The best definition of intelligence is “constructive laziness”.  You can bang your head on a wall, use a hammer to make a hole in it, or pick up the phone and ask your neighbour  what is on his side. The least effort is clearly the most intelligent solution.  So let’s solve a really Big Problem by doing nothing!

To state the Big Problem simply: we would like to live at least as comfortably as we do now, and bequeath a sustainable version of the status quo to our successors.

Unfortunately our current modus vivendi depends on the consumption of fossil fuels which will be exhausted in the foreseeable future – say within 100 years plus or minus 50.

David MacKay’s excellent book “Without the Hot Air” www.withouthotair.com is freely available and gives useful authoritative data. In the UK we currently consume an average of about 6 kilowatts per capita from all sources of artificial power, of which more than 5 kW comes from fossil fuels. There being no economic means of storing energy from unreliable sources such as wind or solar photoelectric  panels, and no great enthusiasm or proven technology for tidal power or nuclear cars, the lazy way points to an alternative photochemical source: biomass.

But, as Mackay points out, we would need to cultivate an area three times the size of Britain to provide the chemical fuel we now consume. Quite a problem.

The answer lies in that neat phrase per capita.  If there were fewer people inhabiting the same land area, we could indeed live as we do now, for as long as the sun shines and the rain rains. So I want to look at the means and consequences of reducing the population in a controlled, ethical manner.

The first job is to model the present population on a spreadsheet. Suppose for simplicity that roughly equal numbers of babies have been born each year for some considerable time.  Suppose also that everyone lives to age 60, and we then die off at a linear rate so that nobody survives beyond 100.

The arithmetically astute will note that the population of this idealised country is 79.5 million, rather more than the present  population of the British Isles, but a convenient figure for a simple spreadsheet since most of the entries are “1”.

The orange rectangle  covers the “working “ population, i.e those who directly or indirectly (through taxes) support children, students and pensioners. The present  “working fraction” is very close to 50%. More of this later.

We can generate the population profile for next year by adding babies to the first cohort and promoting each group one place to the right, so 1 in 40 of the 60-year-olds, 1 in 39 of the 61-year-olds, and so forth, die each year. The population profile is sustained indefinitely by each woman producing two offspring.

Now suppose that each woman will have only one child, somewhere between her 16^th and 36^th year. Stepping along the spreadsheet we get the following profile after 25 years

Rather fewer in the working population, but the working fraction is now over 56%! The pensioner population is unchanged but there are fewer children and students to support, and the total population has fallen to 67 million.

Now suppose the present per capita availability of all natural resources is ”1”. After 25 years, thanks to the decline in population, it has risen nearly 20%. So we would have a larger working fraction, with more resources – surely a recipe for a better standard of living for all, and a small move towards sustainability?

Here are the 75 and 100 year population distributions:

And the derived functions for the next  110 years  look like this:

Conclusions

1. Apart from a brief blip, the working fraction will be at or above the present 50% for as long as we breed below replacement level. The mean value for the next  110 years is around 0.52 compared with the present value of 0.50. If we increase the retirement age to 65 we get a mean of 0.6 compared with the present 0.56  – an even bigger gain. Or we could systematically reduce the retirement age to keep the working fraction constant.

2. Per capita natural resources in 110 years’ time (i.e. when the oil runs out) will be 6 times their present level, so we can indefinitely sustain a 21^st century lifestyle on biofuels with some to spare.

3. Even in the “blip” period when the working  fraction falls below 0.5, per capita resources will have doubled from the present level, so the average standard of living need be no lower than at present.

4. Recent scare stories based on the suggestion that 1 in 6 of the UK population will live to be 100, “but we will live in poverty and squalor because there will be insufficient young people to look after us and pay our pensions”, have no mathematical foundation.  The young are as dependent on the working fraction as the old.

In short,  life will get better for everyone, for ever, if we breed below replacement level for a few generations.

And all we have to do isless than nothing. Making and raising babies is hard work. Half as many is a lot easier, especially if you have more resources to hand, and fewer worries about their future.

The idea is hardly original. The only flaw in its prehistoric  application was that the dinosaurs, in the irrational pursuit of ever greater material comfort, eventually forgot to breed at all. It is left as an exercise for the reader to construct the spreadsheet and determine, by recursive or analytic  means, how long it would take to reach a population of one.

Implementation

The “one child” policy of Maoist China could not be described as a moral success. However despite published fears of the “1:2:4” problem (one child has to support two parents and four grandparents) and the reported outrageous killing of female babies, it is clear that the country as a whole has prospered  and the tradition of respect for elders has not been harmed, because very young children are not productive even in a relatively undeveloped industrial economy.  We therefore need to find an ethical means of implementing such a policy in a country whose inhabitants generally do not contribute to the economy for the first 20 years of life.

Affordable or even free contraception has not reduced the rate of teenage pregnancy in the UK. It can of course be argued that young prima gravidas and their offspring are healthier *, and with child benefit paid for every child there is no financial incentive for teenage girls not to have babies.

An entirely ethical way to make fewer births more desirable would  be to pay women aged 16 – 40 for not being pregnant.

UK child benefit payments are currently about £1000 per year for the first child and £670 per year for every subsequent child. There are additional maternity benefits and child tax credits. Now suppose instead that we invert the concept and pay every female from age 16 to 40, £500 every six months if she is not pregnant.  We allow one “bye”, so she can continue to receive full benefit if she has one child, and another if that child dies before reaching 16. No benefit is paid during any subsequent pregnancy, and no additional payments are made.

The financial incentives are therefore to breed below replacement level and to save and invest the grant for perhaps 5 to 10 years before having the first child. £500 is a significant 16^th birthday present from a grateful nation, and with the promise of more to come every 6 months it is quite likely to delay first pregnancy until the prospective mother has joined the workforce and actually contributed to the economy. The counterbalance is that, having one “bye”, early first pregnancy (which is beneficial to the health of the nation) is not actively discouraged.  There is no draconian penalty for bearing subsequent children (there is no legal limit to family size) but the prospect of a one-off loss of  £1000 grant income each time  will surely deter all but those most able to afford that indulgence.

Female infanticide is positively discouraged by this policy: having one child of either sex will not affect your grant income, and a girl will be worth an extra £1000 per year when she reaches maturity.

Alan Calverd

2 January 2011

*I remember a brainstorming session at the Department of Health a few years ago. The question was put “What shall we do about teenage pregnancy?” All the doctors, nurses and scientists immediately agreed “encourage it – fewest complications in the 16– 24 age group” whilst the policymakers and social scientists recoiled in horror lest common sense should  prevail over Ministerial edict! It’s taken a long time, but I hope this paper brings a few accountants on the side of the righteous.

Alan Calverd

23 December 2010