70 million problems solved

Liberal Conspiracy‘s series on immigration has inspired me too look at something which I have always wondered about. I want to know why various papers in our illustrious press demand immigration be decreased  or stopped to prevent our population reaching 70 million.

Alan Johnson does not lay awake at night worrying about our population reaching 70 million and I’ve not heard a good reason why he should. (In any case, Alan Johnson has some far more serious things to keep him up at night, but I digress).

Officially, the reason an increase in our population to 70 million is a Bad Thing because it would increase the population density of the UK to a point which would damage social cohesion and make life increasing uncomfortable for everyone. It would even help get the BNP elected.

Now I am not going to be so bold as to claim I have solved the riddle which has foxed Migration Watch, The Daily Mail and The Telegraph. I am just going to present some figures and ask some very simply questions.

The first of these being: Why 70 million?

I would argue that its a fairly likely number for our population to reach, and for reasons illustrated below, not a particularly frightening one.

But in reality, like U2, no one knows for sure why it has become so popular.

I suppose, as Anton explains, its at least partly tradition. But to the popular press I believe that the lure of the “70 million” figure is more complex. Firstly, it is large enough to sound threatening. Secondly, it sounds like that this figure will be reached in our lifetimes. And lastly, and most ingeniously of all, its coming is predicted far enough into the future so that no one can convincingly refute it, because sensible people admit they don’t know either way.

But here some little tables performing reductio ad absurdum on their arguments (Scroll to the bottom, they should all be fairly self explanatory, if not leave a comment and I will add a better key). To make things fair I’m even going to assume, like them, that a population of 70 million is a bad thing. The other assumptions which need to be made are listed below.

1. This is not about immigrants.
2. This is definitely not about race.
3. This is about total population in a given land area.
4. Therefore, this is about population density.
5. There is a certain limit to population density of the UK which it would be foolish to exceed.
6. England has the highest population density in the UK.
7. Therefore, the limit which England has reached must be the one which the upper limit which the UK can also reach; 1023 people per square mile.
8. We cannot force people already in the UK to have less children, live less long lives etc. to challenge this rise in population density.
9. The costs of increased population density exceed the benefits of external migration to the UK.
10. Therefore, we must reduce migration to avoid a population of 70 million.

With those assumption I set out to model, very simply, what would happen to the UK’s population density if the UKs population were to reach 70 million. Table 1 is our base, this is the UK population as it is now, or at least according to Wikipedia’s latest updates (not perfect, but close enough for an inexact science)

In Table 2 I show what would happen to the constituent countries of the UK if the population of the UK hits 70 million. In Table 2 it is assumed that the population will remain split in the same ratio as it is currently. Roughly 84: 5: 8: 3 England: Wales: Scotland: Northern Ireland.

As you can see from the Bold Red writing; disaster. Bold Red always means disaster.

However, in Table 3 it is assumed that the popualtion inside the UK is not bound to the ratios which currently exist. In Table 3 we add some extra assuptions:

• People can move (radical, I know, but stay with me)
  
• If having a population denisty above 1023 is bad then they will:
  • move of their own accord
    
  • or, if what is collectively optimal is not optimal on an individual level, can be encouraged to move.

If you look closely you can see that there is no Bold Red. No disaster. The population ratio has changed to 74: 8 : 13 :5 England: Wales: Scotland: Northern Ireland. However, the population density of Wales, Scotland and N. Ireland does not come anywhere close to our Bold Red, in fact, they all maintain population densities below the average for the UK.

So, with a lazy afternoon playing with Open Office and a few uncontroversial figures and assumptions, why have I been able to do what they have not?

For the arguments against an increase in population on grounds of population density to be logically consistent, what needs to be proved is that the result of increasing internal migration is in some way worse than the result of restricting the flow of migration.

(I would not even ask them to prove that the costs of limiting migration are less than the costs of our demographic time bomb. Nor would I ask them what would become of out obligations to refugees under international law. I wouldn’t ask them about the paper Chris Dillow quotes regarding the fact “that immigrants do not crowd-out employment of (or hours worked by) natives but simply add to total employment.” )

I’m just curious as to why they are so fixated on this 70 million figure, and why they wish to present an important topic in such an asinine way. Demographics is a point where sex, race, age, income, disabilities, mobility, educational attainment, home ownership, employment status, and location meet, it should be possible to discuss aspects of it like adults.

Table 1	Population	Landmass sq.mi	Ratio of Total Population	Population Density person/sq.mi	Ratio of Population Density
UK:	61500000	94526	1	650.61	1
England:	51500000	50346	0.84	1022.92	1.57
Wales:	3000000	8022	0.05	373.97	0.57
Scotland:	5200000	30414	0.08	170.97	0.26
Northern Ireland:	1700000	5345	0.03	318.05	0.49
Table 2	Population	Landmass sq.mi	Ratio of Total Population	Population Density person/sq.mi	Ratio of Population Density
UK:	70000000	94526	1	740.54	1
England:	58617886.18	50346	0.84	1164.3	1.57
Wales:	3414634.15	8022	0.05	425.66	0.57
Scotland:	5918699.19	30414	0.08	194.6	0.26
Northern Ireland:	1934959.35	5345	0.03	362.01	0.49
Table 3	Population	Landmass sq.mi	Ratio of Total Population	Population Density person/sq.mi	Ratio of Population Density
UK:	70000000	94526	1	740.54	1
England:	51500000	50346	0.74	1022.92	1.38
Wales:	5687500	8022	0.08	708.99	0.96
Scotland:	9100000	30414	0.13	299.2	0.4
Northern Ireland:	3412500	5345	0.05	638.45	0.86
Population of UK left after controlling for zero change in England’s Population			Original ratio of UK population in Wales, Scotland and Northern Irelandth is 0.16	Wales	0.05
18500000				Scotland	0.08
Ratio of Total UK population remaining for Wales, Scotland and Northern Ireland after controlling for zero change in England’s Population				Northern Ireland	0.03
0.26			Therefore Ratio of the UK population which they are to now contain (0.26)
Original Ratio of Total UK population of non-England constituent members of the UK				Wales	0.08
0.16				Scotland	0.13
				Northern Ireland	0.05

1. As society has not collapsed at this level this must be the safe level.