I'd like to welcome you all to me the
third of the long lectures the speaker
after the last two nights obviously
needs no introduction I'll just give a
brief comment the reason i mentioned
that i'm at the Natural History Museum
and in Washington is that about 12 years
ago I had a postdoc going tom was husky
and we were doing a project analyzing a
lot of fossil data from down in West
Texas and Tom had spent about ten months
counting 750,000 shells which tells you
something about Tom that he would do
that and then we started analyzing the
data and he came in one day and told me
about this this great new technique he
just developed and he was all excited
about using it to analyze the data and
went off to write a paper about it he
came in and about two weeks later into
my office and plopped down in my chair
very morose and said Tom what's wrong he
said that damn Bob May is there anything
he hasn't done Tom had just discovered
that Bob had invented the same technique
and published it in the early 1970s so
with that Robert may and toward
tomorrow's world I'm going to begin in a
slightly curious way because to cure
myself of an embarrassment largely I had
the pleasure and privilege that murray
gell-mann her gave to me this morning
and which he promised to do and they say
he wrote 16 years ago on the basic issue
I talked about in the first lecture on
the relay and it's a paper which if it
isn't on the SFI website certainly I'm
sure will be tomorrow and I commend it
to you very highly because far and away
the best thing I've read on the subject
not going to make an attempt to
summarize it but one of the amusing
things about it Murray uses a very
clever way of thinking about wood
inhabitants of other populated planets
use the same sort of mathematics would
they see the same sort of rules and I
want to give away the end of the essay
but it just so happens that he clearly
invented this idea of thinking of other
planets because that's the way I'm going
to end this lecture I've made may have
got my knowledge minh tinh first what
I'm actually going to do in this lecture
sorry I didn't press it hard enough the
first time first I'm going to give an
overview of the impact humanity as
having just in very general terms and
very briefly and then I'm going to turn
to the components of that which are
partly more people and partly more
impact per person and there are quite a
few aspects of the more people bit about
which people have misconceptions and I
will try and eradicate those and on the
air on the topic of more impact per
person there is a there are a very large
number of issues one could discuss and
I'm going just to mention three that are
tend to be discussed quite a bit these
days infectious disease new and emerging
and re-emerging infectious diseases food
and water and the diversity of other
things and then I'm going to end by
inflicting on you some opinions about
the problems we face in the world of
that we are headed towards at the moment
so just the overview over the past 150
years the human population has increased
Sevenfold and the global average energy
use per person which of course varies
hugely from place to play
but as a global average has also
increased by a factor seven so overall
the footprint in as measured in energy
use which is a good reflection of many
other things the footprint we stamp on
the planet collectively has increased
roughly 50 fold in that span of time and
I apologize for the slightly out-of-date
2003 for this but it's not the relative
things aren't very greatly changed and
the way WWF presented at last time I saw
it I don't think is as lucid as this
what this is and it is an attempt to
show by area of the world and reading
across from your left to your right it's
the North America Canada and the USA the
dark blue one is the EU 23 and the
lighter blue one is the other EU
countries that have some of since joined
and others would like to the green one
is that Middle East and Central Asia the
red one is Latin America and the
Caribbean the really big green one is
Asia Pacific which is China and India
and Philippines and then Africa is the
yellow one on the end and the dotted
lines the height of each of those curves
is the average footprint per person and
I'm not going to go into the details of
how you calculate that which are pretty
dodgy as are so many of these things but
on the other hand I'm going to make a
comparison of what one thinks the
planner could sustain and it contains
the same dodgy elements so that the
comparison of these figures which are
pretty soft numbers are compared with
light by like in a moment so the height
gives the average footprint per person
and the width gives the number of people
in the total area the total impact you
can see for example that both the asian
the China India bit and the North
America bit the footprint per person
exceeds what that area can sustain in
the case of North America it's it's
basically the footprint per person
rather than the number of people in the
case of Asia it's not the footprint per
person which is much lower it's just a
number of persons and then there are
places perhaps surprisingly Europe and
at least the EU part of Europe has a
footprint which is something twice that
it could sustain although the accession
countries less so and so on the
interesting thing is to compare that
against the calculation of what is the
overall footprint being stamped on the
planet taking all those diff variegated
patterns in different places it's been
steadily rising and put it against what
is estimated to be sustainable and as I
say some of the errors or some of the
uncertainties if you have to try and put
error bars on these they'd be too broad
bands but there this is in a sense the
center of a very wide probability
distribution with some of the errors
canceling and it's suggests that we're
already past that point of sister of
them we've already succeeded the
sustainable capacity buried within it
are a wealth of fascinating ethical
questions and the average Australian for
example has a footprint of 7.8 in the
units that are used which coincidentally
is almost as exactly half the biological
capacity per person in that country
conversely in Egypt the average person's
footprint is much smaller than the
Australians but it's four times what
that country alone can sustain the world
average is this a more recent figure is
continuing to creep up to requiring sort
of 1.3 planets
so how do we get to this point why do we
get to this point we began for most of
humanity's history we've been small
bands of hunter-gatherers and that's
what we were for a couple of hundred
thousand years the beginnings of
Agriculture independently in two or
three different places in the Middle
East and also in in parts of China and
began roughly all around the same time
roughly very roughly 10,000 years ago
and once that happened and people it
enabled the beginning of larger groups
and small settled groups the first towns
the first cities and populations started
to increase at a much faster rate even
so the increase was relatively slow for
most of those 10,000 years compared to
what began to happen as our
understanding of how the world worked
and our ability to modify it to our
convenience really gathered pace in the
aftermath of the scientific industrial
revolution in the 16 1700s and humanity
attained its first billion I'm sorry
aren't they more recently the explosive
growth just in the last 50 60 years is
due to the fact that it's only in the
last hundred years of God or so that
we've had a really effective medicine
based on real understanding and even
then it's only in the last 50 years or
so that that's been disseminated more
generally outside the more privileged
parts of the world it's interesting to
look at patterns of survival throughout
this time this is one that shows the
survivorship curve in the
sense of of all the people who were born
what is the chance of surviving to be 10
years old 20 years old 80 years old and
this is this figure is deduced
indirectly from remnants of skeletons
left of hunter-gatherers in caves and
the like it is hard to imagine a way it
basically says of all the kids that were
born half of them were dead before they
were five be even more surprising one
should survive that first bit the
survivorship curve is more like what an
ecologist would call type 2 it's more
like birds your chance of surviving year
to year is independent of how old you
are so the chance of as it were in your
teens surviving from 16 to 17 is not
very different from your chance of
surviving from 8281 50 years ago things
look rather different even in the
developing world but the contrast by
that time was remarkable and this shows
the survivorship curve from a typical
developing country on top I think it's
Sweden where most people who were born
lived out there biblically promised
though threescore years and ten the
lower curve is a typical developing
country specifically I think Uganda and
you see the kids that were born about a
third were dead by the age of five but
beyond that's better than the
hunter-gatherers and the curve while
it's still all through life things are
risky it's it's got more of a hump in it
it's not just flatlining downwards in
within that however there's a huge
amount of variation and it's hard for us
to remember or even recognize just what
things were like in the cities of the
Industrial Revolution in the middle
1800s the mortality rates the
were not very different from what we saw
for hunter-gatherers look at Liverpool
in the 1860s half the kids that were
born were dead by the age of five and
you've got a type to survivorship curve
quite extraordinary all in all however
this is the pattern that we have seen
since population growth really began to
gather pace and just to give you an idea
of what I mean when I say gather pace
the doubling time for human populations
to build from hunter-gatherer
populations when we were humans we were
probably in total somewhere around 20
million maybe a bit more maybe a bit
less and to get to the numbers that we
were round about 10,000 years ago the
population was doubling on overall
average something like once every two
thousand years it took as I said a
moment ago to 1850 to get 1832 the early
1800s to get to the first billion the
population then doubled in the next
century and it doubled again in 40 years
and since then to bring us to now it's
doubling rate is more like as slowed
down it's more like 52 years and what
you see in this 1750 through to the
early 1900's there's slow growth in the
pot the solid bars I the number of
people being born that year and the
black line is the total number of people
you see the survivorship is not all that
it could be and it's climbing slowly big
change past nineteen fifty this is the
combination of Medicine really being
helpful more or less for the first time
to a rough approximation and becoming
more widely disseminated and as you go
forward from 1950 the developing world
is getting more of the benefits and the
net result as childhood survival gets
better in the devel
up in world is that the birth rates
begin to come down but of course there
are so many people now that it's still
climbing that's another way of driving
this point home the average life
expectancy at birth 60 years ago was 46
years and it's changed by 18 years to
the turn of the century and that's hard
to relate to until you recognize that
the gap the average life expectancy gap
between the developing and the developed
world 50 years ago was 26 years and it's
shrunk or it's shrunk by ten years ago
to a still disgraceful 12 but
remembering Liverpool as well to keep in
mind that the developing world today is
better off than the West was in the peak
of the industrial revolution in the
1800s and that's the figures I just send
it took us to 1830 to get the first
billion doubled in a century doubled in
40 years and we're looking at nine
billion maybe more or less that's a soft
dish number it depends how things go if
current fertility trends and I be
curious how many people in the room are
aware that the current fertility average
round the world is that the average
woman is having one child one female
child how many people are aware of that
and that I'm not surprised that's an
astonishing statistic and it's happened
really quite quickly but even so we're
building on that much bigger base you
saw it's the momentum of population
growth of the great surge of the last 50
years so if those fertility rates which
are at replacement level persist will be
9.1 billion by 2050 if people have half
a child fewer we may get in under eight
billion they've have a child more it'll
be that 10.6 and
if the current simple replacement so
it's not a it's not a growth fertility
rate at just simple replacement along
with the momentum of population growth
11.7 so but the 9 billion is assuming
that the downward trend is going to
continue what's caused this downward
trend the most important single thing is
educating women and giving them
non-coercive access to fertility control
here is statistic from six developing
countries and you can read from that the
average girl that completes primary
school is going to have one-and-a-half
fewer kids on average and the average
girl that completes primary school is
going to have three and a half fewer
kids and there aren't enough girls
completing the secondary school to get
any really meaningful students are e
going on to tertiary to get any
meaningful statistics but education is a
big thing but it also has to have access
to fertility control and it is my
understanding I don't know whether the
the legislation has been repealed but I
don't think it has and depending on how
things go it's very unlikely to be you
are probably aware that overseas aid
from the United States may not be spent
on dissemination of condoms or indeed
any advice on fertility control I think
that's one of the most shocking
statements you can make about any
country in the developing world and this
is finally wrapping that all up this is
starting at the top with the position in
1970 and it's
females on the you're right and males on
the left and the red core is but Andy
this Axis's numbers of people and going
upwards is age so if you looked at the
age profile in relation to education in
1970 the red bit is people who never
finished primary school the yellow
bitters people who never finished
secondary school so that the red biddest
people who never went to primary school
the yellow bitters people primary school
a blue Britt it blue bitters secondary
school and the tiny little dark blue
bits are the negligible number of people
who had tertiary education that had
changed many more people of course but
you can see the red is narrowing and the
yellow is expanding and the blue is
expanding and you're even getting a bit
of dark blue and that's too that's now
2010 and the final one is an optimistic
projection into the future very well the
number of people who have only secondary
much less none has been shrinking and
the rest is expanding and that will if
these educated women have control over
their life and access non-coercive
leader fertility control that is the
basis for projecting 9 million by 2050
ok so I turn what are the things we
should be worrying about apart from the
fact that there are more people in terms
of more impact well one of the problems
is that ninety-five percent of the
build-out increase in numbers in
particular in areas in developing
countries is going to occur in more
people in cities nothing wrong with
cities as such but it's an interesting
pattern and that would be an unfamiliar
one to a time traveler from the 1700s
who
popped down here the fraction of the
human population that we're in big
cities in the 1700s was about ten
percent it was about a quarter a hundred
years ago today it's just maybe last
year maybe next year it's gone past
fifty percent and the projection for
2050 is to be two-thirds and the reason
why that's a bit of a problem is when we
were many of the diseases that afflict
us today were not present in
hunter-gatherers things like measles
need dense population that I population
of people who one way or another in
contact that's in excess of at least
half a million and hunter-gatherers
never had the population to sustain that
once it is also interesting the estimate
for that first ten thousand years post
agricultural revolution has one moved up
to the 1700s and science really began to
have an effect the first half of those
five thousand years the human population
grew faster than in the second half and
the reason was the number of new
infections that need large populations
to persist were now able to establish
themselves and they came mainly from
contacts where they mainly derived from
domestic animals in much the way of some
of the influenza things are today a lot
of people worry that this is one of the
big problems of the future and I thought
just so that I wouldn't seem to be
hopelessly pessimistic this is not as it
turns out one of the things that worries
me even though there are contemporary
examples of really nasty things that
have hopped into the human population
from non-human animals and and largely
as a result of more people and more
contact between other creatures and
ourselves and in particular the SARS
epidemic is a really interesting one the
SARS epidemic was that never happened
by sheer good luck of one of the
peculiarities of the infection that the
time between becoming symptomatic and
becoming infectious is very short
otherwise we probably would have had
much more problem with it but you were
able to catch it quick enough but it is
that was a phenomenon of what might be
called the industrialization of the
bushmeat trade with the growth of
prosperous restaurants in southern China
prompting a trade of harvesting animals
so that people could eat exotic things
and that is one area of conservation
concern concern that's not really well
studied but is indeed interesting well I
reason I don't worry so much about that
is I think most people think our current
medicine is really group the ants pants
and and it is it does wonderful things
for us but it still got quite a way to
go in particular to met me air one of
the bees in my bonnet most people don't
realize that most of the vaccines we
actually have and use we hit upon
largely accidentally and when it comes
to something novel and tricky like HIV
or something that's fair where the agent
itself counter adapts to the the attack
you make on it we're not so good at
producing a vaccine and one of my
beliefs is that we may not get an HIV
vaccine until we have really understood
the nonlinear dynamics of the process
whereby although when you're initially
infected the body mounts an effective
response to the first strain but then
there's an escape mutant and the body
deals with that and so there's this
quite long period from infection as
things go on and then eventually it gets
to the point not so much that the immune
systems overwhelmed but
curious dynamics of that system just
means things break down we've attacked
that problem with great success simply
by developing measures whereby you
suppressed viral replication and we're
now trying to think of ways where you
could do that so effectively that you
could maybe stop coming as you could
stop the thing spreading but the idea
that ever more intricate molecular
description of the events that go on
between the virus and the cell brilliant
there they are will somehow lead you to
an understanding of the very complicated
nonlinear dynamics of the process is one
that most people who work in that area
actually resent the suggestion that
mathematics might play a part and most
people who work in that area are not
actually aware that we still don't
understand the pathogenesis of HIV well
that was a brief indulgence on my part
of setting that aside I think we're
going to get beyond that and I think
just as the ecology books up to the 50s
just had no mathematics in them and
today they'll have a reasonable amount
of theory underpinning stuff so to you
pick up an M not an immunology text of
today and it's all descriptive
brilliantly descriptive but I'm you pick
it I make a prediction 20 years from now
the immunology textbooks will be
unrecognizable compared to today's
that's why I'm not so worried about
infectious diseases second thing I is
that we should be worrying about his
supplies of food and water it was in the
1980s that a group of people at Stanford
made a necessarily in precise estimate
of just how much of the green stuff that
grew on the planet each year was taken
directly or indirectly to our purposes
and they suggested a number with a
rather
furious degree of precision of forty
percent I always thought of it as
somewhere between a quarter and a half
or so but interestingly more recently
there's been a very elaborate study
simply of land way from using satellite
imagery of land which has been disturbed
and this disturbed you assume that's us
who did it and it turns out to be around
forty percent that's quite a thing that
but even more dramatic I think of all
the green stuff that grew last year from
the poles to the equator and green
living things all of you and all the
grass are all basically the same
composition all living things are made
up to first approximation of hydrogen
carbon and oxygen in the ratio to two
one two one big complicated molecules
then at the level of about one percent
is nitrogen and down another factor of
the general order of five to ten
phosphorus that's the top five rel the
world last year of all the atoms of
nitrogen that were incorporated into
green plant material more than half came
from artificial fertilizers that's an
extraordinary statement and they
underpinned its production and they have
I mean that good that we can do things
so efficiently and we've done some
things very well indeed with the Green
Revolution that where the our ability to
feed people has increased at a faster
rate than people have increased although
it's coming up against limits now so
there are some good things we've done
but again the question arises as to the
sustainability one of the questions for
sustainability of agriculture
sustainability again
instant increasing population and is
water supplies roughly round the planet
seventy percent of water use is in
agriculture and this is a thing from the
hydrological institute in in Oxford in
near Oxford download the river from
Oxford near wallingford and it's an
estimate of what's the rising demand for
water since 1900 projected forward to
2060 what's the ultimate available water
resource in principle the blue line and
how is that decline what that's how it
was pristine how has it been declining
as a loss from various things from
destruction of watersheds pollution and
other things and it does seem to me
again one shouldn't be too pessimistic
about that because if we were clear if
we were cleverer we could get a rid of
that but the demand thing is going to
keep rising this isn't this estimate
suggests we're going to run into the
point where demand exceeds supply
somewhere around 20 40 and yet again
it's an estimate that could be wrong
easily wrong twenty years one way or the
other but it again puts us within the
limits that we ought to be worrying
about in some ways I the slide should
have been before the one I just showed
that doesn't matter and again from the
millennium ecosystem assessment they
turn to the impact of this on natural
ecosystems and the plants and animals
that inhabit them this is an attempt to
assess how much habitat for plants and
animals has been lost under various
suppositions and the color coding on
this is the overall length of each of
those things whether they're
mediterranean forest or tropical
grasslands is just a measure of the
original volume normalized to one of
those things on the planet when we were
at low density and the
green bits are the bits that were still
there after and 1990 if my memory is
correct I've been going faster than I've
been turning the pages yes to 1990 so
the white stuff is what was lost
sometimes sometimes quite a while ago
sometimes more recently up to nineteen
ninety there are some places where we've
actually regained some of the stuff
that's lost since 1990 in temperate
grasslands and woodlands but more
commonly we've lost more of it
particularly in those four lower boxes
so the creatures and plants in those
habitats are facing threats thus from
habitat loss many of them are facing
threats from over-exploitation over
harvesting and yet a third category of
threat is alien invasions movement of
things round the world that come in and
make for all sorts of a mess so there
are a variety of threats to the
biological heritage we have this one way
of illustrating them in a rather
emotional way is this corner of the
Bronx Zoo in fact one of my ex graduate
students who was the deputy director at
the time put in this cemetery of
tombstones for species that are
certifiably extinct the interesting
thing about them they are without
exception all birds or mammals these are
the these are the upper class of animals
and they get their proper recognition
and attention we don't know nearly as
much as we should about the creatures
and the plants that are there much less
the rate at which they're going extinct
to begin with and this is not this slide
we don't even know how many species
there are we don't even know how many
distinct species we've named and
recorded in our museums the reason we
don't know that you may say that's
impossible if we named and record and we
know yes yes but because so many of
there's no I can tell you exactly how
many books there are in the library of
congress to a given date but for these
individual collections are going to tell
you how many things in the star
catalogue they've been computerized but
the catalogs of individual museums are
in the process it's getting better but
they've not been harmonized in such a
way that there are many things that have
been independently discovered and given
different names by different people and
it's not surprising quite a not trivial
number of beetle species in the British
Museum unknown from one specimen and
quite a few unknown from only one side
and it's quite a lot of work to key
those things out so even for the things
that are knowing where uncertainty
within ten percent or so and even as
we're uncovering past synonyms we're
creating new ones but when it comes to
how many there actually are Esther
plausible estimates range I think
defensible estimates from something like
two million to something like 10 million
and I would put it narrower in the range
three to four some people can argue
about it when you talk about extinction
you will get people who use rather
simplistic mathematical estimates of how
much area species need and stuff and say
really deeply foolish and potentially
embarrassing things like this year we
have lost 27 thousand species and I and
I one of my colleagues who was in the
habit of saying that and to one day
somebody stood up and said could you
name one
yeah now this is an attempt from the
read data books on categories of
endangerment to ask what fraction of and
we do know some things really well we
resonate particularly with birds and
mammals but they sort of look like us a
bit they have a disproportionate number
of taxonomist and system is engaged with
them and that's a I could go off in
another ramble for quarter of an hour on
that but this is an estimate of the
number of known species in the taxon of
mammal vertebrates what percentage are
threatened as distinct from the ones
that you have really systematically
evaluated and you think are threatened
and of course there's a tricky statistic
because you're going to tend to
systematically evaluate the ones that
you think might be threatened it also
tells you a lot about in taksim just
very quickly taxon amidst as best we can
determine i roughly divided one-third on
on vertebrates one-third on plants and
one-third on everything else which does
not map into the number in each of those
things and particularly interesting is
the fraction of all known species of
insects of which there something
variously estimated that around a
million are threatened with extinction
and the suggestion was that its point
zero six percent although its most of
three quarters of the ones have been
evaluated but they are a non-random pic
and of the ones that are certified as in
danger that that's 73 knowin insects if
my memory is right 42 our Hawaiian dove
sofala so that tells you a lot about the
genetics industry but it also tells you
that we know absolutely damn all about
the endangered species of lots of things
even so in that fall
go there is one way you can do something
that I don't think is altogether silly
although it's a bit controversial you
can say we really do know fairly well
mammals and birds there are about 10,000
species of birds and four or five
thousand species of mammals and those
are things where the extinctions by and
large are picked up and it's run in the
last century at about one a year from
that total group so it doesn't sound
like many one a year if you're one of
those species you're playing a game of
Russian roulette each year with a
revolver that has roughly 14,000
chambers so on average if you play that
game each year your life expectancy is
about 10,000 years well I'd settle for
that but I mean in terms of if Europe's
mammal or a bird species the question is
how long are the characteristic time of
species in the fossil record from
origination to extinction and that's a
very difficult question to answer
because first of all sometimes it is
they originate it and then there was a
vent like Permian jurassic boundary and
the lineage just ended sometimes there's
something like the evolution of the
horse as they were sort of relay and
replacement and the things weren't
really going extinct they're just
changing form nonetheless I don't think
it's all together silly to try and get a
handle on that by asking what's the
average lifetime from origination to
extinction in the fossil record of the
average sort of species and variously
you can estimate that as somewhere in
the neighborhood from hundred thousand
years to 10 million years maybe more
maybe less for son but whatever it is
it's certainly a hell of a lot longer
than the average life expectancy at the
moment of bird or mammal species and
that's why that is led to this not
approved by all the people who are
who's profession who are who i would say
have hidden embarrassments about their
professions lack of getting to grips
with the issues but I didn't say that
it's an attempt to suggest just
independent of which species are talking
about what's the extinction rate overall
and if birds and mammals are typical and
maybe they're not there's no reason to
exciting there's a reason to assume
there they are grossly different but
maybe they are but if their
representative then things are set to
speed up in such a way that it's not
unreasonable to say we're on the
breaking tip of a sixth grade wave of
extinction in the history of life on
Earth all of this has implications for a
whole set of things that natural systems
do for us that we don't count in
conventional GDP and another thing that
the millennium ecosystem assessment in
all its imperfection it's still better
than nothing it has tried to classify
these services and it classifies them
under 25 headings and some of them are
forest system some of them a dry land
some of them it's it's like that
classification is by place you could
also classify them by the sorts of
things they're doing pollinating
providing breeding grounds for fish and
so like mangroves and so on and there's
an attempt in each case to ask are these
on average this particular system
declining under the stresses of habitat
change as we saw deforestation climate
change invasive species over
exploitation or just pollution is it
remaining left roughly the same as of
getting better as it getting worse and
the overall answer is that of those
twenty four categories 15 are getting
worse for made lius mainly assumed with
agriculture
to be getting better and five you just
don't know enough to say anything and
the one problem that is for sure that
was foreshadowed a hundred years ago and
is looming larger today is that all
these problems of habitat destruction
and the like are being further made
difficult by changes in the weather that
is an ill and the climate rather that is
being initiated began sometime in the
1780s characteristic time and in fact
I'm not sure whether they actually
passed the resolution or whether it's
still informal of the Geological Society
deciding that we've entered a new era
anthro Anthropocene that were donned in
1780 but we have been putting large
quantum creasing Lee large quantities of
fossil carbon into the atmosphere and it
was predicted well over a century ago
that that would have effects on the
other hand the atmosphere is a hugely
complicated dynamical system and many of
the things that we would like to say
about it with precision we can only put
within very broad error bars if you want
to dramatize it but I think it's a bit
unfair to dramatize it we're currently
putting back into the atmosphere each
year roughly 1 million years worth of
fossil fuel carbon sequestered eighty
percent of it from fossil fuels twenty
percent of it and that's not biomass for
energy trees most of it and taking and
burning them the seven percent nucleo
this is two years old is probably
getting going down maybe down towards
six percent and all the renewables hydro
wind geothermal are probably getting up
around four percent and that is having
consequences
the fair why did agriculture begin about
10,000 years ago if you look at the past
climate on a long time scale in ways
which are fairly well understood and
have to do with perturbations in the
orbits of the earth in respect to the
Sun largely and other events if you go
back beyond 10,000 years we were in a
period of glacial cycles but that having
earlier times been periods of steadiness
for most of the last for most of the
tendency of post agricultural humanity
for most of the past 10,000 years the
climate has been oddly steady certainly
for the last thousand years where we
have good data there are those who would
argue that it that's an interaction that
the beginnings of Agriculture helped
great really stabilize the climate I
don't find that very persuasive but it's
certain that we have it won't even if we
continued if we stop putting fossil fuel
into the atmosphere on the time scale of
thousands of years people are going to
have a problem with the climate
naturally but the problem we're having
now is not something that's natural it
is unambiguously associated with what
we've done it's hard to make definitive
statements of the rates at which things
will happen in particular places and
it's tempting to generalize from
concatenations of extreme events which
have accelerated that that's necessarily
all due to climate change and art my own
view would be a lot of it is due to the
fact that the climate is changing but
there are lots of areas of uncertainty
in this but it's equally my view that
we'd be really bloody stupid to just
assume we can go on doing what we're
doing and hope that it's all a
coincidence that what my see the this i
phi many
people maybe some of you won't many
people find this persuasive what this is
is major area by major area of the late
land surface it shows what the client
what the climate the temperature has
actually done over the last century 1902
2000 and what is the ensemble prediction
of the leading climate models which have
subtly different assumptions and that's
the pinkish areas and then with the same
models but leaving out the additional
carbon web carbon dioxide we're putting
into the atmosphere what should predict
which are the bluish things and whereas
the models agree with what's happened
broadly if you put in climate change is
if you put the burning fossil fuel into
the models and they don't if you don't
economic analysis of this interestingly
done by Nicholas stern and tweaked a bit
more recently by person whose name I'm
having a centaur moment about who was
the Provost at Yale and somebody will
shout out his name no well if you read
the New York Review of Books there's a
very good article by this person and
it's the suggestion is yes it's going to
cost to do things about it but it's
going to cost a hell of a lot more not
to do things about it the estimated cost
for example of doing something about it
is perhaps a percent or two of gdp by
2050 the estimated cost of not doing
something about it is more like fifteen
percent of GDP by 2050 that's why in
Britain we have legislation now that
commits the government to a set of
targets to bring our output of carbon
dioxide
down by a factor of about five and this
is it is feasible if one really works on
it the key thing as one has to
decarbonize electricity all of these
things work come together more people
more impact per person impacts of
different kinds climate change one of
them but only one of them this is not
some touchy feely greeny slide this is a
slide produced by the UK Ministry of
Defense and what it shows in color coded
ways are areas of the globe which are
under stress from water shortages from
too many people for the habitat to
support from declining crops for various
reasons or simply from not enough food
being available or most difficult to get
a really accurate reliable impression of
what's going to happen coastal flooding
and you can see it the coastal flooding
doesn't tend to correlate with 0 and
then recent major conflicts which are
lovely big Asterix Karan what m.o.d was
interested in the coastal flooding
doesn't correlate well with conflict but
the other things do correlate
exceedingly well so it brings me to the
final part of this discussion should
have got here five minutes earlier what
are we going to do about it the problem
here is that and this is where and I am
in the habit I've made myself quite
unpopular on the climate change
committee by keeping saying the really
important science here is the behavioral
science and there's no question in my
mind but that for many many different
reasons is the most important science I
sometimes just as the social scientists
are all getting terribly happy can't
help saying it's
pity there aren't better people in the
subject but rather unkind and gratuitous
the problem itself of getting people to
act particularly to act on behalf of
what still seems a distant future to go
along with I will to try and stop I will
if you will shading into I won't because
you won't is not an easy problem to
solve it it has its origins actually and
goes went right back to darwin in his
own time Darwin had three really big
problems in that classic Wilberforce
Huxley debate if soapy Sam Wilberforce
had actually done his homework he could
have wiped the floor with Huxley three
problems people didn't know anything
about nuclear forces and with
electromagnetic forces and gravity the
Sun couldn't burn you couldn't explain
the Sun being having been around for
more than a few million years so you
didn't have the age that you needed
Darwin answered that by simply taking
all references to actual spans of time
in terms of numbers out of the
subsequent editions of the Origin of
Species second problem was the belief at
that time was that inheritance was by
blending the characteristics of mother
and father and under that kind of
blending inheritance as was pointed out
to Darwin you couldn't preserve the
variability which is the essential
ingredient upon which natural selection
works to produce evolution and despite
the fact that Mendel had done at the
same time the experiments that showed
inheritance is particulate I mean that's
a very elegant example of the need for
mathematics in biology none of the
people in either Darwin's or Agassi's or
anybody else's circle
had the mathematics to recognize that
what Mendel had done is show that
inheritance was particulate and it
wasn't for 50 years later that Hardy and
Weinberg proved the highly
hardy-weinberg theorem that says in the
absence of selective fourth of all
forces mutation selection statistical
drift gene frequencies will remain
unaltered which is sort of the like
Newton's first law of mechanics again
counterintuitive that bodies remain
stationary or in straight line unless
there are forces there always are forces
but hardy-weinberg and I mention it for
the last thing I'm going to do I'm going
to come forward from that the third
problem for Darwin but that was cured
but the third problem is still with us
how why do a Grigori twat do they do
favors to other people that are costly
to themselves and one example prairie
dogs live in small colonies and the
male's take it in turn to give alarm
calls standing up on the mound and your
marmots do it too and you'll see them
sometimes when you're walking they're
putting themselves at risk but they take
it in turns and when they're not doing
it they have a benefit that is far
bigger than the risk so simplistically
you might say well there's no problem
it's obvious it's a sensible thing to do
however it is susceptible to the
cheating Marmot or the cheating prairie
dog that doesn't do it and gets the
benefit without the cost and they
literally have an evolutionary advantage
because insofar as there's any coral it
between behavior and jeans they're going
to have more of their genes in the next
population because they were less likely
they didn't run the risk that the
Sentinels run you can get round that if
you start asking that about us and this
is still an open question in my view and
we'd really satisfactory answer to that
problem we still don't have while we
were hunter-gatherers
we were small bands of closely related
people but once we started sampling in
cities then we have a bigger problem now
when I say it's still an unsolved
problem there is a huge growth industry
in academia most major universities
Oxford has one Harvard has one has a
resource you can go to where by
undergraduates will play games with
money with small sums of money and
public goods games they're called many
of you will be familiar with them
they're things like you're each given
twenty dollars and there are ten of you
and you know make it each given ten
dollars and there are going to be 10
rounds of the game if at the end of the
ten rounds there is a hundred dollars in
the kitty then everybody can keep their
remaining money they're given twenty
dollars I think I've got it right and
anyhow what it's meant to be is if
everybody every time played fair at the
end of the thing everybody would have
half what they started with but the
temptation is there to cheat and not do
it and hope other people will make up
for it so that the end of it you'll all
be successful and your walk work your
walk away with more than half I suspect
if it's played at places like Harvard or
Oxford people just want to win more than
the others because that's sort of people
they are I'm sure that's what I do
fascinating what comes out of these
things typically what happens is some
people cheat they fall behind then
toward the end they realize they've
gotta play catch-up but more than half
the time they don't get their their
various then refinements on these games
you name you let it be identified who
cheated and then other players can
punish you they can pay a small son to
take a what to punish you for having
cheated and
that's really amusing when that happens
first of all depending on the people
playing it they'll get locked into
cooperation or not and there's one
classic study which did it in different
cities and you'll be gratified to know
that the people in Boston Nottingham and
Melbourne US Australia Britain quickly
converged on cooperation others didn't
do it so quickly and in Athens and
muscat it was so extreme that people
went when people were punished you also
identified the Punisher and they just
just get pissed off at the Punisher and
they'd then punish them for punishing
them and the whole thing would dissolve
and everybody they were halfway through
the game that all thrown away all their
money they're punishing each other it's
really fascinating there are other there
are other amusing things you could do
one of my colleagues and I decided what
my daughter did none of these games
until recently had the initial people if
you really want to mimic climate change
where some of them had more money than
the others to start with and people
could only win if it ended up that
everybody had the same amount of money
so the people who started out with more
money had to put more money in and that
doesn't work out quite so well and
another kind of study that came
accidentally out of this thing that i
did with stu west and a student it turns
out that women are entrained in
cooperation much faster than men which
is something that I find not at all
surprising but it's I found it really
strange that people have only recently
started to look at that and incidentally
digressing shamelessly back to finance
there is a wonderful study of people who
invests the family money and it
considered four categories single women
single men married couples where the man
invests the money
married couples where the woman invests
the money and of course the reason I'm
saying this you can guess the answer the
best performers a single women followed
by couples where the woman invests
followed by couples with a man invests
with the worst of the lot being the kind
of people who are running the city
anyhow why am I saying all of this I'm
saying all of this because and I'm going
to read the last bit and I know I'm
running overtime but there we are my own
speculation about how cooperative human
societies evolved is both less academic
and analytic and more gloomy once we
move out of the mists of prehistory we
find stories of Dreamtime creation myths
ceremonies initiation rites spirits and
gods with a unifying theme that all
seeks simultaneously to help explain the
external world but also to provide a
stabilization matrix for a cohesive
society there are striking and
unexplained similarities in belief
systems and rituals from different times
in different places when the Catholic
friars first came across the sacrifice
of the Aztecs they saw it as an obscene
parody of their own taking the wine and
water conscience a simple word for a
complex concept which helps foster
behavior in accord with society's
professed norms has memorably been
defined by Mencken as the inner voice
which warns us that somebody might be
looking and how helpful it is if that
somebody is an all-seeing all-knowing
supernatural entity so the punisher in
the game is not someone you can round
back on but someone who is detached from
the game come common to all these
conjectured stabilizing forces in
essentially all earlier societies a
hierarchical structures serving and
interpreting the divine being or
pantheon along with unquestioning
respect for authority in such systems
faith trumps evidence that's the price
you pay for the glue that works and that
if there is any substance in that idea
about how we solve this problem our
cooperative behavior has evolved and
been maintained in human societies it
could be really bad news because
although such authoritarian systems can
be quite good at preserving social
coherence and an orderly society they
are by the same token not good at
adapting to change I mean I read I'm
Jared Diamond's book is a nice series of
case studies but the reason I mentioned
a moment ago that that the
hardy-weinberg theorem is sort of like
Newton's first law there's another
theorem in biology that's not thought of
that way that it's really like Newton's
second law Newton's second law having
told you with there are no forces
nothing happens he then went on to tell
you f equals ma and and how forces do
produce change in dynamics there's what
there is also in biology just as I think
the hardy-weinberg laura's will sort of
biology's first law there's a thing
called fish's fundamental theorem which
is a fascinating thing that is sort of
an really quite analogous for Newton's
second law and it says that a
populations potential rate of change of
gene frequency which measured measured
stability to adapt to changing
circumstances is proportional to the
variance in gene frequency which will on
the other hand the variability in gene
frequencies within the population is
going to be small if essentially all the
individuals are optimally adapted to
their present circumstance so there is
actually an inherent tension an inherent
tension between on the one hand having
variability so you can adapt and on the
other hand not having it so that you can
all be the best finit
so if there's any substance in those
speculations that are just aired to you
about the answer to Darwin's problem
explaining cooperation in human
societies I think it rests on that sort
of tension and it could be that those
same forces that enabled advanced
societies that promoted cohesion and
everybody agreeing on everything are not
at all good for responding to a changing
world and it could even be argued that
the recent rise of fundamentalism in
both east and west there's an
illustration of this meta level version
of fishes fundamental theorem as complex
faiths complex increasingly through the
years compassionate faiths are reduced
to intolerant ideologies to risk the
chat to resist the challenge of societal
change and if that is true it is an
unfortunate conclusion and I said right
at the beginning I was going to end by
coming back to Tamara's idea of thinking
of other worlds celebrating Darwin's
centenary and sent in Cambridge they had
a big thing for one hundred and fiftieth
a couple of years ago and two speeches
at after dinner Martin Rees gave a very
nice speech about what we were learning
about the world's the stars out there
with particular emphasis on the fact
that we were seeing we have the capacity
to see planets and increasingly we may
get the capacity to see other planets
that are like ours and I abandon the
speech I was going to give and and said
I I thought that was absolutely
fascinating question because really the
question of our time as we confront
really serious problems of too many
people and yet the things we ought to be
doing to help educate them and make
available fertility control are being
resisted by fundamentalist religion on
the right in this country as much
in the Middle East let me just say by
way of conclusion it would be nice if
done oh I know I was the speech of the
thing I i said it's very interesting to
contemplate if these some of these
planets will be kind of habitable and
the really interesting question we're
going to have to ask of them against our
background of the challenges we face are
and which we don't look like doing a
good job with is are we on a trajectory
that is common to most inhabited planets
just as our mathematics and our than
same sorts of laws ah there are others
out there that are started ahead of us
that have gone down this road and not
solved the problem or are some of them
got dr. Spock on board as it were and
we're able to transcend the
rationalities that are part of everyday
life and see their problem and get
together to solve it that's a really
interesting question are the problems
soluble and if we knew more about all
those planets and it's a it's a
different problem from the one about
mathematics and science they're
ultimately related and it's an even more
important problem and it sad indeed in
its essence the problem that lies at the
heart of why it is that the behavioral
sciences are the sciences that we are
going to have to depend on and to save
us
yeah i should say I'm happy to our
answer questions I'm sorry I ran over
time and anybody who feels they should
want to go certainly should feel free to
walk out yeah well some of the things
that I thought you're saying summit for
example the cars that are more
fuel-efficient also may be more
expensive one way you can get around
that and you all of this is amit hard i
think has to be sticks and carrots you
have to some say again we've has happen
in britain the government car fleet is
largely prius now they can do things
like that some of the things that you
can prompt people to do are actually
going to save the money as well as been
simply being more careful of turning
lights out all the time simply asking
yourself whether you need to do this
particular thing or that particular
thing they're one of the way this was an
invitation to get into all the sorts of
things that worth thinking about trying
to simply getting into kids in primary
school and and having this part of what
they're learning about in the hope that
that will then in from there are lots of
things you can do and they don't all
costs some of them are more costly i'm
surprised
one of the things that I've quite
surprised about you're seeing a
mushrooming of us solar panels in Oxford
and that's partly there is a tariff
scheme to encourage people to do it but
at the same time it's it's not something
that's actually going to save your money
and I find it rather astonishing that in
santa fe we're a much more suitable
place to be having solar panels they
haven't caught on and i'm curious as to
whether this is aesthetic or what
but was
I am simply going to duck the question
and say it's an interesting idea sorry I
don't mean to be rude yeah
well I don't I am very reluctant to
believe there isn't a solution and I do
think that to get people to come
together to act on behalf of a seemingly
distant future in a collective way where
people who all take their fair share is
quite a problem and I do see in many
ways working I was I was I'm not a
religious person myself but I grew up in
the Presbyterian Church and I live my
social life through it and so on and it
basically did a lot of good things and
it had a collective cohesive sort of
subscription to a set of values that you
didn't have to accept the entire
infrastructure to see so i am basically
of the view that religion is a very
large part of a potential answer but
equally what I was trying being so
self-indulgent as to air is this worry I
have that I've not seen expressed in
that way that there's just an inherent
contradiction in it because the way that
the thing works is such that when you
put it under stress it wants to respond
by sort of going back to core values and
there is less an inherent tension just
as there is in other circumstances
between the in the bed I've said it once
already and I won't go through it again
you
