Earths mass extinction Peter Ward
[Music]
so I want to start out with this
beautiful picture from my childhood I
love the science fiction movies here it
is this island earth and leave it to
Hollywood to get it just right two and a
half years in the making I mean even the
creationists give us 6,000 but Hollywood
goes to the chase and in this movie we
see what we think is out there flying
saucers and aliens every world has an
alien and every alien world has the
flying saucer and they move about with
great speed
aliens well don brownlee my friend and i
finally got to the point where we got
tired of turning on the TV and seeing
the spaceships and seeing the aliens
every night and tried to write a
counter-argument to it and put out what
does it really take for an earth to be
habitable for a planet to be an earth to
have a place where you could probably
get not just life but complexity which
requires a huge amount of evolution and
therefore constancy of conditions so in
2000 rewrote rare earth in 2003 we then
asked let’s not think about where earths
are in space but how long is Earth Ben
Earth if you go back to billion years
you’re not on an earth-like planet
anymore what we call an earth-like
planet is actually a very short interval
of time well rare earth actually taught
me off a lot about meeting the public
right after I got an invitation go to a
science fiction convention and with all
great earnestness walked in David Brin
was going to debate me on this and as I
walked in the crowd of 100 started Bowie
and lustily but a girl came up and said
my dad says you’re the devil
you cannot take people’s aliens away
from them and expect to be anybody’s
friends well the second part of that
soon after and I was talking to Paul
Allen and I saw him in the audience I
handed him a copy of rare earth and Jill
tarter was there and she turned to me
and she looked to me just like that girl
in the Exorcist it was it burns it burns
because Eddie doesn’t want to hear this
said he wants there to be stuff out
there I really applaud the SETI efforts
but we have not heard anything yet and I
really do think we have to start
thinking about what’s a good planet and
what isn’t
now I throw this slide up because it
indicates to me that even if SETI does
hear something can we figure out what
they said because this is a slide that
was passed between the two major
intelligence is on earth a Mac to a PC
and it can’t even get the letters right
so how are we going to talk to the
aliens and if there are 50 light-years
away and we call them up and you buf
about and then 50 years later comes back
and they say please repeat I mean there
we are our planet is the good planet
because you can keep water Mars is a bad
planet but it’s still good enough for us
to go there and to live on its surface
for protected but Venus is a very bad
the worst planet even though it’s Earth
like it even though early in its history
made very well of Harvard earth-like
life it’s sue succumbed to runaway
greenhouse that’s an 800 degrees
centigrade surface because of rampant
carbon dioxide well we know from
astrobiology that we can really now
predict what’s going to happen to our
particular planet we are right now and
the beautiful Oreo of existence of at
least life on planet Earth following the
first horrible microbial age in the
Cambrian explosion life emerged from the
swamps complexity arose and from what we
can tell we’re halfway through we have
as much time for animals to exist on
this planet as they have been here now
till we hit the second microbial age and
that will happen paradoxically
everything here about global warming
when we hit co2 down to ten parts per
million we are no longer going to have
to have plants or allowed to have any
photosynthesis and there go animals so
after that we probably have 7 billion
years the Sun increases in its intensity
and its brightness and finally at about
12 billion years after first our turd
the earth is consumed by a large Sun and
this is what’s left so our planet like
us is going to have an age at an old age
and we are in its golden summer age
right now but there’s two phase two
everything isn’t there now a lot of you
are going to die of old age but
some of you horribly enough are going to
die in an accident and that’s the fate
of a platitude earth if we’re lucky
enough if it doesn’t get hit by a pale
Bop or gets blasted by some supernova
nearby in the next seven billion years
we’ll finally be your fate but what
about accidental death
well paleontologists for the last 200
years have been charting death it’s
strange
extinction as a concept wasn’t even
thought about until Baron Cuvier and
France found this first Mastodon he
couldn’t match it up to any bones on the
planet and he said AHA extinct and very
soon after the fossil record started
yielding a very good idea of how many
plants and animals that have been his
complex life really began to leave a
very interesting fossil record in that
complex record of fossils there were
times when lots of stuff seemed to be
dying out very quickly and the
father/mother geologists called these
mass extinctions along was thought to be
either act of god or perhaps long slow
climate change and that really changed
in 1980 in this rocky outcrop near
Gubbio where walter alvarez trying to
figure out what was the time difference
between these white rocks which held
creatures of the Cretaceous period and
the pink rocks above which held tertiary
fossils how long did it take to go from
one system to the next and what they
found is something unexpected they found
in this gap in between a very thin clay
layer and that clay layer this very thin
red layer here is filled with iridium
and not just iridium is filled with
glassy cereals and has filled the quartz
grains that have been subjected to
enormous pressure shock quartz now in
this life the white is chalk and this
chalk was deposited in a warm ocean the
chalk itself is composed by plankton
which has fallen down from the sea
surface onto the sea floor so the 90% of
the sediment here is skeleton of living
stuff and then you have that millimeter
thick red layer and then you have black
rock and the black rock is the sediment
on that sea bottom in the absence of
plankton and that’s what happens in an
asteroid catastrophe because that’s what
this was of course this is the famous KT
a ten kilometer body hit the planet the
effects of it spread this very thin
impact layer all over the planet and we
had very
quickly the depth of the dinosaurs the
death of these beautiful ammonites lasts
until here and selasa furs over here and
so much else I mean it must be true
because we’ve had to Hollywood
blockbusters since that time and this
paradigm from 1980 to about 2000 totally
changed how we geologists thought about
catastrophes prior to that
uniformitarianism was the dominant
paradigm the fact that if anything
happens on the planet in the past there
were present-day processes that will
explain it but we haven’t witnessed a
big asteroid impact so this is a type of
neo catastrophism and it took about 20
years for the scientific establishment
to finally come to grips that yes we
were hit and yes the effects of that hit
caused a major mass extinction well
there are five major mass extinctions
the last 500 million years called the
Big Five they range from 450 billion
years ago to the last the KT number for
the biggest of all was the P or the
Permian extinction sometimes called the
mother of all mass extinctions and every
one of these has been subsequently
blamed on large body impact but is this
true the most recent the Permian was
thought to have been impact because of
this beautiful structure on the right
this is a buckminsterfullerene a carbon
60 because it looks like those terrible
geodesic domes of my late beloved 60s
they’re called bucky balls this evidence
was used to suggest at the end of the
Permian 250 million years ago a comet
hit us and when the comet hits the
pressure produces the bucky balls and it
captures bits of the comet helium-3 very
rare in the surface of the earth very
common in space but is this true in 1990
working on the KT extinction for ten
years I moved to South Africa to begin
work twice a year in the great karoo
desert I was so lucky to watch the
change of that South Africa into the new
South Africa as I went year by year and
I worked on this Permian extinction
camping by this Boer graveyard for
months at a time and the fossils are
extraordinary
you know gaze upon your very distant
ancestors these are mammal-like reptiles
they are culturally invisible we do not
make movies about these this is
gorgon opción or Gorgon that’s an 18
inch long skull of an animal that was
probably seven or eight feet sprawled
like a lizard probably had a head like a
lion this is the top carnivore the t-rex
of his time there’s lots of stuff this
is my poor son Patrick this is called
paleontological child abuse
hold still you’re the scale there was
big stuff back then 55 species of mammal
like reptiles the age of mammals had
well and truly started 250 million years
ago and then a catastrophe happened and
what happens next is the age of
dinosaurs it was all a mistake it should
have never happened but it did now
luckily this throwing acid on the size
of a robin egg here this is a skull
discovered just before taking this
picture there’s a pen for scale it’s
really tiny this is in the lowest
Triassic after the mass extinction is
finished you can see the eye socket you
can see the little teeth in the front if
that does not survive I’m not the thing
giving this talk something else is
because if that doesn’t survive we are
not here there are no mammals is that
close one species eats through well can
we say anything about the pattern of who
survives and who doesn’t here’s sort of
the end of that ten years of work the
ranges of stuff the red line is the mass
extinction but we’ve got survivors and
things that get through and it turns out
the things that get through
preferentially are cold Bloods
warm-blooded animals take a huge hit at
this time the survivors that do get
through produced this world of
crocodile-like creatures there’s no
dinosaurs yet just the smo saurian scaly
nasty swampy place with a couple of tiny
mammals hiding in the fringes and there
they would hide for 160 million years
until liberated by that KT asteroid so
not impact what and the what I think is
that we returned over and over and over
again to the Precambrian world at first
microbial age and the microbes are still
out there they hate we animals they
really want their world
and they’ve tried over and over and over
again and suggested me the life causing
these mass extinctions because it did is
inherently anti Guyon this whole Gaia
idea the life makes the world better for
itself and it would have been on a
freeway on a Friday afternoon in Los
Angeles believing in the Gaia theory no
so I really suspect there’s an
alternative and that life does actually
try to do itself in not consciously but
just because it does and here’s the
weapon it seems that it did so over the
last 500 million years there are
microbes which through the metabolism
produce hydrogen sulfide and they do so
in large amounts hydrogen sulfide is
very fatal to humans as small as 200
parts per million will kill you you only
have to go to the Black Sea and a few
other places some lakes and get down and
you’ll find that the water itself turns
purple turns purple for the presence of
numerous microbes which have to have
sunlight and have to have hydrogen
sulfide and we can detect their presence
today we can see them but we can also
detect their presence in the past and
the last three years have seen an
enormous breakthrough in a brand-new
field
I am almost extinct I’m a paleontologist
who collects fossils but the new wave of
paleontologists my graduate students
collect biomarkers they take the set of
it itself they extract the oil from it
and from that they can produce compounds
which turn out to be very specific to
particular microbial groups is because
lipids are so tough they can get
preserved in sediment and last the
hundreds of millions of years necessary
and be extracted and tell us who was
there and we know who was there at the
end of the Permian at many of these mass
extinction boundaries this is what we
find I saw Ernie retain its very
specific it can only occur if the
surface of the ocean has no oxygen and
is totally saturated with hydrogen
sulfide enough for instance to come out
of solution
this led Lee Kump and others from Penn
State and my group to propose what I
call the comp I pas thesis many of the
mass extinctions were caused by lowering
oxygen by high co2
and the worst effect of global warming
it turns out hydrogen sulfide being
produced out of the oceans well what’s
the source of this in this particular
case the source over and over been flood
basalts this is a view of the earth now
if we extract a lot of it and each of
these looks like a hydrogen bomb
actually the effects are even worse this
is one deep earth material comes to the
surface spreads out over the surface of
the planet well it’s not the lava that
kills anything it’s the carbon dioxide
that comes out with it this isn’t Volvos
this is volcanoes but carbon dioxide is
carbon dioxide so these are new data
about burger dive from Yale put together
and what we try to do now is track the
amount of carbon dioxide in the entire
rock record we can do this from a
variety of means and put on the red
lines here when these what I call
greenhouse mass extinctions took place
and there’s two things they’re really
evident here to me is that these
extinctions take place when co2 is going
up but the second thing that’s not shown
on here the earth has never had any ice
on it when we’ve had a thousand parts
per million co2 we are a 380 in climbing
we should be up to a thousand in three
centuries at the most but my friend
David Bautista in Seattle says he thinks
a hundred years so there goes the ice
caps and there comes 240 feet of
sea-level rise I live in a view house
now I’m going to have waterfront alright
what’s the consequence the oceans
probably turn purple and we think this
is the reason the complexity took so
long to take place on planet Earth we
had these hydrogen sulfide oceans for a
very great long period they stopped
complex life from existing we know
hydrogen sulfide is erupting presently a
few places on the planet and I throw
this slide and this is B actually two
months ago let’s throw this slide in
because here is my favorite animal
chambered nautilus it’s been on this
planets this animals for started 500
million years this is a tracking
experiment interview scuba divers you
want to get involved one of the coolest
projects ever this is off the Great
Barrier Reef and as we speak now these
Nautilus are tracking out their
behaviors to us but the thing about this
is that every once in a while
divers can run into trouble so I’m gonna
do little thought experiment here this
is a great white shark that ate some of
my traps we pulled it up up it comes so
it’s out there with me at night so I’m
swimming along and it takes off my leg
I’m 80 miles from shore what’s going to
happen to me well now I died five years
from now this is what I hope happens to
me I’ve taken back to the boat I’m given
a gas mask eighty parts per million
hydrogen sulfide I’m then throwing a
nice pond
I’m cooled fifteen degrees lower and I
can be taken to a critical care hospital
and the reason I could do that is
because we mammals have gone through a
series of these hydrogen sulfide events
and our bodies have adapted and we can
now use this is what I think will be a
major medical breakthrough this is Mark
Roth he was funded by DARPA trying to
figure out how to save Americans after
battlefield injuries he believes out
pigs he puts in 80 parts per million
hydrogen sulfide the same stuff that
survived these past mass extinctions and
he turns a mammal into a reptile I
believe we are seeing in this response
the result of mammals and reptiles
having undergone a series of exposures
to h2s I got this email from him two
years ago
he said I think I got an answer to some
of your questions so he now has taken
mice down for as many as four hours
sometimes six hours and these are brand
new data he sent me on the way over here
on the top now that is a temperature
record of a mouse who has gone through
the dotted line to temperature so the
temperature starts 225 centigrade and
down it goes down it goes six hours
later up goes the temperature now the
same mouse is given eighty parts per
million hydrogen sulfide in this solid
graph and look what happens to his
temperature its temperature drops it
goes down to 15 degrees centigrade from
35 and comes out of this perfectly fine
here is a way we can get people to
critical care here’s how we can bring
people cold enough to last till we get
critical care now you’re all thinking
yeah what about the brain tissue and so
this is one of the great challenges is
going to happen you’re in an accident
you got two choices you’re going to die
or you’re going to take the hydrogen
sulfide and say 75% of you
is safe mentally what are you going to
do do we all have to have little buttons
say let me die this is coming towards
this I think this is going to be a
revolution we’re going to save lives but
there’s going to be a cost to it the new
view of mass extinctions yes we were hit
and yes we have to think about the long
term because we will get hit again
but there’s a far worse danger
confronting us we can easily go back to
the hydrogen sulfide world give us a few
millennia and we humans children ask
those few millennia will it happen again
if we continue it will happen again how
many of us flew here how many of us have
gone through our entire Kyoto quota just
for flying this year how many of you
have exceeded it yeah I’ve certainly
exceeded it we have a huge problem
facing us as a species we have to beat
this I want to be able to go back to
this reef thank you the one question to
Peter so am i understanding you right
that what you’re saying here is that we
have in our own bodies a biochemical
response to hydrogen sulfide that in
your mind proves that there have been
past mass extinctions due to climate
change yeah every single cell in us can
produce my new quantities of hydrogen
sulfide in great crises this is what
Roth is found out so what we’re looking
at now does it leave a signal doesn’t
leave a signal in bone or in plant we go
back to the fossil record and we could
try to detect how many of these have
happened in the past
it’s simultaneously an incredible
medical technique but also a terrifying
blessing and curse
you