Tim F. Flannery, Australian Museum
TF: There are two schools of
thought as far as these extinction-related scenarios go. One
is that a specific cause has been the major cause of extinctions.
The other argues that there are a whole combination of factors that
have been important. A good example would be the
idea that somehow human hunters and climate have worked together
to cause extinctions.
An analysis of that would be:
All right, let's accept that on face value, and then look at
worldwide extinction patterns. What you find is that extinctions
happened before the ice age in Australia, just after it in North
America, and only 600 to 800 years ago in New Zealand.
If you take that argument -- that both
climate and people are working together -- what you have to accept
is that climate is a very weak factor. Because extinction happens
no matter what the climate is doing; it's when people arrive that
determines when extinction happens.
I think that the analysis, as far as I've seen, probably still
overwhelmingly supports the single cause, which
is, I think, just overhunting.
Q: What are the most significant threats to biodiversity?
TF: The single most significant threat to biodiversity
is human population size and growing demand. We're running
out of fresh water; we're tapping ever more river systems to
provide ourselves with water. In the city I come from, Sydney,
for every person that lives there, we need
a storage capacity equal to three Olympic swimming pools worth
of water. As you add population, you're adding
immeasurably to the water demand. We're now tapping catchments
many hundreds of kilometers away from the city. So you can see
how the impacts tend to grow, just as population grows.
There is also the problem of what we call "affluence."
Maybe people are using water unwisely, or just using too
much -- and this is all very true, as well. But unless you can
cap population, you'll just have that demand going on
Q: Why does this matter to the ordinary person?
TF: I'd say to them that if they want to
have clean water, clean beaches, clean air, and a somewhat enjoyable,
diverse environment, then they'd better start taking note of this
biodiversity crisis. At the moment, we're basically cashing in
on the planet. The ecosystem's ability to provide clean water and clean air, and just the greenery around us -- we're cashing all of that in just
for dollars, and that's very silly. One day people will
turn around and things will be dirty and polluted, and there'll
be no jobs for their kids.
Q: What are the steps to take to conserve biodiversity?
TF: The first thing I think we need
is a world population policy. Each nation has to have a population
policy -- that is strategic. It's not that you're going to stop
growth tomorrow, but that, in the long term, you'll get onto a
trajectory which will lower growth rates.
Secondly, we need to do accounting differently.
We need to actually add up environmental capital and social capital
-- because they're two very important forms of capital -- and balance
them against financial capital. All too often, what
we call "profit" is just capital transfers from
environmental or social capital into actual money.
Q: Do you see any signs of hope, of positive steps?
TF: I do, actually. I think the fact that
the world is more aware than ever of these trends is very,
very important. The fact that this conference is happening here
in New York, and has been sponsored by the Biodiversity Center
-- which is a new thing at the Museum -- is all very positive.
Just regionally, where I come from, we had our first state-of-the-environment report -- a big, 600-page document -- which was
an attempt to do some environmental accounting. And we actually
put dollar values on things like degradation of fisheries and
waterways. You end up with a very persuasive
argument if you do that. You can say to the people: Here are
the billions of dollars which are being wasted here, which we're
actually losing . . . or the equivalent thereof in environmental
Q: In what other ways is the current extinction
event different from those of the past?
TF: I think
we have moved down through the trophic levels; and what we're
doing now is attacking soil and water. I mean, we've had our
big hit at the megafauna; we've exploited plants and forests.
But in a lot of the world now, what's under threat are soil,
and water-based ecosystems. And once you start attacking
the ecosystem at those very fundamental levels, you're doing something
quite different. The last time biological productivity
was attacked at such a fundamental level was probably during the
Cretaceous extinction, when photosynthesis was interrupted,
through, we think, an asteroid.
Q: What is the most striking evidence to convince skeptics
that extinction rates are high?
TF: Well, again, from my corner of the world,
we have lost 10% of our mammal fauna, pretty much in my lifetime.
A lot of species seemed to survive to the 1960s -- they're now
gone. Our frogs are having a dramatic decline. The common
frogs of my childhood, which I played with and grew up from tadpoles,
are now on the endangered-species list. Some of
them are actually extinct.
So these are things that are happening all
around where I live, and I guess similar things are happening
here. These are very real changes that, in my short lifetime,
I've noticed. And, you know, when you think that
you're dealing here with a world system that's been this way for
millions of years, and within my lifetime we're starting to dismantle
it -- I mean, that has to be cause for serious alarm.
Q: What are the things museums could do?
in the 19th century, were the lens through which people saw the
natural world. They didn't have the forms of transport or multimedia
that we do today. So you'd go to a museum to understand the world.
Now, modern museums have let a whole lot of other competitive
resources erode that from them. There's David Attenborough on
television, or there's a national park you can get
to in a half a day's drive, or whatever.
That's not necessarily bad. But what the museum needs to
do is redefine its position. After all, we
are the repository for many, many representatives of species that
are now extinct. We're chockablock full of beautiful objects,
real objects. It's like the equivalent of an art gallery, if
you want. We can actually show people what they've lost, in a
I think part of the role of museums is
to be beautiful, attractive, informative places that do show windows
on the world. It's not the world that you see in a video
-- it's the world perhaps as the place used to be. Perhaps it's
looking at cultures, people, places, in the longer term,
in the historic perspective. And that's something that
only museums can do. Other media can't do that effectively,
because they don't own the raw material.
Q: How can we go in and work with local people?
TF: I've attempted conservation programs
in the southwest Pacific, and you realize that
there is a fundamental gap in the way some people view the world,
that is very different from your own. I may see an endangered
tree kangaroo, or an endangered bat, or an endangered possum,
and I think that I can see the reason for it -- overhunting
or habitat clearance, but usually hunting. But when you speak
to the local people, they have a totally different idea. What
affects that animal's abundance, in a very real way
for them, is the magic and ritual which is done around that animal.
Whatever happens in hunting or gardening is just irrelevant
-- it's what the clever men are doing. Or, you know, there's
more over the hill. Well, you know, there isn't, but they just
assume there is.
So it's very difficult, when you come across
people with such fundamentally different world views as that, to
actually win the argument. I mean, you can't. Their view is
-- in many ways, at least to them -- and their experience is as valid
I think my great hope is to try
to train local people, particularly those with some education,
in Western ways of thought and communication. Then have them go
back to their villages and try to do something at that level
-- because they're in a far better position than I would
ever be. I must say, of all of the programs I've tried in
Melanesia, in terms of these conservation programs, only one was
in any way successful, and that was probably fortuitous circumstance,
rather than good planning. It's a very, very difficult thing
Q: What patterns do you see in ancient extinctions?
TF: The important aspects of these
Pleistocene extinctions are that they are in global in scale.
Virtually every area suffers from them. And they correlate in
time approximately with the first invasion of a naïve land
by humans. As soon as humans arrive in a place, extinctions follow fairly
quickly afterwards. In the case of Australia, for example, we
know that people were in Australia before 35,000 to 40,000 years ago.
Some people think it might have been 120,000 years ago. And we know
that we get megafaunal extinction
-- you know, everything in Australia that's bigger than a person
goes extinct sometime before 35,000 years ago. Because of the
nature of the dating techniques that are used at present, we can't
be any more precise than that. But, certainly, it happened a
long time ago. In the Americas, people came about 11,000 to 12,000
years ago, and that's when this great rush of extinctions happens
here. In New Zealand, people arrive 800 years ago, and extinctions
follow hot on their heels there, as well. Although we can't
be precise about how rapidly these extinctions happened after
people came in, I think I'm fairly safe to say that within a millennium
or two, anyway, the majority of the extinctions were finished.
So these are rapid, very dramatic events, that followed quickly
on the heels of the arrival of people -- and they're not related
to any patterns in changing world climate.
Q: In what way did humans coming into new lands
TF: To understand this,
we have to look at those few parts of the planet that escaped
human influence until recently. One of the best examples of
that is Lord Howe Island, which was the only island in the Pacific
of any size that was totally uninhabited and unknown until Europeans
discovered it in 1788, and also the sub-Antarctic islands in Antarctica.
There you see basically a naïve fauna. The
birds of Lord Howe Islands can be plucked off
branches in the tree like fruit. You could go up and lift a pigeon
off its roost and take it to your abode. If that was too hard
for you, you simply broke the legs of any one of the ground birds,
and it would cry out, attracting all of its neighbors. So you
would get a dozen or two dozen birds in an hour or so. These
things are documented -- they actually happened on Lord Howe Island.
In the sub-Antarctic islands, you see a similar
pattern. Even as formidable animals as elephant seals allowed
themselves to be herded to the tri-pots, where they were knocked on
the head with a stick and boiled down. These animals were naïve
-- they had no idea that humans were a problem.
You can imagine then the first humans coming
into North America, or Australia or New Zealand -- there's been
nothing like a hominid in any of these places before. And, in
Australia's case, nothing as big that's a warm-blooded predator.
Of course, the prey species don't recognize humans as a problem, and they
don't get a chance to learn -- particularly the larger ones,
which are slow-reproducing and don't live in big herds. Humans
can easily eliminate them. They don't run away. You put a spear
through the ribs of the thing and it's dead -- it doesn't get
a chance to learn. And, very rapidly, you run through any of
the vulnerable species. And under those conditions humans
have left all of their disease behind, too.
Q: What do ancient extinctions tell us about
predicting extinction patterns now and in the near future?
TF:The past is the key to understanding
the world we're living in today, because all of those extinctions
have happened so recently, in geological terms, that there has
been no evolution of new species to take over these vacant niches.
We're living, essentially, in a crippled world. In Australia,
nothing bigger than a kangaroo survived. There are empty niches
out there for 55 species of large mammals, reptiles and birds.
That concept is important in understanding how these systems
work today and how fragile they are.
Another example from Australia is the
introduction of rabbits and foxes. In 1850, Europeans
brought rabbits to Australia, released them -- and, of course, they
became problematical. There's an empty landscape here, vast amount
of resources for these rabbits to use. If someone had introduced
rabbits into the Serengeti Plain, you can be certain that that
rabbit would be outcompeted, tromped on, or eaten by one of the
megaherbivores there. Take all the megaherbivores off the Serengeti
and put the rabbit in, and all of a sudden you've got a problem
species -- a pest species.
So these ancient extinctions have patterned
the world that we live in today. We can't understand the interactions
of what's happening without cognizance of those structured ancient
ecosystems, which are now badly crippled.
The second point is that this is
an ongoing process, particularly in the Third World. In Melanesia,
where I work, you can see that in the past everything bigger than
20 kilograms in size became extinct -- I think through just overhunting.
That process continues today. Everything above
5 kilograms in weight in New Guinea today is under threat from
overexploitation. And you're dealing here with a land whose population
has trebled or so in the last 50 years, where technology has shifted
from bows and arrows to shotguns, where there's
now roads and airstrips and the potential for trade right around
the island. All of this is just increasing hunting pressure,
you can see that people are just
drawing down on the resource base further.
Here, in the developed world
we've gone beyond that, and we now are taking the soil and
water of these ecosystems. When you start dealing that
low in the tropic system, you're actually precipitating
extinction events on the scale of the Cretaceous extinctions --
where photosynthesis is interrupted and you
get a big cascade. Here we're taking soil and water, and that
kind of interruption in the end will have very profound effects.
Q: Could you explain the concept of "aftershock"?
TF: I've coined the term "aftershock"
to deal with all of the consequences of megafaunal extinction,
which I think are very profound.
You have ecosystems which have many, many holes in them -- if you
want, they're inhabited by ghosts -- because these extinctions,
in geological terms, are so recent that nothing has evolved to
fill those niches; they're still empty. It also has
a profound effect on nutrient recycling. When there was megafauna
about, grass would grow. It would be cropped off; it would be
dropped out the other end of whatever happened to have eaten it;
and 48 or 72 hours later, with the help of dung beetles, the nitrates
and phosphates are back in the soil. Basically, it's like
an economy where the money's going around very rapidly.
Once you take out megafauna, the only substitute
is fire -- and, of course, fire is a much rarer event.
In Australia we typically have to wait 10 to 20, maybe even 30
years before those nutrients are released. And, when they are
released -- many of them are destroyed
in the process. Nitrates, for example, are just volatilized
and lost to the air; soil sulfurs are destroyed by the heat of
the fire, as well. It's a much less efficient system.
You end up having very profound effects within nutrient recycling
of plant communities, and everything else.
There are many, many effects of this aftershock.
The world we inherit, that we
live in today, is the result of megafaunal extinction aftershock.
It's not a balanced, co-evolved system -- it's one which is in
severe disequilibrium. And it's continuing to rebound.
So when we think of management -- of national parks and whatever
else -- we have to take this into account. We're not dealing
with the wilderness -- this is a very severely damaged ecosystem
that we're trying to manage.
Q: What kind of discovery would change your
mind about people being the major cause of extinction?
TF: One discovery that would make me admit that
I've been wrong all along would be simply a long overlap
between people and megafauna. So here, in North America, if you
started picking up full megafaunal assemblages that were only
8,000, or 7,000 years old, or if you were picking up humans
that were indisputably 15,000 years old, I would admit that I
was wrong. But you'd want good evidence -- you'd want lots and
lots of stacked dates in sequential sites, not just the odd date
that looks a bit strange And a significant
overlap between people and megafauna
would have to be in the thousands of years -- perhaps between 5,000 and 10,000
Q: Do you think the search for a cause of Pleistocene extinctions has
TF: I basically do think that the search
for a cause has ended in the majority of cases. There are many
special cases that we still can't explain -- the extinction of
insects in New Zealand, for example. But, basically, I'm satisfied, intellectually,
that we understand the mechanism. The Blitzkrieg theory
that Paul Martin has developed is universal; it's almost all-inclusive;
it fits the known facts well; and, with a few small exceptions
-- a few aberrant or unusual cases -- we have
a solution to the nature, the causes of these extinctions. What
really interests me now is the flow-on from those
extinctions -- what the effects were. We've understood the cause,
but the effects are another matter.