A couple of recent news stories from the BBC caught my eye.
Fertility rate: 'Jaw-dropping' global crash in children being born
This story is looking at one factor: the drop in the fertility rate. Women are not having as many children as they used to; if the average number of children a woman gives birth to falls below 2.1, the result is a population decline. I’m going to grab some numbers from the article. Read the whole thing for the context:
...In 1950, women were having an average of 4.7 children in their lifetime.
Researchers at the University of Washington's Institute for Health Metrics and Evaluation showed the global fertility rate nearly halved to 2.4 in 2017 - and their study, published in the Lancet, projects it will fall below 1.7 by 2100.
As a result, the researchers expect the number of people on the planet to peak at 9.7 billion around 2064, before falling down to 8.8 billion by the end of the century.
...It has nothing to do with sperm counts or the usual things that come to mind when discussing fertility.
Instead it is being driven by more women in education and work, as well as greater access to contraception, leading to women choosing to have fewer children.
...The study projects:
- The number of under-fives will fall from 681 million in 2017 to 401 million in 2100.
- The number of over 80-year-olds will soar from 141 million in 2017 to 866 million in 2100.
The point about women choosing to have fewer children elides another reason: the lack of time, money, and resources to support more children.
Some of the other things discussed in the article include how population numbers will shift; many countries in Europe, Asia will see populations decline significantly, many by more than half. The population of sub-saharan Africa is expected to treble on the other hand. Immigration is going to become more important for countries that will be trying to balance demographics of an increasingly aged population against the need for workers and others to keep their economies running. (Interestingly, the U.S. population is projected as increasing — but only slightly above current numbers...)
NOTE: This is an extremely one-dimensional story. It is focusing almost exclusively on population trends to the exclusion of other factors. It’s not just the birth rate that’s a factor; there’s also the death rate. That too is likely to change. Another article at the BBC looks at just one of many developing trends on that side of the balance sheet.
Climate change: Summers could become 'too hot for humans'
…As global temperatures rise, more intense humidity is likely as well which means more people will be exposed to more days with that hazardous combination of heat and moisture.
Prof Richard Betts of the UK Met Office has run computer models which suggest that the number of days with a WBGT* above 32C are set to increase, depending on whether greenhouse gas emissions are cut.
And he spells out the risks for millions of people already having to work in the challenging combination of extreme heat and high humidity.
"We humans evolved to live in a particular range of temperatures, so it's clear that if we continue to cause temperatures to rise worldwide, sooner or later the hottest parts of the world could start to see conditions that are simply too hot for us."
Another study, published earlier this year, warned that heat stress could affect as many as 1.2bn people around the world by 2100, four times more than now.
*WBGT is “Wet Bulb Globe Temperature” It combines heat with humidity to give something like the equivalent of wind chill — what the temperature feels like for humans above and beyond what the thermometer is showing.
The heat story places the problem in the context of doctors dealing with Covid-19 patients in Singapore. The PPE is hot to begin with, and they can't run the air conditioning because of the danger of spreading the virus. They are approaching the limits at which they can work effectively. US guidelines say humans should stop strenuous physical activity when the WBGT reaches 32°C; computer projections by the UK Met Office expect the number of days that happens will increase.
There are several related stories available at the article:
We are reaching the point where access to air conditioning is going to be a matter of life and death, especially for those with health issues. In recent years summers have seen a spate of news stories about heat deaths around the world from extended summer heat waves. In the US we’re currently focusing on civil unrest and the pandemic; how many heat deaths will it take to get attention? I live in upstate NY. It’s supposed to get up into the high 90s F today. [It hit 99° F at my house.] The spring and summer to date have been warm; winter just past did not deliver snow the way it used to 20 years ago around here.
Along with the heat stress cited in the article, other climate change effects include impacts on food production, availability of potable water, decreased outdoor productivity, increasing stress on infrastructure, more extreme weather events, climate refugees… the list goes on and on. Disease and Death are grabbing our attention now, but War and Famine aren’t far behind. At a guess, rising heat is going to cut into that projected African population growth, which means the projected stresses from a declining birth rate are going to get worse even as the death rate rises and more and more of the globe becomes harder to live in.
Thomas Robert Malthus, 13/14 February 1766 – 23 December 1834, worked out the problem: population growth is limited by resource constraints. While he was looking at the food supply and famine, we are running up against the limits on many other things.
Population density is a problem all by itself; John B. Calhoun, May 11, 1917 – September 7, 1995, ran a series of experiments with rats and mice where he gave them access to unlimited food and water, but in a confined space. As their numbers grew, the stresses of overpopulation alone were enough to cause what came to be known as a behavioral sink, “a collapse in behavior which can result from overcrowding.”
Of course you can also get behavioral breakdown long before exhaustion of food and water if other stresses are applied...
One way or another, the human population of this planet is going to decline. The only question is how fast, by what routes, and what level we end up at. If coping with the pandemic is a test of US ability to do what needs to be done, the results are unsatisfactory. The prospects for dealing with climate change are even dimmer; there are very few places around the world that are getting it right, and as with wearing masks in the Covid-19 era, we need greater compliance to succeed.
One of the things that comes up in Biology 101 is the Bacterial Growth Curve. Place a single bacterium into growth medium, and low initial numbers grow exponentially as the population doubles and redoubles. This continues until the bacteria begin to exhaust critical nutrients, toxic waste products build up, and mortality increases. The final phase is a decline in numbers which can go all the way down. It’s a very simple model, but the implications are clear. Unthinking growth is always fatal, as is unthinking.
Natural laws know no pity, neither for bacteria nor humans.
UPDATE 1400 hrs Eastern Time: After looking through comments, I thought I’d add a few more observations.
...researchers expect the number of people on the planet to peak at 9.7 billion around 2064, before falling down to 8.8 billion by the end of the century.
It’s a good thing that numbers are coming down. The question is, how will 8.8 billion by 2100 match up with what condition the planet is in by then? What will per capita energy consumption be? What shape will global food production be in by then? What level of inequality will be seen across the global population? What level of technology will be supportable — and who will have it? How will government have to evolve to cope while preserving both a viable future and individual opportunity? What if 8.8 billion is still too many — or if other factors lead to a population crash and the collapse of this current iteration of civilization?
Population is coming down because we have new tools to control fertility — but will population come down fast enough to stay ahead of Malthus? There are other methods besides contraception to bring population down; coronavirus is one. To quote the late Alvin Toffler, “The future always comes too fast and in the wrong order.”
David Brin came up with a rather pertinent simile in Existence while speculating about the Fermi paradox. He noted the continuing problem for intelligent life forms is that as their capabilities expand, so do their opportunities for disaster. He compared it to tap-dancing through a minefield — and stopping isn’t an option. The video below is a set up for his book, but the opening looks even more prophetic than it did in 2012.