## Ruthless Extrapolation

This is a guest post by Tom Murphy. Tom Murphy is an associate professor of physics at the University of California, San Diego. This post originally appeared on Tom's blog Do the Math.

We humans owe much of our success to our ability to recognize patterns and extrapolate trends to anticipate a future state. My cats, on the other hand, will watch a tossed toy mouse travel toward them across the room—getting ever-bigger—all the way until it smacks them between the eyes (no, they’re not strapped down—I’m not that sort of scientist). But far beyond an ability to avoid projectiles, our ancestors were able to perceive and react to changes in local food and water supplies, herd movements, seasonal cues, etc. Yet this fine tool can be over-used, and I see a lot of what I call ruthless extrapolation. In almost every case, extrapolation works until it doesn’t. When the fundamental rules of the game change, watch out!

As with many aspects of human behavior, some of the finest commentary on the matter is served up by The Simpsons. In one episode, Lisa Simpson is taken to the orthodontist to evaluate whether or not she needs braces. The “doctor” runs a simulation based on current growth rates, producing an alarming graphic of teeth gone wild.

Image obtained from saucesome.net

Marge shrieks and is ready to do whatever it takes to protect her daughter against this cruel fate. Extrapolation can, of course, be used to argue both for impending doom or future prosperity—sometimes based on the same data. I started this blog with an extrapolative foil to demonstrate the insanity of continued physical growth, in fact. A tangential follow-up illustrated the hopelessness of differentiating a steady-state energy future from an energy crash using current data (although a continued exponential rise is already a poor fit).

### The Problem with Extrapolation

The danger with extrapolation is that it can’t work forever. Trends change. The picture I carry in my head is one I’ve shown before: the long-view history of fossil fuel energy use on Earth.

On the long view, the fossil fuel age is a blip, with a down side mirroring the (more fun) up side.

We found a one-time resource in the ground—like an inheritance—and are doing everything within our means to promote the fastest practical use of this finite deposit. By this, I mean that we have engineered a world that rewards economic growth—thus far carrying a nearly one-to-one physical/energy aspect, requiring ever more energy to keep the growth engine running. The finite nature of the underlying energy resource is not seriously under question. The overall impression of the figure above therefore must be approximately correct.

When we realize that this incredible surge—of planes, trains, and automobiles; of radio, television, and the internet; of industrialization, industrialized agriculture, and swelling population; of supersonic, nuclear, and space capabilities—in the past century or so are all reflections of the scale of surplus energy derived from fossil fuels, we come to understand that we need to stare the plot above directly in the face and recognize the peril of extrapolation.

We sit near the peak of the fossil fuel saga (the star on the plot). Our tendency is to note the incredible slope of the past century and expect more of the same phenomenal performance for the foreseeable future. It’s not a bad model. It has a pretty decent chance of being right over the coming years and possibly decades. Alternative forms of energy may take up some or all of the fossil fuel slack. But even this state of affairs does not look much like a continued skyward trajectory, even if it were possible.

I recently became aware of a story that highlights the degree to which the Earth has already been scoured for resources. In the remote, glacier-ridden Wrangell mountains of Alaska, prospectors found a certain copper-rich deposit in 1900. By 1911, a railroad was constructed and the copper bonanza began, discovering ores that were as rich as 70% copper. Compare this to typical copper ore mined today containing 0.3–6% copper (usually less than 1%). Production from the Kennecott mines peaked in 1916, declining more sharply after 1927, becoming uneconomic from 1932–1935, and reopening from 1935–1938 after which the resource was depleted. The mines and town of Kennecott were hastily abandoned. No ores this rich have been found since. It’s hard to get more remote and inaccessible than the interior mountains of Alaska a century ago. Yet if the rich resources were found and exploited so efficiently so long ago, I am left with lowered expectations for low-hanging fruit elsewhere in the resource world. Seems a bit picked-over.

### Examples of Ruthless Extrapolation

We have no shortage of examples, but I’ll throw out a few to give a flavor of what I’m talking about. I think it would be fun to have readers contribute other glaring instances of ruthless extrapolation in the comments section.

#### To Infinity, and Beyond!

I have commented previously on the disappointment of space. Shouldn’t we be living on Mars right now? Ask an American in 1962 where they think we would be fifty years hence with respect to space travel. How many would say: “grounded, without a means to launch humans even into low-earth orbit”? No, only a lunatic would say that: the trend was clear. The space race was on, and we were tooling up for our first trip to set foot on another planetary body. Common sense (another term for ruthless extrapolation) would demand that the answer be far more ambitious than the Moon—millions of miles from the correct answer of “grounded.”

More generally, the extrapolation often goes that our evolutionary ancestors crawled out of the ocean onto land, so the next “logical step” (often substituted for “ruthless extrapolation” in casual conversation) is for us to take to the cosmos. Gibberish.

Science fiction—as inspiring and entertaining as it may be—is largely an exercise in ruthless extrapolation. Even less constraining, obeyance of the laws of physics (or grammar, in my case) is optional in this genre. For sure, I would be the last person to claim that we know all there is to know about physics. But any deviation from what we do know presently is a pretty substantial extrapolation.

Note that I’m not saying that all extrapolation is wrong—just flimsy to sometimes extraordinary degrees.

#### Faster than a Speeding Bullet

Logarithmic plot of transatlantic crossing time in hours. A straight line represents an exponential (compound) function on this plot. Select data points are labeled above or below the associated point. The red bar represents the era of the Concorde. Some data are from here.

Traveling between Europe and the U.S. used to take months by sailing ship. Improvements in ship design and navigation trimmed this down slowly over time, but a decent model would have been “it will always take about two months.” Enter the steamer—a game changer, thanks to fossil fuels—and suddenly a new field opened up, ripe for development and improvement. The old extrapolation broke down. For a few hundred years, crossing speed improved at a rate of 1.2% per year. Extrapolate to now, and we would expect to be able to cross in 37 hours. Oops. This extrapolation fails in two respects. Not only is a 37 hour ship crossing not possible today, but more importantly we missed another game-changer called the airplane. After the airplane entered the picture, improvements came fast and furious, at a whopping rate of 5.7% per year! This culminated in the supersonic Concorde, crossing in typically three hours and change.

Extrapolate the progress of the aeronautical age to 2012, and we should expect crossing time to now be 19 minutes. By 2050 it would take a cool 2 minutes, and our crossing would exceed the speed of light by the year 2200. Another big oops. Not only did we saturate at 3 hours with the Concorde, we don’t achieve even that any more! Why? It was too expensive to operate: beyond our means.

Sometimes we step backwards: the space program and the Concorde are two striking examples.
There are several oopses on the plot above: sometimes missing game changers that improved things; and sometimes missing the exhaustion or saturation of a technology. Moore’s Law is today’s celebrated joy ride of amazing progress. Physical limits are bringing this ride to a stop too. Note that the new mode of CPU expansion is in multiple cores, not intrinsically faster chips.

#### Visionary Virus

I attended a conference (the Compass Summit; talks viewable online) in October 2011 aimed at mapping out our future path. Its subtitle was: “what’s possible, what matters, what’s ahead.” It was here that I first put the words “ruthless” and “extrapolation” together, in reaction to many of the talks. The boiler-plate talk was: look at the tremendous advances we’ve seen in the last decades; what amazing, mind-blowing futures await if we extrapolate these trends forward? Only a few speakers rung alarm bells about soils, monetary systems, and the impossibility of maintaining growth indefinitely (ahem).

Virtually all talks failed to acknowledge the fundamental role that surplus energy has played in the amazing trajectory we’ve seen. Unlimited energy availability seems to be an unexamined assumption for most. This might be fine if we did not know that our primary energy resources are finite and are expected to peak this century. We can hope for a seamless replacement, but as I have worked to illustrate in the past, this extrapolation is far from guaranteed.

Meanwhile, we are attracted to stories of optimism. They are infectious. It’s fun to dream of a world where everyone can live like Bill Gates does today (or even better than Bill—why not?). Moreover, optimism for the future inoculates the market economy against loss of confidence—which is vital to maintain a growth trajectory. In so doing, optimism helps propagate itself—like a good little virus.

I recently listened to a radio segment on 3-D printing and the arbitrarily complex structures and devices whose fabrication by this method may soon be possible. In response to the question about whether there is anything that can’t conceivably be made by this technique, the answer was the familiar refrain that human ingenuity is unlimited—so no—nothing is out of bounds. A lovely sentiment that is all well and good in the absence of physical limitations. Again, the allure of ruthless extrapolation wins out.

#### The Trajectory of Physics

Okay, this one is a little obscure as a form of extrapolation, but it’s one I relate to professionally in the world of physics. Physics has a marvelous track record of reductionism. The same thing that pulls an apple from the tree keeps the Moon moving about the Earth. Electricity and magnetism—seemingly much different—are in fact different shades of a unified theory of electromagnetism. In the latter half of the 20th century, all fundamental particles and forces (including nuclear flavors) were bundled into the symmetry-group-fashioned “Standard Model”—leaving only gravity in the lurch as a thing unto its own. But the sense of imminent grand unification (theory of everything) was palpable. String theory pounded out many-dimensional mathematics in an attempt to provide a coherent framework for uniting gravity and the quantum domain of the Standard Model.

Then things came off the rails a bit. Neutrinos turn out to have mass—in open defiance of the vanilla Standard Model. Cosmological observations indicate the existence of not only dark matter (new stuff not made of atoms on the periodic table), but also dark energy (providing a repulsive force and accelerating the expansion of the Universe). These have no place in the current Standard Model. Meanwhile, a sizable cadre of string theorists—in trying to understand the geometries of extra dimensions—stumbled on the concept of a Landscape: a near-infinite number of ways that the compactified extra dimensions of spacetime could be arranged/folded, each resulting in its own unique set of rules for physics. Most would be utterly unsuitable for the formation of atoms or stable nuclei—let alone stars, galaxies, chemistry, and life. A tiny subset of the myriad arrangements would host conditions likely conducive to life. Obviously, our Universe would have to be one of these. Because this line of thought involves the “selection effect” of humans in the mix, it is referred to as an “anthropic” view of physics (not to be confused as implying that humans are required for the Universe to exist—just that we can’t overlook our presence—and that of nuclei, atoms, stars, galaxies—as an observational fact/constraint).

There is currently something of a schism in physics. Ask any particle physicist, cosmologist, astrophysicist, etc. where they come down on the anthropic view, and you’re bound to get an earful of…gibberish (including from me). Why gibberish? Because we don’t know whether physics unravels into random instances among a Landscape of choices in a multiverse, or whether the loose ends get tied together into a coherent picture with no freedom to be anything other than what it is. Some physicists believe one thing, and others believe another. But it’s still just belief either way—a religion of sorts.

In the unification corner, the track record of success in reductionism makes a very persuasive “exhibit A.” If early physicists had decided that the energy levels of atoms were somewhat random, then we would have missed the chance to understand something deeper and more fundamental (i.e., quantum mechanics). While there is no apparent rhyme or reason to the approximately 20 Standard Model parameters (masses of particles, coupling strengths, mixing angles), the hope is that one day not only will these be understood, but the current observational anomalies will also be incorporated and explained. In addition, the hope goes, there will be no mathematically self-consistent description by which the Universe could have ended up any other way—life and all. To the unificationists, the anthropicists are throwing in the towel prematurely. The anthropicists caution against blind extrapolation, and point to disturbing examples of fundamental constants that cannot be changed very much without destroying the life-support system of the Universe.

In this case, one could argue that there is little downside to assuming that the reductionist trend of physics will continue. The potential upside for discovery is rather large. A king of old could send a few ships over the horizon, accepting the comparatively inconsequential risk that the ships would disappear off the edge of the world in exchange for the possible huge gain of a newly discovered land. There will always be scientists to push into the unknown. The extrapolative view that physics may accomplish a “theory of everything” may well be wrong (and ultimately feels wrong to me, such is my bias). But unlike extrapolating societal growth/development trends, getting this one wrong doesn’t pose a threat to humanity’s happiness.

For me, I think there are questions that are too fundamental for physics to ever touch—like: why is there something rather than nothing? So I am not willing to embrace the ultimate extrapolation that physics holds all the answers to the how and why of our Universe. Meanwhile, physics certainly offers abundant opportunity to describe our world in a systematic and prediction-enabling way. And continued exploration is bound to be fun no matter what the ultimate end.

### Human Boon; Human Bane

Our ability to extrapolate is indeed a valuable adaptation for our survival. I do not claim that it is unique to humans (other animals can anticipate and prepare), but we have abstracted the practice to a real art form. Many of our greatest accomplishments owe to this fundamental skill.

Yet we’re a little too married to the concept. From a mathematical point of view, we’re first-derivative machines. We sense and react to local gradients, or current trends. It’s a powerful technique. Again speaking mathematically, Newton’s Method, Runge Kutta Integration, the Method of Steepest Descent, and many other techniques are devastatingly effective using only first derivatives.

Yet sometimes the game changes, for better or worse, and our linear—or at least monotonic—extrapolations fail. We would do better with second-derivative sensitivity—to perceive “curvature,” or the trend of the trend. But real-world complexity often throws distracting noise into the data, making it difficult to discern more subtle behaviors.

Evolutionary processes tend to satisfy minimal requirements to outperform the competition, or to edge out environmental impositions. Human cultural memes aside, there are no deluxe model organisms with far more “adaptiveness” than is needed to get the job done (and procreate). So why would we expect to leapfrog evolution and develop a subtle perceptive tool beyond simple extrapolation. The simple technique is enough to exert powerful anticipatory action relative to our surroundings.

But this human boon turns into a bane if we are collectively too shortsighted to spot abrupt and detrimental phase changes ahead, like the end of the fossil fuel age. We’re smart enough to dip a stick into the ground and have it come up dripping with oil. But we may not be smart enough to realize that we shouldn’t use the stuff (and all of it) as rapidly as our growth machine can manage. Right now, the wind’s in our hair, we’re flying faster and higher, and isn’t that just the way it will always be?

Never mind. Don’t answer that question. We’re too poorly equipped to get the right answer.

That might be the funniest episode of "The Simpsons."

Bart's reaction is, "Cool! She'll be a freak. We can drive her around the South and charge two bits a gander."

Also, look up "It was the best of times, It was the blurst of times" on youtube for another hilarious clip from this episode.

But this human boon turns into a bane if we are collectively too shortsighted to spot abrupt and detrimental phase changes ahead, like the end of the fossil fuel age.

Some thoughts on Cosmology, String Theory, Grand Unification, Particle Physics and last but not least the Anthropic Principle etc..

A Universe From Nothing' by Lawrence Krauss, AAI 2009

String Theory Explained
http://xkcd.com/171/

The J. Robert Oppenheimer Lecture - Frank Wilczek

July 2012 scientists at CERN report detecting a boson perhaps not quite the Higgs...
http://blogs.discovermagazine.com/cosmicvariance/2012/07/03/live-bloggin...

Yet the question remains, are humans, in the aggregate smarter than yeast?!
My personal hunch is that we are not!

CERN has not been kind to String Theory.

Supersymmetry has been absent, and this is a problem.
Maybe we have wandered into a box canyon, and accept that some elegant math came out of it?

Speaking of CERN...

This past Monday, Michael Dittmar, gave a presentation on "sustainability" at conCERNed Colloquium on "Thinking about the RIO+20 disaster." Video and slides here:

https://indico.cern.ch/conferenceDisplay.py?confId=198162

Speaking of CERN; I may go there this fall, depending on some things going on or not.

PBS aired a repeat episode of NOVA featuring Brian Greene explaining the space-time "fabric" to a lay audience. I was struck by how inadequate many of the visualizations seemed to be.

For example, the same old image of electrons whizzing in planet-like orbits around a cluster-like nucleus. Granted my understanding of physics is limited, but I thought we had figured out a long time ago that electrons and other particles are fields of probability that only collapse to a point when required, such as when a physicist attempts to observe them.

Or even worse, the tired old metaphor of planets creating dimples in a sheet of rubber to visualize gravity. Um, last time I looked space is three dimensional, not two.

I know, sometimes it needs to be "dumbed down" to get across complex mathematical concepts, but I think in part we also have a plain failure of imagination.

Cheers,
Jerry

"Or even worse, the tired old metaphor of planets creating dimples in a sheet of rubber to visualize gravity. Um, last time I looked space is three dimensional, not two."

This is another bit of legerdemain. Imagine this sheet of rubber in outer space and a satellite along the edge. It would not spiral down just because of the dimple, unless there was--gravity. The old idea of gravity is still needed. Otherwise the satellite would just float away as things do in, for example, a spacecraft, regardless of whether there is a dimpled piece of rubber nearby or not.

As a mathematician I have always found physicists to be an irrational tribe whose lack of imagination and gross misuse of mathematics gets them into trouble.
Lets take the big bang. The universe is expanding; everything is accelerating away from everything else.
But the question they never face is: what about the meter stick? Since space itself is expanding, why shouldn't the molecules in the meter stick, and indeed the atoms in the molecules, also get further from one another, thus making the meter stick proportionally longer and the expansion of the universe unmeasurable. Physicists have learned how to skid over uncomfortable questions. They meet them with silence, scorn, or questionable explanations.

Here is a lecture on the subject by renowned physicist Leonard Susskind.

At the four minute mark a student asks the above question. Susskind draws a picture of a spring attached to a wall. He argues that the force causing the universe to expand is too small to overcome the atomic and electronic forces within the atom. Then he brushes the question aside. Now the picture of the spring is the wrong picture, for the force the spring applies becomes greater as the spring is stretched, but strong atomic and electromagnetic forces decrease with distance. And indeed the forces would have to be like the spring, not like what they actually are to have the proper effect. However, no student in this obviously large lecture to advanced physics students challenges this picture. Why? I suggest the answer is fear of ridicule, palpable in every physics class I ever attended. And so absurdities like space-time and bending space live on.

A much better explanation of the red shift than the big bang can be found here

http://www.newtonphysics.on.ca/bigbang/index.html

Paul Marmet was a serious physicist, his equations are solid, but we can be sure physicists will not want to give up their exciting world of big bangs, multidimensional space-time, and statements like, “Nothing isn't nothing any more,” as Lawrence Krauss says in a video referenced by another reader.

Then answear this question,to wich I have never got a clear answear: If speed of light is absolute, and not relative, then why do they say that light is subject to the doppler effect? (Yes, they do. They ALL do. Even astro-physics say this, I know of none who say otherways). The doppler effect is the result of speed relativity right? Then why does light have it?

To answer the implied question, which seems to be more important than the literal question: just 'cos you don't understand it doesn't mean it ain't so...

The speed of light is not changed by doppler shift; the wavelength is. Red light travels at the same speed as blue light.

It's a frequency shift... light still traveling at the same speed.

Space is expanding not stretching...

but strong atomic and electromagnetic forces decrease with distance.

That is incorrect. The strong interaction (atomic force that keeps the nucleus together) increases with distance.

Since space itself is expanding, why shouldn't the molecules in the meter stick, and indeed the atoms in the molecules, also get further from one another, thus making the meter stick proportionally longer and the expansion of the universe unmeasurable.

For a long enough stick (say between here and a nearby galaxy) the expansion of the stick would occur, making it indeed unmeasurable.
That is why light (with it's frequency shift) is a better tool to measure this expansion. This discussion is too long for this forum but if you're a mathematician I recommend reading a post-grad level book on general relativity to understand how the space metric can be consistently defined incorporating such questions (a good intro is for ex. Torsten Fliessbach's in German or Carrol, Stephani, or Wald in English)

You are quite right. The strong force does increase with distance. And thank you for the references although I certainly do not have time to get up to speed on this. Leaving aside for a moment the question of what is known and what conjectured about the strong force. I ask the questions of a naive beginner.

Aside from the strong force, that works within the nucleus of an atom—though why it doesn't work at a far larger range, since it increases with distance, is certainly a mystery-- the other forces do decrease with distance.

Let us take a very strong meter stick, made of carbon steel. I pull very gently on either end. What happened to the meter stick? Clearly the force I applied on either end must be transmitted down to the atomic level. Some force within the molecular and even atomic structure of the meter stick must have countered even the little force I applied. Now the force I applied would separate particles and indeed everything on every level. Since all forces except the strong force weaken with distance, the only force that could prevent the meter stick from flying apart is the strong force. This force must work at far greater than subatomic distances. For the force I applied at either end is transmitted to every level. If what holds molecules together is electromagnetic this force too must counter my tug or the molecules would fly apart however well their atoms retained their integrity. But electromagnetic forces do decrease with distance. So, even though, as you rightly wrote, the strong force, rather mysteriously, increases with distance, the problem remains, unless we want to claim that tensile strength is entirely attributable to the strong force, which would require it to be a force between molecules and indeed planets themselves.

Since you were discussing an ordinary macroscopic object like a meter stick: between atoms and molecules the distance is determined by an energy minimum of various forces, pull on it (strain in the engineering sense), and the atoms are displaced from the minimum energy distance and want to resist the strain. The strain rate from the atoms trying to follow the expansion of space-time is very small (roughly the inverse of the age of the universe), so the molecules barely notice it. Obviously at most only a single point on the meter stick can be stationary in space, the other points are moving wrt to it.

I've never liked the big bang analogy. It couldn't have been an explosion, since it was just expanding space being created and filled with matter/energy -no kaboom!

If the space between molecules increases at all, no matter by how small an amount, the forces holding them together will be weaker, those pulling them apart stronger, and they will begin moving apart ever faster at an exponential rate.

They may hardly feel it, but they "feel" it.

On the relation between math and physics

"Sie haben gar nicht mit ein und ander zu tun".

Which I believe for no reason except that suggested in another famous quote

"You vant me to explain the Holocaust? I can't even explain a can opener".

Anthropic arguments really don't look so bad with what we now know; they just don't jibe well with the common misinterpretation of Occam's Razor... it applies to the number of assumptions, not the number of universes.

Of course, the problem with finding oneself existing in a universe for anthropic reasons is that other than making you aware, it doesn't construct a universe that necessarily does you any more favors.

And hey, other critters have been shown to be self-aware by the same standard, we need a better word than "anthropic".

If your question refers to yeast simply reproducing until thier food supply runs out or other variables causing the current population to die off. Then No, we are not smarter than yeast. Anothr way to phrase it is we are very very good at the single purpose of life. The purpose of ALL life really only has one function, to make copies of itself, any other secondary functions (food and shelter for humans) merely exist so the lifeform can survive long enough to reproduce.

We as a species seem a little different, we can a do predict the future with regularity and amazing accuracy. It is our inability to use this information, to counter our Primary function that seems to have set us on our current path. Make us sound like some of those robots from Scifi movies.

Why would the question "why is there something rather than nothing?" be too big for science?

That's a sort of quasi-religious attitude.

That has NOTHING to do with religion. And at the same time, everything. In the human experience, everything that exist, exist because of something made it. So then why does anything exist at all? Where did this seemingly endless chain of cause and effect begin? Something "at the beginning" was obviously very much different than anything else we know of. The question may very well indeed be to big for science. (Or rather,outside the realm of science.)

As a matter of fact, it is one of the two identified by me as "largest mysteries of the universe". The other is the question of conscience.

Some people get alergic reactions from raising these questions, and automaticly assume a religious pamphlet will soon be up their nose. While it is no secret on this side that I am a christian, let me assure you that my attitude is to follow the science to its absoulte dead end, as far as we possibly can.

Please do not assume any possitions from my side that I have not made. I am used to atheists (I guess you are one) writing possitions on my forehead without asking if I have them, due to their previous experiences with other christians.

Where did this seemingly endless chain of cause and effect begin? Something "at the beginning" was obviously very much different than anything else we know of. The question may very well indeed be to big for science. (Or rather,outside the realm of science.)

Excellent question. Along that line of questioning, one of the things that bothers me is this idea the Big Bang was the beginning. Well maybe for this expansion, but we don't know what led up to the initiation of that event, so how can science put a stamp of that as the beginning? Also, here's another question never asked: Where did the energy come from that was infused into the mass at the onset of the expansion? Wouldn't the discipline of science in which there are physical laws like for every action there is an equal and opposite reaction, and the laws of thermodynamics suggest at minimum there was a transfer of energy from one source to another? So I ask where did the energy come from? But that question so vexes science that it is ignored and what is looked at only is what came after.

Also, isn't it just as likely that through some yet unknown process the Universe oscillates, i.e. expands and contracts over and over again? Isn't that possibility just as likely as this expansion being a one time event?

"but we don't know what led up to the initiation of that event"

If the Big Bang was the beginnings of space and time then how could anything lead up to that event? Wouldn't that require there being time before time? How could there be time before time? This seems to be a question our brains cannot wrap themselves around as we are wired to look at "the world" with an objective viewpoint, that cause has effect, and that objects exist independently of each other. The idea of the beginning of time has no meaning.

If the Big Bang was the beginnings of space and time then how could anything lead up to that event?

Your suggesting nothing existed, not even space itself, yet somehow the expansion generated space and time out of nothingness? Is that really good science? I think not.

What do you mean by "exist"? In order for something to exist there has to be a greater reference frame of objectivity (i.e. space and time). If there was such a thing, then by definition space and time wouldn't begin then.

Science is about creating objects and observing the world to test hypotheses about them. There is nothing in the scientific method that says anything has to exist.

You're rejecting the laws of science to provide a convenient starting place so no questions can be posed before the fact. That's a cop-out. Answer the question: Where did the energy come from that was infused into the mass? Remember the laws of thermodynamics before answering.

Can I imagine there was suddenly something from nothing? Sure, but do I think it necessarily means that beginning was when the big bang occurred? No, that is a presumption a good scientist does not make.

What if there are equal amounts of two forms of matter in opposite dimensions, and over the duration of the Universe equal compression on both has opposite effects. So as mass loses energy some other form of matter in an opposite dimension is gaining energy. That would suggest a differential energy expression and mean a transfer of energy is possible in the big bang. That would be an oscillating Universre.

To presume the big bang is the beginning, rejects the idea space and time could be eliminated but with these two opposite forms of matter overlapping in a big crunch, the energy could then be transferred, and presto another expansion occurs.

Neither this universe being a one time event or the idea of an oscillating universe have been proven, therefore both are possible. That's good science. Never get caught in a web of concluding something, or worse yet get arrogant about any one position that has not been proven. Just because in your mind it must be true, does not make it so. That gets into the realm of religion where all is needed is a good belief.

Extrapolation has a use in helping create hypotheses that can be tested. It's when some of these hypotheses make a close match with the new observations that we get to head scratching time again and need to go back to the drawing board. There is a thought that if the exquisite accuracy of quantum mechanics when predicting what you will find by certain accurate observation does not give you the heebie-jeebies, then you have not understood the theory. Same for a lot of stuff.

A lot of what by previous reasoning seemed impossible can turn out to be true, but some things, probably not.

Tom said it well in his article. We should not be doing some of the things we are doing, like burning fossil fuel. It follows then that we should not take the fact that we learn amazing new stuff the while; you know ... quantum physics and astonishing cosmology etc., as confirmation that we can change a very bad idea into a good one. That would be a step too far in our 'ruthless extrapolation'.

Your suggesting nothing existed, not even space itself, yet somehow the expansion generated space and time out of nothingness? Is that really good science? I think not.

No reputable scientist would give such an incomplete answer. A far better and very scientific answer would be "We don't know." But there are various theories. I'd highly recommend the Lawrence Krauss video above about a "A universe from nothing" which does provide some plausible theories based on a persistent multi-verse.

Time has always existed. So has the basics of "stuff". That's all my Joe Ave IQ can handle (though I'm open to the Big Bang - or multiples/variations of it - of course).

I did enjoy the end of the first Men In Black movie as the camera pulled back from Earth, through galaxy, out to a spherical universe, back further to reveal several more universe-spheres, then further again to alien fingers that picked up a sphere and tossed it like a marble across the alien game board. Hey, why not?!

But anything else and I think my head would explode... In a small-bang kind of way.

Cheers, Matt

Also, isn't it just as likely that through some yet unknown process the Universe oscillates, i.e. expands and contracts over and over again? Isn't that possibility just as likely as this expansion being a one time event?

Nope!

We know absolutely 100% for certain that the universe is expanding at an accelerating rate and that it won't ever contract again. How do we know that? Because we've very precisely measured it... Cosmology is not just a purely theoretical science...

"..and that it won't ever contract again. :

DANGER, DANGER! Violation of the Irresponsible Extrapolation Continuum!

".. But what we know for sure that just ain't so." (or is impossible to know..)

DANGER, DANGER! Violation of the Irresponsible Extrapolation Continuum!

LOL! Hey, go argue that with Laurence Krauss! He's a particle physicist and a cosmologist and he gives a pretty darn convincing presentation of why our universe will continue to expand forever. I'm willing to take his word on this matter for now.

If and when the evidence to the contrary should come in, I'm sure he and other cosmologists, will, as a true scientists, reassess their positions at that time.

Cheers!
Fred

Good enough for me..

To fit it into the serenity prayer, "To have the strength to change what I can change, the humility to accept what I can't change, and the wisdom to know the difference." This isn't one that we can change.. it might not be one that we can ever really know.. but I'm glad there are those who are trying to find out.

You know how "Never" and "Always" statements just get to me.. I don't suppose either Krauss or I will ever really get an 'I told you so' moment on this question in any case.. so just pass along another beer, eh?

We don't have even a clue why the expansion rate is increasing. We can only guess, and extrapolate from what we have been able to see/deduce. If the expansionary force (dark energy), were going to reverse, would we even be able to detect that in the current era?

But real-world complexity often throws distracting noise into the data, making it difficult to discern more subtle behaviors.

Perhaps we need to pay more attention to the noise; what does it tell us? The signal to noise ratio seems to be increasing of late. Like the squeaky wheel, it says we're running out of grease. Things aren't functioning as they should, yet many would blame my ears, saying that I hear too much. This tells me a lot, the fact that every day denial is progressing to delusion. That so many devote so much time and energy to not dealing with inconvenient truths is a pretty good indicator that these truths are becoming harder to ignore.

Ecclesiastes 3.11: (KJV) He hath made everything beautiful in his time: also he has set the world in their heart, so that no man can find out the work that God maketh from the beginning to the end.

Ecclesiastes 3.14: I know that, whatsoever God doeth, it shall be forever: nothing can be put to it, nor any thing taken from it: and God doeth it, that men should fear before him.

More philosophy from Ecclesiastes.

On the energy crisis:

1.8: All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.

On sustainability:

1.9: The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under thew sun.

1.8: All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.

I promise you, I first read that as "nor the ear filled with herring".

You Swedes!

(my daughter, 1/8 Swedish confirmed that pickled Herring is the only fish that she likes.. aside from the English part of her that has just discovered Fish and Chips..)

Then things came off the rails a bit. Neutrinos turn out to have mass—in open defiance of the vanilla Standard Model. Cosmological observations indicate the existence of not only dark matter (new stuff not made of atoms on the periodic table), but also dark energy (providing a repulsive force and accelerating the expansion of the Universe).

Wouldn't it be more honest to say matter fudge factor and energy fudge factor?

A fudge factor[Wikipedia] is a quantity introduced into a calculation in order to "fudge" the results: that is . . . to make them match better what happens in the real world.

Similar thoughts from xkcd:

(alt text in original = "Though 100 years is longer than a lot of our resources.")

Can't include that one without this one: http://xkcd.com/605/

jeez... can't believe I've never seen xkcd before. I really MUST be a hermit. There's some great stuff there.

Not only are people generally ill equipped to think in terms of non-linear behavior but we also have trouble with the concept of feedback delays, a flaw with just as much if not more potential to be fatal.

For example, if you had a car that took several minutes to respond to actions on the gas and brake pedals it wouldn't be long before very bad things happened. Pressing the gas pedal for a few minutes as you impatiently waited for the car to start moving would result in the car smoothly accelerating up to speed, then well beyond as it continues to respond to your actions of a few minutes earlier. Frantically stomping on the brakes at this point has no immediate effect on your now high speed journey to disaster. Oops.

Now consider the feedback delays inherent in various earth systems, most of which are measured in decades if not centuries, and you begin to understand why our window of opportunity to avoid a number of potentially civilization ending disasters probably passed many years ago.

Cheers,
Jerry

and you begin to understand why our window of opportunity to avoid a number of potentially civilization ending disasters probably passed many years ago.

Not to mention that there is an incredibly powerful, well financed armada of propagandists and "think tanks" whose sole purpose is to debunk and discredit any claims that the status quo is not perfectly wonderful, and to slime the few pesky dissenters as Communists, doomers and freedom haters. Which continues to crush aforementioned dissent (and those delayed reality feedback signals) with near perfect success, all thanks to an intellectually lazy, innumerate and willfully ignorant public that only wants confirmation bias signals sent to the only part of their brains they regularly exercise --the reptilian complex.

We have such vehicles. They are called "large ships". Takes much longer time at school before you are alowed to drive one, than a car.

...you begin to understand why our window of opportunity to avoid a number of potentially civilization ending disasters probably passed many years ago.

The topic subject, Ruthless Extrapolation, didn't give you at least a slight pause before posting that?

This idea of feedback delay and its tendency to remove control from a system was probably the most important take-away for me when I read the classic 1972 Limits to Growth last summer.

I was so intrigued that I made some toy models of an otherwise logistic system, adding delay to the negative consequences. The overall tendency this fostered was overshoot and decline; becoming more exaggerated as the delay increased.

See my Discovering Limits to Growth writeup on DtM for more.

There needs to be deeper analysis of the economic reasons for some goal or prediction.

What would be the purpose and economic drivers for faster Atlantic crossing times ?

What has been increasing is the amount of information and the quality of communication at near light speed or at light speed.

Telegraph
Telephone
Satellite, television
internet, fiber
Skype and teleconferencing

coming
3D virtual reality conferencing

Speed of human travel will increase.
Speed for crossing the Atlantic will get back up to supersonic and hypersonic speeds at some point. There is progress on the Skylon spaceplane which would also apply to a hypersonic transport. There are projects towards supersonic business jets that have muffled the sonic boom.

Space travel could have had nuclear pulse propulsion (Project Orion). With that there would have been humans on Mars and other places in the solar system. Now we will wait until other developments enable space travel better than what we have now. Spacex and reusable rockets will enable costs to access orbit to drop by up to 100 times. As would success with the Skylon Space Plane. There is other funded work towards early nuclear fusion space propulsion.

You get what you pay for in space. The US has spent an inflation adjusted \$3 trillion on space. (NASA about \$1 trillion and then \$2 trillion on defense and spy agency space.) So we got a lot of facilities on the ground (political pork that is the states of powerful senators and congressmen, but that is like most of the rest of the US budget). And we got a lot of spy satellites, comm satellites, satellite TV, weather satellites etc...

It is pretty clear what is possible for improvements over the next ten years. Because there is relatively little work on the improvements to capabilities. I track all of the projects (except some of the secret ones) and know the state and progress and what is possible.

I notice that the failed Mars expectation was not matched up to failed expectations on peak oil. Many decades of misses there. Also, you put the energy scale on some silly 16000 year scale and do not have speed on a larger scale. A few decades of blips does not indicate what will happen in the future.

Speed of human travel will increase.
Speed for crossing the Atlantic will get back up to supersonic and hypersonic speeds at some point. There is progress on the Skylon spaceplane which would also apply to a hypersonic transport. There are projects towards supersonic business jets that have muffled the sonic boom.

Can't wait to see 9 billion humans whizzing around the globe to business meetings at hypersonic speeds, all powered by what? Pixie dust?! Oh wait, never mind, we are well into ecological overshoot and are hitting REAL resource limits!

Yes, more limits than previously imagined:

RALEIGH, NC—A coalition of geologists are challenging the way we look at global stone reserves, claiming that, unless smarter methods of preservation are developed, mankind will eventually run out of rocks.

I have been aware for sometime when ever I hear the comment " the stone age never ended because we ran out of stone " that actually if you meant building stone then we have not left that stone age

now it appears we will!

cool

Forbin

Ps: I must do some research on that stone age thing - I remember some archo TV program talking about deeper and deeper tunnels for flint ( the industrial "stone" of the stone age ) becoming more dangerous and the shortage of Deer pickaxes to dig tunnels ......

F - "...mankind will eventually run out of rocks." Actually we already have run out of rocks...in some areas. And the Bakken drilling boom is one cause. One of my Texas vendors has trucked "location boards" (8'X8' pallets made of 2X6's) from the Gulf Coast to ND because they can't source enough of the gravel they had been using for roads/locations. Companies only rent the boards...usually runs around \$40k to \$60k per month plus installation costs. When you think about it mankind has seldom run out of anything (exceptions like the dodo bird). It's just that what's left is too expensive to use.

Ummmm ...... The Onion.

When it is hypersonic planes.it will be the 0.1% who travel that way. So 9 million.

To get to a lot more moving at high speed it would be with vacuum maglev trains. Pipes that are.pumped down towards a vacuum. Need better magnets and more of them. China could start on that direction. With low pressure tube trains.

http://www.china.org.cn/china/2010-08/02/content_20624621.htm

The National Power Traction Laboratory of Southwest Jiaotong University is developing a vactrain, or a maglev train that runs through in an airless tunnel, allowing it to run at speeds of 600 kilometers to 1,000 kilometers per hour, Beijing Times reported.

The new technology can be put into operation in 10 years, said Zhang Yaoping, a researcher at National Power Traction Laboratory.

In high-speed evacuated tube transportation, the absence of air friction allows trains to run at extremely high speeds. The train carriages will be pressurized so passengers will not feel dizzy, Zhang said.

While the traditional railroad costs 150 million yuan (about US\$22 million) each kilometer to build, the vactrain will be less expensive because it has smaller tunnel section. But ticket prices for the vactrain will be more expensive than that of the high-speed trains, though they will become cheaper as technology improves, Zhang said.

==== If that is achieved
1100 kilometers Shanghai to Beijing. \$22 billion.
75 minutes Shanghai to Beijing for first generation vactrain.

http://www.et3.com/

ET3 can provide 50 times more transportation per kWh than electric cars or trains.

Speed in initial ET3 systems is 600km/h (370 mph) for in state trips, and will be developed to 6,500 km/h (4,000 mph) for international travel that will allow passenger or cargo travel from New York to Beijing in 2 hours. ET3 is networked like freeways, except the capsules are automatically routed from origin to destination.

alltough not stated in the wiki text if you read the book

http://en.wikipedia.org/wiki/A_World_Out_of_Time

you will see that larry had the earth crossed with such railways - and some thing that could go wrong with them

SciFi coming true - if our own world is not out of time , of course

Forbin

The new technology can be put into operation in 10 years, said Zhang Yaoping, a researcher at National Power Traction Laboratory.

Unfortunately I don't have 22 million dollars to spare or I'd bet that much but I'm willing to place \$1,000.00 in an escrow account for ten years, if you do the same. I'm betting that these trains never get built for use as mass transport and most certainly not in a ten year time frame.

I'm also betting that Joseph Tainter is right! Furthermore I'm betting that China is not exempt from resource limits and the problems of becoming an overly complex society. Care to take my bet?

Collapse of Complex Societies by Dr. Joseph Tainter

I am willing to have a couple of \$200 bets.

I would want it to be handled through Long Bets. Which means the money goes to the charity of the winner. ie \$400 per bet goes to the winners charity. Thus it would be legal and would have handled money.

It also lets us both write up why we believe our side of the bet now.

http://longbets.org/faq/

1. By Dec 31, 2031, high speed rail will exist for commercial use that can operate with a top speed over 600 mph.

2. By Dec 31, 2031, there will be either low pressure tube transport of people in commercial operation or for launching space cargo.

My main concern with the bets are that regular high speed rail is politically dominant in China. China may have ways to radically improve it to the 500-600 mph range. they would not be as energy efficient, but if there is abundant energy that will not be as important. The Beijing- Shanghai high speed rail trip falls from 5 hours now to 90 minutes. Regular Maglev needs more deployment. There is the one line in China from to the Shanghai airport. The extension was delayed. On the maglev side I am expecting massive improvements in the cost and technology for superconductors. I think the low pressure tube could see more initial value at the 350 mph range. Lower costs and very efficient. Low pressure vacuum launch systems might also get deployed. However, possibly not for people.

I am confident of the technology. I am confident of magnets improving. I am confident of the energy efficiency reasons. I see the economic benefit that China will see in tighter integration. I am not as sure about a 10 year timeframe because of politics. That is also why I did not want to limit it to China. If it is feasible and worthwhile and another country chooses to do it then I do not want that to count against me.

I do not think your reasons in related to resource limits and complex society are in any way valid or relevant.

Just as I have won my bets with Dittmar on uranium production, where he said lack of ability to increase uranium production would limit nuclear. Any limits have been because of bad choices and misplaced fear from Japan and Germany. Politics and society not technology and resources.

1. By Dec 31, 2031, high speed rail will exist for commercial use that can operate with a top speed over 600 mph.

2. By Dec 31, 2031, there will be either low pressure tube transport of people in commercial operation or for launching space cargo.

That time frame is way too far in the future for me to make a bet on it, not that I think there is much chance that it will actually happen but I just probably won't be around anymore by 2031...

Yair . . . Bloody Hell!! This sort of crap gets right up my nose!! Why? Why? Why the Hell would there be any need for this B/S?

The human race can survive and live productive contented lives if no one in the world ever travelled faster than fifty kilometers per hour.

This mindless quest for speed has been the cause of most of our problems. . . in my opinion

Cheers.

Too bad for humanity and many other species that more great minds haven't been used to find a way for humans to live sustainably.

For every great mind put to the task of finding a way for humans to live sustainably there are many more dedicated to the works of Edward Bernays

Hi JWS,

Well...there's always today and tomorrow - for the great minds to be "used," i.e., focused on sustainability.

They sometimes need to be asked.

Take the National Academy of Sciences, for example. They require a directive, usually from Congress and/or the POTUS and/or *any* State Legislature.

Please do take a moment to look at this, will you? We welcome feedback - and assistance!

IMVHO, there's a better and worse way to approach the "?" Tom has labeled.

maybe it has - and we just don't like the results

Forbin

Was this brought up due to the discussion about "The Singurality"? . . . a terrible example of ruthless extrapolation.

Extrapolating from a geological time frame, I surmise that this sudden and explosive use of stored sunshine will soon be over and all of the structures that distributed the energy for accelerated mixing with oxygen and subsequent combustion will become useless and valueless. The maximum entropy principle will have succeeded again and we can go back to living beneath a cooling evaporative forest canopy, eating lemurs and sloths, and radiating our own heat into the flow into space. Since all of the gradients will be gone, our minds will not longer need to process technical information, no need for “formal” education (and no energy for it either). We will all live on as competitive thermal, cellular radiators, the heat of our lives radiating skyward in a suitably Godly direction, as our bones and tissues are recycled by kindred beasts, releasing their own share of heat in unique ways.

Without this slow release of heat through a seemingly infinite variety of organic structures, the earthly landscape will seem rather impoverished, but I’m pretty sure kudzu and roaches will survive (but then again, trilobites, seemingly robust for millions of years, didn't make it). The structures we have concocted to rid ourselves of fossil fuels don’t compare to the great variety of organic structures that have performed a similar function over a much greater period of time. We’ve already unraveled forest ecosystems in exchange for the structures necessary to deplete the fossil fuel gradients. But, we must recognize that evolution commonly sends its conduits into dead ends.

Of course, we can look at forecasts of resource depletion (such as the Limits to Growth analysis) as another example of Ruthless Extrapolation.

In fact, let's look at walking: every step is a controlled fall. If we didn't put the next foot in place, we'd crash to the ground.

So, every step we take as we walk can be extrapolated to a disaster...

I would put the primary message of Limits to Growth (LTG) in a different category than the typical "ruthless extrapolators." The reason is that they used nonlinear models containing all the feedbacks they imagined may be important, and let the computer "solve" the dynamics. They did not know what to expect, and after initial dismay over the results, worked very hard to engineer their model to avoid a decline in human welfare before 2100. They succeeded in stabilizing the model—but only by introducing extreme (impractical) global controls on reproduction and industrial activity.

The main point is that calling LTG an example of ruthless extrapolation is grossly unfair considering the sophistication of their approach. Remember that ruthless extrapolation carries the flavor of "look what's been happening the last X years. Project this (unchanging state) forward, and look at the unbelievable result." Unbelievable is right. LTG does not fall into this trap. And they repeatedly state clearly that they are not making predictions, but rather trying to elucidate modes of behavior in a complex system.

If you are focusing on their materials table rather than their model, then you're doing what many others who aim to discredit LTG have done: pick a minor, early part of their text (also explicitly described as not being a prediction) and using this to throw mud at the entire thing&mdah;presumably because the overall message is unpalatable, so must be destroyed. And even on this front, your walking comparison skips over the notion that all our earthly minerals are finite, implying that there will be no limits if we just have the courage to put the next foot out. Ever seen someone walk into a wall? It's not the "controlled fall" that ends up hurting. Other modes can assert themselves.

See Ugo Bardi's account of the methods by which various people strove to discredit LTG.

Tom,

The problem with LTG is that they assumed the result: the model assumes hard limits to resources (aka depletion), and does not allow substitution.

It's a model of the dynamics under which limits to growth would be reached, but does not examine the fundamental assumption of the existence of practical limits (as opposed to theoretical limits, like those you've explored).

The only renewable resource in the model is agricultural: the idea that wind and solar power could replace fossil fuels is simply not in the model.

That is why I would describe LTG as an exercise in Ruthless Extrapolation: they're ruthlessly extrapolating the depletion of fossil fuels.

--------------------------------------------------

Let me say it again, with different words:

The Limits to Growth scenarios were designed not to prove that there were limits to growth. Instead, they were designed to show the behavior of a system that contained limits (overshoot). The limits were assumed by the model.

I would agree that the LTG model was useful - it showed what overshoot looked like, and showed that overshoot was possible in a model of limited resources.

It did not demonstrate that it was a model of the real world. The model was extremely simple. For instance, resources were unitary: they weren't broken down into minerals, energy, food, or anything like that: just "resources". There wasn't an explicit recognition of renewable energy - wind, solar, etc. That's a mighty simple model.

This simplicity, and the exclusion of substitution of non-limited resources for limited resource made the model very, very far from anything that might be expected to model the real world. As the authors said repeatedly, these were scenarios, not forecasts. It was treated as such by the economics community, much to the puzzlement of environmentalists who didn't understand just how limited the model was.

The problem with LTG is that they assumed the result: the model assumes hard limits to resources (aka depletion), and does not allow substitution.

???

'Hard Limits' to resources is not some arbitrary assumption. It is an undeniable fact of life!

Whether or not there are any suitable substitutes for fossil fuels or any other specific resource completely misses their main point!

http://connect.clubofrome.org/ecms/files/resources/What_was_the_message_...

Limits to Growth says that the human ecological footprint can not continue to grow indefinitely because Planet Earth is physically limited and in fact rather small relative to human activity. Humanity cannot – in the long run - use more physical resources and generate more emissions every year than nature is capable of supplying in a
sustainable manner.

Well, yes, there are limits. But, are they practical limits?

Humans use very roughly 20TW of energy. The sun radiates 100,000TW of energy on the earth continuously.

So, the LTG model should be re-run using a resource multiplier of at least 100, not 2x.

Similarly, is it plausible to describe silicon as being a limited resource, as a practical matter?

Or, iron and aluminum, which are large percentages of the earth's crust?

---------------------------------

Let me hasten to add that I think that Climate Change is a big problem. I just don't think describing it as a resource-limit problem is useful.

We can call it a problem of depletion of the CO2 sink, but that's like walking on a wood floor in hobnail boots, and calling it a "nail-damage-sink depletion" problem. If I wear hobnail boots on my wood floor, the wood floor's life will be very limited, and wood flooring won't be sustainable (it will wear out too quickly to replace economically). If I wear soft slippers, it will become sustainable. If I'm used to wearing boots inside, then slippers are a big change from BAU. OTOH, I think slippers are a great lifestyle, and there's no sacrifice to changing to them.

The idea of "depletion of the CO2 sink" comes from thinking of fossil fuels as necessary energy sources, thus thinking of their pollution as necessary and analogous to waste heat (which requires a sink).

---------------------------------

Let me also hasten to add that I think we should kick the fossil fuel habit ASAP - FF in general and oil in particular are polluting and hazardous, and we have better alternatives.

Thanks for clarifying your point. Indeed, lumping all resources into a monolithic entity is a substantial simplification. But as long as any one of the resources vital to our modern society hits a non-substitutable limit, then the dynamical modes exposed by the model may well have relevance. It would be hard to convince me that all of our present day resources have adequate substitutes—given the finite nature of the periodic table, for instance.

We're only now getting society to the scale where we are straining the inheritance bank account. The myriad substitutes that have presented themselves thus far are overwhelmingly of the sort that the substitute is superior to that which came before. What happens when substitutes become inferior? What if species extinction results in crippling vital natural services for which we cannot engineer adequate substitutes? Our faith in substitutes is therefore predicated on the up phase, and may be coloring our perceptions of how things unfold in the future (ruthless extrapolation).

While I am certainly a big fan of our trying it, I cannot be certain that wind, solar, nuclear, etc. will successfully substitute the one-time gift of fossil fuels. My main stance is that we should not wave warnings away, and pursue a high-stakes route with no backup plans in the event that nature is not keen to play our "we can substitute and grow indefinitely" game. The fact that LTG exposed a fairly generic mode of overshoot and decline in their simple model makes me sit up.

Tom,

Broadly speaking, I'd say we're in agreement. I agree strongly that as a society that we need to plan carefully for the future, take much better care of our environment, and move away from fossil fuels ASAP (first through greater efficiency, 2nd via alternative energy sources).

I think there are some details that are still worth discussing, however:

Climate Change, species extinctions, and fossil fuels are not a necessary part of modern civilization, and framing them as such is counter-productive. Framing them that way only gives ammunition to the enemies of change - the minority of fossil fuel industry workers and investors who would be directly harmed by change.

The fact is that our world would be cleaner, more prosperous and more peaceful without fossil fuels. The enemies of change use misinformation as their primary tool to prevent change, and the meme that "change in our way of life would be "The End Of The World As We Know It" only helps that disinformation campaign.

In fact, we have all the technology and engineering needed to eliminate fossil fuels right now. Further tech advancement will lower costs and solve remaining problems, but those costs are low enough, and the problems have clear solutions. Alternatives to fossil fuel are "good enough".

There are many, many ways to skin a cat. For instance, there are dozens of chemistries and methods for collecting solar power, and dozens of battery chemistries and ways to store energy. I haven't seen any credible candidates for elements that can't be substituted and/or recycled effectively. Look through the periodic table - can you think of any? (there was a pretty good article on TOD about that, called "Metal Minerals Scarcity and the Elements of Hope", at http://europe.theoildrum.com/node/5559 - it's worth a look)

The myriad substitutes that have presented themselves thus far are overwhelmingly of the sort that the substitute is superior to that which came before.

That's not really true. Hunting & gathering had a much higher E-ROI than agriculture. Local wood had a much higher E-ROI than distant coal. And, wind and solar are actually very high E-ROI. This can be a complex topic - I can provide further info on it if it seems like a key sticking point to you.

In general, I applaud your desire to plan ahead, and analyze our challenges. Still, that analysis needs to be realistic, so that we identify the true challenges. Personally, I think Climate Change is our biggest threat, and the biggest practical problem we need to solve is how to overcome the resistance of the minorities that are threatened by change.

We need to move away from fossil fuels in general, and oil in particular, ASAP. Let's not aid those obstructive minorities with overly simple analysis that suggests that alternatives are not better.

Climate Change, species extinctions, and fossil fuels are not a necessary part of modern civilization, and framing them as such is counter-productive. Framing them that way only gives ammunition to the enemies of change - the minority of fossil fuel industry workers and investors who would be directly harmed by change.

Nick, you are still missing the point! We simply, already have too many F'n people on this planet consuming resources. That's the biggest threat we face to our collective survival... everything else is completely moot!

Population Growth in a Yeast Colony

We simply, already have too many F'n people on this planet consuming resources.

Well, no, we don't.

OECD population growth is pretty low, with many countries with below replacement fertility. World population growth is likely to end by very roughly 2050.

Obesity is a greater health threat around the world than undernutrition.

Fossil fuels can (and should, ASAP) be replaced.

Humanity is certainly wrecking it's environment, but that can change. Changing that would be a heck of a lot easier and less painful than reducing the population....

Changing that would be a heck of a lot easier and less painful than reducing the population....

Nick, that is denial and wishful thinking at its worst!

http://www.sustainablescale.org/conceptualframework/understandingscale/m...

Ecological Overshoot Demonstrated
Dividing the 11.2 billion hectares available by the global population indicates that there are on average 1.8 bioproductive hectares per person on the planet. The 2004 Living Planet Report indicates that the actual usage was 13.5 billion global hectares or 2.2 hectares per person – more than a 20% overshoot.2 The overshoot result indicates that our annual draw down of natural capital is liquidating natural capital income, as well as reducing natural capital itself ( see Natural Capital and Income). Such an overshoot is ecologically unsustainable. Time series of the global Ecological Footprint indicate that human activities have been in an overshoot position for approximately three decades, and the overshoot is increasing over time.

Well, no, it isn't at all.

The majority of the "Ecological Footprint" described above is due to fossil fuel consumption (it's described in terms of land, which suggests that it's due to food production, but that's misleading). Fossil fuels can be replaced relatively easily. Far faster and more easily than population could be reduced.

Leibig's law of the minimum is what will stop the ruthless extrapolation of the growth in renewables. Nick you are one who always extrapolates into the future, especially with your substitutes, without necessarily mentioning them.

An example I keep raising is silver, that PV currently uses 6% of world production. The iron, silicon and aluminium may be fine, but the more technology involved with products, the more complexity and the greater the use of 'minor' resources. If the answer is 'there are always substitutes', then I would like to know what substitute you could use for magnesium in plant health. Assume we can have as much of every other nutrient as needed, yet no magnesium. What do you propose as a substitute?

In the real world there are indeed limits of resources and only with unlimited energy could we do things lie extract gold and uranium from the ocean water. Of course with unlimited energy we would cook the planet in very short period of time.

We are very close to finding that oil is indeed the lubricant that allows the world economy to function. The high oil prices in 2008 that helped crash economies, also dried up funding for the growth rate of renewables.

Leibig's law of the minimum is, in essence, what Tom and I were discussing nearby. I've seen no good evidence that such items exist for the purposes of this discussion..

Silver is not essential to PV. It's a handy conductor, but it's far from essential.

oil is indeed the lubricant that allows the world economy to function.

Nah. It's just a temporary addiction.

Silver is not essential to PV. It's a handy conductor, but it's far from essential.

Perhaps... however NPK is essential for producing food and there are no substitutes!

Environment: The disappearing nutrient

Phosphate-based fertilizers have helped spur agricultural gains in the past century, but the world may soon run out of them. Natasha Gilbert investigates the potential phosphate crisis.

Maybe we can just substitute our carbon based biochemistry with silicon based life forms.

Magyar,

Just because something is essential to biochemistry doesn't mean that it qualifies as eligible for inclusion in the LTG model. It has to be several things: essential, in limited supply, recyclable, part of the human economy, etc.

There is an enormous amount of phosphate out there, and it can be recycled.

That makes it fall into the Y2K category of problems: it needs to be planned for, but it's eminently solvable.

Here's info:

Phosphorus limits are greatly exaggerated: Florida provides 25% of world production. For decades, it has been said that the phosphate in Florida could be mined for about another 25 years. Technological advances and market changes, however, have continually lengthened the expected life of phosphate mining, allowing mining of rock that wouldn’t have been mined in previous years.

The Hawthorne Formation, which contains much of the Florida phosphate deposits, covers much of the Atlantic Coastal Plain of the southeastern United States. In the heart of the Central Florida phosphate district, the Bone Valley Formation overlays the Hawthorn Formation. The two are separated by a limestone layer of varying thickness. It is the Bone Valley Formation that has produced the majority of mining activity in central Florida to date. The Hawthorne Formation is being mined in North Florida. It is also the Hawthorne Formation that is being mined in the southern extension of the central Florida phosphate district.

Florida phosphate reserves alone contain about 10 billion tons of soluble phosphate rock. Based on the current mining rate in Florida, this would last more than 300 years.

It appears that the USGS resource is understated, if the footnotes on the 2007 report are accurate:
"Large phosphate resources have been identified on the continental shelves and on seamounts in the Atlantic Ocean and the Pacific Ocean. High phosphate rock prices have renewed interest in exploiting offshore resources of Mexico and Namibia."

Offshore resources would certainly be more expensive, but they'd create a buffer to prevent overshoot - a zone where consumption became more expensive, and pushed us towards recycling.

Consumption could be reduced with improved farming practices - roughly half of US ag production goes to livestock. Recycling their phosphorus shouldn't be that hard, in the grand scheme of things.

I'd say we have quite a lot of time to set up really thorough recycling that includes ag and human input/outputs.

And they repeatedly state clearly that they are not making predictions, but rather trying to elucidate modes of behavior in a complex system.

To the extent that LTG does not make predictions is the extent to which LTG is at best an intellectual exercise or a conjecture, and otherwise unimportant scientifically. Predictive power is the defining characteristic of useful scientific theory (as the author surely knows). Sophistication in approach does not make for an exception to the rule.

Excellent point.

The authors of LTG would like to have their cake and eat it too. They often claim that their models display predictive powers, but when this is demonstrated to be unrealistic they retreat to a more defensible (but contradictory) position, which is that the LTG model is not intended to generate forecasts, but only model how an economy might behave when dealing with limits.

That, of course, is the correct position. On the other hand, the results of the model are trivial given the unrealistic nature of the model and it's assumptions.

Falstaff - "..and otherwise unimportant scientifically..." While I agree with your general sentiment I wouldn't say "unimportant". I don't tend to have much use for models in general (in particular as predictive tools) but I do find value in seeing the impact (or lack) of factors as they vary. If the acceptable range of Factor A produce little change in the outcome of a model then there's a value. Assuming, of course, the model dynamics are correctly designed.

Modeling? As I've crudely made the point before: modeling is a lot like masturbation: it's Ok as long as you don't start believing its the real thing. LOL.

Ruthless extrapolation, nice term. Another classic cartoon on this: the sorcerer's apprentice.