[Applause]
hello and welcome to just have a think
so we're spending the first few weeks of
this year having a look at the massive
global scale technologies that might
actually contribute towards the almost
unimaginably Herculean task of reversing
the freight train of global human CO2
emissions increases and replacing fossil
fuels for good there really are loads of
Technologies to look at with more and
more coming online every week but
alongside these amazing initiatives and
inventions there remains a second
possibly even more important challenge
one that needs to be addressed just as
urgently and just as comprehensively and
that challenge is population growth and
resources management we've touched on
this before of course when we looked at
the UN and ipcc reports that came out in
2018 but I thought it was just worth
taking stock of where we're at right now
and have a think about all the changes
our societies need to make to make sure
that we don't undermine the
technological changes that are coming
online now you regular viewers out there
have demonstrated yourself to be a very
well-informed group of people so no
doubt you're already very well aware of
all this stuff already but it never
hurts to remind ourselves of some of the
facts and figures and a lot of you also
know that I do love a good graph so
here's one from the United Nations
showing population growth since 1 a
agriculture got going about 8,000 years
ago and at that point it's reckoned
there were about 5 million human beings
by the year 1 AD we'd reach something
like 200 million global population Rose
constantly from then on with the notable
exception of this dip when Europe got a
bit of a kick in from Bubonic plague and
lost about 60% of its population by 1800
though there were a billion people on
the planet by which time some bright
spark had invented Coal Fired steam
engines and in industrial Revolution
erupted out the United Kingdom spreading
all over Europe to North America and
eventually across the world by the early
20th century the graph had gone
exponential when my dad was born in 1943
the population number was 2.36 billion
and experts said that the planet
wouldn't be able to sustain more than 3
billion people but by the time I came
along in 1969 we'd already grown to 3.6
billion today that number stands at 7 .6
billion and you'd be forgiven for
thinking that we had ourselves a full
scale completely out of control
population explosion going on but here's
the remarkable thing there's been a
massive drop in fertility rate since the
second half of the 20th century as
living standards gender equality and
women's education have all taken a
positive tilt upwards here's another un
chart showing fertility rates around the
globe back in 1950 dark blue represents
fewer than 1.5 kids on average and as
you go through the Light blues and
indigos and into the greens and yellows
and oranges the number of kids per
family increases until you reach dark
red which represents seven or eight kids
per family so what happens to that map
as we travel through time to the present
day well this
happens clearly there's still work to be
done in subsaharan Africa but even with
that facted in the global average
fertility rate today is just below 2.5
children less than half what it was only
50 years ago nowadays you're more likely
to read reports like this one talking
about fertility slowdowns and problems
with population replacement than reports
of population booms despite that though
we're still on track to hit 11 billion
people by the year 201100 so how come
well to demonstrate that I borrowed a
visual aid from a brilliant statistician
called Hans rosling sadly Hans is no
longer with us but his shows were
brilliant and you can watch one of his
best by clicking the link at the top of
the screen so anyway I've got some cubes
here made out of uh fairly badly wrapped
old boxes of tea I am English after all
and each one of these represents a
billion people and to keep things simple
we'll use the same 7 billion population
that Hans rosling used four years ago so
how do the age groups stack up well
you've got 2 billion kids here under the
age of 15 then you've got 2 billion
people between the age of 15 and and 30
then you've got another billion people
between the age of 30 and 45 and another
billion between the age of 45 and 60 and
then a final billion uh over 60s so
straight away you can see you've got 3
billion people missing from these age
groups so where are those people well
some of them aren't there because they
died early but most of them aren't there
because they were never born in the
first place because of course back
before 1980 there were fewer people and
so fewer people having B babies so what
happens to this construction as time
goes by from now well this group of over
60s unfortunately in 15 years time time
to die for them so they go everyone gets
15 years older the young people have two
billion
children and then another 15 years goes
by unfortunately for this group of over
60s which I think is my group now time
for them to die as well so they go
everyone gets another 15 years older
these young people have two billion
children we go another 15 years this
group of over 60 is time for them to go
these young people have 2 billion
children and there you have it before
long within three generations with no
increase in fertility rates and no
increase in life expectancy just by the
inevitable fill up of human beings based
on how many people are on the planet
today you get to 10 10 billion people
and actually statisticians do say that
old people will live a little bit longer
and they have to add another billion
people on for that so there is your 11
billion people by
201100 so the big question is can our
planet sustain 11 billion people well
the answer to that crucial question of
course is that it depends on how we live
and use the resources that are available
to us now I'm just getting warmed up
here so brace yourselves let's look at
population density first of all back on
our un map we've changed our color code
to show how density is distributed
globally very dark brown represents over
a thousand people for every square kilm
of land the very light beige color
represents between 0 and 10 people per
square kilm it's pretty easy to see the
impact that India and China have with
1.35 and 1.4 billion inhabitants
shoehorned into those two countries but
northern Europe and Eastern United
States actually have very similar
population densities as well in fact if
everyone in the world today lived in the
same way as the residents of Manhattan
then the entire 7.6 billion other us
would fit onto New Zealand well
according to that Map There's masses of
space all over the place for a
population expansion and our planet will
barely even notice 11 billion people
right well of course it's not just space
that we need but food and water water
and shelter as well as you know leaving
a little bit of space for all the other
species of Flora and FAA to coexist so
that our Global ecosystems have some
chance of staying in balance and that
means we get to look at some more
graphs some of you may have seen program
four of just have a think way back in
April of last year back then we
established that 50% of all habitable
land on our planet is used for
agriculture we also found out that of
that 50% of land 77% is used for
livestock and only 23% for human
consumption crops it also turned out
that the livestock land yielded only
177% of human consumed calories and only
33% of protein whereas the 23% of land
used for crops yields 83% of human
consumed calories and 67% of protein so
straight off the bat if anybody tells
you you won't get all your protein if
you don't eat meat they're just plain
wrong now obviously those statistics are
not evenly distributed around the globe
so here's your next chart this one comes
courtesy of the website ourworldindata
toorgle websites in the comments section
below you can navigate this one for
yourself because it's interactive so
let's start over here in the East if
everyone adopted the diet of the people
of Bangladesh and there's 160 odd
million of them now then we'd need less
than 15% of our habitable land for
agriculture
Indonesia is pretty close at just over
18% and there's about 270 million of
them then you've got the 1.35 billion
people of India if we all adopted their
diet then we'd use up 22% of our
available land or if you're not a big
fan of Curry and you prefer a Chinese
then we could all adopt their diet and
still only use about 40% of our land and
you can see that Africa is similar
statistics and the reason for this
frugality of land use of course is that
the diets of all these count trees at
least currently are predominantly
plant-based so they don't have to set
aside vast tracks of land to grow cereal
crops to feed the animals in order to
fatten them up so that they can kill
them and eat them no they just eat the
crops contrast that to our
mind-bogglingly overindulgent lifestyles
in the so-called Advanced Western
civilizations and you start to get an
idea of where the real issues lie our
famously food passionate European
Neighbors in France and Italy as well as
in the Alpine regions have a very meat
dominated diet as a result if we all
live the same way as them we'd need 122%
of our total habitable land to
sustainers which I think you'll agree is
arithmetically impossible Scandinavia is
very similar with Sweden coming in at
126% then we swing over to you guys in
Canada if we all adopted your average
diet then we need about 130% of all
habitable land to keep going and down in
the states that number number increases
still further to almost 140% and don't
think you get away scot-free down there
in Oz just because you're parked out of
the way no no we can see you and we can
see that you're the second worst
offender on the planet at are whopping
158% of habitable land required based on
your average
diet but the prize for the most
ridiculous and propagate dietary habits
goes to
Argentina if we all ain't like those
folks then we'd need to set aside
agricultural land equivalent to almost
162% of all habitable space on Earth so
let's be clear those global disparities
are a insane B unnecessary and C
unsustainable the World Resources
Institute produces some really great
information about how we in the West can
tweak our diets to reduce our impact all
the links will be in the comment section
below but here's some highlights number
one currently the world is actually
increasing the amount of meat it
consumes as developing nations grow more
wealthy number two Rich Western Nations
already consume far more calories and
protein than they need this chart shows
animal-based protein consumption in red
and plant-based protein consumption in
green the black horizontal line is set
up 50 gr of protein per person per day
which is the amount we actually need in
our diets so only India is anywhere near
the the mark and the rest of us are
massively overc consuming in fact if
you're an average American then in order
to supplement your plant-based protein
intake with meat to get you to your
total daily requirement of 50 g you
would actually only need to eat a single
4 oz chicken breast or you could of
course just eat more plant-based
protein number three this chart shows
the land and water resources required to
produce various animal and plant-based
food stuffs all the plant-based stuff on
the left is low in land use and
irrigation at the other end of the scale
beef production is such a
catastrophically profer overuse of
precious resources that if we just took
this one food stuff on its own out of
the equation then the resources problem
will be more or less resolved
immediately number four we'll need 70%
more calories to feed 9.7 billion people
by 2050 and even more than that for the
11 billion people that we expecting by
2100 but here's the good news if you're
a meat eater although you would be far
better off and healthier if you did move
to a fully plant-based diet you don't
have to go the full vegan in order to
make a massive positive difference this
chart shows that even if you keep eating
meat but reduce your overall intake by
half for example by only eating meat 3
days a week you'd get your land use and
greenhouse gas emissions down to levels
that are not much more than people on a
vegetarian diet so that's the message
sackcloth and Ashes and ritual weekly
self flatulation are not actually
required on this one we just need to
have a think about what we consume and
get ourselves out of our own healthy
Western mindset that a meal is not a
real meal unless some part of a dead
animal is on the plate it's not true it
never has been true and it will not be
sustainable into the
future that's it for this week we're
back on the technology track next week
with a look at direct air carbon capture
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have a great week and remember to just
have a think see you next week