Reading Leviticus

This past shabbat marked the start of Leviticus, the third book of the Torah, for the parashat shavua (weekly portion). In Hebrew, the book is called, as biblical books usually are, by a word for the first sentence, in this case, Vayiqra, "And He called" - that is, G-d called to Moses, saying ... and so on. The first part of the book contains detailed instructions on sacrifices, or offerings, in the Tent or Mishkan (later in the Temple). The later parts include most of the laws of kashrut and the Jewish holidays, as well as the famous Holiness Code of chapters 18-19. Many commandments in those chapters are punctuated by the injunction to "be holy, for I am holy." They include bans on sexual immorality (incest, bestiality, homosexuality) and the commandments to love both "neighbor" (meaning fellow Israelite) and "stranger" as oneself. The latter is repeated 36 times in the Torah, probably it so cuts against the grain of human nature, especially in a tribe- or clan-based society.

In Persian-Hellenistic-Roman times, the book was sometimes called Torat Kohanim, the "teaching for the priests," because so much of it is (chapters 1-16 and 27) directed at them - hence the Greco-Latin name for it, Leviticus, after the Levi'im or Levites, the priestly tribe. In its original form, it was probably intended for the priests alone. But over time, the influence of prophets and rabbis changed that, and it became a book read and followed by all Jews. All religions tend to become democratized over time. In this case, this trend is enjoined by the book itself, which envisions the whole people - not just the Levites - as a "kingdom of priests" (Exodus 19).

Expecting memorable narratives and theological puzzles, readers and worshippers today often have a hard time relating to Leviticus. The system of sacrifices seems especially off-putting to modern sensibilities. This isn't a new reaction. Even in ancient times, the prophets frequently attacked, not the offerings per se, but the mechanical performance of sacrifices with no accompanying inward change. Some rabbis of late antiquity envisioned a messianic era with a restored Temple, but no animal sacrifices. The great medieval philosopher and commentator Rambam (Maimonides) viewed the system of offerings as a concession to the habits and mentality of ancient peoples. He even viewed the building of the Tent and later the Temple in the same light. People need something tangible and visible related to worship. If not properly channeled, this impulse becomes misdirected into idolatry, like the Golden Calf episode toward the end of Exodus. According to this argument, Moses' apparent original vision was too demanding for the people, because it required too much abstraction and faith in the unseen. After the Golden Calf, the Tent, the Altar, and the sacrifices were thus put in place as an acceptable substitute for common pagan practices. Sacrifice, like other tangible and quid-pro-quo forms of religion, was common in ancient times. But in the Jewish case, idolatry itself was forbidden, and the authority of the priests subordinated to that of the Torah and its prophets.

Not everyone agreed with Maimonides, then or now. Another great medieval commentator, Ramban (Nachmanides), rejected this whole line of thinking, and viewed the sacrifices as an unequivocally positive way for man and G-d to meet.

While sacrifice in religion seems odd to us today, it's important to recognize that most later developments in religion are all derived from sacrifice in some way. Prayer is the verbal and mental substitute for an offering; even more so is tzedakah (what Christians call charity). Jewish tradition views study as akin to sacrifice as well. Speaking of Christianity, the whole religion has sacrifice at its heart. Many Muslims make sacrifices for certain holidays.

Of course, there are negative connotations to sacrifice, and modern people especially dislike the self-negation implicit in it. There are also destructive forms of sacrifice associated historically with religion, such as persecution or (nowadays) suicide bombers.

The key to understanding sacrifice in Judaism as something positive is to see that what G-d demands is not a lifeless corpse or flesh and bone blown up and burned, but a living offering: a life properly lived. It is an offering of "holy living" - in Hebrew, a qorban (something brought near) - not something destroyed nor "holy dying" - and that makes all the difference.

Climate as heat engine

It's helpful to conceptualize the climate, like any thermodynamic system, as if it were an engine driven by the second law. Heat flows from higher temperatures to lower - it's disorganized energy that seeks increasingly disorganized forms, sometimes doing organized work along the way. The ultimate source of the energy flow is the Sun. But the immediate reservoirs for the captured solar energy lie on the Earth: the tropical oceans and the Earth's surface. These two heat baths drive two distinct engines.

This double heat engine has two parts, a vertical one in the air, and a horizontal one in the oceans. The vertical engine has a water evaporation-condensation heat subengine inside. Since the climate is an open system, the heat is not absorbed and stored all at one time. Some parts are really good at absorbing and storing heat - water above all. Others pose "bottlenecks" that make heat flow difficult, and the heat flow gets "backed up." We saw earlier that big reservoirs with a lot of heat capacity (water in all its forms, mainly) tend to moderate temperature changes. Heat "backing up" tends to raise "upstream" temperatures above what they would have been otherwise.

Recall the three basic heat transport mechanisms: convection, radiation, and conduction. It's helpful to break out water evaporation and condensation as a separate heat flow mechanism, even though efficiently moving evaporated water up in the atmosphere requires vertical convection, together with diffusion. Heat flows in the most efficient way possible, if that's available. If it's not, heat will flow in the next most efficient way, etc. The most efficient method is dominant, but that doesn't mean the less efficient mechanisms are not also at work - just that they aren't dominant.

The poleward flow of ocean heat. In the oceans, heat flows from the tropics, around the equator, towards the colder poles. The organized work is manifested as ocean currents. This flow is "horizontal" (actually, parallel to the Earth's curved surface) and does little work against gravity.

This ocean heat transport is a combination of conduction and convection. Water is denser and more conductive than air, so a lot of heat does spread by diffusion in the oceans and other bodies of water. But convection, where it happens, is more efficient, and that (in the form of well-defined currents like the Gulf Stream) is the dominant way ocean heat is transported.

Air currents also transport heat from equator to poles, but the oceanic heat transport is responsible for the bulk of the transfer.*

The upward flow of surface heat. In the atmosphere, heat flows upward from the surface as radiation and as turbulent, convected air holding evaporated water. Some of the radiation heats the lower atmosphere by absorption; the water vapor, upon condensation, deposits its heat there as well. The remaining flow heats the upper atmosphere. This flow is "vertical" (actually, outward from the Earth's surface). The radiation is essentially unaffected by gravity, but the upwards convecting moist air does have to do work against gravity. Its vertical flow represents another type of organized work.

Vertical heat transport in the atmosphere breaks down into these mechanisms, in ranked order:

• Radiation
• Evaporation/condensation (when available, which is many times and places)
• Convection (when available, which is most times and places)

with the second working together with the third. The lower atmosphere (troposphere) is dominated by radiation, but convection, in combination with evaporation, is still significant, representing about 1/5 of the upward heat flow. The tropospheric convection is turbulent and inefficient, at least in the clear air. (It's a lot more efficient in clouds.) As parcels of air are convected upwards, they expand and cool, sometimes enough for water vapor to condense as clouds. The condensation, when and where it happens, mitigates the cooling and makes the temperature-altitude profile less steep than it would be for unstaturated air.

The junction of the troposphere and the stratosphere (the tropopause) is a critical layer, where upward convection stops. In the upper atmosphere (above the tropopause), only radiation matters. There's no convection, and the air is too thin and dry for conduction or condensation to be important. Because the stratospheric temperature is, at first, constant and then rising with altitude (we'll learn why in a later posting), no matter-based heat transport would be possible anyway: heat cannot flow from colder to hotter temperatures. But the radiative heat transport encounters little obstacle in the upper atmosphere and just proceeds on its merry way. The stratosphere acts as a "lid" on the boiling, convective troposphere below.

An interesting, if extreme, case is the polar regions during polar night. In that situation, neither evaporation nor convection is available. Vertical convection of air requires heating from below, which typically comes from the Earth's absorption of light from the Sun and conversion of that into heat. For six months at the poles, this source is out of sight, and the lower atmosphere at that time and place moves heat upward by radiation only. It's as if the sky had fallen down to the ground - the stratosphere resides at the surface.
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* Conduction and convection are also important in the solid interior of the Earth. The source of heat deep down is the decay of long-lived but unstable radioactive elements left over from the Earth's formation. That heat diffuses out slowly by conduction and, here and there, by much faster convective plumes that sometimes burst forth on the surface as volcanoes. This core heat raises the Earth's surface temperature slightly beyond the solar heating-alone value and drives plate tectonic motions. Volcanoes also change the chemical composition of the Earth's atmosphere when they erupt.

Told you so

Remember all that stuff about the failure of string theory? Peter Woit, author of Not Even Wrong, now has a scientific talk about the failure of string theory. It's in the usual PowerPoint format used in many scientific conferences today (except this version is converted to PDF). I like his first section title: "Introduction and Excuses."

As Woit points out, it's not usual to give talks about scientific failure, at least not if you want a career in the subject. Of course, Woit is not a physicist, but a string-savvy mathematician, so he has less to lose here - which makes the talk a lot easier for him.

Perhaps Woit has unwittingly inaugurated a new era of negative scientific conferences and presentations, which in the future might be filled with mea culpas - perhaps they can include something like the Al Chet confessional from Yom Kippur in the final plenary session, and the whole final day can require fasting.

The trouble with strings is not that they're just a theory with wrong predictions. The trouble with strings is that they're not a theory at all and make no predictions.

More about Iran versus Iraq

A friend took me to task for being too pessimistic in a recent posting about the prospects in Iraq, and for implying something not true about the neoconservatives.

My point about the neocons is not that they were clueless about radical Islam before the Iraq war. A few were even conscious of it before 9/11 (many were overly obsessed with China back in those days). My point was the misguided attempt to connect the new post-1991 trend of radicalism in the Middle East to Saddam. The fact that Saddam was making nice with some Islamic radicals only proves my point - he was cozying up to them because they (not he) were in the drivers' seat. It's like when he put Allahu `Akbar on the Iraqi flag after the Guf War. It was clear which way the wind was blowing, and he was trying to keep up with the latest. He was a trend-follower, not a trend-setter.

The major countries incubating Sunni radical Islam are clear: Saudi Arabia, Pakistan, and (to an extent) Egypt. A few other countries (like Algeria) playing a tag-along role under the influence of the more important ones. It's rather unfair to lump Egypt and Algeria together with Saudi Arabia and Pakistan on this score, because the Egyptian and Algerian governments have been tireless in their efforts to squash the radical movements. (In Egypt, there has been some compromise between the government and the radicals.) But the Saudi and Pakistani governments have a long-standing role in promoting radical Islam - on the world stage, since the 1970s, even before the fall of the Shah. Pakistan in particular suffers from an identity and legitimacy crisis, and that makes radical Islamic movements attractive because they're politically useful. Countries such as Afghanistan and Sudan have ended up as test laboratories for the Sunni radical movements to try out theocracy and take in jihadis, all with Saudi and Pakistani sponsorship.

The other axis of jihad is Iran, with its little brother, Syria, and its Shi'ite laboratory in Lebanon. Like its Sunni sibling, the Shi'ite version of radicalism took off in the late 70s, after the decline of secular ideologies in the Arab world set in and the fall of the Shah.

Iraq is not on either list.

At a high level, the neocon goal of promoting constructive political change in the ME is a good idea - no, better than good - necessary. Carried through consistently and subtracting out their obsession with Iraq, it would involve cooling relations with Egypt somewhat, sharply cooling them with Saudi Arabia and Pakistan (even to the point of issuing them ultimatums), and engaging Iran with peaceful but unceasing pressure towards serious political change. The model should be Reagan in the 1980s, with Iran taking the place of the Soviet Union, and America's erstwhile "allies" - right-wing authoritarian governments then, Saudi Arabia, Pakistan, and Egypt now - subject to a serious push towards reform and opening up. Even a liberal revision of American policy - thought through its logical conclusions - wouldn't look that different. The stylistics and atmospherics might feel otherwise, but not the substance or goals.

It's a mistake to think of the Bush foreign policy as being neoconservative, because much of this agenda has not been translated into policy, only the obsession with Iraq - the one neocon idea that remains the flimsiest. Much of that can be attributed to personnel and history, not ideology. Cheney, Rumsfeld, Wolfowitz, and Feith were all central in the Persian Gulf war, and Bush Jr.'s fixation on Iraq is obviously mixed up with Oedipal father-son issues. The Iraq obsession got translated into reality by Bush because it resonated the most strongly on a personal level with key administration figures. There's been no coherent reconsideration of policy towards Saudi Arabia, Pakistan, or Egypt. Iran has been faced as a problem only very recently.

The course of policy in Iraq has been on the whole poor in design and execution since the summer of 2003, with some bright spots here and there, especially in the Kurdish north. It's also been politically costly. But my earlier posting is really about Iran - Iraq is a secondary point. My pessimism about the Middle East might not be justified in the long run. There are positive trends, like the bloggers. But an overall positive direction of change is a hope and an assumption, not a proven fact.

Postmortem on the Israel-Hizbollah media war

Sentient people nowadays don't need a lot of reminding of the political bias and limitations of the mainstream news media (MSM). But a distinctive event well-defined in time and scope can be a moment for some systematic research that captures these issues more thoroughly than just impressionistic snapshots during the event.

Such an event was last summer's month-long war between Israel and Hizbollah, the Iranian- and Syrian-sponsored Shi'ite militia of southern Lebanon. A new study (PDF) from the Shorenstein Center at the Kennedy School of Government (Harvard) captures perfectly the MSM's combination of ignorance, clueless bias, and gullibility. The authors are Marvin Kalb, formerly of CBS and NBC and now a Shorenstein fellow, and Carol Saivetz, an associate and lecturer at Harvard's Davis Center for Russian studies. Their most fundamental conclusion is that the media is no longer an independent observer, nor is it an advocate in its own right. Instead, it's become an unconscious or conscious propaganda tool - a tool almost always better manipulated by groups such as Hizbollah or dictatorships like Iran than by open societies like Israel. As they say at the Pentagon, it's now part of the "battle space." Another bad omen for the future of press freedom.

But there's a bright side: bloggers! Today, when the MSM messes up, they get fact-checked and carefully sifted in ways unimaginable even 10 years ago. All the more reason why we need to remember that First Amendment freedoms are individual rights of everyone, not corporate or guild privileges.

The coming war with Iran

It's usually bad a idea to stick one's neck out like this, but the coming crisis with Iran requires it. There will be war involving Iran by the end of 2008. The next president's first crisis will be this, not Iraq. See here for the skinny (requires subscription). An immediate consequence will be the end of the nuclear non-proliferation regime in place since the late 1960s, with Saudi Arabia, Egypt, Turkey, and others crowding in to get their nuclear weapons too. This is a certainty if the US can no longer demonstrate an ability to shield its "allies" (read: dependencies).

The latest idiocy on this issue emanates from the usual places and postulates a détente with Iran. Apparently, the chattering classes don't yet realize that détente with Iran has already come and gone - the faux-reformers of a few years ago are without influence in the era of Ahmadinejad. The original détente, with the Soviets in the 1970s, made a limited sense then; although in the long run, it was no more than an interlude. With the present Iran, it's loopy. The real problem is that by getting ourselves into Iraq with little preparation for the cost and consequences, we're now hobbled in dealing with a much more serious threat from Iran. The Iranian problem would have happened anyway, but the Iraq war has accelerated it. Bush has not used the Iraq war in any advantageous way against Iran. He clearly needs to be replaced by someone - of either party - who knows what he's doing.

What were the neocons thinking in the 90s? Some of them did correctly emphasize Iran, but that's not what got transmitted into policy. What got into policy instead was an undeserved obsession with a country - Iraq - effectively neutralized in 1991 and a lot of dubious, fuzzy ideas about how the Middle East was "ripe" for constructive, Western-style political change. Nothing could show more clearly how little connection neocon theorizing has with Israeli views than this. The Israeli political, military, and intelligence establishment shows rare unanimity when it comes to Iran: since the early 90s, they have viewed Iran's quest for nuclear weapons as their biggest threat. OTOH, they regarded Iraq as defanged, a spent force. And Israelis would have laughed themselves to death at the neocon fantasy of "democratic transformation" of the Arab world.

OTOH, the fantasy of "realism," as it's played itself out in the last year, largely consists of conventional wisdom recycled from 10, 20, or 30 years ago. They include myopic denunciations of American policy as being "too tough" on Iran - when in fact, it's more likely too little, too late. Here's a really real principle of realpolitik the chatterboxes in the news media might consider - if they're not distracted by Britney Spears' latest underwear malfunction: peacemaking negotiations are possible when there isn't a powerful player able to block peace. E.g., Sadat kicked the Soviets out of Egypt in 1974, moved towards the US, and was able to make peace with Israel. The end of the Soviet Union and the defeat of Iraq in 1991 made the Oslo process and the Israel-Jordan peace deal possible. When a hardline rejectionist state like Iran is on the ascent (helped by a large, sustained jump in crude oil prices), peacemaking becomes much harder. When Iran gets nuclear weapons, peacemaking will become history.

Iran's insistence on butting into the Israeli-Palestinian conflict and using it as an inflammatory rallying cry for Islamic radicalism means that a new "warrant for genocide" is being assembled before our eyes - that was the real meaning of the Holocaust-denial conference in Tehran. While the academic liberals and leftists bellow on and on about "never again" - meaning, never again the Nazi Holocaust in 1940s Europe - the next one is being prepared. The left in particular has played a disgraceful role in paving the way for the next crisis - as apologists, rationalizers, and liars - just as the isolationists and Nazi fellow-travellers did in the 1930s. Along with Jim Baker and Lee Hamilton, they will be remembered - if they are remembered - as the Chamberlins and Halifaxes of this generation. The media will be remembered - if they're remembered either - as having helped the crisis happen - just as the media of the 1930s did.

And it's not just Iran that keeps dragging Israel into the region's problems - for some never-clear reason, so do a lot of other people. What the Shi'ite revival, the Iranian missile threat to the region or to Europe, or the near-destruction of Lebanon by Hizbollah, Syria, and Iran have to do with the Israel-Palestinian conflict is a mystery. Really, they have little to do with each other, except perhaps indirectly. In any case, how Israel is supposed to negotiate seriously with a Palestianian quasi-state now at war with itself is a further mystery. The fatal obstacles to the formation of a Palestinian state come from Arab governments and the Palestinians, not from Israel.

The Bush administration's expensive fiasco in Iraq also has nothing to do with Israel, except in the fervid imaginations of certain people. The driving impulse, as far as we know from the people who did it, came from the desire to finish the Persian Gulf war in a different and more decisive way. It would have been a good idea then, and you can thank Baker & company for that not happening. But, after the 9/11 attacks, this predominantly neoconservative view failed to see that the rising threat in the Middle East comes from radical Islam. After the Persian Gulf war and the end of the Cold War, secular nationalist tyrants like Saddam have become yesteryear's failed idols. Such men - starting with Nasser and proceeding to the late Assad père and Qaddafi - have clearly had their day. The new, rising, cutting-edge radicals who replaced them are the bin Ladens, the Ahmadinejads, the Nasrallahs, and so on, with a new ideology and a new base.

There is a grand irony in the fantasies of Israeli control of American foreign policy, and it is this: if the United States had been channeling Israeli thinking under either Clinton or Bush, it would have been paying attention to Iran, its radicalism, its terrorism, and its quest for nuclear weapons much sooner. Israeli judgment, even in regards their own self-interest, is not flawless: witness the Oslo process. But the Israelis grasped soon after 1991 that the future major threat to them would come from Tehran, a point that has taken 15 years to sink in over here. They rightly discounted the post-1991 threat from a contained and nearly-vanquished Iraq. We would be in a very different place today had this history played differently: we could be consistently rallying Americans and other countries against radical Islam, undiverted and unburdened by having to straighten out the remains of Saddam's mini-gulag. Of course, we'd still have the Sunni branch of radicalism (al Qaeda) to deal with - a largely Saudi-Egyptian-Pakistani creature. Not accidentally, all three countries are major US allies - we're their protector and sugar daddy and hence a target of those governments' radical malcontents. Some people say the Iraq war has diverted American attention from al Qaeda, and that may be. Nonetheless, the real negative legacy that Bush leaves will probably be, not Iraq, but the failure to do something about Iran.

And naturally, if the Bush and two preceding adminstrations had been on this wavelength, the 2003 Iraq war would not have happened.

You're all wet

And you're just standing there, naked, in the cold night air, freezing.

I won't ask why this happened - that's between you and your rabbi. In keeping with the canons of modern Western science, I'll only explain what's happening and how. It's an amusing application of the last posting's discussion of heat capacity and thermal conductivity.

Water is a decent conductor of heat, 25 times better than air, but a far better retainer of heat, 3000 times better. Heat capacity is a volume effect of a material (so many calories of heat per volume), while heat conduction is a surface effect (so many calories of heat flowing through a surface per surface area per time).

When you're standing there shivering in the cold, reflect on the fact that the water on your skin is mainly having a surface effect. It's conducting heat away from your skin 25 times faster than the air would. That's why you're shivering. Your body isn't used to it and responds by generating more internal heat. When you're not wet, the body mainly loses heat by infrared radiation, not conduction. If you shiver long enough, you tax your body's heat-producing ability to the point where you get sick.

Of course, the water itself also has some heat, and, if it's warm water, you won't shiver quite as much because you'll benefit by absorbing some of it. But water on the skin is mainly a surface effect. Even a thin film of water will dramatically change the heat conduction at your skin, while adding little heat content.

OTOH, suppose you're lounging peacefully in tub of cozy, warm water. (Remember, we won't ask any personal questions here - it's just about thermodynamics.) The water is warm, but now there's a lot more of it, not just a thin skin layer. Your body gratefully absorbs some of that heat from the water. You won't shiver - quite to the contrary. You're enjoying the volume effect of heat capacity.
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POSTSCRIPT: This is just too good to pass up: a "global warming walk" started this past Friday in Massachusetts - the same day as the worst snowstorm of the winter. This is like the well-known "Gore effect."

Climate for a wet planet: Water in all its guises

Water has profound effects on climate. The most obvious thing about the Earth, viewed from afar, is that 2/3 of its surface is covered by oceans. These are in contact with the air at the water's surface, as visible to the eye. What is not visible to the eye is that oceans and other bodies of water evaporate unceasingly, putting water into the air in molecular form. The water can condense, with the results visible as clouds, haze, and fog. Less often, it precipitates and falls back to earth as rain or snow. Most of the effect that water has on climate is due to its much higher density and its far larger capacity to absorb and retain heat, for a given increase in temperature, compared to dry air.

The essential effect of water is that the Earth's climate is - compared to what it would be otherwise - warmer, less prone to large temperature variations, and more stable.

1. Water vapor makes the air warmer overall than it would be otherwise. The coastal tropics experience the most intense heating (from the Sun more or less directly overhead), the most evaporation, and higher temperatures overall (considered over the entire day-night cycle) than, say, deserts at the same latitudes (where the air heats up rapidly during the day, but cools off quickly at night). Water vapor acts like a blanket in the atmosphere. But even more importantly, the condensation of water vapor in the air releases the vapor's latent heat and acts like a steam bath.

An ideal blanket is one that absorbs and retains heat well, but doesn't transmit the heat through from one side to another. Although heat is conducted through water better than it is in air, it is water vapor's strong absorption, retention, and release of heat that create the steam bath- and blanket-like effects in humid air.

2. The presence of liquid and evaporated water moderates the change of temperature in time and space. Water is harder than air to heat up, but if hot, acts as a heat reservoir. It's harder to raise the temperature of a system of (dry air + water) than dry air alone. But, once warmed up, the (dry air + water) system cools off more slowly. We're all familiar with such effects, which are spelled out in more detail below.

If the Earth's atmosphere were dry, its thinness (low density) would make it prone to more violent winds and larger temperature variations. A good comparison case is Mars, which has a thin, cold atmosphere routinely subject to extreme wind storms, more extreme than anything here on Earth.

An opposite extreme is Venus. Its atmosphere, although very different from Earth's in some ways, illustrates how a very dense gas, as an excellent heat reservoir, tends to exhibit little variability of temperature - and thus little "weather."

Let's break these assertions down further to the basic physics.*

Mass density and mechanical inertia. Both air and water are "fluids" in physics lingo. But air is a gas and much less dense than water, about 770 times less dense.

The amount of mass in a given volume of fluid is a measure of that fluid's mechanical inertia - that is, the tendency for it to stay still if already still and to keep moving if already moving. A given force will accelerate a parcel of air much more quickly than the same volume of water, but it's also easier to stop that parcel of air than already-moving water. That's why winds are much more variable than convective streams (like the Gulf Stream) in the ocean.

A few years ago, some fairly imprecise new measurements of the Gulf Stream were compared to fairly imprecise old measurements from the 1950s. The two measurements were actually consistent with each other, within both their large measurement uncertainties. But their central values were quite different, leading to an absurd speculation that "global warming" was going to stop the Gulf Stream - and thus, paradoxically, lead to a cooling in Europe, which is warmed an extra amount by the relatively warmer Gulf Stream streaming through an otherwise cold north Atlantic. The law of inertia means that large ocean current changes take much longer (decades or centuries) than changes in wind patterns. The Gulf Stream is safe, for now, at least.

Heat capacity, thermal conduction, and thermal inertia. Heat capacity is the amount of heat energy it takes to warm something up by one degree. The heat capacity of water, per volume, is about 3000 times that of dry air, at constant density. The amount of heat energy that causes a one degree rise of air temperature causes a temperature rise of about 1/3000th of a degree in the same volume of water. It's a lot harder to heat water up than air. By the same token, once it is heated up by that one degree, the water retains about 3000 times as much heat energy as does the same volume of air heated up by the same one degree. You can think of heat capacity as a thermal version of inertia: the more heat capacity, the harder to heat up, but also the longer to cool off.

Land has a smaller heat capacity than water. That is why temperatures rise and fall in more extreme ways in continental interiors than on coasts. A nearby large body of water moderates extreme temperature changes. The land-water contrast also gives rise to strong winds near the shore. During the day, the more rapid heating just over the land surface causes the air to rise there, sucking in air from over the water - an onshore wind. At night, the air cools more rapidly over the land and sinks, pushing the air out over the water - an offshore wind.

It's also interesting to compare how easily air and water conduct heat. The essential material property is the thermal conductivity, a measure of how fast heat travels through a substance. Water conducts heat about 25 times faster than air. It's not a huge ratio, but it's enough to make heat conduction important in the ocean and at the air-ocean interface, while still being unimportant in the air itself (compared to convection and radiation: see the earlier discussion on heat transport).

Evaporation and latent heat. The major effect of water on the atmosphere, apart from the contact of air with liquid water surfaces, results from the water in the air itself, either "dissolved" at the molecular level as an invisible vapor or "condensed" as clouds of suspended liquid droplets.

When liquid water evaporates by absorbing heat, it absorbs more than just the heat implied by the heat capacity figure. The heat capacity of liquid water assumes that the water, in fact, remains liquid. When water evaporates to a gas, it's undergone a change of phase, and that requires an additional heat input called the heat of vaporization. Once in the air, the water vapor carries around all that extra heat that it needed to get there starting from liquid form. This extra is the latent heat.

Saturation, relative humidity, and dew point. The amount of water vapor air can absorb is limited; at any given temperature, this definite limit marks the saturation point. The saturation amount of water vapor rises as temperature rises. The absolute humidity is the ratio (by weight) of water vapor to air; it's rarely ever more than about 1% by number. The important number for weather is the relative humidity, the ratio of the actual absolute humidity to the maximum absolute humidity possible at a fixed temperature (the saturation value of absolute humidity).

Imagine an atmosphere with a fixed pressure, absolute humidity, and a relative humidity less than 100%. It has some temperature, but imagine lowering the temperature - and thus the saturation humidity - until the saturation humidity falls to the actual humidity. The temperature for which that is true is the dew point, and it's less than the actual temperature. If the relative humidity were exactly 100%, the actual and dew point temperatures would be equal. If the temperature were to fall below the dew point, the humid air would start getting rid of vapor by turning it back into liquid water droplets.

Water vapor and infrared absorption. Water vapor - dissolved water molecules in the air - continues to enjoy its extra heat absorption and retention powers (in comparison to dry air). It can absorb incoming solar radiation as heat, but its main effect in the air is to absorb and retain extra heat re-radiated from the Earth's surface (infrared radiation). This creates the "blanket effect" and makes the air warmer than it would be if it were dry.

Of course, the heated-up water vapor itself re-radiates heat, until the heat reaches the upper atmosphere and makes it back to space. But that takes time, a longer time than if the Earth's re-radiated heat simply faced a dry atmosphere on its way out.

Condensation, clouds, and radiation. If a parcel of humid air moves from a warmer to a colder region, cold enough that the dew point now rises above the parcel temperature, some of the water vapor will condense into tiny liquid droplets - steam, essentially. A big blob of floating steam in the air is otherwise known as a cloud, and that is in fact how clouds actually form.

The two most important such cloud-forming situations result from vertical and horizontal motion, respectively. A parcel of humid air, having acquired some water vapor at the surface, rises in altitude. At higher altitudes the temperature falls, eventually enough for the cloud to condense. That's why clouds usually form at some altitude above the surface. Another common situation is when a colder, drier air mass slams horizontally into a warmer, wetter air mass. At the surface of contact, vapor condenses rapidly and extensively. That is the origin of weather fronts. A less common but still familiar siutation is when warm, humid air cools down enough at night to set off condensation near the ground - fog, which is nothing more than a cloud at the surface.

Clouds have an additional effect on the movement of radiation in the atmosphere, because their surfaces are generally fairly white. That means they reflect visible and ultraviolet radiation away from themselves, while they also absorb essentially all incident heat radiation. The cloud bellies absorb and re-emit heat both up and down, while their tops reflect incoming solar radiation back into space, significantly altering the distribution of heat. Heat emitted back down makes the air warmer than if the cloud were not there. OTOH, radiation reflected back into space makes the air colder than it otherwise would have been. The two effects compete with each other, and the net effect depends on cloud details and other conditions. You might call the reflectivity of clouds a "tin-foil effect."

Condensation and release of latent heat. When water condenses from vapor to liquid, it releases into the dry air all that latent heat it was carrying around - the reverse of vaporization - appropriately called the heat of condensation. Since this is how a steam bath works, it's fitting to call this the "sauna effect."

Evaporation-condensation is the most important way that water vapor warms the atmosphere beyond what it would be dry - in addition to the smaller effects of the water vapor heat-absorbing "blanket". The net warming effect of water vapor can be dramatic. For example, although temperature falls with altitude in the lower atmosphere, the rate of decrease is quite a bit less for humid air (a quarter to a third less) than for dry.

Closing the cycle: Condensation and precipitation. In an air free of dust and other tiny particulates, those liquid water droplets would stay suspended in the atmosphere. But sometimes they don't. The droplets start out as so tiny that their weight is not enough to overcome the other forces (like updrafts) that they're buffeted with.

But if a droplet latches on to a little solid particle, it can accumulate more liquid from other droplets. If the growing droplet gets big enough, its weight can become large enough to overcome the forces that keep it up in the air. Enough such mega-droplets, and you get rain. If the air temperature near the ground is low enough, it comes down as ice crystals (snow). Even if it isn't cold enough near the ground, the temperatures aloft might be so cold that large ice clumps form and stay solid all the way down, where they land as hail.

Some of this fallen water gets absorbed by the ground. But most of it ends up in bodies of water and eventually back into the ocean, to repeat the cycle.
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* The basic principles and numbers are taken from the Physics Vademecum of the American Institute of Physics (out of print) and the books of Byers and Fleagle & Businger.

She is weird

People - even conservatives - have started to comment on how strange Ann Coulter is.

Peggy Noonan discusses the decline of niceness in the Wall Street Journal. Half of it is the juvenile behavior of Coulter and other "conservatives." But the other half is the crude attempt to stifle speech and discussion through censorship (political correctness). As Noonan says, neither approach is nice. But read the whole thing.

And Camille Paglia brilliantly sketches out the gender weirdness of Ann in Salon: maybe Coulter is just putting on a show - but maybe she's also become her mask. BTW, is there anything Hurricane Camille doesn't do brilliantly?

Paglia points out something about Coulter that really applies to conservatives across the board in the last fifteen years:

... Coulter seems to be regressing rather than growing intellectually and sharpening her analytic skills. She evidently leaves no room in her life for study and reflection. I take books seriously ... and thus hold against Coulter the part she has played in the debasement of that medium. Her books may rake in millions but won't last because they are shoddily constructed. Coulter should be using her syndicated column for her topical opinions but her books for more considered contributions. Godless, for example, which intriguingly postulates the quasi-religiosity of contemporary liberalism, should have stimulated wide discussion but was so thrown together and full of holes that it was easy to dismiss and went unread outside her core audience.

That's why you won't find too much "news" here on Kavanna. A lot of conservative organizations and publications have been backing away from Coulter for some time now. But they're so deep into the Washington-media echo chamber that they (mostly) don't sense how far they've drifted from what they once were. And those "books" - they are constructed, rather than written.

The world according to Yogi

For some comic relief, don't miss these classic Yogi-isms at the official Web site. The books are much more complete.

On a completely different yet parallel plane, don't give into despair.

Middle East blog ferment

Some of my previous posts on the Middle East have emitted an unmistakeable aroma of pessimism about the place, leaving me wondering if I'm just too damn negative. Are there any positive trends? Yes, there are. I don't know how significant they are, but they are. One of those trends is bloggers and their sometimes-brazen challenge to both authoritarian governments and authoritarian cultures.

The bloggers in question are often brave, in ways that bored and pampered Americans can't even begin to understand. Many must use pseudonyms or noms de blog. Here's a partial list (partial in multiple senses), a taste of what the Middle East has to offer. Whatever my serious doubts about the future of the Middle East, I hope these bloggers prove me wrong!

I've organized the list by country/region and picked the ones I know the best. But that's just my experience and bias. Many of these sites have links to other bloggers, who shouldn't be missed. Be adventurous. Notice also that many of them, like Kavanna, are housed by Blogspot/Blogger. It's Google's mitzvah, whatever else they might do right.

North Africa: I couldn't find many here. These are two I've looked at a few times.
* The Moor Next Door (Algeria)
* Winds of Change in Algeria (Algeria, mostly in French, some English)

Egypt: Largest and most important Arab country, with small but active blogging culture, not as conservative as the Gulf countries (see below). Nonetheless, the Egyptian government can move slowly but effectively against bloggers it doesn't like.
* Big Pharaoh
* Mona Eltahawy (blog by a well-known professional journalist)
* Sandmonkey (Abdel Kareem Nabil Soliman - now the best-known Egyptian blogger, because he was recently sentenced by the Egyptian government for his blogging)

Lebanon: Very active and varied blogging culture. Played an important role in covering the March 2005 protest movement against Syria and the Hizbollah war last summer. Israeli bloggers (see below) and Lebanese bloggers communicated via blogs even as the missiles and bombs were dropping.
* Lebanese Political Journal (important multi-blogger site)
* Lebanese Bloggers (clearinghouse for many individual blogs)
* Daily Star (Lebanon's most important newspaper, in English)

Iraq: In spite of all the violence in and around Baghdad, Iraq has a significant and very informative blog culture. It's a useful corrective to the inevitably misleading conventional media coverage of Iraq.
* Salam Pax (the famous pseudonymous "Raed" of pre-2003 fame, who went off the air in 2004 - he has a book out)
* Iraq the Model (best-known and most important Iraqi blog)
* The Messopotamian (Alaa is the pseudonym - life in Baghdad)
* Iraq Pundit (an Iraqi exile comments from afar)

Perisan Gulf: The most conservative part of the Middle East, outside of Talibanland, dominated by the Salafi (Wahhabi) school. These bloggers have to tiptoe.
* Silly Bahraini Girl
* Saudi Jeans
* Arab News (the most important English-language Saudi newspaper)

Iran: The largest and most active of Middle Eastern blogging cultures, apart from Israel. Bloggers there play a complicated cat-and-mouse game with the Iranian government. There are too many blogs for me keep track of. Here's a partial list. If you look at only one, look at this one:
* Hoder (Hossein Derakhshan - he has a Persian blog too)

Israel: Israeli has a large number of blogs, some more active than others; some highly political, others mostly personal. Ones I look at:
* Israpundit (multi-blogger, with an excellent linked list of other blogs)
* IsraellyCool (Australian and Israeli - check it out)
* An Unsealed Room (Allison Sommer's sharp-witted diary from a Tel Aviv suburb)

Another newspaper I should mention is Al Hayat, the London-based independent, Arabic-language publication. They have an English edition. And all serious students of the Middle East must keep up with MEMRI (Middle East Media Research Institute), which bridges the language gap between Arabic-, Farsi-, and Turkish-language media and English.

Finally, anyone who thinks or writes about the Middle East these days is indebted to the indefatigable Michael Totten, who has without question the best English-language blog on the region. In a just world, his lengthy postings would be articles in the New Yorker or Atlantic. When you visit his site, consider donating via PayPal. I don't think he has any other regular source of income right now.

The strange case of Scooter Libby

The bizarre Libby trial is over, a good time to take a hard look at this strange case. There's been a lot of commentary on the essentially empty nature of the trial, and even from quarters not sympathetic to Libby or the administration, a sense that the whole thing should never have been allowed to go this far. Like many such prosecutions, once the substance of the case (the supposed leak of Valerie Plame's name as a covert CIA agent) had evaporated, all that was left was to prosecute for "resisting investigation." Even the Washington Post, while accepting the verdict that Libby had lied to investigators, was harsh on special prosecutor Patrick Fitzgerald and his media-enabled obsession with taking down anyone he could:

Yet after two years of investigation, Mr. Fitzgerald charged no one with a crime for leaking Ms. Plame's name. In fact, he learned early on that [the] primary source was former deputy secretary of state Richard L. Armitage, an unlikely tool of the White House. The trial has provided convincing evidence that there was no conspiracy to punish Mr. Wilson by leaking Ms. Plame's identity .... It would have been sensible for Mr. Fitzgerald to end his investigation after learning about Mr. Armitage. Instead, like many Washington special prosecutors before him, he pressed on, pursuing every tangent in the case. In so doing he unnecessarily subjected numerous journalists to the ordeal of having to disclose confidential sources or face imprisonment. One, Judith Miller of the New York Times, lost several court appeals and spent 85 days in jail before agreeing to testify. The damage done to journalists' ability to obtain information from confidential government sources has yet to be measured.

Similarly, the New Republic, even before the Libby verdict came down, expressed serious forebodings about the prosecution and jailing of Miller, essentially for inaccurate reporting and (eventually) unpopular opinions on Iraq (article requires subscription). This may be the most serious damage the trial does, since Libby's conviction is likely to be overturned on appeal. Jailing Miller for refusing to divulge journalistic sources has opened a large breach in the protections that once sheltered reporters from being railroaded for covering controversial topics. The same army of pundits on the left who supported Miller's jailing will soon be regretting it, if they aren't already. The New York Times' Anthony Lewis forsees an impending crisis for the press in the US (requires registration).

Of course, journalists are not a priesthood or a fourth branch of government. The superficial professionalization of journalism in the last 50 years has fed such delusions. Freedom of speech and communication are basic and universal civil rights - not corporate or guild privileges of the press. Unfortunately, the line between media and government has become so blurred that reporters - who are, after all, not constitutionally elected or appointed by anyone - are in real danger of becoming routine legal targets in future political battles. It's an open question whether the continuing, dramatic decline in the general public's respect for journalists weakens society's overall respect for First Amendment rights. See here and here for further thoughts.

Once the underlying facts had become fully public (last summer, at the latest), the Libby case should have been dismissed. We know who identified Valerie Plame, wife of Joe Wilson, as a CIA agent. Plame was not a covert agent to begin with, and Plame and Wilson are the only people we know for sure lied during this entire story. And Miller never had any connection with Libby at all. In the end, the case amounted to, at most, a cover-up without a crime; a deranged left-liberal commentariat looking for someone's blood, somewhere, no matter how absurd their vendetta; and a figure now familiar in America, the out-of-control prosecutor. This last fact argues strongly for ending the indefensible and mischief-causing special prosecutor law - as if previous cases, like the overkill of the Clinton impeachment, didn't already make that case.*

The more basic problem is the misuse of the legal system to carry out what are really political or policy fights. Liberals pioneered this misuse of the law a generation ago. Occasionally, as in the Clinton impeachment, conservatives have gotten in on it, but the diversion of liberal politics into media spectacle and the courtroom remains a striking reminder of the decline of liberalism - why liberals no longer command a majority: they abandoned politics and persuading people to vote for them and, instead, decided to misuse the courts, the media, and academia as alternatives. And it has done them no good. All it's done is to bring those once-respected institutions into disrepute.
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* Don't expect it any time soon, though - the media loves special prosecutors, since they promise an unending series of scandals and pseudo-scandals and will launch a smear campaign against any politician who tries to stop this madness.

Cool books 3

Here are some more cool books read here chez Kavanna in the last year.

Israel has many fine writers and novelists, probably none more famous than Amos Oz. A few years ago he published his most remarkable book, a memoir in novelistic form called A Tale of Love and Darkness. It's available in English from Harcourt in a graceful translation by Nicholas de Lange. Oz's life from his earliest Jerusalem childhood in the 1930s through the Second World War and Israel's War of Independence and into the 1950s is recalled in an almost Chekhovian manner, each short chapter something like a fine etching or ink drawing. The American reviews were very positive, but tended to emphasize the centrality of his mother's suicide overly much, to the detriment of other parts of the story.

The cure for the existential head cold is Yi-Fu Tuan's Escapism, which starts as a meditation on the relation between culture and animality and ends by exploring heaven and hell. Read it to see what I mean. I was reminded of a beautiful classic, Walter Kaufmann's Critique of Religion and Philosophy, which covers some of the same ground albeit from a very different direction. Tuan is a geographer and historian at the University of Wisconsin. Born in China in 1930, he came to Great Britain and then the United States after the 1949 Revolution.

Rat-a-tat-tat

That's Ann Coulter for you. Shunned by conservative publications, she careens out of control and embarrasses everyone.

Coulter's M.O. has always been slash-and-burn, going for the jugular. She usually has some point, even an intelligent one at times - if she knew when to stop. But she doesn't. It's like watching a hyperactive 14-year-old with a machine gun.

The falling star of Edward Said

One of the most influential and damaging intellectual trends of the last quarter century - one that still echoes in academic and media culture - was set off in the late 1970s by the publication of Edward Said's Orientalism, a superficially serious attack on an entire academic discipline whose history stretches back to late medieval times, with an intellectual pedigree reaching back further to Herodotus. The book simultaneously exhibited shoddy scholarship, execrable writing, and bad faith; while at the same time demonstrating a sharp eye for catching the then-rising academic wave of junk post-humanism: post-structuralism, post-Marxism, post-colonialism - all later to known to most of us through post-modernism and political correctness.

The consequences have been unrelievedly awful - for academia and general intellectual culture - enthroning a sanctimonious ignorance-cum-PC mythology that rules in certain quarters concerning the Middle East. Based on the undeserved deference paid to him, Said's quackery has been institutionalized in certain universities as "Middle East studies," a PC parody of an older, real academic discipline. The writings of real Arabist and other Middle Eastern scholars against Said - such as those of Bernard Lewis and Martin Kramer - were not enough to stop the spread of the virus.

Dangerous Knowledge, an important new book by Robert Irwin, a prominent British historian, literary scholar, and Orientalist himself, marks a turning of the tide against this ascendancy. The book has received almost entirely favorable reviews (see here, here, and here) - a clear sign that the post-modernist lunacy hatched in academia a quarter century ago is abating. Unfortunately, the entrenched legacy remains. Orientalism, Irwin summarizes, "seems to me to be a work of malignant charlatanry in which it is hard to distinguish honest mistakes from willful misrepresentations."

Said's doctored autobiography as a Palestinian refugee contributed to this debacle and helped to delegitimize real scholars and real scholarship. (See here for a free summary and here for discussion.) Said's position at Columbia also contributed strongly to the rise of "Middle East studies" there and elsewhere, a critical component of political correctness. That in turn has led to censorship and intimidation of Jewish and other students, abetted by the usual administrator spinelessness. But as always with the Middle East, "radicalism" also weirdly converges with the "realist" establishment (Baker, Carter), lubricated and backed by oil money.

In reality, Said was from an upper-middle class Egyptian Christian family and educated in Egypt and the US. (Further irony: his family, as Christians, were dispossessed and exiled: from Egypt, by Nasser's revolution in the 1950s.) He later became a successful literary critic who, in the 1970s, re-invented himself as an oppressed Third World peasant and then began shoplifting other people's identities. He created a potent academic cult around himself made up of gullible followers who thought, "He must know what he's talking about - he's one of them." His cult represented an historic failure to tell the truth about Islam and the oppression of non-Muslim and non-Arab minorities in the Islamic world.

Instead, he concocted for the Arab world bogus claims of victimhood as a postmodern layer pasted on a deeper and older layer of theocratic and tribal intolerance. Said's influence validated the suffocating and sometimes violent obscurantism that has engulfed the Middle East in the last 30 years. His ideas have been consistently used as they were intended: clubs to intimidate and strangle free thought. Orientalism caricatures many of the great Western scholars of the Near East of the last few centuries - all of whom probably forgot more than Said ever knew - omits critical facts that undermine Said's argument, and shows a sometimes astonishing ignorance of history and even geography. Instead, the book combines the barely-comprehensible agit-prop of late Marxism with the then-new jargon of post-modernism - and in 1978, failed to anticipate the fall of secular nationalism and Marxism and the rise of Islamic radicalism. Said spent the last decade of his life rationalizing his multiple stories, while spreading a fog of misinformation about the Middle East and pursuing a now-familiar dual career of printing xenophobic nativism in Arabic-language publications, then elegantly repackaging this poison for Western audiences.

That makes Christopher Hitchens' favorable review of Dangerous Knowledge all the more remarkable. Hitchens was a friend of Said and wrongly defended him when Said's embroidered tall tales were exposed. Writing this review not too long after Said's death must have been a painful exercise in honesty and bidding adieu to a documented fraud. Hitchens has emerged as a brilliant critic of the modern Middle East, its intolerance and oil money corruption. (See his earlier 2003 retrospective on Orientalism here.) Said posed as an alternative to this pre-9/11 status quo. In fact, he offered an escapist fantasy that appeals to the historical ignorance and passionate self-hatred of Western leftists. To his very great credit, Hitchens has slowly backed away from the moral squalor of the man and his ideas.

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Is there no greater contrast than with Asia? Here was a clash of civilizations that started in the 19th century, when modern Europe encountered then-declining Asian societies and came to influence or control them, then was overlaid with 20th-century ideological conflicts (World War II, Cold War), sometimes mixed in confusing ways, as in Vietnam (confusing to Asians, not just to us). The rebirth of Asian civilizations, under the impact of Western ideas and technology, is complete, after a seventy-year period of wars and violent revolutions. The interaction of the West and Asia since about 1980 has been peaceful, and the exchange between the two is now extensive. While you still hear occasional grinding noises, the "clash" has been converted into a productive symbiosis, with the two maintaining distinct identities even as they borrow from one another. Only a few relics remain from the war-revolution era: North Korea, Burma, and the Chinese Communist Party (in form only, not in content). Even appeals to traditional Chinese concepts of Confucianism play less and less role in Asia.

The Middle East is obviously different, in a politically very incorrect and devastating way. As someone famous once said, Asia solves more problems than it creates, while the Middle East creates more problems than it solves.* The Middle East no longer forms an important civilization. Take away its oil money, and you have a region as backwards as and poorer than Africa. (For example, the Arab world publishes fewer new Arabic books a year than does Israel, its supposed mortal enemy; it has produced fewer translations in four centuries than Western countries publish from Arabic in a year.) Its powerful mix of tribalism and religious intolerance is what makes the place so intractable, unlike Asia. Lewis' classic essay on the "roots of Muslim rage," published in 1990, still hits the mark.

In place of a public culture based on facts and realistic history, the Middle East is dominated by a phantasmagoria of imaginary dream palaces. Not a civilization either, it is rather the collapsed ruin of one, like one of those decayed grands maisons you see at the edge of an old town. It doesn't produce much beyond oil and, technically, doesn't even produce that. In place of the unraveling foreign policy paradigms of realism and liberal internationalism, neoconservatism has had its day in the sun recently and been given the chance to tackle the issue. There are many things wrong with neoconservatism (that's a whole other discussion), but here I want to zero in on one thing: the false idea that the Middle East is "ripe" for constructive and quasi-Western political change. (Even Lewis, as smart as they come and not a neoconservative, has bought into it.) There's no evidence for this; all the evidence is opposite and virtually screams "No!" The Middle East has been moving away from European-inspired paradigms (liberal democracy, nationalism, fascism, communism) for more than a generation and shows few signs of turning in a different direction.

The decline of the Arab nation-state and secular Arab nationalism has created a void that radical pan-Islam is trying to fill. No factor has contributed so powerfully to the strength of radical Islam than the feeling that it has no serious opponents in the Muslim world. It opposes the existing, largely illegitimate state structure of the modern Middle East, but at the same time, derives major support from those states, such Egypt, Saudi Arabia, and Pakistan.

Lacking much introspection or self-examination, hatred in the Islamic world has classically been directed outwards. (The violence directed at apostate, deviant, and lapsed Muslims is a more recent phenomenon.) The broad features of the spread of Islam - conquest, forced conversion, triumphalism combined with a contemptuous rejection of the pre-Islamic past - continue to shape the Islamic world, including its complete unity of the political, military, and spiritual. The contrast with Christianity could not be more complete - its division of spiritual and worldly, its emphasis on inward examination and change, its absorption of the classical and Hebrew past by Christianizing instead of simply rejecting it, its religious violence largely directed inwards, Christian against Christian.

Of course, Mohamed wasn't thinking about these issues in the seventh century. By all evidence, he was seeking to unite disparate Arabian tribes into a super-tribal religious "nation" (the `umma). But he only partially succeeded. The tribal mentality remains - Islam carried it within itself wherever it went by Arab conquest - and conflicts profoundly with the demands and possibilities of civilization. Historically, within a few centuries of their initial conquests, the Arabs demonstrated their inability to rule themselves, and political leadership in the Islamic world passed over to non-Arabs: the Berbers, the Turks, the Persians, the Indians, and others. The intellectual and economic achievements of classical Arabic civilization depended heavily on the presence of the tolerated (dhimmi) Christians and Jews; as they converted under the pressure of economic and legal discrimination, Arabic civilization began its long decline (see Bostom's Legacy of Jihad).

See now why leftists and Islamists hook up with each other? The haters unite with the self-haters - perfect fit! This is a reminder that the real "Other" here is the West itself, in relation to an isolated and incurious Middle East enraged by its own decline and marginalization. For an introduction to this way of looking at things, see Buruma and Margalit's disturbing but insightful Occidentalism.
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* That would be Paul Wolfowitz, in better days, some time in the 1980s.

The crumbling cake

An update on inequality, class, and the breakdown of marriage: as if they were reading Kavanna, comes this story from the Washington Post, which headlines the decline of married households, but correctly paints the full picture involving class, inequality, and education.

America has become an education-driven meritocracy, albeit in some strikingly unexpected ways.

Digression on radiation

The previous postings on thermodynamics talked about matter, radiation, and their thermodynamics - the organization or disorganization of energy at the molecular level. In those postings, I cheated a bit in the discussion of what drives climate change, by the statement that "differences drive climate." That's true, but only for the matter part - the air, ground, and water. In the case of radiation, it's not true, and the distinction between radiation and matter in these respects has important implications for climate and its theory and modeling.

Recall the ideal gas law and the important conclusion of that discussion: you need only three numbers to characterize the physical state of non-moving air (ignoring the qualitative phase of atmospheric water - vapor, condensed, or precipitated.) These are the temperature, pressure, and chemical composition (which in practice means, how much water vapor). The magic of statistical thermodynamics shows that the need for these three numbers is a direct result of the conservation of three summed physical quantities in a closed system of matter particles: energy, volume, and particle number. Think of it like a budget: lots of things can happen in the meantime, but the sum of all the energies and the sum of all the volumes associated with the particles have to remain the same over time, as well as the number of particles. The association between conserved quantity and local thermodynamic measurement is:

• Conserved energy <-> temperature
• Conserved volume <-> pressure
• Conserved number <-> chemical composition

Radiation in every respect is simpler than matter. Matter is made up of molecules of different types that can be transformed by chemical reactions, although the identity and number of each kind of constituent atom remains the same during these reactions. (A related fact is that the amount of matter, measured by its total mass - in grams or whatever - remains constant as well.) Matter can travel, both at the molecular level and in macroscopic bulk, at any speed from zero to the speed of light. OTOH, radiation is made up of photons, which by definition can travel in a vacuum only at the speed of light. (I don't just mean the vacuum of outer space. The space between molecules is a vacuum too.) One consequence is that photons have no mass, so there's no "conserved" mass associated with them. The only distinction between one photon and another is its energy and direction of travel.* The total energy and volume taken up by a "gas" of photons is conserved, but not their number: photons are absorbed and emitted by matter in arbitrary number. All that's conserved is the total energy in the radiation; that fixed energy can be subdivided among many photons, or few; and ditto for the volume.

The result is that a gas of photons needs only two numbers to characterize its physical state, numbers associated with total energy and volume. And if we take a local point of view and consider only densities (such as energy per volume, instead of total energy), we only need one number. That number is usually taken to be the radiation temperature. The radiation pressure and energy density are functions of that temperature alone. Compare with the ideal gas law:

• Energy density of radiation = universal constant*T³
• Pressure of radiation = universal constant*T⁴

For climate, what's even more important, is that the emission and absorption of radiation depend only on the radiation temperature (also as the fourth power). A localized patch of surface on a hot body emits so much power per area (say, watts per cubic centimeter), a quantity that depends just on the local temperature. In particular, it doesn't depend on temperatures somewhere else - that is, it depends on local temperature alone, not on temperature differences.

You can feel this emission of radiant heat from a hot body without touching it, and if its temperature is high enough, you can even see the thermal radiation at frequencies higher than infrared, in the visible part of the electromagnetic spectrum. The heat and light are transmitted as

Hot body (matter) -> radiation -> warm skin and eyes (matter) ,

which drives home the independent physical existence of radiation. If you touch the hot body, the heat is trasmitted more directly:

Hot body (matter) -> warm skin (matter)

Because radiation is so simple, it's easy to not only express the complete theory of how it's emitted and absorbed, it's also easy in many cases to solve that theory exactly or with accurate, controlled approximations. The relationship of radiation to the larger conservation laws (especially for energy) is transparent, unlike the murky case of matter. Photons also have no differential velocity (they all travel at the speed of light), so there's no friction of the kind you see with fluid viscosity, where different fluid layers slide past one another at different velocities. And photons do not interact with each other; they are created and destroyed only by matter.

The part of climate theory dealing with radiation alone is straightforward, and it if it weren't for the complicated nature of matter, climate theory could be solved exactly or in excellent approximation. Simplified textbook treatments of climate for students often use caricatures of climate that emphasize the inflow, absorption, and re-emission of radiation, hiding the complexity of air and ocean - and get results that match observation surprisingly well. But such treatments sweep the hard stuff under the rug by taking important facts as givens from observation instead of explaining them theoretically. It's the mess of matter - its hetereogeneous make-up of different atoms and molecules, its more complex conservation laws and thermodynamics, its complicated flows and phase changes of water vapor - that makes climate theory impossible to solve. That in turn forces climate theorists to turn to simplified models and dubious, uncontrolled approximations.
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* Equivalently, its frequency and wave vector. I'm ignoring the photons' spin or polarization, which for climate is irrelevant. Polarization is important if you're wearing sunglasses on a sunny day, especially on the water 8-)

How about that Chinese market?

So how about that Shanghai stock market? It's been going like gangbusters - a typical emerging market in its early stages - and now it's dropped 9%, sending the other equities markets around the world into a tizzy. Perhaps China is headed for a developing world financial crisis à la 1998, or Japan in 1990. Some pessimists here think it might trigger a recession. US economic growth will slow in the next couple years, but a recession is unlikely in that same period.

International market gyrations affect everyone now. Many retirement accounts took a hit, and long-term interest rates may rise if there isn't as much Chinese capital available in the global bond market.

It's interesting to consider the future of China, not only in comparison with other emerging markets, but also compared to the theories fashionable in the US for the last decade or so. One theory, promulgated by neoconservatives and others, is that China is like imperial Germany circa 1900. China is the world's last empire, but the theory is almost certainly false. China has a booming economy, but it is also politically weak, and its economic boom is driving multiple social upheavals that the ruling Communist Party struggles to contain. China's foreign policy is fundamentally defensive, but it also - in spite of its economic boom - has little interest in joining a Western- or US-led liberal international order. Its interest in overseas investment is strictly mercenary, with no larger governance or political dimension. (For example, because of its need for oil, China plays a crucial role in backing the petro-dictatorships - Russia, Iran, Sudan, the pre-2003 Iraq, etc. The foreign policy the US is sometimes accused of having, China actually has.) These facts put the kibosh on another, less fashionable but still widely held view, that China is about to fully join the current world order or reshape it as a new hegemon.

There's another circa-1900 analogy that fits China better, and it is the great pre-1914 empire-states that disintegrated as a result of World War I. Austria-Hungary is the most obvious analogue: politically weak, economically booming, undergoing rapid social change as a result. Of course, except in some border areas, China is overwhelmingly Han Chinese in its ethnic makeup, making it very different from the Hapsburgs' polyglot, multiethnic empire. That source of instability is not at work in China's case, and Taiwan will probably not play the part of Serbia - at least, one would hope not.

China is an ancient civilization that will survive and even prosper one way or another. But its current incarnation - politically repressive and corrupt communism, booming capitalist economy on the coast, the rest in a post-communist limbo - has only a limited time left.