Sunday, April 29, 2007

Driving Etiquette

Two driving etiquette issues:

1. A situation that has often occurred: I'm in the middle lane waiting to turn left across two lanes of traffic. Someone coming the other way in the inner lane decides to stop to let me turn. But I can't -- because there's a stream of cars coming towards me in the outermost lane, and they're not stopping. So I wave at the person to go ahead and go, i.e., to stop waiting for me and blocking traffic unnecessarily in their own lane. But then the person waves back, as if to say, "Hey, I'm being polite here, you go ahead and turn." So is there a symbol or signal that says, "No, really, I can't possibly turn right now; you're only clearing one lane of traffic; if you don't go ahead and drive, we'll be sitting here for a long time"?

2. Here's a little quiz. Suppose you are driving down a two-lane road, you're nearing a hill or a curve, and you see a runner or a bicyclist on your side of the road. What do you do?

A. Whiz right by the runner or bicyclist as close as possible, without slowing down.

B. Swerve out into the middle of the road.

C. Slow down and swerve into the middle of the road.

People who do A are jerks. B is better, but it's still a very bad idea, because there could very well be another car approaching from the other side of the curve or the hill, and if you are hurtling toward that car at top speed in the middle of the road, well, you're going to be in a tight situation.

A similar rule applies if you see a runner or cyclist on the opposite of the road near a curve or hill. Even though you don't need to swerve yourself, you should still slow down, just in case some not-very-smart driver coming the other way is about to swerve into your lane.

Saturday, April 28, 2007

War on Drugs

The way that our country treats chronic pain sufferers who use too much pain medication seems insane to me. I can't find any evidence that Oxycontin, say, is anywhere near as dangerous as alcohol -- i.e., tens of thousands of fatalities every single year. But we don't make people get a prescription to buy a beer, let alone throw people in jail for 25 years for having a bottle of vodka in the house. Given that stories like the above seem to come and go with no noticeable effect on public policy, I have to wonder why early 20th-century Americans were so much quicker to realize that Prohibition wasn't a good idea.

Tuesday, April 24, 2007


A few bands that I've come across in the past year that I really like:

1. Leeland. This is a new Christian band with a sound that resembles, at times, U2, Coldplay, and Travis. (Listen here.) The lead singer (named Leeland) was only 17 when their album was recorded, and is an incredibly talented singer and songwriter.

2. Eisley. This family-based group has a very whimsical pop/rock sound. Videos here and here.

3. Copeland. VH1 says of them: "Angelic, breathy vocals, melodic, lush instrumentation all backed by an unwavering rock drive."

Toilet Paper

Long ago, my dad gave me a word of wisdom that I have taken to heart to this day: "You can skimp on lots of things around the house, but the one thing that you do not want to skimp on is toilet paper."

Saturday, April 21, 2007


When one's children get a bit older, one has to deal with constant tattletaling. "Mom, Ethan took my crayons." "Dad, Jonathan messed up my Legoes." "Mom, Eva is copying me."

But the other night, I was stumped. Here's what came from one child's mouth as everyone was settling into bed:

"Daa-aad, Christine said I'm a tattletale."

Recipe for Chocolate Syrup or Sauce

Google seems to lack access to a really good recipe for chocolate syrup or chocolate sauce, as I recently found out when I tried to find a recipe that resembled the one my grandmother used to make. Everything that came up on Google seemed to be geared towards the Hershey's Syrup model: cocoa powder, water, and sugar as the main ingredients.

So I got my grandmother's recipe from my mom. It has a lot of butterfat in it -- not surprisingly. Any good chocolate bar, you might have noticed, has a lot of fat in it; eating a spoonful of cocoa powder isn't the same thing at all. Good chocolate needs "mouth feel," which butterfat provides.

Here's the recipe:

1 cup sugar.

3 heaping tablespoons cocoa powder (I like to use 4, which makes a thicker and heavier taste, almost like eating liquid fudge, except not as sickeningly sweet as fudge).

1 stick butter.

1 can of Carnation evaporated milk. You can also use half-and-half or cream here; I've never tried it with pure cream, but I can only imagine . . . .

A pinch of salt.

Mix it all up as best as you can, then bring to a boil for a minute or so. Be sure to stir a lot. If you don't stir pretty much all the time, it will burn on the bottom.

After everything is over and it's cooling down, add a teaspoon of real vanilla (don't even buy artificial vanilla). I'm actually not sure why the vanilla is used here; next time, I'll have to try it both before and after the vanilla is added to see what difference it makes.

You may or may not like this. It depends on what you're used to. To me, this chocolate syrup is to Hershey's Syrup as a fine French wine is to a wine cooler -- it's so much richer and more pleasurable that the two don't even belong in the same category.

Wednesday, April 18, 2007

Chesterton on Divorce

Also from What's Wrong With the World
If Americans can be divorced for "incompatibility of temper" I cannot conceive why they are not all divorced. I have known many happy marriages, but never a compatible one. The whole aim of marriage is to fight through and survive the instant when incompatibility becomes unquestionable. For a man and a woman, as such, are incompatible.

Chesteron Quote

From What's Wrong With the World:
We often read nowadays of the valor or audacity with which some rebel attacks a hoary tyranny or an antiquated superstition. There is not really any courage at all in attacking hoary or antiquated things, any more than in offering to fight one's grandmother. The really courageous man is he who defies tyrannies young as the morning and superstitions fresh as the first flowers.
* * *

There is one metaphor of which the moderns are very fond; they are always saying, "You can't put the clock back." The simple and obvious answer is "You can." A clock, being a piece of human construction, can be restored by the human finger to any figure or hour. In the same way society, being a piece of human construction, can be reconstructed upon any plan that has ever existed.

There is another proverb, "As you have made your bed, so you must lie on it"; which again is simply a lie. If I have made my bed uncomfortable, please God I will make it again. We could restore the Heptarchy or the stage coaches if we chose. It might take some time to do, and it might be very inadvisable to do it; but certainly it is not impossible as bringing back last Friday is impossible. This is, as I say, the first freedom that I claim: the freedom to restore. I claim a right to propose as a solution the old patriarchal system of a Highland clan, if that should seem to eliminate the largest number of evils. . . . I claim the right to propose the complete independence of the small Greek or Italian towns, a sovereign city of Brixton or Brompton, if that seems the best way out of our troubles.
* * *
Nevertheless, I do not as a fact propose that the Browns and the Smiths should be collected under separate tartans. Nor do I even propose that Clapham should declare its independence. I merely declare my independence. I merely claim my choice of all the tools in the universe; and I shall not admit that any of them are blunted merely because they have been used.

Tuesday, April 17, 2007

Law Professor

It's not often that constitutional scholars are as forthcoming as Pennsylvania law professor Kim Roosevelt is here:
But Roosevelt doesn't think academia is entirely disinterested. "You don't necessarily have a client, but maybe you have your particular political beliefs that are driving you to try to reach a certain conclusion. I try very hard to justify Roe v. Wade. Very difficult to do. But I wouldn't be trying so hard if I weren't ideologically pro-choice. It's still difficult to try and be completely objective."

Friday, April 13, 2007

The Costs of Global Warming

In the mail today: This month's copy of American Economic Review. One of the articles that caught my eye was Olivier Deschenes and Michael Greenstone, "The Economic Impacts of Climate Change: Evidence from Agricultural Output and Random Fluctuations in Weather," at pages 354-85. The authors looked at county-level panel data on "whether agricultural profits are higher or lower in years that are warmer and wetter." I'm not qualified to judge their data or methods, but the conclusion looks interesting: "The preferred estimates indicate that climate change will increase annual [agricultural] profits by $1.3 billion in 2002 dollars . . . or 4 percent. This estimate is robust to numerous specification checks and relatively precise, so large negative or positive effects are unlikely."

Robert Epstein's Book

In September 2003, I posted about Robert Epstein's then-forthcoming book, tentatively titled "Adolescence Abolished."

As Glenn Reynolds points out, that book is finally here: The Case Against Adolescence: Rediscovering the Adult in Every Teen. Glenn and Helen Reynolds interview Dr. Epstein about his book here. I very much look forward to reading it.

And here's a provocative and recent article by Epstein in Education Week:
Let's Abolish High School
By Robert Epstein

Well, not quite. But while writing a new book called The Case Against Adolescence: Rediscovering the Adult in Every Teen, I explored some ideas that go almost that far.

I’m a father of four children, and about 10 years ago I noticed—I couldn’t help but notice—that my 15-year-old son was remarkably mature. He balanced work and play far better than I did, and he seemed quite ready to live on his own. Why, I wondered, was he not allowed to drive or vote, and why did he have so few options? Simply because of his age, he couldn’t own property or do any interesting or fulfilling work, and he had no choice but to attend high school for several more years before getting on with his “real” life.

As a longtime professor and researcher, I got curious. Were our young people always required to attend school, and were their work opportunities always limited to babysitting, yard work, and cleaning the floors at fast-food joints? Were they always subject to so many restrictions? Are teenagers necessarily incompetent and irresponsible, as the media tell us? Is there really an immature “teenage brain” that holds them back? After all, past puberty, technically speaking we’re not really children anymore, and presumably through most of human history we bore our young when we were quite young ourselves. It occurred to me that young people must be capable of functioning as competent adults, or the human race quite probably would not exist.

Over time, through interviews, surveys, and scholarly research, I began to investigate these matters in depth. What I learned amazed me — even shocked me.

Monday, April 09, 2007

Walter Murphy

Many bloggers are criticizing the Bush administration for political profiling, based on this story from Walter Murphy, Princeton professor:
"On 1 March 07, I was scheduled to fly on American Airlines to Newark, NJ, to attend an academic conference at Princeton University, designed to focus on my latest scholarly book, Constitutional Democracy, published by Johns Hopkins University Press this past Thanksgiving."

"When I tried to use the curb-side check in at the Sunport, I was denied a boarding pass because I was on the Terrorist Watch list. I was instructed to go inside and talk to a clerk. At this point, I should note that I am not only the McCormick Professor of Jurisprudence (emeritus) but also a retired Marine colonel. I fought in the Korean War as a young lieutenant, was wounded, and decorated for heroism. I remained a professional soldier for more than five years and then accepted a commission as a reserve office, serving for an additional 19 years."

"I presented my credentials from the Marine Corps to a very polite clerk for American Airlines. One of the two people to whom I talked asked a question and offered a frightening comment: "Have you been in any peace marches? We ban a lot of people from flying because of that." I explained that I had not so marched but had, in September, 2006, given a lecture at Princeton, televised and put on the Web, highly critical of George Bush for his many violations of the Constitution. "That'll do it," the man said."
But as Orin Kerr points out, Senator Ted Kennedy was stopped at airports several times "because the name 'T. Kennedy' has been used as an alias by someone on the list of terrorist suspects.

To which I'd add: An anti-war activist named Jan Adams made headlines in 2003 because she was stopped at airports, although it turned out that this was likely because "reservations systems were rounding up anyone with a name similar to 'J. Adams,' including a Virginia attorney (J. Christian Adams) and a young woman (Jodi Adam)."

Similarly, one of the judges for whom I clerked (David Nelson), as well as many other David Nelsons around the nation, was stopped at airports for the same reason.

Anyone else detect a pattern here? Several common names -- "T. Kennedy," "J. Adams," "David Nelson" -- have been selected for extra screening, possibly because someone with terrorist ties has a habit of picking a non-descript alias. Perhaps that's the real explanation as to Mr. Murphy as well.

Indeed, given that there are hundreds of thousands or millions of people out there who have marched in an anti-war rally, or posted an anti-war message on a blog, or written a letter to their congressman, etc., then if people with suspected terrorist ties have used aliases based on common American names, it is probably inevitable that their aliases will seemingly match the real names of some anti-war individuals. Thus, a handful of Adamses or Nelsons or Murphies who happen to be anti-war will find that they are in for some extra screening at airports. But that doesn't mean that they are being targeted for their political views.

This is not to say that the no-fly list is managed well, or even that it's a good idea -- it seems to sweep in a lot of obviously innocent people, and unless there is some good evidence that it has ever stopped an actual terrorist, I'm not sure what the point is.

UPDATE: A commenter at Volokh's blog points to the fact that a dozen "Robert Johnsons" have been stopped at airports.

Executive Power to Disregard the Law

A potentially interesting paper:
The Executive's Duty to Disregard Unconstitutional Laws

University of San Diego School of Law
March 29, 2007

San Diego Legal Studies Paper No. 07-95

Recent Presidents have asserted a power to ignore statutes that they believe are unconstitutional. Critics have made an array of arguments against these assertions. As a matter of text, the Faithful Execution Clause bars such non-enforcement. As a matter of history, the English specifically prohibited a discretionary power to disregard statutes. And American Presidents did not assume a power to ignore unconstitutional statutes until almost a century after the Constitution's creation. Taken together, these arguments are said to refute the regal pretensions of modern Presidents. This Article serves as an antidote to such claims while sharpening our understanding of Executive Disregard. The critics are correct in arguing that the President lacks a discretionary power to refuse to enforce unconstitutional statutes. Instead, the President has a duty to disregard such laws that arises from two sources. First, the Constitution never empowers the President to enforce unconstitutional statues. He no more has the power to enforce such statutes than he has power to enforce the statutes of Georgia or Germany. Second, the President's duty to preserve, protect, and defend the Constitution requires the President to disregard unconstitutional statutes. When the President enforces a statute he regards as unconstitutional, he acts to violate the Constitution no less than he would were he to imprison citizens without hope of trial. Both John Adams and Thomas Jefferson argued that executives could not enforce unconstitutional statutes, with Jefferson being the first President to actually invoke the duty of Executive Disregard. Upon entering office, Jefferson ordered the termination of Sedition Act prosecutions on the grounds that the Sedition Act was unconstitutional. Jefferson justified his non-enforcement decision by arguing that the Sedition Act was no law at all and by noting that he had a duty to preserve, protect, and defend the Constitution, a duty that prevented him from implementing measures that violated it.

Joshua Bell at the Metro

What happens when Joshua Bell, one of the world's best violinists, plays his Stradivarius at a Metro station in Washington, D.C.? Only one or two people out of thousands are smart enough to recognize that something is out of the ordinary.

Saturday, April 07, 2007

Social Psychology

Of all branches of academia, I suspect that social psychology gives its practitioners the most opportunities to have fun. Some of the classic studies might as well be Candid Camera stunts. Indeed, Philip Zimbardo (of the famous Stanford Prison Experiment) collaborated with Allen Funt to put together a video entitled, "Candid Camera classics for teaching social psychology. And in an interview, Zimbardo has said, "There's an interesting parallel between some of my research and Allen Funt's 'Candid Camera' show, where he put ordinary people in unusual situations to see how they would improvise. I've always thought of Allen Funt as a brilliant, intuitive social psychologist." (See also this article for another comparison by Zimbardo.)

Some examples:
J. Richard Eiser, "Cooperation and Competition Between Individuals," in Introducing Social Psychology, edited by Henri Tajfel and Colin Fraser (1978), at p. 170:

They also cite a study by Allen, in which travellers on the New York subway heard a confederate give obviously false directions to another travellers (also a confederate). They were less likely to correct the misinformer if the request for directions had not been directed to them specifically, or if the misinformer had already created the impression of being a dangerous character by looking up from a magazine on muscle-building and shouting threats of physical assault at a fourth traveller (yet another confederate) who tripped over his feet.
I'll bet.

From another article:
Martin T. Orne, "On the Social Psychology of the Psychological Experiment," American Psychologist 17 (Nov. 1962): 776-783.

[T]he subject agrees to tolerate a considerable degree of discomfort, boredom, or actual pain, if required to do so by the experimenter. Just about any request which could conceivably be asked of the subject by a reputable investigator is legitimized by the quasi-magical phrase, "This is an experiment" . . . .

A number of casual acquaintances were asked whether they would do the experimenter a favor; on their acquiescence, they were asked to perform five-push-ups. Their response tended to be amazement, incredulity and the question "Why?" Another similar group of individuals were asked whether they would take part in an experiment of brief duration. When they agreed to do so, they too were asked to perform five push-ups. Their typical response was "Where?"

. . .

In order to test this question, we tried to develop a set of tasks which waking subjects would refuse to do, or would do only for a short period of time. The tasks were intended to be psychologically noxious, meaningless, or boring . . . .

For example, one task was to perform serial additions of each adjacent two numbers ons heets filled with rows of random digits. In order to complete just one sheet, the subject would be required to perform 224 additions! A stack of some 2,000 sheets was presented to each subject -- clearly an impossible task to complete. After the instructions were givin, the subject was deprived of his watch and told, "Continue to work; I will return eventually." Five and one-half hours later, the experimenter gave up! . . . Since we were trying to find a task which would be discontinued spontaneously within a brief period, we tried to create a more frustrating situation as follows:

Subjects were asked to perform the same task described above but were also told that when [they] finished the additions on each sheet, they should pick up a card from a large pile, which would instruct them on what to do next. However, every card in the pile read,
You are to tear up the sheet of paper which you have just completed into a minimum of thirty-two pieces and go on to the next sheet of paper and continue working as you did before; when you have completed this piece of paper, pick up the next card which will instruct you further. Work as accurately and as rapidly as you can.
Our expectation was that subjects would discontinue the task as soon as they realized that the cards were worded identically, that each finished piece of work had to be destroyed, and that, in short, the task was completely meaningless.

Somewhat to our amazement, subjects tended to persist in the task for several hours with relatively little sign of overt hostility. . . . The postexperimental inquiry helped to explain the subjects' behavior. When asked about the tasks, subjects would invariably attribute considerable meaning to their performance, viewing it as an endurance test or the like.
Another experiment was designed to see how people react to potentially dangerous situations when alone, or when part of a group.
Bibb Latane and John M. Darley, "Social Determinants of Bystander Intervention in Emergencies," in Altruism and Helping Behavior, ed. by J. Macaulay and L. Berkowitz (1970): pp. 13-27.

In this experiment we presented an emergency to individuals either alone or in groups of three. It was our expectation that the constraints on behavior in public combined with social influence processes would lessen the likelihood that members of three-person groups would act to cope with the emergency.

College students were invited to an interview to discuss 'some of the problems involved in life at an urban university.' As they sat in a small room waiting to be called for the interview . . ., they faced an ambiguous but potentially dangerous situation. A stream of smoke began to puff into the room through a wall vent. . . . The 'smoke,' copied from the famous Camel cigarette sign in Times Square, formed a moderately fine-textured but clearly visible stream of whitish smoke. It continued to jet into the room in irregular puffs, and by the end of the experimental period, it obscured vision. . . .

The typical subject, when tested alone, behaved very reasonably. Usually, shortly after the smoke appeared, he would glance up from his questionnaire, notice the smoke, show a slight but distinct startle reaction, and then undergo a brief period of indecision . . Soon, most subjects would get up from their chairs, walk over to the vent and investigate it closely, sniffing the smoke, waving their hands in it, feeling its temperature, etc. The usual Alone subject would hesitate again, but finally would walk out of the room, look around outside, and finding somebody there, calmly report the presence of the smoke. . . . The median subject in the Alone condition had reported the smoke within 2 minutes of first noticing it.

. . .

Subjects in the three-person-group condition were markedly inhibited from reporting the smoke. Since 75% of the Alone subjects reported the smoke, we would expect over 98% of the three-person groups to include at least one reporter. In fact, in only 38% of the eight groups in this condition did even one person report (p < .01). . . .

Subjects who had reported the smoke were relatively consistent in later describing their reactions to it. They thought the smoke looked somewhat 'strange.' They were not sure exactly what it was or whether it was dangerous, but they felt it was unusual enough to justify some examination. 'I wasn't sure whether it was a fire, but it looked like something was wrong.' 'I thought it might be steam, but it seemed like a good idea to check it out.'

Subjects who had not reported the smoke were also unsure about exactly what it was, but they uniformly said that they had rejected the idea that it was a fire. Instead, they hit upon an astonishing variety of alternative explanations . . . . Many thought the smoke was either steam or airconditioning vapors, several thought it was smog purposely introduced to simulate an urban environment, and two actually suggested that the smoke was a "truth gas" filtered into the room to induce them to answer the questionnaire accurately! Predictably, some decided that "it must be some sort of experiment" and stoically endured the discomfort of the room rather than overreact.

Thursday, April 05, 2007

Global Warming

A lot of people are solidly convinced not just that global warming is happening, but that human emission of carbon dioxide is one of the main causes, which means that the only way we can reduce or slow global warming is to take significant action to limit carbon emissions.

There is an abundance of scientific evidence for this view, and most of certainly seems convincing. But here's one thing that bothers me. A post at Stubborn Facts points to this graph, from an EPA website:

Figure 1: Fluctuations in temperature (blue) and in the atmospheric concentration of carbon dioxide (red) over the past 400,000 years as inferred from Antarctic ice-core records. The vertical red bar is the increase in atmospheric carbon dioxide levels over the past two centuries and before 2006.

As you can see if you look closely, there are several places where the lines don't exactly match up. So I did a bit more digging. Turns out that there are several scholarly articles finding that CO2 usually lags temperature changes.

One such paper is Manfred Mudelsee, "The phase relations among atmospheric CO2 content, temperature and global ice volume over the past 420 ka," Quaternary Science Reviews 20 (2001): 583-589. His finding is that over the past 420,000 years -- according to the Vostok ice core -- "CO2 variations lag behind atmospheric temperature changes in the Southern Hemisphere by 1.3 [plus or minus] 1.0 ka." ("Ka" means a thousand years.) So, temperature goes up, and CO2 goes up 300 to 2300 years later. Temperature starts to go down, and CO2 goes down 300 to 2300 years later.

Then, in another paper, several scientists found that "high-resolution records from Antarctic ice cores show that carbon dioxide concentrations increased by 80 to 100 parts per million by volume 600 +/- 400 years after the warming of the last three deglaciations. Despite strongly decreasing temperatures, high carbon dioxide concentrations can be sustained for thousands of years during glaciations; the size of this phase lag is probably connected to the duration of the preceding warm period, which controls the change in land ice coverage and the buildup of the terrestrial biosphere." H. Fischer, M. Wahlen, J. Smith, D. Mastroianni, and B. Deck, "Ice core records of atmospheric CO2 around the last three glacial terminations," Science, Mar. 12, 1999, vol. 283, no. 5408: 1712-4.

So again, CO2 increased "after" the warming, and high CO2 was maintained for thousands of years after "strongly decreasing temperatures" -- which obviously must have been caused by something other than CO2 decline.

And here's a third paper finding that over the past 750,000 years, CO2 lagged behind temperature by up to 2800 years: Siegenthaler et al., "Stable Carbon Cycle–Climate Relationship During the Late Pleistocene," Science 25 November 2005: Vol. 310. no. 5752: 1313-17:
By shifting the time scales of the entire CO2 and deuterium records between 390 and 650 kyr B.P. relative to each other, we obtained the best correlation for a lag of CO2 of 1900 years. This lag is significant considering the uncertainties of age. Over the glacial terminations V to VII, the highest correlation of CO2 and deuterium, with use of a 20-ky window for each termination, yields a lag of CO2 to deuterium of 800, 1600, and 2800 years, respectively.

Maybe these findings are untrue; maybe Antarctic ice core doesn't reflect what's happening in the rest of the planet; maybe there's something else going on here. But if these findings are accurate and relevant, then I can't figure out how a CO2 rise in year 2000 causes a temperature rise that began in year 1. Given the CO2 lag, I have to wonder if we're looking at a basic correlation/causation mistake, much like what happened for decades as to lactic acid (scientists used to be very defensive in their belief that lactic acid in muscles causes fatigue, when the opposite is true -- lactic acid is correlated with fatigue, but only because the body produces it to fuel tiring muscles).

Like the poster at Stubborn Facts, the only attempt at a response that I could find was this blog post by Jeff Severinghaus, Professor of Geosciences, Scripps Institution of Oceanography, University of California, San Diego. (I found lots of other websites that purport to address the lag issue, but they all ended up linking back to the Severinghaus post.)

Here's what he says:
What does the lag of CO2 behind temperature in ice cores tell us about global warming?

This is an issue that is often misunderstood in the public sphere and media, so it is worth spending some time to explain it and clarify it. At least three careful ice core studies have shown that CO2 starts to rise about 800 years (600-1000 years) after Antarctic temperature during glacial terminations. These terminations are pronounced warming periods that mark the ends of the ice ages that happen every 100,000 years or so. Does this prove that CO2 doesn't cause global warming? The answer is no.

The reason has to do with the fact that the warmings take about 5000 years to be complete. The lag is only 800 years. All that the lag shows is that CO2 did not cause the first 800 years of warming, out of the 5000 year trend. The other 4200 years of warming could in fact have been caused by CO2, as far as we can tell from this ice core data.

The 4200 years of warming make up about 5/6 of the total warming. So CO2 could have caused the last 5/6 of the warming, but could not have caused the first 1/6 of the warming.
The lag is "only" 800 years. CO2 "could have caused" some of the warming. But did it actually do so?
It comes as no surprise that other factors besides CO2 affect climate. Changes in the amount of summer sunshine, due to changes in the Earth's orbit around the sun that happen every 21,000 years, have long been known to affect the comings and goings of ice ages. Atlantic ocean circulation slowdowns are thought to warm Antarctica, also.
The fact that there are lots of factors besides CO2 that affect climate doesn't seem to strengthen the case that CO2 "could have caused" most of the past warming.
From studying all the available data (not just ice cores), the probable sequence of events at a termination goes something like this. Some (currently unknown) process causes Antarctica and the surrounding ocean to warm. This process also causes CO2 to start rising, about 800 years later. Then CO2 further warms the whole planet, because of its heat-trapping properties. This leads to even further CO2 release. So CO2 during ice ages should be thought of as a "feedback", much like the feedback that results from putting a microphone too near to a loudspeaker.

In other words, CO2 does not initiate the warmings, but acts as an amplifier once they are underway. From model estimates, CO2 (along with other greenhouse gases CH4 and N2O) causes about half of the full glacial-to-interglacial warming.
So CO2 "acts as an amplifier." But then, what accounts for the fact that the planet may occasionally start to cool even while CO2 is still rising? Why doesn't the CO2 just keep on amplifying, amplifying, amplifying? Severinghaus doesn't even try to explain this.

On the other hand, maybe the big picture looks like this:

1. There are lots of factors that make the earth's temperature go up and down.

2. Once the temperature goes up because of one or more of those factors, CO2 starts to increase several hundred or a thousand years later.

3. An increase in CO2 acts as an amplifier, although it obviously has to be of modest impact (given that it doesn't seem to increase the rate of historical warming, and given that subsequent temperature declines can start even while CO2 is still rising).

4. When the other factors affecting climate start to shift back towards a cooler temperature, they outweigh any effect of CO2, and several hundred years later, CO2 starts to decrease.

5. Nonetheless, in modern industrial times, there is so much CO2 being independently emitted by human activity that the amplifying effect might overwhelm the other factors that otherwise cause the earth's temperature to fluctuate up or down.

Number 5 very well could be true. That's the only logical possibility I can imagine that would account for the current link between CO2 emissions and temperature increases, in the face of past cycles where CO2 has lagged temperature both on the upswing and the downswing.

But is 5 actually true? It seems to me that one would need an account of (a) what those other factors are (whatever is in the category that Severinghaus says is "currently unknown"); (b) exactly how strong those factors are, and under what circumstances; (c) whether those factors are present now, and to what extent; and (d) why those factors are now going to be overpowered by CO2 rather than the other way around. Is there any such explanation out there? What am I missing?

Tuesday, April 03, 2007


What's the difference between the following statements:

1. The universe depends on a force that "our five senses can’t detect," that "doesn’t interact at all with electricity or magnetism," and that is compared by those who work in the field to the "tooth fairy."

2. The universe depends on God.