April 17, 2007
Water Shortages Mean Energy Shortages
Water to generate electricity for a household is 3 times as much as water used directly by a home.
Albuquerque, N.M. - The drive to build more power plants for a growing nation – as well as the push to use biofuels – is running smack into the limits of a fundamental resource: water.
Already, a power plant uses three times as much water to provide electricity to the average household than the household itself uses through showers, toilets, and the tap. The total water consumed by electric utilities accounts for 20 percent of all the nonfarm water consumed in the United States. By 2030, utilities could account for up to 60 percent of the nonfarm water, because they use water for cooling and to scrub pollutants.
Rising per capita energy consumption combined with rising populations is especially problematic for arid regions. But cheaper solar and wind power could reduce the use of water for electric generation. Also, superconductor technologies could enable placement of more generators near coastlines.
Biomass energy is also a big source of water usage and looks set to grow due to government subsidies.
Smaller populations would reduce environmental burdens and make per capita improvements in living standards easier to accomplish. But the idea of population growth control became taboo after the 1970s. Pity that.
Electric power plants do not consume water. Water passes through them and get warmer in the process.
One has to distinguish between withdrawals -- a measure of how much water is taken from a river or lake -- vs. consumption -- the water that is actually removed and not put back.
Once-through cooling systems have high withdrawals but low consumption (they have some, since some of the heat released into the water causes evaporation downstream). Evaporative cooling systems, such as those with the iconic cooling towers, have lower withdrawals than once-through, but higher consumption, since essentially all the water that is withdrawn is used to make up evaporative losses in the tower/cooling ponds.
It's possible to build 'dry' cooling systems that dissipate heat to the air with heat exchangers, essentially like huge automotive radiators. There's a coal-fired powerplant in Wymoming (Casper, I think) that uses this because of water limitations. It increases cost and decreases efficiency slightly, but it is feasible.
Fertility rates have gone to or below replacement for the majority of the world, especially the OECD countries.
The best remedy for excess population growth in the rest of the world is education and economic growth, especially for women. Coercion isn't necessary: they will stop having excess kids as soon as they have an alternative.
Where there are pockets of excess pop growth in specific religious groups, it operates primarily through limiting access to education and employment for women - break these groups' coercive hold on women, and the problem will solve itself.
This doesn't factor in flexible prices. There won't be a water shortage or enerrgy shortage unless the government causes it as was the case under the Nixon administrtion with respect to gasoline.
Most people do not live in OECD countries.
Again, my reasons why population growth is going to become a big problem:
1) Natural selection. People with stronger instincts to reproduce are having more kids. Their kids will have more kids.
2) Biotech for reproduction. Older women will be able to have kids.
3) Rejuvenation therapies. People will live for centuries. So the death part of the equation will get removed.
4) The rejuvenation therapies will also add centuries to how long women are fertile.
5) Robotics will reduce the work involved in child-raising.
Just because a trend is happening now does not mean the trend will continue. The declining fertility trend will end just due to selective pressures. But the technological factors will make a huge difference as well.
The majority of the world's population lives in countries with fertility rates at or below replacement. A majority of the remainder lives in countries where the fertility rate is plummeting, like Mexico. For these countries, representing a large majority of world population, pop control policies are working just fine. For the remainder, see my earlier note.
1) Do you have any reason to believe natural selection works that fast? Historically, I would guess that the main thing that was selected for was the desire to have sex, and children just came naturally - an actual desire for children wasn't necessary, and was maybe even counterproductive in men. Seems to me that the correlation between a higher than average genetic desire for children, and actually having children, is still pretty weak: it has much more to do with where you live, and a host of other factors. Maybe in 20 generations (400+ years) natural selection might have an impact....
2) Only a small % of people want to have children post-menopause: most of those who wanted children have had them, and most people who have had them when asked if they would have more, say: "done that, been there..."
3) Sure. But sadly, that will probably happen much more slowly than fertility is falling. You see, immortality will take a little while to develop, and also take a little while to be accepted, and will likely be available only to the relatively affluent, i.e., not people who have lots of children. Meanwhile countries like Japan and Italy are already shrinking. Immortality will have to pick up the pace to catch up....
4) see 2.
5) Sure. But most people are already having as many children as they want. When people are fully empowered to have exactly the number of children they desire, there are a lot more people who will have fewer, than more.
A couple of years ago I watched a demographer on C-SPAN explain how in some countries the fertility rate decline has reversed.
Australia's fertility stopped declining at around 1.8. I expect it will eventually increase due to selective pressures.
Mormon Utah's fertility rate is more than 40% higher than the US national average. So white fertility can be boosted by religious beliefs. Note from that page that Mormon women are highly educated and yet still fertile.
Selective pressures can operate very quickly if the pressures are strong enough and the alleles which make a big difference already exist.
Actaully, many more countries will be entering the OECD club within just a few years. That is the great news: one big OECD coming to a planet near you.
"A couple of years ago I watched a demographer on C-SPAN explain how in some countries the fertility rate decline has reversed."
AFAIK, several countries have stabilized their fertility rates with public policy supportive of parents, and the US has risen a bit, with high fertility immigrants, to right at the replacement rate, but I'm not aware of any sizable increases.
"white fertility can be boosted by religious beliefs."
Sure, but there's no reason to believe that members of the religion have a higher genetic desire to have children, so this is actually counter-evidence to the idea that fertility rates will rise due to natural selection, and an example of what I was talking about, with cultural attitudes relating to women being very important.
" Mormon women are highly educated and yet still fertile"
Hmmm. Well, they've graduated from high school, and gone to college somewhat more often than average, but where did they go??
"The more students learn in an academic setting - particularly one in which eternal truths and life values are emphasized-the more they realize the truthfulness of gospel principles," said Janet S. Scharman, vice president for student life at BYU in Provo." (quote from your source, http://www.adherents.com/largecom/lds_dem.html )
This suggests that the quality of the education is also important....
"Selective pressures can operate very quickly if the pressures are strong enough and the alleles which make a big difference already exist. "
My point exactly: I don't see any evidence of strong selective pressures, and not much for the existence of such alleles (as opposed to cultural teachings). This is a fairly sophisticated mental construct ("must have children" - as opposed to sexual desire) and natural selection has had perhaps 200M years of mammalian evolution to select for it. Right now that mental construct, if it exists, seems to bend pretty easily to the decisions of the forebrain...I don't see any reason to believe than another 50 or 100 years will make much difference, and I'm not much concerned beyond that. The economic progress you cite as supportive of child-bearing will, in the long-run, also make the economic problems of over-population irrelevant. Assuming that, with a little luck, we get through the next 50 years.....!
The evidence for selective pressures for higher fertility exists.
Fertility increases: think Africa. Niger was at 8 babies per woman last I checked. Yemen was not far behind. Niger's population is growing rapidly:
Niger's population is growing by 3.4% a year, with one of the highest fertility rates in Africa at 7.9 children per woman and only 14% of married women using contraception. Niger's population is projected to grow more than threefold from 14.4 million in 2006 to 50.2 million by 2050 (World Population Data Sheet 2006, Population Reference Bureau.)
Niger's total fertility rate went from 7.5 in 2000 to 8 in 2003 to 7.9 in 2006.
Religion: But Mormonism is getting selected for. Sure, it is not at the level of genes. But belief systems that increase fertility are getting selected for. Mormonism is rapidly growing via the womb.
The article cited in http://www.futurepundit.com/archives/001476.html gives further evidence that education & religion matter: catholics have higher birth rates, educated women have lower rates. Combine that with the info that Mormon women educated at religious colleges have both higher test scores and higher fertility rates, and the evidence is clear that this is a matter of education: conservative religious education (both in-home and academic) vs liberal education.
Yes, Africa has some very high fertility rates. Africa is the global exception, due to great poverty, low education, social disintegration, and conservative religions.
Yes, I do have the impression that Mormononism is a successfully reproducing meme, both via communication and the womb. I would guess that there will be limits to it's growth (there are many examples of such things that get limited, and assimilated by the surrounding culture), but I'll have to find out more about it...
As I think about it, I have to agree with the basic idea of your original point, that pop planning, contraception education, etc is a good idea. I just thought it was important to point out that overall, in the developing world, that the basic idea seems to have succeeded pretty well.
I take issue with your "overall" comment. Natural selection operates on differences. Do some have beliefs or genes that make them less susceptible to pressures for smaller families? If they do then their ideas and their genes will get selected for.
Averages are misleading when looking at reproductive trends. The outliers determine the future.
hmmm. Well, overall is what's relevant to concerns about the effect of pop growth trends on the economy and environment.
As to natual selection, I still don't see evidence of selective pressures significantly greater than have already been operating for millions of years, or of genes for them to operate on. As to ideas...well, they're important, but they can change relatively quickly, just as they have for almost everyone in the world in the last 50 years in the direction of lower fertility.
I just don't see any realistic reason to expect fertility to rise in the great majority of the world.
Selective pressures do not operate at the same speed in all time periods. Greg Cochran and John Hawks are arguing that human evolution accelerated by a couple of orders of magnitude in the last 40,000 years.
When environments change selective pressures can change very rapidly. That's happened to the human race. We are under much different selective pressures regarding reproduction than we were a few hundred years ago.
Fertility will rise because some alleles boost fertility as compared to other alleles. Selective pressures have allelic differences to operate on and they are operating. IQ is getting selected against and that is going to boost fertility. Other alleles that affect feelings about kids are also getting selected on.
The Cochran and Hawks study seems to make sense, but "faster" is not the same as "happening before our eyes". I wonder, how do we quantify the speed of natural selection?
"A study in the Jan. 14 British Dental Journal found such a trend visible in England in just the past millennium, he noted, a mere eyeblink in evolutionary time. "
"Fertility will rise because some alleles boost fertility as compared to other alleles. Selective pressures have allelic differences to operate on and they are operating. "
hmmm, maybe. What are the pressures, specifically, and what are the alleles?
"IQ is getting selected against and that is going to boost fertility."
Both of those are questionable. The first seems plausible, but how strongly? Certainly educated people are having fewer children, but how close is the link between educational attainment and IQ? If IQ accounts for 20% of variance in educational attainment, IQ is 50% genetic, and education accounts for 60% of variance in fertility, then only 6% of variance in fertility is determined genetically. That's a pretty weak connection.
Again, the dental study found a measurable change in 1,000 years, and that was considered a very fast change. Why would we expect to see a significant difference in just 50 years?
We are under much different selective pressures regarding reproduction than we were a few hundred years ago.
Heck, the selective pressures changed profoundly 53 years ago when the pill was invented. That changed the selective pressure from "anyone who enjoys sex" to "anyone who wants lots of children". If "wants lots of children" previously produced 10% of the children, 1% would be double "wants lots of children". Now, "wants lots of children" might be 30% with 10% doubled up. It might only take a couple generations before the ratios are fully reversed with 10% or fewer children produced from "likes sex".
The "likes sex" folks are not going to reproduce at replacement rates, while the "wants lots of children" folks will reproduce at well above replacement rates.
Why would you suppose IQ accounts for only 20% of variance in education? I would expect it to account for well over half. Similarly, I would expect genes to account for almost all variance in intelligence.
"That changed the selective pressure from "anyone who enjoys sex" to "anyone who wants lots of children". "
You greatly overestimate the effectiveness of family planning. Roughly 50% of births in the US are unplanned - the "anyone who enjoys sex" people are still having kids, even if they don't want kids much at all.
It is not all clear that there is a single genetic variation that selects for desire for children - like most complex human attributes, it is likely to be a complex constellation of genes, which are not passed on like blue eyes vs brown. We have less than 30,000 genes, and they have a lot of work to do, and rarely can have such single purpose functions.
Reproductive selection for desire for children has had millions of years to work: even if the rate of evolution of this trait is accelerated by 100 times, logically we would be talking about tens of thousands of years to get the same effect.
"Why would you suppose IQ accounts for only 20% of variance in education? I would expect it to account for well over half. Similarly, I would expect genes to account for almost all variance in intelligence."
No to be rude, but that shows that you share a common misconception that genetic inheritability is more important, and simpler, than it really is. Twin studies have shown quite clearly that IQ is determined roughly 50% by inheritance. The 20% estimate (as well as the 60% share of educations’s effect on fertility) was conservatively high: schools have found that SAT tests provide very little predictive power of academic success, let alone for post-graduation earning power.
The people who are getting pregnant by accident and going through with their pregnancies are dumber and otherwise different than those who do not get pregnant by accident. So natural selection is happening.
There doesn't have to be a single genetic variation that affects fertility. Natural selection can work on many alleles at once.
No, the desire to have children wasn't as strongly selected for in the past because pregnancy was less controllable and its causes less understood back thousands of years ago and before.
No, selection does not take tens of thousands of years when the selective pressures are different and strong. Groups of animals placed on islands hundreds of years ago by humans managed to undergo selection for much smaller size due to fewer predators and greater need to handle cold winds. There've been a few cases of this documented.
You share a common misconception that natural selection takes millions of years and that multi-allelic features are somehow more immune to selection than single allele features. Neither is true.
Your estimate of education's effect on fertility is wrong. In an industrialized society IQ strongly correlates with years spent in school. Yes, time spent in school causes many smarter women to delay reproduction. But if all women had IQs less than 90 the delay from education would be much smaller.
"natural selection is happening."
Seems plausible, though I'd like to see research first. This kind of hypothesis can often turn out to be factually incorrect. For instance, homosexuality has a genetic component, and it would appear to be something that would be very strongly selected against, and yet it's still here. No one knows why, yet.
"Natural selection can work on many alleles at once."
Sure, but it makes things more complex, and makes confounding by other factors much more likely. Single genes have a 50% chance of being passed on, while a complex pattern is less to go to the next generation completely unchanged. Don't forget, we're talking about societies where there's very little premarital counseling, and couples can have greatly differing genetics, and, unfortunately, very different desires. This is a complex situation.
"No, the desire to have children wasn't as strongly selected for in the past because pregnancy was less controllable and its causes less understood back thousands of years ago and before. "
Yeah, but it's causes have been understood for at least 7,000 years. Further, if it wasn't selected for before then, then it wouldn't it be unlikely that there were any genetic components at all to the desire for children for natural selection to act on now? If there are genetic components, wouldn't that prove that there was selection for this trait for a much, much longer period?
"Groups of animals placed on islands hundreds of years ago by humans managed to undergo selection for much smaller size "
First, size is much less complex than a cognitive thing like desire for children. Much more importantly, these animals likely have a reproductive cycle measured in months, rather than decades. You're probably talking about 200 generations, or the equivalent of 4,000 years of human generations.
"Your estimate of education's effect on fertility is wrong"
Do you feel that formal education is responsible for more than 60% of variation in fertility?? I thought that was really, really conservatively high. Realistically, informal education, job opportunities, and a myriad of other things are likely important. For instance, in South America, informal education in the form of soap operas showing young independent women doing things other than parenting have had an enormous impact, and have reduced fertility rates all by themselves.
"In an industrialized society IQ strongly correlates with years spent in school. "
I didn't say "correlated", I said "determined". There are lots of confounding factors, including the likelihood that education raises IQ, and that other factors raise both IQ and the likelihood of education. Again, once kids are admitted to college, SAT tests provide very poor prediction of graduation rates, and other forms of educational success. However, an R squared of .20 (which would correspond to my rough estimate of 20% determination) would be pretty strong, even for just a correlation - a scatter chart would show a very nice pattern of relationship. Have you seen something higher?
"You share a common misconception that natural selection takes millions of years and that multi-allelic features are somehow more immune to selection than single allele features. Neither is true."
You forgot the "not to be rude". :) More seriously, I didn't suggest millions of years, just significantly more than 2 generations. I could be wrong about multi-allelic features being more susceptible to confounding, and taking longer to select for - it might be worth some research. I think I'm not, though, especially for something this complex. In any case, it's not necessary to my central argument that changes in the population average fertility rate due to natural selection will take long enough that it will be much slower, and much less powerful, than economic, technological and cultural changes. I think any evolutionary biologist would agree. Remember, that article about accelerated evolution chose as it's best example something that took 1,00 years.