry about elephants,
we worry about pandas, we worry about many individual species. Many of those have high-risk factors. So for example, an elephant is very large. This means they need a lot of food, they need a lot of territory
to walk around. And so it’s much harder to keep a sufficiently large
population of elephants breeding and successfully in the wild. We don’t need to worry
about rats, for example. They’re small and there’s lots of them. So body size is one risk factor. Being big is not a good thing
if you want to survive as a species. What about the panda? They’re not so huge.
They’re about human size. They have a specialised diet. They have evolved into a crazy position. As you know, they are eating bamboo without the real ability
to consume it properly. If that food supply disappears, they’re stuck. So, secondly, restricted
diet is a problem. The third one is shown by the dodo. If you live in only a very
small geographic area rather than over the whole world, you are at risk. So there are three things to be: medium-sized or small,
if you want to survive; broad diet, willing to eat everything; and living over the whole world. So that includes human beings
and rats and cockroaches. They will survive and many other species
will not survive whatever we do. So risk is something we can
determine from the present day, but also we can test when we look
at mass extinctions in the past. So this is where
we come back to palaeontology, because I think most people here know that the end of the dinosaurs
was marked by a mass extinction. Many millions or thousands
of species died out rather rapidly. The cause of that extinction definitely
was largely the impact of a meteorite, a huge asteroid, maybe ten kilometres across, and the model for extinction
of the dinosaurs 66 million years ago was the asteroid hit the Earth – this is unpredictable,
when this may happen or not – it penetrated into the crust, it vaporised, and all that rock of the asteroid
plus the crust that it had penetrated turned into rocks and dust, mainly dust. This was thrown up high
into the atmosphere and went all round the Earth,
blacking out the sun, and so that you get two effects
there, no light, no heat. So there was a cessation
of photosynthesis. The plants died.
There was darkness and cold. So this was not good for dinosaurs and other groups that enjoyed
the warm climates, and so you get extinction. And you might think, of course,
‘What do we learn from this?’ Yes, that’s all very well, but that’s not
something we can do anything about really. And indeed, asteroids do come close
to the Earth from time to time. Earlier this week, one did.
Luckily it didn’t hit the Earth. We can’t really prepare. But the key point is that the other
mass extinctions in the history of life were not caused by impact. They were caused by climate change. Immediately, you can see now
how that matters. I will briefly characterise one of them
that I have worked upon. At the end of the Permian Period,
250 million years ago, there was another major extinction. This was before the dinosaurs. And the sequence of events was
that massive volcanoes errupted in Russia. They were so huge that they poured out
enormous amounts of lava, of course, but more importantly, they poured out
gases into the atmosphere, including carbon dioxide. And carbon dioxide is famous
as a greenhouse gas, meaning it heats the atmosphere. We have primary evidence
that around the equator, ocean temperatures
warmed up to 40 degrees plus. So this is like a very warm shower. You might think that’s OK. Maybe for 10 minutes
but not for day after day after day. And so life had to progressively
flee out of the equatorial zones. It became crowded at the poles
and there was great extinction. So we learnt from that that carbon dioxide and global warming
can cause extinction whatever the cause of that carbon dioxide, whether it comes from volcanoes
or human activity. So we’ve learnt three things that we can illustrate
and use for predicting into the future, what may happen to life. We’ve learnt that we can
calculate the rate of extinction by looking at historical extinctions and at that rate of extinction,
even at the minimal figures, it’s at least one hundred times
what it ought to be. Secondly, we’ve learnt
something about risk, which species are
most at risk of extinction, and I think that’s fairly straightforward. But we need the evidence
to be able to argue the case. And thirdly, we’ve learnt
that the whole history of the Earth records a rich record of climate change. We don’t need to do experiments,
we don’t need to imagine what a world would be like
without the polar ice caps. It has existed and we can study it. So to conclude, my aim has not been
simply to spread doom and gloom, but to indicate that we have
the power to change. And in order to change,
we have to accept reality along the lines that we’re mentioning. And we have to ask the right questions
about what we should do. And in order to decide what we should do,
we need to use evidence. And some great evidence comes
from the history of the Earth and the history of life. Thank you very much. (Applause)

Comments 42

  • Excellent talk, I enjoyed it immensely. Thanks>

  • Intellectually sharp…straight-talk!

  • What an amazing talk.

  • Reminds me of a temporary duty trip to thessaloniki way back in 1982 🙂 …from Athens… and the Mass extinction is well under way… just look out your window at the weather. 🙂

  • Denialism is another form of insanity that is prevalent these days. Despite the best efforts of the denialist community to try and refute any claim that ecological collapse is actually in progress, deep down inside they acknowledge the truth. They are fully aware that a perfect storm is now forming, but the coping mechanism for these people is just to deny every piece of evidence that becomes manifest. How more obvious can these catastrophes become— a human population explosion as 78 million more human consumers are added to an existing population of 7.600.000.000 every 365 days while during this same time frame, thousands of animal and plant species are driven to extinction aka “6th Mass Extinction Event” due to pollution, chemical contamination, desertification, oceanic dead zones, ocean acidification, mass coral die-offs, deforestation, ground water depletion, etc.
    Why is it so difficult for the denialists to comprehend that the Earth's life support system depends on an intricate chain of life. As mankind destroys link after link in the chain of life through species extinctions and other environmental pillaging, at some point soon the entire ecology will implode, and mankind will follow many other species into the extinction abyss. The signs are everywhere, In North America, Honey bees and native pollinators are in a steep decline. Bats are dying in the millions due to White Nose Syndrome (as with the bees, a combination of negative factors is causing the immune system of bats to crash), and has spread from the Northeast to the South and Midwest. Amphibian species around the world are going extinct in unprecedented numbers due to Chytrid. With the loss of each species, another intricate link in the chain of life is lost.

  • Though this bs about this T-Rex is irrelevant in my opinion, he's right. We have been fuelling a heat engine for many many decades (about 20-25 decades), and we felt like a frog in heating water, we could afford that for a long while, I think the sting will be in the tail. It will go haywire in no time at all, 12-20 years, starting within a few years from now. There is not much we can do now, which will have a positive effect, the damage has been done. Within a few hundred million years, there might have been risen a conscious out of some amphibians or insects, and they will find some of the stuff we had been making, and try to guess what killed us off. Who knows.

  • At the edge of extinction only Ocean Mechanical Thermal Energy Conversion remains so we can love more often..

  • Don't limit your diet to eating 4 animals. Expand your diet to the millions of species of plants and fungus. Save the world by going vegan.

  • Guy McPherson

  • 3:21 Boom in the shot!

  • Well we See the Future..,?

  • 4:00 great white shark does not have the biggest bite force

  • Dinosaurs are not the only creatures paleontologists study

  • PLANET EARTH IS OUR ONLY HOME. There is NO "near Earth" which we can rocket off to. Our nearest neighbor planets are uninhabitable. SO, FOLKS – either preserve the planet we live on, or die a slow death. YOUR CHOICE !

  • Can we get off the planet before the next one?

  • Trippy. It's funny when scientists bash each other over perceived intellectual superiority.

  • That's a lot of hypothetical mathematics. I don't think I'll buy in yet. Neat accent though. Not sure where it originates, but it's definitely worthy of an audio novel.

  • Gourmet mushrooms are considered meat when seasoned & taste like it with nutrients & medicinals. never injected with drugs, etc. seasoned Maitake taste like steak, Oyster Mushrooms-Chicken. Lions Mane-seafood lobster. According to Paul Stamats research they have more protein than cattle & fish. He owns the company Host Defense, You can find him on You tube etc. A wise elder. COOK WELL while pressing down with Maitake Steak Mushroom. YUM!! neurological, brain & other benefits.

  • Antitrumpites even infect these red talks?
    Moving on

  • I've often wondered if some of the previous mass extinctions have also been caused by the rapid spread of a particular species that then goes extinct itself. If this happened over a short period how likely is it that the evidence would exist in the fossil records and would we be smart enough to connect it.

  • Not all ted talks are great. This guy is awesome.

  • Blah blah

  • Aliens deduce that the best things on Earth are beer, pizza, and ice cream, systematically buying up all of our manufacturing capacities in these areas, and moving the beer/pizza/ice cream technology to their facilities on the dark side of the moon. Without beer, pizza, or ice cream, mass human rioting then ensues, escalating to the point where our AI overlords are compelled to release the zombie virus…

  • I'm not an expert in extinctions but size is certainly not a major factor – recently a snail and a bat have become extinct. He also for me lost validity when Al Gore and Trump were mentioned. Who really cares what politicians say in this subject.

  • Climate change has been caused by interstellar impact and plasma. The earth is part of a cosmic community and electrically connected to the sun. Sunspots correlate with volcanoes and earthquakes.

  • I don't know what's more frightening. The facts in the video, or this comment section.

    Both. Both.

  • Humans count as megafauna. We wont survive

  • the weight of polar meltwater will reactivate the Pacific ring of fire…then Yellowstone from the increase in seismic action..then nuclear winter…a scripture i found in the christian bible at revelation 11:18 says " the time came for God to destroy those destroying the earth" man brought this upon us….

  • Are you a member of the global elites (top 20%) who are responsible for
    over 70% of the carbon emissions? If so, how much have you lowered your
    emissions? "Do as I say, not as I do," will not be a winning story –
    so far that's all we've been given by the global elites.

  • There was massive volcanic activity from the Deccan Traps in India at the time of the meteor impact that wiped out the dinosaurs. They were already suffering in numbers before the double whammy happened.

  • Did not know TED had speakers of this calibre they are normally plastic., sensationalists . Dr Benton is authentic facts, no excitement to blur the accuracy of the subject

  • How does 100 per day come to 40,000 per year? That's some fancy rounding.

  • Remind me not to get bitten by a shark….or T-rex!!!

  • This primate is fkn delusional if he actually 'thinks' humans won't go extinct as the biosphere/ecosystems which sustains complex life is exponentially expunged by our mindless destructive actions (selfish greed). Bye bye bipeds,

  • CHANGING CLIMATE'S going to do in us Primates.
    Also the birds, though they can't read these words.
    (The dodo was doodoo we flushed down the loo, too.)
    And the trees and the seas and the bugs and the pugs.
    And not just the plants and the animal "zoo" …..
    …. the tiniest planktons that make the O2.
    It's so terribly sad when ONE species ….. just ….. ceases.
    You'd think we'd had a special plot,
    "Exterminate the bloody lot!"
    DENIERS and LIARS and INDUSTRY HIRES, weave and deceive us, their gullible buyers.
    So now we have the great distinction of bringing on our own extinction.
    And know what's really, really funny?
    We're FOSSIL FOOLS in love with money."
    The End??????

  • There is some evidence that the Dodo bird was not eaten because it tasted like dead skunk. The Dodo bird was very violently territorial and it was big enough to do some damage when it chased humans down and bludgeoned them with their big beaks. So the islanders murdered them all.

  • This gentleman can speak exceptionally well. He has mastered the ability to draw the listener into his world and captivate them.

  • 12:25 funny that he throws human beings in the same category as rats and cockroaches

  • Check out Guy Mcpherson for more truth this video fails to address – Aersol Masking Effect –

  • There's no way we can stop 6 masa extinction be Prepare ☝️☝️🇲🇨🇲🇨

  • We humans had our run……just as millions of other earth species have. We will kill ourselves. Only a short 1 million
    year from now there will be other earth species and then others and then others……..

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