Why economic growth will be spectacular

I've previously predicted mind-bogglingly spectacular economic growth in the 21st century.  My reasoning is fairly simple:

1)  Human brains (or their equivalents) are what create wealth (see Julian Simon), and

2)  Computers can be expected to equal and then vastly exceed human biological brains in the 21st century (see Ray Kurzweil).

But I've never actually worked out the numbers...until now.  Here is a graph of additional "human brain equivalents (HBEs)" added each year, due to increases in computer power.  The graph shows very few HBEs added at the beginning (only ONE HBE added in 1995!)...but absolutely astounding numbers added in later years...e.g. 1 million HBEs added in 2015, 1 billion HBEs added in 2025, 1 TRILLION HBEs added in 2033...all the way up to 1 SEPTILLION (1 x 10^24...or 1,000,000,000,000,000,000,000,000) HBEs added in the year 2057.

How did I do this calculation? 

1)  I took historical data for the number of personal computers produced each year (the value was only 17 million in 1990, but increased to 175 million in 2005)...and then projected into the future at an increase of 7% per year.  (Probably a very conservative assumption.)

2)  I multiplied the number of personal computers produced by the power of a the computers relative to a human brain (2 x 10^16 calculations per second) as predicted by Ray Kurzweil.

Anyway, THAT'S why economic growth will probably be so spectacular in the 21st century:  by the second quarter of the century, we will be adding to the effective human brain population at a staggeringly large rate.

Comments

[Bryan]

Hedonic treader - I think one of the aspects you miss is this: in a post scarcity world like Mark Bahner is discussing, no one would build unlimited numbers of copper statues of Bill Gates. There simply wouldn't be any good reason to do it. People build statues to iconize individuals and to display wealth and power. If Mark's 2100 comes to be, wealth won't be an issue, and power will significantly reduced as an issue. There will be little need to iconize people in a world where so many have so much means and computers do most of our thinking.

[Hedonic Treader]

"I would like to see Mars terraformed so that it is possible for humans and other life from earth to live there in the same comfort as they can here on earth."

It deeply worries me that people state preferences like these without questioning the value of such projects. By "other life from earth", you probably mean wild animals in their natural state? Well, they don't live comfortably at all, they live in Malthusian ecosystem dynamics, eat each other alive, starve to death, succumb to slow painful deaths from parasites etc. etc. I am gravely concerned that people are comfortable with a concept of "wealth" that departs so greatly from hedonistic utility. If there is more pain in those systems than the pleasure is worth, than what's the point of calling it "wealth"?

Interestingly, this is also one relevant distinction for Mark's and John A Weigant's disagreement about future growth. Let's say we use a material definition of wealth, and "doing what one wants" means, say, "building many large copper statues of Bill Gates". I don't know how many of them he could afford today, if he really wanted to. But clearly, the total amount of available copper is restricted by physical limits even for our hyperintelligent descendants, so the growth in the capacity to build them is limited as well. Using optimistic technological assumptions, maybe through asteroid mining or more efficient resource extraction on earth, they could manufacture many more copper statues than Bill Gates could today. But the limit would still be physically available copper.

If, however, we see wealth as hedonistic utility (i.e. prevented suffering and created pleasure for sentient beings), the limits should be much more flexible. We currently have a hard time to prevent suffering reliably, or to create happiness reliably, in an energy-efficient way. Our descendants' ability to create energy-efficient minds feeling highly intense pleasure free from suffering is probably much greater than ours, and much more so than their ability to create copper statues than ours. Of course, there would still be hard physical limits, but they would kick in after much higher utility growth. The total increase in hedonistic value would come not only from more available resources, but also from the knowledge how to create and sustain more minds feeling more intense pleasure more efficiently. Using the current dollar worth of pleasurable experiences, I would expect the limits to growth to be many orders of magnitude higher than it would be using the current dollar worth of building copper statues.

The important question then is, what motivations will drive this future? Will our descendants maximize pleasure? Or something else? If they end up playing sadistic net-negative games against each other, or populate the planets with suffering life, the world may actually become worse than it is now even if "wealth" (ability to do what they want) increases.

[Mark Bahner]

Mark Bahner (November 2005): "...it will only be a few years before on-the-fly language translation will allow one to go anywhere in the world, and speak to anyone, without having to know their language."

Jorma (July 2012): "Does 7 years count as "a few years"? According to the date of the comment quoted above, it has been about 7 years since the comment was written. And I don't think that "on-the-fly language translation" that allows what was described exists yet..."

Ouch! That's hardly fair, bringing up my old predictions against present reality! ;-)

Seriously, though...here's a January 2011 Wired magazine piece: http://www.wired.com/business/2011/01/google-translate-real-time/

The headline is: "Google Translate Android App Translates Real-Time Speech." This is essentially the type of thing I meant. Obviously, it's not as widespread as I thought it would be. And apparently, the Android app had some significant glitches at the time. However, note some of the comments on the article:

"FYI: This technology is nothing new..... iPhone users have been using this functionality for over a year through an app called Jibbigo. I think they have about a dozen languages. Someone should write a comparison of the apps."

"SpeechTrans for iPhone a(and soon android) is powered by Nuance with 90% voice recognition and allows multi lingual voice input, unlike its competitors. Simply press record, speak in either language and it speaks back the translation. It's been that simple! SpeechTrans ultimate just been released. Ultimate will allow 39 different language combinations and Facebook chat integration so it is like having a personal interpreter for facebook Chat or a remote SpeechTrans user. The accuracy as seen in the video for Google's translator is 50-60%, if you need a real speech to speech translator that works, checkout SpeechTrans on the App store or go to www.SpeechTrans.com We were also featured at the Pentagon Language Conference in Dec 2010"

So apparently, iPhone had this capability circa 2010.

Overall, I'd give myself a "B" for prediction accuracy. :-) Or maybe a "C". :-) (As Niels Bohr so accurately remarked: "Prediction is very difficult, especially about the future.")

Thanks for the blast from the past,
Mark

[jorma]

Mark Bahner | November 21, 2005 at 12:20 PM:
>it will only be a few years before on-the-fly language translation will allow one to go anywhere in the world, and speak to anyone, without having to know their language.

Does 7 years count as "a few years"? According to the date of the comment quoted above, it has been about 7 years since the comment was written. And I don't think that "on-the-fly language translation" that allows what was described exists yet...

[Tim Curtin]

Hi Mark

Following may be of interest. BTW, your GDP growth projections for the next 100 years are being vindicated almost daily - see The Economist for the extraordinary CURRENT growth rates of the emerging economies, far higher than anything achieved by "the West" in BOTH the 19th and 20th centuries.

Comments on John Quiggin's Submission to the Stern Review, "Assessing the costs and benefits of reducing emissions of greenhouse gases", 17 March 2006
Tim Curtin, 31st May 2006.

Quiggin seeks to show that "the cost of substantial reductions in emissions implemented over a long period is likely to be of the order of 3% of national income or about one year's economic growth. On the other hand the potential costs of failure to mitigate global warming may be much greater than this" (p.2). But in reality, as this Note shows, Quiggin actually implies either zero income growth from now to eternity or else unspecified technological advances that somehow eliminate the emissions resulting from rising demand for energy as incomes grow. But if such technological advance can costlessly offset or prevent the emissions otherwise concomitant with the income effect on energy demand, then it can also more painlessly achieve the reductions in emissions that Quiggin attempts to show can be derived from price effects alone.

1. His numerical estimate of "only" a 3% reduction in national income resulting from a reduction of "energy demand" (and thus emissions) by 50% implies a reduction in total energy demand even though his worked example refers only to demand for transportation fuel. Achieving his 50% reduction in the latter would not achieve the total reduction in emissions of 50% proposed by the British government, as energy for transport acounts for only 30% of total emissions in USA (and somewhat less in Britain and the EU). Thus to reduce total emissions by 60% as proposed by Quiggin (p.4) just by reducing those in the transport sector would require total elimination of all use of petroleum there and some other fossil fuels in other sectors as well, since petroleum accounts for only 40% of total emissions in the USA (and less in Europe)! Yet Quiggin asks us to believe that eliminating all use of petroleum would produce only a 3% reduction in national income! Quiggin's worked example refers only to the motor vehicle end-use of petroleum, and omits aviation; to achieve the targeted reduction in emissions from just motor vehicle use would require cessation of all such use.
2. Quiggin claims that although Nordhaus and others have estimated that the elasticity of demand for energy in the OECD is - 0.7 (e.g. an increase of 10% in price reduces demand by 7%), the "long run price elasticity of demand" is more likely to be "at least 1 and probably higher" (p.4), along with an income elasticity of just 1 (e.g. a 10% increase in income produces only a 10% increase in fuel demand). Even if Quiggin's elasticity estimates are correct, the truth is that with per capita income growth in the OECD currently at 2.5%p.a., average incomes will rise by over 60% by 2025, and energy demand by the same amount using Quiggin's own income elasticity, so that the increase in price needed to reduce transport fuel demand by 50% by 2025 would not even reduce emissions below today's "catastrophic" level! To achieve the 50% reduction in emissions would involve both preventing the 60% increased demand that results when incomes rise, as well as the 50% reduction in today's usage he claims to be feasible at minimal cost. Thus his model requires if not a reduction in incomes of at least 60%, back to levels not seen since 1980, then at least a total cessation of growth so as to keep national income at 2005 levels in perpetuity. The forgone cost by 2025 would be 64% of average OECD per capita income in 2005, or more than 20 times larger than the one-off loss of 3% of GDP touted by Quiggin. Quiggin does at one point (p.4) again acknowledge that income growth raises energy demand, but claims that unspecified "exogenous" technological change along with unspecified induced "changes in the emissions-intensity of efficiency use will yield emissions reductions sufficient to offset the effects of income growth and reduce emissions by a further 20% for a total reduction of 60%". These unspecified changes are un-costed, and like the whole paper merely assume what was announced would be proved.
3. Quiggin's neglect of the effect of rising incomes as an offset to rising fuel prices is indicated by his assumption that the latter is "already" leading to a fall in demand for SUVs, for which he offers no citation. However it has been reported that it is rising demand for its SUVs that has improved General Motors' prospects this year. Quiggin again overlooks the income elasticty of demand and its associated scale factor: a 3% increase in an income of $100,000 p.a. or $3000 is clearly enough to offset the effects of doubling petrol costs for average annual usage from even as much as $1,000 in 2000 to say $2,000 in 2006 (the actual increase in pump prices in Canberra Australia on 28 May 2000 was A$0.889, and on the same day in 2006 A$1.32, an increase of 48%).
4. Quiggin's paper is equally unreliable on the costs of doing nothing about global warming. He rejects the estimates of the costs of the alleged loss of biodiversity arising from climate change by Nordhaus and others as trivially low, when the truth is that first, there are pace Nordhaus unlikely to be any net losses, and even if there were, there is no evidence that there will be any measurable financial or economic cost of any such loss. En passant, it is curious that while global warmers tend to be as much evolutionists as apparently deniers like Roy Spencer are agnostic or even creationist, yet the former totally discount the ability of almost all known species that already cope with daily changes in temperature of as much as 20 degrees C (as in Canberra at present) - not to mention an annual range from -7C to 35C - to adapt (or evolve!) to handle the IPCC "scenario" rise of 3C, implying a new range here of say -6 to 37, and mutatis mutandis elsewhere. And if they do not so adapt or adjust, tant pis, we have survival of the fittest. As for flooding in Venice, what's new there? but in any case there is NO evidence of net rises in sea levels anywhere else.
5. Quiggin concludes that doing nothing "carries with it both a small but economically significant possibility of catastrophic loss and the certainty (!!!) of massive damage to natural ecosystems" (for neither is any evidence offered). However quite near to his home, the recent cyclone Larry in North Queensland was certainly catastrophic for the affected communities, and has resulted in a severe shortage of bananas (in Australia, largely because of refusal to import) - but both these effects are short term, and it is doubtful even if global emissions had been reduced by 50% since 1990 that Larry would have been avoided, since the cyclone that hit Darwin in 1976 was even more catastrophic, despite much lower emissions then than now. Not only that, the damage incurred in Darwin is a distant memory, and the city has been rebuilt in a manner that makes it more able to withstand a future cyclone.

Conclusion

As a former economics lecturer, albeit 36 years ago, I am fearful for those who sit at the feet of John Quiggin, with his apparent inability to cope with income and price elasticities of demand. I know he can do better that, and I hope he will demonstrate that by NOW withdrawing his submission to the Stern Review.

[TokyoTom]

Tim, I share your optimism about what people can do, given clear property rights and minimal government interference. To the extent these assumptions are not met, we necessarily end up with alot of theft, economic rent-seeking behavior (more theft) and destructive exploitation of common/public resources (more theft), and expensive and destructive conflicts as a result - such as we see in Iraq. As you know, much of the third world is handicapped by kleptocracies and/or are still living on a subsistence basis under communal property regimes without clear land or property titles; they will remain handicapped and unproductive without infrastructure assistance focusing on governance and property rights issues, and population growth and kletocracy will continue to stress regional environmenal services. Globally, we are confronted with climate change and how to deal with it despite the fact that so much warming is already built into the system. We can choose merely to react and adapt - a task for which the third world, which is most threatened, is least prepared - or we can also chose to take measures that would end the current tragedy of the commons problem by essentially enclosing the atmospheric commons to manmade GHGs by handing out limited but transferable rights, and letting private markets function. If you think that private markets are what liberate human intelligence to create wealth, then I imagine you would be in favor of an effort such as this (not similar in principle to private transferable fishing rights).

[Tim Curtin]

John Weigant: have you ever heard of renewable resources? or recycling? most of what I consume is all of that already and the rest could be.

[John A Weigant]

Hi Mark--
I agree with all your comments to Chris. Governments are slowly being replaced by multinational corporations. I continue to disagree with your comments about growth and Meadows et al.

The key concept is the nature of exponential growth. If the exponent remains constant and positive, then anything can grow to any predetermined size in a known amount of time. For example (quoting Jared Diamond in "Collapse" (2005, pg 510), using Julian Simon's projections for growth, the mass of humanity would equal the mass of the universe in about 6000 years. I doubt if Simon would have predicted what his assumptions project.

Contrary to your claim, real scientists don't make predictions when the number of variables is large and they are not under control. Rather, they state their assumptions and make projections based on the assumptions. Changing certain assumptions changes the projections. Only when the number of input variables are very small, and they are under precise control, can a real scientist afford a prediction. Real scientists understand probability, and don't predict what they can't control and don't understand. Some of the variables are chaotic. Some are political, like when China's leaders said "One child only!" Is China today a consequence? Some are religious. Example: What if a new Pope said, "I've seen China's quality growth as a result of restricting quantity growth. So use birth control, and abortion if you have to." What if there are major wars, pandemics, the dollar collapses, or fusion doesn't pan out? What if Einstein is wrong, and we invent a way to travel faster than light? Too many questions; too few answers. So never predict; only project based on a set of assumptions. And the Meadows' team does this better than anyone else.

There's a one-page sidebar in "Beyond the Limits" that's also reproduced in "...The 30-Year Update". It shows exponential growth forever, sigmoid growth leveling off at limits, overshoot and oscillation, and overshoot and collapse. The first leads to ridiculous conclusions (as Diamond points out) for any real entity. The second requires perfection in the response system. We don't even understand the responses. The third and fourth are similar, but focus is on the size of the downturn in the near future. Both evenually oscillate to some limit. The Meadows team suggests that we are most likely headed for the fourth unless we change some of our assumptions. Their various scenarios reflect different assumptions.

I find this interesting: In science, when knowledgable researchers disagree with someone else's conclusions, they replicate the experiment or seek alternate explanations, attempting to show better science than the original. I have seen no scientific refutation of 'Limits'. No one has repeated the modeling with different conclusions. (If you know of any, please advise me.) But don't just tell me people like Ronald Reagan repudiated their work. His knew simplistic communications, but little else. Tell me about serious modeling at the same level or better.

Meadows' work is all about exponential growth. Capital grows exponentially, too, and is subject to the same limits as anything else real. Since capital drives consumption, and consumption consumes stuff, consumption has the same limits. Sooner or later. Meadows say it's sooner than we think.

Regarding your specific questions. All high-level demographers (ie Census Bureau, UN, World Bank, etc) seem to agree that the "demographic transition" is happening and agree that population will peak about mid 21st century, give or take a few decades. Evidence is also supplied by EVERY other living population in ecology. Nothing grows forever, and most species oscillate, sometimes wildly, about some limit, if they don't grow extinct. Since humanity is a biological population, I don't see how it can escape these universal standards. We haven't met our limits yet, but they're there. The only unanwered question is "when?"
The numbers I quoted were just one scenario based on one set of assumptions modeled out. Everything I see in the world today seems to track with the assumptions.

A good argument is analogous to Pascal's. Should he believe in God? If there was a God, and belief meant eternal salvation as opposed to eternal hellfire and damnation, then belief had high value. If there was no God, then belief was a waste of time. Given the cost/benefit ratio of the two choices, belief had a higher payoff. I believe we can restructure our lives to seek quality, which can grow without limits, and we do not need to seek ever more quantity, which has limits, and can even lead to collapse. Our grandchildren can have a good life by choosing some limits now. If we don't, their children are likely to die of starvation or social collapse. In short, the cost of believing in the Limits projections and changing behavior accordingly is lower than the cost of behaving as usual and having grandchildren suffer the consequences.

Thanks for the dialogue.
--John

[Mark Bahner]

Hi Chris,

You write, "Potentially, however if government puts undo restraint on the economy (over taxation, etc) then that type of growth will be difficult to achieve."

I see governments as becoming less and less powerful as the 21st century progresses.

The reason is "increased competition." For example, last night there was a piece on "60 Minutes" about Internet gambling. It's illegal in the U.S., but legal in many other countries. But what happens is that U.S. citizens simply ignore the law. And no government in the U.S. (local, state, or federal) has the resources or demands from their constituents to enforce the law.

Similarly, it's becoming easier and easier for one to move one's money and one's person to another country. If tax laws are too burdensome in the U.S., move to Costa Rica or Bermuda, or wherever else has lower taxes.

It used to be that moving overseas might mean that one would never see one's family again (the cost, time, and danger of cross-ocean voyages were so great). Now, one can fly to Europe for only a few hundred dollars. And email and Internet telephony (with video capability, to boot) mean that one can be in close contact virtually daily.

Further, it will only be a few years before on-the-fly language translation will allow one to go anywhere in the world, and speak to anyone, without having to know their language. (A large part of the world's population now speaks English anyway.)

[Mark Bahner]

"I'm sorry you dislike the work of Meadows, et al. I think it is simply the best, most comprehensive work around, and even recognizes its own limitations, in understanding the complexities of the issues and the uncertainties of projecting futures. Name-calling, however, is not a suitable response."

What annoys me most about them is that I don't think they are merely poor scientists. I think they are actually dishonest (which is inexcusable in a scientist). I think that's why they specifically refuse to make predictions, and instead make "projections." And they specifically refuse to estimate probabilities. Therefore, their work is completely unfalsifiable. That makes it pseudoscience, not science.

"Here's my challenge to you. Pick any sentence, paragraph, section, or chapter from any of their books that you wish to challenge on facts. I'll do my best to defend them."

Well, I actually did a silly thing last night, and ordered their latest book. So I'll make a specific critique when it arrives, and I have time to analyze it.

But let's start with this. You wrote: "Scenario 2, perhaps the most likely, has goods per person by 2100 at about 1970 levels, food per person well below 1900 levels, and services per person quite high. One reason for such "high" numbers is that world population will have dropped to about 1950 levels, and life expecancy to about 1940 levels."

Carl Sagan had an excellent saying (which he may have borrowed from someone else): "Extraordinary claims require extraordinary evidence."

What evidence is there for the possibility that, by 2100:

1) Goods per person will drop to 1970s levels,
2) Food per person will drop well below 1900 levels,
3) World population will drop to 1950s levels, and
4) Life expectancy will drop to 1940s levels.

When have **any** of those sorts of declines happened in the last few hundred years?

What are the mechanisms by which each of those items will decrease...i.e., how is it goods would go down, how would food go down, how would world population decline so dramatically, and how would life expectancy go down?

[John A Weigant]

Thanks for a prompt reply. Looking ahead 200 years is the utmost of speculation, so I shouldn't wish to look ahead more than 100. Some things I have faith in. Like the laws of physics--the conservation of mass and energy, and stuff like that. I invite you to do the energy computations to find out the raw energy it will take to get a spacecraft to Mars. Or the energy it would take to divert a comet into Martian orbit, and then the energy it would take to harvest its ice without crashing in to the surface. The laws of conservation of momentum still require that mass has to be ejected from a spacecraft to give it a momentum of its own. Perhaps fusion can power it, but fusion power is still at least 30 years away, as it has been ever we began to understand fusion. The drive is not yet known. Currently contemplated ion drives have grams of thrust, not Gs. That is, any contemplated drive is short on thrust, by many orders of magnitude, to even lift itself off the ground. What's really needed is a warp drive, stargate, worm hole, or some other fictional creation to allow us to exceed C, the speed of light. I fugure all these are about equally likely. I say that as a science fiction buff that loves Star Trek and life in a galaxy far, far away. But I can separate fact from fiction. Kennedy said, "Let's go to the moon" and it was possible because engineering at the time said everything was feasible with current technology. We did it, and haven't done it since because it's just too expensive. Perhaps fusion will solve the energy problems on earth, just like fission was supposed to do. The problem with fission is too much polution. Too little is known about fusion to know the radiation side effects. If your stance is that wealth will overwhelm all problems, I have yet to believe it's that easy.
If wealth "is the ability to do whatever one wants," how do we handle people who want to consume resources and pollute the sinks of the earth beyond sustainable levels. Sure, wealth is an intangible, but if it's spent on anything tangible, we're in trouble. The issue isn't if there's $10^15 to terraform Mars. As you said, money at such levels is irrelevant. The real question is how many joules of energy or kilos of titanium can you buy? Perhaps your dream is everlasting life, in perfect health. Some of my joy now is in my grandchildren, and if I hang around forever, not making way for new generations, there won't be room for them. Contrary to Julian Simon's claim that we can continue to grow for another 7 billion years, the laws of conservation of mass deny that. If you believe Simon's claim, then we have no basis at all for reaching an understanding.
I'm sorry you dislike the work of Meadows, et al. I think it is simply the best, most comprehensive work around, and even recognizes its own limitations, in understanding the complexities of the issues and the uncertainties of projecting futures. Name-calling, however, is not a suitable response. Here's my challenge to you. Pick any sentence, paragraph, section, or chapter from any of their books that you wish to challenge on facts. I'll do my best to defend them. Your readers can delare the winner. You can even bundle the exchange as the review you wanted to do.

I appreciste you willingness to discuss these issues. The planet depends on who's right.
--John

[Chris]

Potentially, however if government puts undo restraint on the economy (over taxation, etc) then that type of growth will be difficult to achieve.

[Mark Bahner]

"Your projection of over $1 million GDP/capita (1990$) by 2100 is nonsense. If you can go 100 years, why not 200? At 7% annual growth, Human Brain Equivalents double about every 10 years, or over $1 billion GDP/capita by 2200."

Yes, that's right. What it means is that money becomes irrelevant.

"The sources, sinks, and throughputs of the earth will not tolerate that level of physical consumption."

Specifically, what constraints can you identify?

Do you think the world could tolerate if every family was as rich as Bill Gates' family? If not, why not?

"Only non-tangible stuff can grow at that rate for that time."

Wealth ***is*** "non-tangible." Wealth can be described as "the ability to do whatever one wants." If you were as rich as Bill Gates, what would you want? Well, I would want myself and everyone I knew to live forever in absolutely perfect health...never growing old or dying. Even Bill Gates can't do that today.

I would like to see Mars terraformed so that it is possible for humans and other life from earth to live there in the same comfort as they can here on earth. That would require diverting hundreds or thousands of comets to create oceans. Which would require fusion rockets. Maybe it would be even be good to have a (fusion-powered) artificial sun revolving around Mars. Suppose 1 million people on Earth share my desire. Well, if each of us had $2 billion, and was willing to give $1 billion to get our desire of a terraformed Mars put in place, we would have 1 billion x 1 million = $1 QUADRILLION dollars to carry out that desire.

"Meadows, Randers & Meadows, "Limits to Growth, the 30-Year Update," 2004, present a far more comprehensive analysis of the earth system than Simon's. Scenario 2, perhaps the most likely, has goods per person by 2100 at about 1970 levels, food per person well below 1900 levels, and services per person quite high. One reason for such "high" numbers is that world population will have dropped to about 1950 levels, and life expecancy to about 1940 levels."

John, I hate to tell you, but Meadows, Randers, and Meadows are laughable hacks. I'm not sure I'll buy their latest foray into pseudoscientific hackdom, but I DO have "Limits to Growth" and "Beyond the Limits." They are laughably bad. I was planning sometime to do a critique of their nonsense. But I have limits to the amount of time I can devote to debunking nonsense. (See, if I didn't have to sleep, I'd have a lot more time.) (And if I could have a robotic assistant who would re-read "Beyond the Limits" and summarize the nonsense, that would be great, too.)

Best wishes,
Mark

[John A Weigant]

When I taught physics 40 years ago, one of the hardest concepts for students to grasp was "Does this answer make sense?" Your projection of over $1 million GDP/capita (1990$) by 2100 is nonsense. If you can go 100 years, why not 200? At 7% annual growth, Human Brain Equivalents double about every 10 years, or over $1 billion GDP/capita by 2200. The sources, sinks, and throughputs of the earth will not tolerate that level of physical consumption. Only non-tangible stuff can grow at that rate for that time. Perhaps the $1 billion figure might take a form of 99.99% music and video, generated by computers for consumption by computers, but GDP is a meaure of human welfare. Perhaps the source of the nonsense is Ray Kurzweil's figure that a brain does 2*10^16 computations per second. I don't know his work, but the brain does a lot of housekeeping, and its linear processor (commonly called the left brain) does only about 44 bits per second of information flow. The visual processor (right brain) can handle about 4.3 million bps. BPS are not Comp/sec, but your assumptions are at least a dozen orders of magnitude too high. Thinking like Julian Simpon's, that ignores earth as a system, will lead to collapse. Meadows, Randers & Meadows, "Limits to Growth, the 30-Year Update," 2004, present a far more comprehensive analysis of the earth system than Simon's. Scenario 2, perhaps the most likely, has goods per person by 2100 at about 1970 levels, food per person well below 1900 levels, and services per person quite high. One reason for such "high" numbers is that world population will have dropped to about 1950 levels, and life expecancy to about 1940 levels. It's going to be a very hard life on the path you propose.
However, I have one caveat: if we invent a much-faster-than-light space drive, growth might be unlimited. But ONLY if. --John Weigant

[Steve Bloom]

"If only (they) would use (those) brain(s) for good instead of evil."