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How to pronounce family aplodontiidae in English?

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- [Narrator] We are the paradoxical ape. Bipedal, naked, large brained, long the
the master of fire, tools, and language but still trying to understand
ourselves. Aware that death is inevitable, yet, filled with optimism. We grow up
slowly. We hand down knowledge. We empathize and deceive.
We shape the future from our shared understanding of the past.
CARTA brings together experts from diverse disciplines to exchange insights
on who we are and how we got here.
An exploration made possible by the generosity of humans like you.
- [Elizabeth] I particularly appreciate being invited because I'm not a
paleoanthropologist, and I don't really study climate specifically. Instead, what
I'm going to do is give you the perspective of the other animals that
occupy the earth, these small animals, large animals. And I'm going to definitely
delve us into the future and ask some tough questions about our population. So I
title my talk somewhat provocatively about tipping points. And tipping points are-
they're situations of a state where you have a non-linear kind of system. And when
you move beyond some particular point in that non-linear system, you can't go back
to where you started. Now I'm going to advocate that we're poised on the edge of
a tipping point for planet Earth. So, when some threshold is crossed, and the
question is are we about ready to cross it or have we already? This system is going
to move into a new state. And the example I put up here is an egg about ready to go
off the edge. Ice melting in the Arctic might be another one to think about. So,
mass extinctions. I've been asked before whether or not the Earth has shown tipping
points. We know they happen in ponds. They happen in small ecosystems. But mass
extinctions, in fact, can happen on a planetary scale. We already saw this mass
extinction graphic. They're labeled there, the Ordovician-Silurian, the Late
Devonian, the Permo-Triassic where we lost 95% of all the species on the planet. The
Triassic-Jurassic in the KT where we lost dinosaurs and a lot of marine reptiles.
The point is, is that these are mass extinctions, and you'll see in every case
there's a drop in diversity. This is generic marine diversity.
So this is a marine record, not a terrestrial one. But the point is, is that
when it recovers, and it takes between 5 and 10 million years
for life to recover after these mass extinctions,
life is completely different. We've lost those organisms that
founded the diversity on the planet prior to the extinction, and they don't come
back. So it reassembles. It is, in fact, a new state. So the earth is warming
rapidly. You've seen many versions of this. But I'm providing here a little bit
of a perspective about- from our perspective. So, we're here on this
graphic. All of those different colored squiggles show different scenarios.
Depending on what models are used by IPCC, we will be here. Now, you've heard a lot
about the evolution of humans, modern humans. By the time we get to that point,
in 2050, we will have global planetary temperatures warmer than our species has
ever experienced on its time on earth. And if we happen to make it to 2100, and to
temperatures somewhat above 4 degrees, Earth has not been as hot as that
projected temperature in 14 million years. Now the perspective is, and this is one
I'm giving you, mammal species don't live that long. We don't have mammal species on
the planet that are 14 million years old. So the memory of this climate, in the
genome of these species, is gone. World population is still growing. Now, there
will be 9 billion people on the planet by 2045. So, 2045 here, there will be 9
billion people. And if we continue at- these are current fertility rates shown
in the upper blue, current fertility rates. You can imagine.
I mean, 15 million people on the planet. Unbelievable. In fact, fertility rates are
slowing but not fast enough. Instead of replacing ourselves, a male and a female,
with two children. We would have to go down to just .5 children per person to
follow the lower blue curve. So human population growth is the elephant in the
room. It is tremendously terrifying. So, even though the Late Quaternary,
transition from a Pleistocene, the cold, arid Pleistocene to the warmer more
wetter, Holocene is not exactly analogous and, in fact, very different in many ways
to the kinds of climate we're experiencing today. In fact, there are two similar
features. One, we are warming the environment as we move from the
Pleistocene to the Holocene. And we're also expanding. As humans, we're
colonizing the globe. So those two features are, in fact, something we share
with what's happening today. So you heard a little bit about these dramatic warming
and cooling events. Here's the Bolling-Allerod and then followed by an
abrupt Younger Dryas. It's a cooling event that saw the extinction, for example, of
Irish elk in Ireland as that environment cooled rapidly. And then we end up into
what's called the Holocene or really about the last 10,000 or so years of relatively
constant temperatures. However, we expanded in this latter part of a
Quaternary. You know, we left Africa around 200,000 years ago. We colonized
Europe and Asia. We colonized Australia somewhere between 40 and 60,000 years ago.
And then we made it to the Americas last, somewhere between 13 and 35,000 years ago.
Now, with our colonization of these isolated areas, we caused extinctions.
This is a photo. This beautiful image is the menagerie of animals that used to roam
in North America and are now no longer here. There are
[[inaudible 00:08:04]] giant ground sloths, glyptodons. There's the giant
bison. Camels which basically evolved in North America left colonized Asia,
colonized South America and went extinct in North America. And then horses which,
again, have millions of years of history in North America and went extinct only to
be recolonized by Spanish explorers. Historically, about half the world's large
animals, animals larger than 44 kilograms or about 100 pounds, went extinct at this
time. Incidentally, humans are about that size. So it's not just our impact that
cause change in animal distributions and abundance. In fact, there are some small
mammals, like this bog leming that went extinct at this Pleistocene, Holocene
transition. So we know that ice covered much of Canada, and there was no place for
these bog lemings to live. Every one of those black dots you see in North America
were occupied by bog lemings during the Pleistocene. They're no longer found
really in the lower 48. In fact, what they are- they're occupying this orange
range up here. They are really an circumarctic species. So they responded as
you'd expect a species that likes a relatively cold environment. As the ice
left, they tracked that environment northwards. But not all species responded
that way. These are two images of two species that are found in a cave called
Samwell Cave that excavated several years ago in northern California, shown by the
black dot there. These two species didn't really respond north. In fact, they
contracted their ranges to higher elevation but also much wetter
environments that's currently found in Samwell Cave today, which is located on
the shores of Lake Shasta. So these animals- the mountain beaver, it's not
confined to mountains nor is it a beaver. It is the last species of what was a very
large group of species in the family aplodontiidae which is a very ancient,
North American family of rodents. And it is the only species left in the family
today. It's very primitive, and it cannot concentrate its urine. And so it has to be
by running fresh water all day, all the time. And so you find them confined into
very dense old-growth Douglas fir forests along the coast and the pacific northwest,
a very ancient lineage that is threatened by warming temperatures and dry
conditions. The other animal you see is the white-footed vole. Very little is
known about this animal accept the fact that it's somewhat arboreal, and it's
found in deciduous trees and probably up in these old-growth Doug fir forests.
This animal contracted with the Doug fir forest of a wetter condition, not so much
higher up in elevation. Animals today are moving pole-ward just like they did in the
Pleistocene. This is a range map of the current distribution in 2013. The black
line is the current distribution of the armadillo. The armadillo is related to
that glyptodon, that giant thing I showed you in the previous slide. It's a South
American animal, and it is expanding. It made it across the Rio Grande in 1850, and
it's expanding northward. It's limited by winter temperatures. So if there are 24
freeze days or more, this animal can't survive, it's young can't survive. And
what's happening is, as our North American climates are warming, this animal is
progressively colonizing further and further north. So what you
see, not the Xs but every other symbol on this are instances where armadillos have
advanced beyond their 2013 static range. Be interesting to know where they are
after this winter. However, the thing about this that I want to point out, it's
not just that animals respond the way you predict they would based on what we know
from fossils. But the other thing is, this particular animal, the armadillo, is the
only mammal we know about in the world that carries leprosy. And so this is an
example of these unexpected synergistic things that can, in fact, impact humans in
ways we don't anticipate. Actually, they got leprosy from us. Leprosy evolved in
Asia, most likely India. And they contracted leprosy from us probably
somewhere around Louisiana. But this animal can transmit leprosy to humans as
well. So, similarly to what I explained to you about the mountain beaver and the
white-footed vole, animals will find their proper environments. And so it's not just
that they move further north, they, as warming conditions prevail and as drying
conditions prevail, they'll also move up in elevation. So many of you might have
hear about the pikas. This is one of the Asian species. There are, in fact, 28
Asian species of pikas. They're related to rabbits and heirs. They're just the most
wonderful thing to work with. They have this enormously interesting physiology.
They have a resting body temperature of about 104 degrees, and they live really
high. In the Himalayas, they live above 15,000 feet. Now, the problem with- so
we've been studying these particular animals all along the Himalayan front in
India and Nepal. And it turns out that only some of these species can tolerate
the hypoxic conditions that are characteristic of that high
elevation. So these particular animals and, in fact, they've shown to be moving
up much more rapidly than American pikas of which have moved up around 150 meters.
In the Himalayas, they've moved up, at least, 1,000 meters. And they're pinched,
right, from above, because of those hypoxic conditions and from below
from warming and also human alteration of their environment. Now,
another kind of unexpected example, and, again, to demonstrate just what ecosystems
mean in terms of how species are connected. The map you see on the left is
a map of the distribution, on present, the whitebark pine distribution in North
America. Whitebark pine is high elevation pine. It's the last conifer until you get
to tree lines, so it's the thing that you often see. It's krumholtz in the Rocky
Mountains. It's a five-needle pine, and it has these really, really calorically rich
nuts in the cone. If we just look at climate models for the distribution of the
whitebark pine and you can go to 2030, 2060, and 2090. You can see by 2090,
there's barely any whitebark pine left in the lower 48. Now that projection was made
before we saw what happened with the mountain pine beetle. For those of you
that have traveled anywhere in the Rocky Mountains, you know that in the last
decade, conifer forests, all the way up to tree line, have been desonated. In the
Yellow Stone region, in some of these areas, whitebark pine are down 80%. This
is a photo from one of the high elevation areas that I work in, in Yellow Stone. And
you can see a lot of standing dead trees. Because the beetle is allowed to survive
over the winter. It's not killed off, it's a native beetle. The climate is definitely
implicated in the expansion of this beetle. It now goes all the way up to tree
line. It's not killed off. And it probably
reproduces several times per year instead of having to recolonize every year. Well,
why is that? Why do I have a picture of a grizzly bear? It turns out that the number
of whitebark pine cones in a tree is directly correlated with over winter
survival of adult bears and their cubs. And it's indirectly correlated with
problem bears the following summer. So when there's not a lot, in some cases they
may it 40 to 50% of their fat as a result of eating these middens of cones. They're
mostly, again, another player in this are the Clark nutcrackers and the red
squirrels here. But these grizzly bears need this to pack on the fat. And what
happens is they come out of hibernation earlier, and they start getting into
trouble, looking for food in human dwellings. So, again, an unanticipated and
kind of surprising but very major impact from climate change. The other thing that
happens and these are data, I'm not showing you the actual data. But during
the Pleistocene, Holocene transition, there were lots of different small mammals
in the Samwell Cave site in northern California I talked about. But the animal
that just took over that site is the deer mouse, peromyscus maniculatus. And, in
fact, this animal has dominated the entire Holocene assemblage. So the community
structure of small mammals changed. And this is not due to human hunting, this is
due to the fact there are many more disturbed environments in the Holocene.
This animal has very high intrinsic rates of growth. They don't care what the
environment it. They don't mind if it's just been burned. They don't mind if it's
the edge of a field or if it's an old-growth forest. They like disturbance.
This animal is the most commonly trapped small mammal in North America. So if you
lay a trap anywhere outside of human habitation, you're likely
to catch this guy. It also tends to carry a lot of diseases. So this is a witty
species and it thrives with human environments. And the specialist species
are the ones that take a nose dive. Now I'm sure there are some of you that are
gardeners here, and they don't consider the pocket gophers as a particularly
favorable friend in their garden. But, in fact, these guys took a hit at the end of
the Pleistocene. This is a pocket gopher, it has fur lined cheek pouches, and it
stores its seeds and digs. And, in fact, this is a specialist species. It is so
energetically expensive to live under ground. It takes between 360 and 3,400
times the energy to do this than to move the same distance above ground. This is,
by any accounts, a very specialist species. So they decline. Humans are
directly causing the extinction of animals. We are threatened to lose almost
a quarter of our species. I just read an article that said about a third of our
bird species in Europe are threatened. Most of these are from hunting. We're
about ready to see the loss of elephants in the next decade or two. One out of
every twelve elephants was killed in just the last three years. This is a crisis.
Fifty-one percent of humans of the terrestrial land, has been co-opted for
human use. The only place that's left on this map, that aren't show in purple, are
deserts and tropical forests. Those are the least easily farmed land on the
planet, but they're also, in some ways, especially the tropical forest, some of
the most important. Everywhere else, we have made a mark. We have an extinction
debt, and we will lose a lot of biodiversity in the near future.
I get asked a lot, "Can speciation rescue biodiversity?"
Absolutely not. Species take between two and five million years,
this is mammal species, to evolve.
So, we can cause them to disappear in a
decade or two, but it takes millions of years to accumulate the diversity we might
have lost. So how do we avoid this planetary tipping point? We increased
energy conversion, obviously. We stole habitat loss. We increase global
cooperation. This has got to be done globally. And we stabilize population
growth. And, finally, how do you stabilize population growth? I get asked what is the
most- in my opinion, the single most important thing for us to do is to educate
women globally. And the reason is because as education goes up, fertility rate goes
down. The more girls that are in school, secondary school, the number of years is
really important, the more fertility rates go down. And interestingly, GDP and
poverty rates also go up. Human innovation is remarkable. We can see the origin of
the universe. I can't believe we can see the origin of the universe. And we can see
ourselves in our beautiful planet from space. Why can't we
avoid the next tipping point? Thank you.