Tuesday, February 15, 2011

Some speculations on the frontier below our feet

The biggest problem we face with the frontier below that we're literally in the dark. We have a number of crude geophysical techniques (seismology, gravity field, electromagnetic, etc.) but none of them allow creating a detailed map like we can make of the surface of a distant moon of Saturn or even of a cloud-covered planet like Venus. So in some important ways we are more ignorant of the ground a few hundred meters down in most places on our own planet than we are of the surface of most of the other planets and moons in our solar system. We know less about the distribution of the common molecules below the earth's crust, only 35 kilometers below our feet, than we do of the distribution of those molecules on the surfaces of dust clouds in distant galaxies.

One possible fix to this earth-blindness is the neutrino, and more speculatively and generally, dark matter. We can detect neutrinos and anti-neutrinos by (I'm greatly oversimplifying here, physicists please don't cringe) setting up big vats of clear water in complete darkness and lining them with ultra-sensitive cameras. The feature of neutrinos is that they rarely interact with normal matter, so that most of them can fly from their source (nuclear reactions in the earth or sun) through the earth and still be detected. The bug is that almost all of them fly through the detector, too. Only a tiny fraction hit a nucleus in the water and interact, giving off a telltale photon (a particle of light) which is picked up by one of the cameras. It is common now to detect neutrinos from nuclear reactors and the sun, and more recently we have started using some crude instruments to detect geo-neutrinos (i.e. neutrinos or anti-neutrinos generated by the earth not the sun). With enough vats and cameras we may be able to detect enough of these (anti-)neutrinos from nuclear reactions (typically radioactive decays) in the earth's crust to make a detailed radioisotope map (and thus go a long way towards a detailed chemical map) of the earth's interior. For the first time we'd have detailed pictures of the earth's interior instead of very indirect and often questionable inferences. A 3D Google Earth. These observatories may also be a valuable intelligence tool, detecting secret nuclear detonations and reactors being used to construct nuclear bomb making material, via the tell-tale neutrinos these activities give off.

Other forms of weakly interacting particles, the kind that probably make up dark matter, may be much more abundant but interact even more weakly than neutrinos. So weakly we haven't even detected them yet. They're just the best theory we have to explain why galaxies hang together: if they consisted only of the visible matter they should fly apart. Nevertheless, depending on what kinds of dark particles we discover, and on what ways they weakly interact with normal matter, we may find more ways of taking pictures of the earth's interior.

What might we find there? One possibility: an abundance of hydrogen created by a variety of geological reactions and sustained by the lack of oxygen. Scientists have discovered that the predominant kinds of rocks in the earth's crust contain quite a bit of hydrogen trapped inside them: on average about five liters of hydrogen per cubic meter of rock. This probably holds at least to the bottom of the lithosphere. If so that region contains about 150 million trillion liters of hydrogen.

Sufficiently advanced neutrino detectors might be able to see this hydrogen via its tritium, which when it decays gives off a neutrino. Tritium with its half-life of about 12 years is very rare, but is created when a more common hydrogen isotope, deuterium, captures a neutrino from a more common nuclear event (the decay of radioisotopes that are common in the earth's crust). About one-millionth of the deuterium in the heavy water moderating a nuclear reactor is converted into tritium in a year. This rate will be far less in the earth's interior but still may be significant enough compared to tritium's half-life that a sufficiently sensitive and calibrated (with respect to the much greater stream of such neutrinos coming from the sun) neutrino detector of the future may detect hydrogen via such geotritium-generated neutrinos. However, the conversion of deuterium to tritium in the earth's core may be so rare that we will be forced to infer the abundance of hydrogen from the abundance of other elements. Almost all elements have radioisotopes that give off neutrinos when they decay, and most of these are probably much more common in the earth's core than tritium.

Another possibility for detecting hydrogen is, instead of looking for geo-neutrinos, to look at how the slice of earth one wants to study absorbs solar neutrinos. This would require at least two detectors, one to look at the (varying) unobstructed level of solar neutrinos and the other lined up so that the geology being studied is between that detector and the sun. This differential technique may work even better if we have a larger menagerie of weakly interacting particles ("dark matter") to work with, assuming that variations in nuclear structure can still influence how these particles interact with matter.

It's possible that a significant portion the hydrogen known to be locked into the earth's rocks has been freed or can be freed merely by the process of drilling through that rock, exposing the highly pressurized hydrogen in deep rocks to the far lower pressures above. This is suggested by the Kola Superdeep Borehole, one of those abandoned Cold War super-projects. In this case instead of flying rockets farther than the other guy, the goal was to drill deeper than the other guy, and the Soviets won this particular contest: over twelve kilometers straight down, still the world record. They encountered something rarely encountered in shallower wells: a "large quantity of hydrogen gas, with the mud flowing out of the hole described as 'boiling' with hydrogen."

The consequences of abundant geologic hydrogen could be two-fold. First, since a variety of geological and biological processes convert hydrogen to methane (and the biological conversion, by bacteria appropriately named "methanogens", is the main energy source for the deep biosphere, which probably substantially outweighs the surface biosphere), it suggests that our planet's supply of methane (natural gas) is far greater than of oil or currently proven natural gas reserves, so that (modulo worries about carbon dioxide in the atmosphere) our energy use can continue to grow for many decades to come courtesy of this methane.

Second, the Kola well suggests the possibility that geologic hydrogen itself may become an energy source, and one that frees us from having to put more carbon dioxide in the atmosphere. The "hydrogen economy" some futurists go one about, consisting of fuel-cell-driven machinery, depends on making hydrogen which in turn requires a cheap source of electricity. This is highly unlikely unless we figure out a way to make nuclear power much cheaper. But by contrast geologic hydrogen doesn't have to be made, it only has to be extracted and purified. If just ten percent of the hydrogen in the lithosphere turns out to be recoverable over the next 275 years, that's enough by my calculations to enable a mild exponential growth in energy usage of 1.5%/year over that entire period (starting with the energy equivalent usage of natural gas today). During most of that period human population is expected to be flat or falling, so practically that entire increase would be in per capita usage. To put this exponential growth in perspective, at the end of that period a person would be consuming, directly or indirectly, about 330 times as much hydrogen energy as they consume in natural gas energy today. And since it's hydrogen, not hydrocarbon, burning it would not add any more carbon to the atmosphere, just a small amount of water.

Luckily our drilling technology is improving: the Kola well took nearly two decades to drill at a leisurely pace of about 2 meters per day. Modern oil drilling often proceeds at 200 meters/day or higher, albeit not to such great depths. Synthetic diamond, used to coat the tips of the toughest drills, is much cheaper than during the Cold War and continues to fall in price, and we have better materials for withstanding the high temperatures and pressures encountered when we get to the bottom of the earth's crust and proceeding into the upper mantle (where the Kola project got stymied: their goal was 15 kilometers down).

A modern drill bit studded with polycrystalline diamond

Of course, I must stress that the futuristic projections given above are quite speculative. We may not figure out how to affordably build a network of neutrino detecting vats massive enough or of high enough precision to create detailed chemical maps of the earth's interior. And even if we create such maps, we may discover not so much hydrogen, or that the hydrogen is hopelessly locked up in the rocks and that the Kola experience was a fluke or misinterpretation. Nevertheless, if nothing else this exercise shows, despite all the marvelous stargazing science that we have done, how much mysterious ground we have below our shoes.

Wednesday, February 09, 2011

Great stagnation or external growth?

Tyler Cowen posits that we are going through a Great Stagnation. Civilization has harvested the low hanging fruit of the internal combustion engine, electricity, and so on that drove great increases in value and productivity from the end of the nineteenth century. But we have made so few similarly productive discoveries in recent decades that as a result progress is slowing down. Markets have thus overestimated economic growth, resulting in the dot-com bubble and crash and the more recent market problems as real estate prices failed to keep pace with expectations. This thesis echoes much that Peter Thiel and others have been saying, that the financial industry has, in its expectations about financial returns, been counting on 20th century levels of economic growth in the developed world but instead has hit the reality of lower growth rates here, resulting in market volatility and drops.

These pessimistic observations of long-term economic growth are in many ways a much needed splash of cold water in the face for the Kurzweilian "The Singularity is Near" crowd, the people who think nearly everything important has been growing exponentially. And it is understandable for an economist to observe a great stagnation because there has indeed been a great stagnation in real wages as economists measure them: real wages in the developed world grew spectacularly during most of the 20th century but have failed to grow during the last thirty years.

Nevertheless Cowen et. al. are being too pessimistic, reacting too much to the recent market problems. (Indeed the growing popularity of pessimistic observations of great stagnations, peak oil, and the like strongly suggest it's a good time to be long the stock markets!) These melancholy stories fail to take into account the great recent increases in value that are subjectively obvious to almost all good observers who have lived through the last twenty years but that economists have been unable to measure.

In many traditional industries, such as transportation and real estate, the pessimistic thesis is largely true. The real costs of commuting, buying real estate near where my friends are and where I want to work, of getting a traditional college education, and a number of other important things have risen significantly over the past twenty years. These industries are going backwards, becoming less efficient, delivering less value at higher cost: if we could measure their productivity it would be falling.

On the other hand, the costs of manufacturing goods whose costs primarily reflect manufacturing rather than raw materials has fallen substantially over the least twenty years, at about the same rate as in prior decades. Of course, most of these gains have been in the developing and BRICs countries, for a variety of reasons, such as the higher costs of regulation in the developed world and the greater access to cheaper labor elsewhere, but those of us in the U.S., Europe and Japan still benefit via cheap imports that allow us to save more of our money for other things. But perhaps even more importantly, outside of traditional education and mass media we have seen a knowledge and entertainment sharing revolution of unprecedented value. I argue that what looks like a Great Stagnation in the traditional market economy is to a significant extent a product of a vast growth in economic value that has occurred on the Internet and largely outside of the traditional market economy, and a corresponding cannibalization of and brain drain from traditional market businesses.

Most of the economic growth during the Internet era has been largely unmonetized, i.e. external to the measurable market. This is most obvious for completely free services like Craig's List, Wikipedia, many blogs, open source software, and many other services based on content input by users. But ad-funded Internet services also usually create a much greater value than is captured by the advertising revenues. These include search, social networking, many online games, broadcast messaging, and many other services. Only a small fraction of the Internet's overall value has been monetized. In other words, the vast majority of the Internet's value is what economists call an externality: it is external to the measurable prices of the market. Of course, since this value is unmeasured, this thesis is extremely hard to prove or disprove, and can hardly be called scientific; mainly it just strikes me as subjectively obvious. "Social science" can't explain most things about society and this is one of them.

What's worse for the traditional market (as opposed to this recent tsunami of unmonetized voluntary information exchange), this tidal wave of value has greatly reduced the revenues of certain industries. The direct connection the Internet provides between authors and the readers put out of business many bookstores. Online classifieds and free news sources have cannibalized newspapers and magazines. Wikipedia is destroying demand for the traditional encyclopedia. Free and cut-price music has caused a substantial decline in music industry revenues. So the overall effect is a great increase in value combined with a perhaps small, but I'd guess significant reduction in what GDP growth would have been without the Internet.

What are some of the practical consequences? Twenty years ago most smart people did not have an encyclopedia in the home or at the office. Now the vast majority in the developed and even hundreds of millions in the BRICs countries do, and many even have it in the car or on the train. Twenty years ago it was very inconvenient and cost money to place a tiny classified ad that could only be seen in the local newspaper; now it is very easy and free to place an ad of proper length that can be seen all over the world. Search engines combined with mass voluntary and generally free submission of content to the Internet has increased the potential knowledge we have ready access to thousands-fold. Social networking allows us to easily reconnect with old friends we'd long lost contact with. Each of us has access to much larger libraries of music and written works. We have access to a vast "long tail" of specialized content that the traditional mass media never provided us. The barriers to a smart person with worthwhile thoughts getting fellow humans to attend to those thoughts are far lower than what they were twenty years ago. And almost none of this can be measured in market prices, so almost none of it shows up in the economic figures on which economists focus.

Cowen suggests that external gains of similar magnitude occurred in prior productivity revolutions, but I'm skeptical of this claim. A physical widget can be far more completely monetized than a piece of information, because it is excludable: if you don't pay, you don't get the widget. As opposed to information that computers readily copy. (The most underappreciated function of computers is that they are far better copy machines than the paper copiers). It's true that competition drove down prices. But the result was still largely monetized as greater value caused increased demand, whereas growth in the use of search engines, Twitter, Wikipedia, Facebook etc. largely just requires adding a few more computers that now cost far less than the value they convey. (Yes, I'm well aware of scaling issues in software engineering, but they typically don't require much more than a handful of smart computer scientists to solve). Due to Moore's Law the computers that drive the Internet have radically increased in functionality per dollar since the dawn of the Internet. Twitter's total capital equipment purchases, R&D, and user acquisition expenditures are less than fifty cents per registered user and these capital investment costs per user continue to drop at a ferocious rate for Internet businesses and non-profits.

The brain drain from traditional industries can be seen in, for example, the great increase in the proportion of books on computer programming, HTML, and the like on bookstore shelves to traditional engineering and technical disciplines from mechanical engineering to plumbing. It is not so blatant in the relative growth of computer science and electrical engineering relative to other engineering disciplines, but that's just the tip of the iceberg and vast numbers of non-computer scientists, including many with engineering degrees or technical training in other areas, have ended up as computer programmers.

Fortunately, the Internet is giving a vast new generation of smart people access to knowledge who never had it before. The number of smart people who can learn an engineering discipline has probably increased by nearly a factor of ten over the last twenty years (again largely in the BRICs and developing world of course). The number who can actually get a degree of course has not -- which gives rise to a great economic challenge -- what are good ways for this vast new population of educated smart people to prove their intelligence and knowledge when traditional education with its degrees of varying prestige is essentially a zero-sum status game that excludes them? How do we get them in regular social contact with more traditionally credentialed smart people? The Internet may solve much of the problem of finding fellow smart people who share our interests and skills, but we still emotionally bond with people over dinner not over Facebook.

As for the great stagnation in real wages in particular, the biggest reason is probably the extraordinarily rapid pace at which the BRICs and developing world has become educated and accessible to the developed world since the Cold War. In other words, outsourcing has in a temporary post-Cold-War spree outraced the ability of most of us in the developed world to retrain to the more advanced industries. The most unappreciated reason, and the biggest reason retraining for newer industries has been so difficult, is that unmonetized value provides no paying jobs, but may destroy such jobs when it causes the decline of some traditionally monetized industries. On the Internet the developed world is providing vast value to the BRICs and developing world, but that value is largely unmonetized and thus produces relatively few jobs in the developed world. The focus of the developed world on largely unmonetized, though extremely valuable, activities has been a significant cause of wage stagnation in the developed world and of skill and thus wage increases in the developing world. Whereas before they were buying our movies, music, books, and news services, increasingly they are just getting our free stuff on the Internet. The most important new industry of the last twenty years has been mostly unmonetized and thus hasn't provide very many jobs to retrain for, relative to the value it has produced.

And of course there are the challenges of the traditional industries that gave us the industrial revolution and 20th century economic growth in the first place. Starting with the most basic and essential: agriculture, extraction, and mass manufacturing. By no means should these be taken for granted; they are the edifice on which all the remainder rests. Gains in agriculture and extraction may be diminishing as the easy pickings (given sufficiently industrial technology and a sufficiently elaborated division of labor) of providing scarce nutrients and killing pests in agriculture and the geologically concentrated ores are becoming history. Can the great knowledge gains from the Internet be fed back to improve the productivities of our most basic industries, especially in the face of Malthusian depletion of the low hanging fruit of soil productivity and geological wealth? That remains to be seen, but despite all the market troubles and run-up in commodity prices, which have far more to do with financial policies than with the real costs of extracting commodities, I remain optimistic. We still have very large and untapped physical frontiers. These tend to be, for the near future, below us rather than above us, which flies in the face of our spiritual yearnings (although for space fans here is the most promising possible exception to this rule I have encountered). The developing world may win these new physical frontiers due to the high political value the developed world places on environmental cleanliness, which has forced many dirty but crucial businesses overseas. Industries that involve far more complex things, like medicine and the future of the Internet itself, are far more difficult to predict. But the simple physical frontiers as well as the complex medical and social frontiers are all there, waiting for our new generations with their much larger number of much more knowledgeable people to tap them.