Terror 20 Sweden
Edgar Allan Poe's 'The Raven' illustrated by Gustave Doré
Dore “Raven”
https://hyperallergic.com/102457/rediscovering-the-dark-splendor-of-gustave-dore-with-edgar-allan-poe/   downloaded Feb 18, 2018
It is the 9th of April 2018.  The chase is still on to run down the mechanism for inbreeding depression and for outbreeding depression. 
Another of my heroes we have lost recently has been Hans Rosling.  He assembled an amazing amount of data about national statistics worldwide and posted the collection on the internet as gapminder.com Alas I cannot find it today, but it was very interesting to watch the statistics play out over time. 
For about 30 years birth rates in rich countries have been somewhat below replacement levels and have been reasonably stable.  That does not sound so scary.  But is there any evidence that a fertility crash is sneaking up on us?  Sure.  Here is the experience of Sweden between 1955 and 2005 with the births per woman on the horizontal axis and age at first marriage on the vertical axis.

 

graph, sorry they are all graphs described in the text except for the chromosome diagrams described in the text. I didn't count right, obviously, so even those simple labels are probably out of order.
Taken from gapminder.com  Each circle is a year.  1955 is where the label is.  From there the trace wanders a bit but then fertility drops below 2 children per woman where it mostly remains.  No sooner has the fall gone below replacement than the age at first marriage begins to rise.  This is typical for developed countries; in some year, varying from country to country, fertility abruptly begins to fall, to go below replacement and then more or less to stabilize but with an immediate rise in age at first marriage for women. 
Although fertility, as you can see here, may vary that probably only means that couples are choosing to have their babies sooner or later.  We have already seen, most clearly in Iceland, that the actual total number of children is governed entirely by kinship issue. 
On the other hand, once the marriage age starts upward, in the context of fertility below replacement, it never turns back.  In fact, it never slows down.  This is true of all the developed countries, and as we showed with the UN numbers, that means for the entirety of humankind that is visible in the statistics.
This give us the sad opportunity to determine when some country will suffer the fate of the Calhoun mice and experience total fertility collapse, again within the limits of what the statistics can show. 
I worked with gapminder until I could list years from 1975 to 2005 and the age of marriage in each year.  It rose from 24 to 32 during those 30 years or about one year’s delay for 3.75 calendar years.  The graph shows eloquently how implacable is the advance. 

 


1963     25
1964     24
1965     24
1966     24
1967     24
1968     24
1969     24
1970     24
1971     24
1972     24
1973     24
1974     24
1975     24
1976     24
1977     25
1978     25
1979     25
1980     25
1981     25
1982     25
1983     26
1984     26
1985     27
1986     27
1987     27
1988     27
1989     27
1990     28
1991     28
1992     28
1993     29
1994     29
1995     29
1996     30
1997     30
1998     30
1999     31
2000     31
2001     31
2002     32
2003     32
2004     32
2005     32
Assuming the pattern holds, the age of marriage in 2006 should be 33.  I am making an assumption here that unmarried women are following the same trend and married women.  If that is not true it could skew the results.  I assume that by age 38 a woman’s ability to have children drops drastically as menopause approaches.  And I am happy to leave out the statistics since 2005 since for several years there has been immigration into Sweden that again probably alters the actual numbers. 
So from age 33 to menopause would be 5 years.  5 times 3.75 is 18.75; we’ll call it 19.  19 plus 2005 is 2024.  That should be the year that fertility collapses.  And in our mostly global culture, and since just about everybody in Sweden is in the productive middle class, that probably holds for the productive middle class worldwide.  It will be hard to maintain our high tech civilization once the bbyoungest productive people are fifty years old.  The year 2074 may be a bad one.
I have no cure in mind.  Maybe cloning will become cheap and safe.  Some other fix might be discovered if we were to search diligently.  But a simple change in mating strategy does not appear promising; those last fertile women are already among us and have already chosen their permanent partners. 

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