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mathematics behind population modelling are they complicated? Not so much
populations grow at a global level anyway by a simple number of births
minus number of deaths and so it's simply a matter of that interaction
between mortality and fertility of course at a national level or at a regional
level migration is a very significant factor in many places like Australia as
well but it really is simply births minus deaths so anticipating future
fertility and mortality change is really crucial when anticipating what
future population growth would be. So Udoy birth rates that's one factor that
we have managed to manipulate what's been happening with birth rates and what
effect does it had? I would like to take a very optimistic view like what
Crames say it's not not that terrifying in numbers it looks very big but we
should remember that the world has done extremely well humanity has done
extremely well now we have world fertility rate around 2.6 at the
moment global fertility which has come down from around six and seven so the
success is there and birth rate of course played a vital role in pulling down the
population which as Crame mentioned probably will stabilize hopefully by
nine billion but I think the World Bank says it will be around 9.7 by 2075 and
they're also predicting that in fact but after 2075 world will see a shrinking
population if everything goes alright so it is quite optimistic that way. So what's
actually happened with birth rates specifically are they coming down
worldwide or are they coming down in pockets some countries have a higher
decrease in birth rates. No it has come down worldwide in fact in the
developing countries if you see in Asia the reduction in birth rate total
fertility in last 50 years the highest it came down by in last 50 years by 55
percent which is most of the developing countries are there. I think there's a
there is an issue it worries me that African fertility is still so high I
mean it has come down as I suggest. I think it's interesting that the United
Nations has actually changed its projections from thinking that the
world's population would stabilize at nine billion in the middle of the
century to about ten billion towards the end of the century and I think part of
that has been that the fertility isn't coming down as quickly as we thought it
would in Africa and in a few pockets around Asia and that to me is a bit of
a concern and I think part of the concern is that I think we've taken our
foot off the pedal with respect to programs which tackle the fertility
rate and the reality is that the things which bring down fertility are things
like improving women's education improving reproductive health services
family planning programs the whole range of things which tackle poverty and
which really attack the role and position of women in society and and I
suspect that to some extent as a global community we've thought okay the
fertility thing is one we've got there we've achieved all we need to achieve
we'll turn to look at other things and I think you know I worry that perhaps
there isn't the expenditure and effort and passion going into bringing down
fertility in Africa as there was in Asia say 20 or 30 years ago the death
rate which has also been coming well actually the death rates are always a
hundred percent everyone dies but people are living longer and that has had an
effect on population can you talk to me a bit about death rate I guess we're
wonderfully inventive aren't we that particularly well in both developed and
developing countries we're finding a way to get rid of a whole lot of the ills
that used to kill us earlier and of course particularly in developed
countries we're putting in a whole lot of ills that are making us sicker along
the way so there's it's this challenge between birthing and dying if you like
and we've extended it mainly through lifestyle changes and technological
changes and so that means in my demographic colleagues will say it a lot
better than me that we have the rump of us oldies you know who to some eyes in
the political space are saying that this is the thing that's going to undo us
the pure cost of looking after an aged semi-majority it's those baby boomers
again and yet as Graham and who do I point out you know this is this is part
of our supreme technological advantage that we're we're bringing one down but
we're the buggered if we're going to get out of the way you know that's the
thing so you know this is the the race between two ends if you like when you
actually look at the modeling you know it it took us by some estimates 250
thousand years to make the first billion people it took us 12 to make the last
billion that that that that I personally find that a little startling well the
20th century in my view was the demographic century because we added
five billion people to the to the planet in in that century thank goodness it's
not going to happen again we may add only a couple more billion before it
stabilizes but but that you know really is one of the defining features of the
20th century that that huge number of people you know before that we'd added
less than two billion in the whole of of our history up until the beginning of
that century and you know it really is a an enormous statistic in terms of in
terms of our history
