Tuesday, December 22, 2015

Friday, December 18, 2015

How To Lie While Telling the Truth: Part II

My previous example was an attack on religion. This time it is a defense of AGW catastrophism.

It has long been known that increasing the concentration of CO2 increases the yield of C3 plants, including most crop species. The usual estimate is that doubling CO2 concentration, roughly what is projected for the end of this century, increases yield by 30% or more. This is an inconvenient fact for people who want to argue that AGW will reduce food supplies. Clearly what they need is a scientific article to cite, proving that CO2 is actually a bad thing for crops. 

And they have one, in Nature no less: Increasing CO2 threatens human nutrition.

 The article itself is behind a pay wall, but a good deal of its content is revealed in the abstract and various admiring news stories, including this one:

A quick google found the following table of minerals for wheat:

It includes ten minerals, zinc and iron among them. The fact that the authors of the article could find two whose concentration went down, not by very much, is interpreted as a threat to human nutrition. No information on any that went up.

It's worse than that. The figures, at least according to the news story and the abstract of the article, are for concentration. Increasing CO2 increases the yield of C3 crops. If the concentration of zinc goes down by nine percent but the total crop yield goes up by more than nine percent, total yield of zinc goes up, not down.

Further, the abstract makes it clear that the effect varies from one cultivar to another—so if there really is a problem with the concentration of zinc and iron, farmers will have an incentive to switch to cultivars for which there isn't.

If, with a doubling of CO2 (the abstract does not say what concentration was used in the experiments), crop yield goes up by 30% but the concentration of two minerals goes slightly down and the yield of protein only increases by 24%, that is a "threat to human nutrition."

A striking example of propaganda disguised as science.


[I have sent a message to the lead author of the article inviting him to respond here]


Another paper, not behind a pay wall, by many of the same authors. It makes it explicit that "we believe the simplest approach is to model diets that are unchanged with respect to calories and composition."

Friday, December 11, 2015

Not a Conspiracy

Someone on the FaceBook Climate Change group asked a reasonable question:
I'm trying to understand this big conspiracy everyone keeps hinting at, but never explains, now lets say AGW is a complete Hoax and Obama has somehow tricked the world to help him to trick americans to pay more taxes and put solar panels on their roof, now can someone explain how this evil conspiracy works, like who wins,who profits from this con, , what is the end game...?
I thought my response might be of interest to readers here:

"Conspiracy" is too simple. There are a variety of reasons why different people wildly exaggerate the implications of AGW. They include:

Politicians in poor countries who want to use claims of harm to their countries to get rich governments to give th
em money.

Politicians in rich countries who want arguments for subsidizing firms run by their supporters, passing regulations that give them power, collecting taxes, and a variety of other things.

News media that want to get readers. "Global warming is going to flood New York City" is a better story than "Global warming has raised sea levels by eight inches over the past century and might raise them by another couple of feet by the end of this century."

People who want to pretend to themselves and others that they are part of the intellectual elite, know important things that others deny.

People who like imagining catastrophe. You see the same pattern on the other side of the political spectrum with survivalists, and more generally with collapse of civilization science fiction.

The combined effect has been to convert positions on global warming from a scientific dispute to an identity marker for ideology. You can see the effect reading this group--people keep wandering away from climate questions to gun control or whether Obama is good or bad or other things linked to ideology.

Once you have that linkage, there is strong pressure on either side to take more extreme positions. Believing that global warming is a problem marks you as a loyal member of the blue tribe. So believing that it is a really big problem marks you as a very loyal member, whereas suggesting that it might be a minor problem marks you as a possible traitor to tribal loyalty. Similarly on the other side. Doubting the catastrophic story is all very well--but it's a stronger signal of red tribe loyalty to claim that warming is a fraud due to doctored figures, or that you have a scientific proof that AGW is wrong, or ... .

Thursday, December 10, 2015

How Can Law Be Enforced Against the Executive?

The nonpartisan Government Accountability Office concluded that the Obama administration violated a “clear and unambiguous law.”
A recent post to the Volokh Conspiracy blog argues that a 2014 prisoner swap was blatantly illegal, in violation of a statute requiring that Congress be given thirty days advance notice of such an action. What interests me about it is not whether the claim is correct but, if it is correct, what ought to be done about it. More generally, how can either statutory or Constitutional restrictions be enforced against the executive branch?

In the case of an ongoing action, the obvious answer is that opponents can ask the courts to block it. Examples would be the various suits, past and present, over Obamacare, and Obama's policy on illegal aliens. But what about an action which is already over at the point when opponents learn of it—as was apparently true of the case that the post deals with?

The usual solution to that problem, in both tort law and criminal law, is to punish the tortfeasor or criminal. But government officials are not usually held liable for obeying the orders of their superiors, which shifts the responsibility to the President. If the violation is sufficiently serious, he can be impeached—the President of Brazil is currently threatened with impeachment for spending very large amounts of money in ways alleged to have been in violation of Brazilian law. But it's hard to argue that the particular case alleged reaches the level of “treason, bribery, and other high crimes and misdemeanors.”

One problem is that the responsibility is on the President, who is effectively immune from any sanction short of impeachment. Another is that all crimes are treated as offenses against the government, prosecution is by the executive arm of government, hence crimes that the head of the executive arm approves of are unlikely to be prosecuted. That is the same issue that arises in the very different context of offenses by police.

Solutions? Either in current law or in ways one could imagine altering it?

Tuesday, December 08, 2015

Why am I seeing ads on this Blog?

I have never arranged for any advertisements here. But sometimes recently, when I click on a post, I get a timed ad and have to wait some seconds. I have no idea what is going on. If any of my readers observe the same thing and can figure out where the ad is coming from, please let me know.

Sunday, November 29, 2015

Trudeau and Putin: Ideology vs Interest

Warmth is, on the whole, a good thing when you are cold, a bad thing when you are hot. Generalizing to nations, the countries most likely to benefit by global warming are ones close to the poles. The habitable area of Canada, for example, is a narrow strip several thousand miles long bordered by the United States on one side, snow and ice on the other. A few degrees of warming would make it substantially wider, as well as making the currently inhabited parts a little more habitable. 

Along similar lines, the countries most likely to lose by global warming are those where it is already too hot. India, for example. Which is why I was struck by a news story about the Prime Minister of Canada's plans to lecture the Prime Minister of India on the dangers of global warming.

Meanwhile, Putin has announced that he does not believe in AGW. My guess is that what that really means is that he is in favor of it. Russia is, after all, the only country in the world with a longer arctic boundary than Canada.

(Very low lying countries are also at risk from warming, but there are not many low enough to be seriously threatened by a meter of sea level rise, which is the upper bound of the current IPCC high emissions projection for 2100.)

Tuesday, November 24, 2015

Is the Chicago Police Department an Accessory After the Fact?

A Chicago police officer, Jason Van Dyke, has been charged with first degree murder for shooting and killing a black teenager. The killing occurred more than a year ago. If the accounts appearing in the news are correct, the reason the indictment took so long is that other officers covered up the facts of the case.

If that is true—we will know more after the trial is complete—then other officers, probably quite a lot of other officers, were accessories after the fact to murder. Under Illinois law, an accessory after the fact to a felony is liable to the same punishment as the felon.

It will be interesting to see if any of them are ever charged

Thursday, November 19, 2015

Security Theater

In all the talk about whether to admit Syrian refugees, nobody I have seen has made what seems to me the most obvious argument. The U.S. hosts about sixty million tourists a year from all over the world. Does anyone seriously believe that any terrorist organization competent enough to buy or produce passports would find it difficult to get a dozen of their people in? That's about what a terrorist attack like the recent one in Paris requires.

As best I can tell, there simply is no practical way of preventing terrorists willing to die from killing Americans while doing so. Which makes the present antics of a majority of the House security theater.

Monday, November 16, 2015

Wednesday, November 11, 2015

Barack Obama, Supervillain

My younger son is an aspiring novelist; most of what he has been writing is set in a fictional world of superheroes and supervillains. Some of the villains are likable characters, which raises the question of in what sense they are evil. When I put the question to him in the context of the central character of his first novel, The Titanium Tyrant, who is both superintelligent and honorable, his response was that he was a villain because he did not mind killing innocent people in the process of his crimes.

It occurred to me that, by that definition, there are a lot of villains. Churchill and FDR were prepared to murder very large numbers of German civilians by mass bombing campaigns designed to kill as many, not as few, as possible. Obama has taken responsibility for drone strikes which, in the process of trying to kill terrorists, have clearly killed quite a lot of innocent civilians. In theory, we all believe that all lives matter, but in practice we divide people into our ingroup and everyone else and mostly ignore costs imposed on the latter. In the modern world, that largely means the division between our fellow citizens and foreigners.

It is not limited to national governments and warfare, although that’s the clearest example. U.S. immigration restrictions impose enormous costs on people who would like to come and are not allowed to. Most of those people are much poorer than most Americans. Yet Americans who regard themselves as favoring the poor, most obviously at the moment Bernie Sanders, feel no guilt at keeping foreigners desperately poor in order to keep American poor from getting, by world standards, a little less rich.

In the year 1000, Iceland faced a conflict between pagans and Christians. Before it was resolved by peaceful arbitration, there was a brief period when the two sides declared themselves out of law with each other. Put in modern terms, they were declaring Iceland two countries located on the same territory, each viewing the other as foreigners.

The Titanium Tyrant is out of law with the rest of us, loyal to his own people. By some standards that makes him a villain—but not obviously more of a villain than a lot of the people who many of us approve of.

Sunday, October 25, 2015

Why Do I Waste Time Arguing With Unreasonable People Online?

My son just put the question to me (I was commenting on Facebook at the time), and I thought some here might be interested in my answers:

1. As an excuse not to work on my current book. The chapter drafts I have just been looking at are in worse shape than I thought, which is depressing.

2. In the hope that by putting ideas out, some of them will spread, with some (small) effect on the world. Posts here probably get more readers, but comments on Facebook reach a different audience, one less likely to be familiar with the ideas.

3. In the hope of finding someone reasonable to argue with, which might result in changing his views, or mine, or both, in a desirable direction, as well as being fun. It happens very rarely, perhaps once every few months, but I'm an optimist.

4. Because arguing with unreasonable people online, and watching unreasonable people argue with each other, gives me useful, if depressing, information about what such people are like and (I hope an exaggerated) picture of how common they are. Like most people, I live mostly in a bubble, interacting with a very nonrandom set of people, and this gets me a view outside it. The same is true of reading trade chat in WoW, also depressing.

5. For the same ignoble reason that people spend time beating up on NPC's in WoW and similar games.

Tuesday, October 13, 2015

Some Economic Puzzles

Visiting China last year, I was struck by an interesting puzzle. In the U.S., if you are in a big building selling clothes or groceries, a department store or a supermarket, the people selling them to you are employees of the firm that owns the building. In China, you are much more likely to be in a building whose owners rent it out in small pieces to a lot of individual sellers. Instead of a supermarket, you have a large building with half a dozen butcher stalls, eight fish stalls, ...  . Instead of a department store, you have the same pattern with different stalls selling different sorts of clothing, jewelery, electronics. 

The pattern is not perfect. There are supermarkets and department stores in China and I once saw a Chinese style food market in Baltimore. But one form of retailing is the norm in China and the exception in the U.S., the other form the norm in the U.S., the exception in China.

The puzzle is why.

On my recent visit to Brazil, I came across another such puzzle. In Brazil, at least in Sao Paulo, restaurants frequently sell food not by the dish but by the kilo. You fill up your platter with whatever combination of salad, beans, meat, desert you want, they weigh it and charge you. I do not believe I have ever seen that pattern in a restaurant in the U.S. The closest I can think of is the cafeteria in my university, which sells salad by weight, most other things by individual price.

There are obvious advantages and disadvantages to that way of selling food. The puzzle is why it is common in one country, rare or non-existent in another.

That reminds me of another puzzle that struck me a very long time ago. Some of the costs that a patron imposes in a restaurant depend on what he eats, some on how long he sits. Why are there no restaurants that price the two separately—charge a lower than usual price for the food, but add an additional charge for the time you sit?

For any reader who teaches economics, I suggest that working through the logic of these three puzzles, seeing what the costs and benefits are of one form of organization over another, would be a good problem to set your students. For any graduate student looking for a thesis topic who is more interested in doing economics than proving how much mathematics he knows, one of these puzzles might be worth considering. 

The first step, of course, would be a survey of the literature to see if someone else has already offered an adequate answer. If you find one, let me know.

Good Advice From the Fourteenth Century

Ibn Battuta was a 14th century North African world traveler—I like to describe Marco Polo as his 13th century Italian imitator. He started by going on pilgrimage to Mecca and Medina, got bit by the travel bug. In the course of his travels he went down both the East and West African coasts, providing our only source for those areas in that century. Hearing that Mohammed ibn Tugluq, the fabulously wealthy sultan of Delhi, was generous to foreign scholars, Ibn Battuta set off for India and ended up spending several years as the chief Maliki Qadi of Delhi. His account of his visit to China is dubious, but he probably got at least as far as somewhere in south-east Asia. Eventually he came home and wrote an account of his travels, the Rehla, which survives.

Early on, he swore never, if he could avoid it, to return by the same route he went out on. In my travels, mostly wandering around foreign cities (at the moment Sao Paulo), I have found it good advice. Walk out by one route, back by another, and you see twice as much.

Saturday, October 10, 2015

In a Market in Sao Paulo


Tourist Class Sleepers?

I am currently sitting in San Francisco airport waiting for a flight to Houston, where I change to a flight to Sao Paulo, Brazil, scheduled to arrive at 8:45 in the morning. I am, as usual, flying tourist class.

Some years ago, I flew to New Zealand business class at someone else’s expense. It was a much pleasanter experience than I expect this flight to be. The stroking that goes with an expensive ticket was nice, but the real benefit was a seat that turned into a bed. That makes me wonder whether it would be possible to provide sleeping accommodations on overnight flights at something closer to the cost of an ordinary tourist class ticket.
What that probably requires is a plane whose seats can convert into beds—I suspect the cost of having a plane only used for sleeper flights is too high to make it an attractive option. Not everyone on the plane will want to sleep, so you don’t want all seats to convert. In order to fit the same number of people in lying as seated, you will need to stack the beds. Stacking two might do it, but stacking three probably works better. Sleeper cars on a railroad are sometimes set up that way, and although I think the ceiling is a little higher than in a plane you should still be able to manage it.
One problem is how to get in and out of bed without having to ask the sleeping person next to you to move. Two solutions occur to me. One is that with beds stacked three deep there might be enough room for a narrow space between each stack and the next sufficient to get out. The other, for a wide body plane, is to have seats in their usual arrangement along the wall, than an aisle, then two convertible seats, then an aisle, possibly repeating if the plane is wide enough. That way every seat is next to an aisle.
There must be a lot of business travelers for whom the benefit of an extra day at their destination would be worth a good deal. No doubt some of them now fly business class. But I expect a lot more would fly tourist sleeper if it was available at a price somewhat higher than ordinary tourist and much lower than present business class fares. As would I.

Monday, October 05, 2015

Some Links

The Truth About Ancient Greece

If you happen to be Jewish and press the wrong button on the time machine.
18) The Michelson-Morley and Sagnac experiments attempted to measure the change in speed of light due to Earth’s assumed motion through space. After measuring in every possible different direction in various locations they failed to detect any significant change whatsoever, again proving the stationary geocentric model.
(from a list of 200 proofs of the geocentric model of the universe)
A detailed critique of recycling.

Sunday, October 04, 2015

How Not to Defend Islam

In a recent piece on Salon Qasim Rashid, described as "the national spokesperson for the Ahmadiyya Muslim Community USA and Visiting Fellow at Harvard University’s Prince al-Waleed bin Talal School of Islamic Studies," takes Ben Carson to task for "absurd lies" about Islam. Some of Carson's claims about Islam may well be false—it is not true, for instance, that "Under Shariah law ... people following other religions must be killed.” Most Americans do not know much about other religions; there is no reason to expect Carson to be an exception. 

Rashid, who surely is well informed, writes:
Islam gave women equal rights in 610 that our own United States haven’t given even in 2015. To this day America has not passed the Equal Rights Amendment. Meanwhile the Quran 33:36 emphatically declares the equality of men and women:
“Surely, men who submit themselves to God and women who submit themselves to Him…God has prepared for all of them forgiveness and a great reward.”
God may treat men and women equally but Islamic law, fiqh, does not. A daughter under Islamic law receives half the inheritance of a son—a rule directly from the Quran. A man is permitted to marry up to four wives, a woman one husband. A man may freely divorce his wife, a woman is not free to divorce her husband. Each spouse has rights to sexual intercourse with the other, but the rights are not the same.
In truth, the Qur’an only permits fighting in self-defense, or to protect  “churches, synagogues, temples, and mosques” from attack. Prophet Muhammad issued numerous charters with Christians, Jews, and pagans to affirm his commitment to universal religious freedom and equal human rights for all people regardless of faith.
Mohammed attacked and destroyed the  Jewish villages near Medina. In one case, after the village surrendered, all of the male inhabitants were killed at his orders. He fought a long war with the Quaraysh, his fellow tribesmen in Mecca, which ended only when they surrendered and converted.

When Islam began, the two great powers of that part of the world were the Persian Sassanid empire and the Byzantine empire. In the course of the first century after Mohammed's death his followers conquered all of the first and a large chunk of the second, one of the more impressive accomplishments of human history. It was not done by fighting in self defense.

Under Islamic law, the other peoples of the book—Christians, Jews and (probably) Sabeans—were permitted to live under Islamic rule. But they did not have "equal human rights." A Muslim man could marry a Christian or Jewish woman, a Christian or Jewish man could not marry a Muslim woman. Christians and Jews were required to pay a special tax, the jizya.

According to the Shafi'i school of law, the indemnity for killing a woman is half that for killing a man, the indemnity for killing a Jew or a Christian is one third that for killing a Muslim, the indemnity paid for a Zoroastrian is one fifteenth that of a Muslim (The Reliance of the Traveler o 4.9). Details vary among the four schools.

Rashid never mentions that the Ahmadiyya Muslim community for which he is the spokesman is a heterodox offshoot of orthodox Islam originating in India in the late 19th century, one that regards its founder, Mirza Ghulam Ahmad, as the Messiah. For all I know his claims are true about current Ahmadiyya doctrine. But presenting them as  doctrines of Islam without qualification, when his sect represents about one percent of the total Islamic population, is roughly equivalent to a Mormon presenting Mormon doctrine as Christianity without qualification or explanation to an audience unfamiliar with Christianity. 

And, while his sect is free to choose its own legal rules, it is not free to change the historical facts to suit.

Monday, September 28, 2015

How to Lie With Statistics Updated

How to Lie With Statistics is an old and good book on how not to be fooled by statistical tricks. I just came across one that, so far as I can remember (I read the book a long time ago) was not not included. 

Someone commenting on a Facebook global warming post put up this graph. Two comments later he wrote "Notice a trend?"

The trick, of course, is that the years are arranged in order of how hot they were. 2014 is at the right end not because it is the most recent year but because it was the hottest. 2012 is at the left end because it was the coolest of the years shown. Arranging them that way guarantees the appearance of a rising trend, whether temperatures are actually going up or down.

I am not certain that the person who put it up intended to imply that it showed a trend. He may have only meant that 2014 was hot and 2015 expected to be hot, as mentioned in his comment immediately after he put up the graph. But my guess is that either he had been fooled by the trick of drawing the graph that way or else he was deliberately trying to fool others.

I commented on it in the thread and will be interested to see his response.

Saturday, September 26, 2015

Hillary, Crichton, O'Rourke, Coulter and GKC

Scott on Slate Star Codex sometimes posts a collection of links with brief comments. I thought I would try it.


According to
Bloomberg, the FBI has succeeded in recovering some of the emails on the server that was supposedly wiped before handing it over to them. The reason this is a news story is that it might provide evidence against Hilary, emails that should have been turned over and were not because they contained information she did not want to get out. But whatever is on the server, the fact that the FBI was able to recover it is relevant to Hilary's qualifications to be president. Anyone living in the modern world and using computers should know that erasing a disk does not guarantee that the contents cannot be recovered. Even if she does not know much about computer technology, she ought to have people working for her who do. If she does not, that is evidence of incompetence, not in wiping a hard drive but in hiring and managing subordinates—a large part of a president's job.


Aliens Cause Global Warming is an essay by Michael Crichton on the way in which he believes that science has become corrupted in recent decades. The obvious application is to current climate controversies but the more general problem is what he views as a shift of the enterprise from the search for truth to a way of convincing people of things you want them to believe. His best example is probably the Nuclear Winter campaign:
The first announcement of nuclear winter appeared in an article by Sagan in the Sunday supplement, Parade. The very next day, a highly-publicized, high-profile conference on the long-term consequences of nuclear war was held in Washington, chaired by Carl Sagan and Paul Ehrlich, the most famous and media-savvy scientists of their generation. Sagan appeared on the Johnny Carson show 40 times. Ehrlich was on 25 times. Following the conference, there were press conferences, meetings with congressmen, and so on. The formal papers in Science came months later.
This is not the way science is done, it is the way products are sold. 
Part of the reason I agree with his point was an article I read at the time, written by one of the teams whose work fed into the nuclear winter conclusion. They conceded that a criticism that had been offered of their work was correct, concluded that fixing the error would reduce the length of nuclear winter from years to weeks. But they also found another mistake in their initial work with the opposite effect. Fixing that got it back to years.

There is nothing surprising or disturbing about the fact that published scientific articles sometimes have mistakes. I am currently in the middle of redoing an old project, my research on Icelandic law, and have concluded that at least some details in what I published more than thirty years ago were wrong. But there is a problem with proclaiming something as scientific fact before other people have had a chance to look at your research and critique it.

One interesting thing about that particular case is that it might be defended as a case of justified dishonesty. I can imagine a reasonable person deliberately misrepresenting the evidence, claiming it was much stronger than he believed it actually was, on the grounds that almost anything that reduced the risk of nuclear war, honest or dishonest, was worth doing. The counter-argument is implicit in Crichton's essay—that treating science in that way converts it from a mechanism for determining truth to a tool of partisan debate, with very bad long-term results.

A recent piece by P.J. O'Rourke takes Ann Coulter to task for tweeting during the September 16th debate:
Cruz, Huckabee Rubio all mentioned ISRAEL in their response to: “What will AMERICA look like after you are president.” 
How many f—ing Jews do these people think there are in the United States?
I am no fan of Coulter and enjoyed the essay, but with two reservations. The first has to do with the tweets. The reference to "f—ing Jews" is not about ethnicity. The implied point was that candidates focus on support for Israel to attract support from Jewish voters, and there aren't enough Jewish voters to make it worth doing. It is abrasively put, but it implies nothing about her view of Jews other than their numbers.

The point is, however, wrong—not because there are a lot of Jewish votes but because winning Jewish votes is not the reason the candidates talk about Israel. American conservatives are mostly pro-Israel for reasons that have nothing to do with their view of Jews, just as the American left is mostly anti-Israel for similar reasons. Republican candidates are trying to appeal to conservative voters; trumpeting their support for Israel is one way of doing so.

My other reservation had to do with O'Rourke's reference to Chesterton’s essay “The Problem of Zionism,” which implied that it was antisemitic. While it is possible to excerpt passages that sound antisemitic, it is also possible, perhaps  easier, to find ones that make Chesterton sound like a Zionist. For instance:
"It is our whole complaint against the Jew that he does not till the soil or toil with the spade; it is very hard on him to refuse him if he really says, 'Give me a soil and I will till it; give me a spade and I will use it.' It is our whole reason for distrusting him that he cannot really love any of the lands in which he wanders; it seems rather indefensible to be deaf to him if he really says, 'Give me a land and I will love it.'" 
For a more detailed discussion and defense of Chesterton, see the chapter on him in the second edition of my Machinery of Freedom.

Question: Would readers prefer it if I had posted this as three short posts instead of one long one?

CAGW and Consensus

Some years ago, Richard Tol published an article in the Journal of Economic Perspectives that pooled the work of everyone in the field to produce estimates of the net effect of various levels of warming, measured relative to pre-industrial temperatures. It included a graph showing estimated net cost, with an error range. The green lines show his results after correcting some errors in the original paper.

The solid green line shows the estimate. It is positive up to about two degrees, negative thereafter. The dashed lines are the boundaries of the 95% range. The high end (optimistic) does not go negative until 3°C.

What about the low end? At 3°C, the welfare impact is a reduction of 10%. The IPCC high emissions scenario, RCP8.5, which gets us to that temperature sometime in the second half of the century, assumes continued economic growth. If so, the 10% reduction in welfare due to AGW will be combined with an increase several times that large.

My previous post discussed an article in the Journal of the National Academy of Sciences which criticized the IPCC models and concluded that warming due to AGW had been reasonably stable for the past century at a little less than one degree/century. If that continues, by 2100 global temperature will be less than two degrees above its preindustrial level. On Tol's estimate, we will be better off than if there had been no AGW, worse off than if AGW had been a little slower. 

If, on the other hand, we accept RCP8.5, when we reach the 3° mark we will be worse off than if warming had not occurred, better off than we are now—even if we take the low end of Tol's predicted range of effects.

Which I think is an adequate response to people who tell me that to deny catastrophic effects of warming is to ignore the scientific consensus.

Friday, September 25, 2015

Modafinal, Steroids, and Competition

A recent discussion of a post on my favorite blog dealt with the implications of smart drugs, in particular modafinil. A number of people argued that the problem with permitting such things was competition. If one person uses them, others have to use them in order to compete with him, so you end up with whatever negative side effects the drugs have—modafinil does not seem to have many, but nobody knows for sure—and everyone in the same position as before.

That argument views economic competition as something like a football game, where one side wins and the other side loses—if you are not the best you are nothing. If that were true, most of the population of the world would be unemployed. Even without smart drugs, people vary in how able they are—they cannot all be the best.

Suppose the use of modafinal makes me 10% better at whatever I do. The result is not that someone with the same abilities who does not take it is useless, merely that I am ten percent more useful and so can expect an income about ten percent higher, whether my salary as an employee or my earnings if I am self-employed. I can decide for myself whether the additional income, or the additional leisure if I choose to work fewer hours instead of making more money, is worth whatever I think the risks of side effects are. If many people use smart drugs, some of the benefit might to go to other people either as lower prices for what the more productive workers produce or higher returns on other inputs to production. But somebody still gets the benefit of the additional productivity.

The source of the mistaken intuition is probably the analogous case of steroids in sports. There the right answer is less clear, depending on what it is that athletes produce. If what the fans care about is only relative ability, whether or not their team can beat the other team, then if everyone uses steroids the players are worse off—assuming significant negative side effects—and the fans no better off. If fans value absolute quality, enjoy watching athletes more the better they are, then the argument I have offered applies to that case as well. 

Not being a sports fan, I cannot offer an informed opinion on which is the case.

The same confusion between economic competition and sports competition shows up in one of George Orwell's mistakes. In a very interesting joint review of The Road to Serfdom and a  book by Konni Zilliacus, a left wing Labor politician, he wrote:
The trouble with competitions is that somebody wins them. Professor Hayek denies that free capitalism necessarily leads to monopoly, but in practice that is where it has led ...
Which, fortunately, is not true.

[An earlier discussion of the same issues, not in the context of smart drugs]

Sunday, September 20, 2015

An Explanation for the Pattern of Warming

I have been arguing for some time that what the pattern of global warming suggests is a rising trend due to AGW with an alternating trend from some other cause superimposed on it, the latter having a period of about sixty years. On that interpretation, the period of stable to slightly falling temperatures from about 1940 to 1970 and the period of roughly stable temperatures from 2002 on represent periods when the two trends were pushing in opposite directions and so roughly canceling each other, the rapid warming from about 1910 to 1940 and 1970 to 2002 periods when they were reinforcing each other.

The conventional explanation for the mid-century pause is that it was due to aerosols producing a temporary cooling effect. That became less plausible, at least to me, when the pause reappeared, roughly on schedule. If I am correct, the IPCC models, by special casing the earlier pause instead of treating it as part of a recurring pattern, overestimated the average rate of warming, treating periods when the two trends reinforced as if they were the norm, the period when they canceled as a special case.

I have now come across an article in the Proceedings of the National Academy of Sciences that supports my interpretation of the pattern, based on analysis of the 353 year Central England Temperature Series, the longest instrumental temperature record that exists. The authors conclude that there is a recurrent multidecadal oscillation with a period of about seventy years, likely due to the Atlantic Multidecadal Oscillation. They reject the aerosol explanation and conclude that:
The underlying net anthropogenic warming rate in the industrial era is found to have been steady since 1910 at 0.07–0.08 °C/decade, with superimposed AMO-related ups and downs that included the early 20th century warming, the cooling of the 1960s and 1970s, the accelerated warming of the 1980s and 1990s, and the recent slowing of the warming rates.
Almost precisely my conjecture—I slightly underestimated the period of the oscillation—with an explanation and a lot more data.

Friday, September 18, 2015

If Obama is a Muslim, He is a Very Bad One

Various people, including Donald Trump, have suggested that Obama was not born in the U.S. and may be a Muslim. The former claim, while it may be false, is not absurd—there is no obvious way of being certain of the details of the birth more than fifty years ago of someone of no particular prominence. The claim he is a Muslim, on the other hand, has at least two serious problems. 

One of the binding obligations of Islam is to pray five times a day, in a specified manner (with some possible variations), at specified times. If Obama has managed to do that through most of two terms without anyone noticing, he is a very talented man. A second binding obligation is to fast through the month of Ramadan—neither eat nor drink in daylight hours.

Thursday, September 17, 2015

Did Ahmed Make a Clock?

Speaking at an afternoon news conference outside the family’s home, Ahmed’s father said he’s proud of his son and wowed by his skills.
“He fixed my phone, my car, my computer,” Mohamed Elhassan Mohamed said. “He is a very smart, brilliant kid.”
Public discussion of the case centers on whether or not the school and the police unreasonably over reacted. As best I can tell the answer is that they did. But what interests me is an entirely different question. A central feature of the story is how talented Ahmed is, a fourteen year old engineering marvel. That makes it a better story, better for the news media and better for Ahmed. But is it true?

One commenter on a blog I read, looking at the picture of what he brought into school, concluded that what it was was an old clock the innards of which Ahmed had taken out of its case and transferred to a briefcase. I do not know enough about electronics to offer an intelligent guess as to whether he was right, but it seems plausible enough—and well within the ability of a fourteen year old. 
If so, this is not only about school officials over reacting. It's also about the willingness of the media to tell a good story without any serious effort to find out if it is true.

P.S. A fairly detailed analysis of what the clock was:


Monday, September 14, 2015

President Carson

My preferred candidates are Rand Paul for the Republican party and Gary Johnson for the Libertarian Party, but the candidate I find most interesting at the moment is Ben Carson. I do not think he is likely to get nominated, let alone elected. But if he did end up in the White House, what kind of a job would he do?

He is intelligent and likable, both useful assets, but he has no experience at anything close to the job he is running for. There have been Presidents before with a background outside of politics, such as Grant and Eisenhower, but both were generals, men who had successfully run large organizations. Have there been any Presidents like Carson, successful men whose success did not involve either politics or administration? None occur to me—but it is not a subject I know much about. Perhaps one of my readers can offer an example.

The job of president is, long has been, too big for one man, so the question will be how good he is at building and running a team. Can he select competent subordinates, coordinate them, evaluate the advice they give him? Judging by my one first hand experience of neurosurgery, that too is a team job. But I have no idea whether Carson as surgeon was the creator and leader of a team or merely its star member.

If he does make it, it should be interesting.

Sunday, September 13, 2015

The Author as Sponge

A correspondent recently emailed me links to a couple of YouTube videos from a firm that trains people in the use of modern weaponry, with the suggestion that it might be more relevant to the discussion of how a stateless society could defend against states than the example of paintball that I offer in a chapter in the new edition of The Machinery of Freedom. The first video included a discussion of a technical point new to me, the distinction between open bolt and closed bolt firearms. 

After the video finished, I went downstairs to tell my younger son about it. Bill is unlikely to ever have any use for an open bolt, or even a closed bolt, firearm. He is, however, a would-be novelist, I think likely to be a good one, and almost any information is potentially useful in that profession—which is the point of the title of this post.

For instance ...  

Most modern firearms are closed bolt. When the gun is ready to be fired the bolt is closed, holding the cartridge firmly in place. Pulling the trigger releases the firing pin, which strikes the primer, which fires the gun. 

In the less common open bolt design, the firing pin is a fixed part of the bolt, not a piece free to move within it. When the gun is ready to fire, the bolt is open, pulled back. Pulling the trigger releases the bolt, which slides forward, closing the breach and driving the firing pin into the primer. 

That works fine, provided you are standing still. But with the bolt open, there is nothing holding the cartridge in place. If you are running around with the weapon ready to fire—not a problem with the closed bolt weapons you are used to—the cartridge can come loose, either falling out entirely or jamming the mechanism that is supposed to fire it. 

That is what happens in the video to a trainee using a weapon new to him. It could happen easily enough to a fictional character, providing both one more way in which the author can complicate the action and a nice technical detail to help the author pretend to know what he's talking about. 

Which is why I thought my son would be interested.

Friday, September 11, 2015

If We Burned All Our Fossil Fuel

If we burned all the coal, oil and gas that’s left in the ground, we’d melt Antarctica and global sea levels would rise as much as 60 meters (200 feet) over the next ten thousand years. Coastal cities from New York to Shanghai would wind up deep underwater.
(One of multiple news stories reporting on a newly published journal article.)
That sounds scary—if you miss "over the next ten thousand years."

The article the news story is based on is webbed. It gives an estimate of the consequences of burning all of Earth's fossil fuel over the next few centuries. The conclusion is that "Antarctica is projected to become almost ice-free with an average contribution to sea-level rise exceeding 3 m per century during the first millennium." Figure 1d from the article shows a rapid rise, close to forty meters in the first thousand years, gradually tapering off thereafter.

Three meters a century is considerably faster than the current rate of rise—not surprising since it would be driven by a CO2 concentration about eight times the current level. One way of getting a feel for how serious it would be is to convert it into a rate at which coastlines move inward, assuming no diking. The rule of thumb for that is about a hundred meters shift for every meter of rise. So three meters per century of SLR implies coastlines shifting in by about three hundred meters a century, more in some places, less in others, but well short of the catastrophe implied by "coastal cities deep underwater."

Another way of looking at it is in terms of what could be done via diking. The lowest city in the Netherlands, a country with centuries of experience protecting land below sea level, is more than six meters below sea level. With two centuries to do it in, I expect New York or Shanghai could match that.

Another conclusion of the article is that the Antarctic would end up almost ice free, but it is not clear why that would be a bad thing. We are currently in an ice age, defined by the existence of ice on the poles. There have been earlier ice ages, but for most of the history of the Earth, including most of the period with living creatures and even most of the period with mammals, the poles have been free of ice.

Figure 1c shows the estimated effect on average global temperature—an increase over about a thousand years of a little over 10°C relative to the current value, followed by a gradual decrease thereafter. That looks like a much bigger problem than sea level rise—but how big? At the same time that the hotter parts of the Earth were becoming unihabitable, the colder parts—Antarctica and currently frozen parts of the Northern Hemisphere—would be becoming habitable. An accurate calculation of the net result would require more expertise than I have and more effort than I am willing to put into the project, but I can at least try a rough back of the envelope estimate.

Warming due to CO2 tends to be greater in cold times and places than in hot, because water vapor is also a greenhouse gas, the warmer it is the more water vapor is in the air, and the more of one greenhouse gas the less the effect of adding another. I do not know how large the difference would be for warming on the scale I am looking at. To simplify my calculations, I will assume that high temperatures in hot areas go up by five degrees, low temperatures in cold areas by fifteen—readers are welcome to recalculate the numbers with other assumptions.

How high do high temperatures have to be to make a place uninhabitable? India is a very hot place and densely populated. Looking at a list of July high temperatures by city, I observe a high of 36°C in Tamil Nadu and Pondicherry. If that represents the upper bound for habitability, another five degrees would make any city currently above 31° uninhabitable. Counting cities, which is less work than looking up regional areas and adding them, I observe that twenty-four out of fifty-two cities are above that, so my very rough estimate is that the projected warming would make almost half of India uninhabitable by a thousand years hence.

Looking at a list of highest temperatures ever recorded by country, the figure for India is 50.6°. Algeria, Iran, Iraq, Kuwait, Mexico, Pakistan and Saudi Arabia equal or exceed that, and a few other countries come close. If I add up the area of India and all countries whose highest temperature is at least as high, I get a total of about 12.7 million square km. To allow for countries a little cooler than India, take it up to 14 million, then divide in half, since my very rough calculation suggests that only about half of India would become intolerably hot.

Very, very rough estimate: A five degree increase in maximum temperatures would make about seven million square km intolerably hot. What would we get in exchange?

Antarctica and Greenland would be ice free, for a total area of about sixteen million square km. How much of that would be warm enough to be habitable I do not know. Siberia is about thirteen million, Canada about ten million. Parts of both are presently habitable, but large parts are not. Similarly for Sweden, Norway, and Finland.

I conclude, from my very rough estimates, that the total habitable area of the Earth would almost certainly go up, not down. I leave to someone more ambitious the task of a more careful and precise calculation. A lot of people would have to move—but a thousand years is a very long time.

Why does all of this matter, given the difficulty of predicting anything a thousand years, even a hundred years, into the future? It matters because it suggests an upper bound to climate catastrophe, at least slow catastrophe. In the worst case, the long term result would be a physical world not strikingly worse for humans, possibly better, than the present world.
If the changes happened over decades there would be enormous human costs. If they took many centuries, probably not.

Thursday, September 10, 2015

Why Unlikely Events Are Not Unlikely

A recent FaceBook post starts:
Is it really a coincidence that so many unprecedented weather events are happening this year
with a link to a news story about a "once in 50 years" rain in Japan. It is an argument I frequently see made, explicitly or implicitly. Lots of unlikely things are happening and there must be a reason. When the subject is climate change the unlikely things are mostly about climate.

It looks convincing until you think about it. The world is large. There are lots of different places in it where, if an unusual weather event happens, it is likely to show up in the news. There are at least four categories of unusual weather events that could happen—unusually hot, unusually cold, unusually large amount of rain, unusually small amount of rain—and probably a few others I haven't thought of. A year contains four seasons and twelve months and a record in any of them is newsworthy—a recent news story, for example, claimed that this August was the hottest August in the tropics on the record.

For a very rough estimate of how many chances there are each year for an unlikely event to happen and make the news, I calculate:
100 countries prominent enough + 100 cities prominent enough +10 geographic regions (tropics, poles, North America, ...) + 50 U.S. states = 260
12 months + 4 seasons=16
4 kinds of events that would qualify 

=16,640 opportunities each year for an unlikely weather event to occur and be reported.

So we would expect more than 300 once in 50 years events to happen each year and about sixteen one in a thousand events.

My guess is that those number are too low—the story about floods in Japan does not make it clear whether the one in fifty years record is for the whole country or only one region. But they at least show why we should expect lots of unlikely things to happen each year.

If you flip a coin ten times and get ten heads, you should be surprised. If you flip sixteen thousand coins ten times each, you can expect to get ten heads about sixteen times—and should not be surprised when you do.

Tuesday, September 08, 2015

Another Angle on the Kim Davis Case

One of the less sympathetic features of the case, at least to me, is that her action is entirely symbolic. It does not prevent gay couples from getting married and it only prevented them from getting married in her town for a few days. That makes me suspect, perhaps unfairly, that she is acting not out of religious conviction but either because she likes attention or because she hopes to use the controversy to jump start a political career.

Which gets me wondering how people would feel about her action if it was more than symbolic, if by disobeying a legal rule she disapproves of she could actually keep it from taking effect. It is hard to imagine a version of her story that achieves that, but consider the same issue in a more plausible context:
You are a law enforcement official charged with enforcing the law against marijuana in a state with severe penalties for its violation. You believe marijuana should be legal. You can quietly subvert the application of the law by failing to follow up evidence of marijuana usage, recommending on spurious grounds against prosecution of arrested users, perhaps sending anonymous warnings to targets of investigations by other officers. You expect that you can get away with such actions for many years, since those supervising you are either sympathetic or incompetent. The result will be to save hundreds of people from arrest, conviction, and imprisonment.
Should you do it or should you resign?

For those who think it obvious that you should resign, that obedience to the law takes priority over moral beliefs, consider two real world situations along somewhat similar lines.

1. Jury nullification. If you are on the jury trying someone for a crime of which you believe him guilty but that you do not believe ought to be illegal, should you vote for conviction or acquittal?

2. President Obama's decision not to prosecute a specified subset of illegal immigrants.

Immigration, Welfare and the EU

The strongest argument against free immigration, from the standpoint of supporters of the free market, is that immigrants from poor countries may come not in order to work but in order to take advantage of a rich country's welfare system. Seen from one side it is an argument against free migration, seen from the other an argument against a welfare system. The easier it is for poor people to come to take advantage of welfare, the less attractive redistribution looks to the taxpayers paying for it, hence the less generous the system is likely to be. That may explain why levels of redistribution are generally lower in the U.S., where welfare was traditionally handled at the state level and intrastate migration was free, than in Europe, where welfare was handled at the national level and interstate migration was restricted.

Was. Within the E.U., there is now free migration. That puts pressure on national welfare systems either to reduce the level of transfers or raise redistribution to the supranational level. That pressure was limited as long as all E.U. members were relatively wealthy countries, became greater with the admission of poorer members from eastern Europe.

It is now greater still as the willingness of some European states to accept refugees and treat them generously, combined with conflicts that produce large numbers of actual refugees while making it difficult to distinguish them from voluntary migrants, is creating a flood tide of would-be residents on Europe's southern and eastern borders

One way in which the E.U. might respond is by restricting immigration. That will be difficult when many of the would-be immigrants are fleeing  real dangers, hence natural objects of sympathy. How do you distinguish real refugees from migrants seeking to take advantage of generous transfers (330 € monthly, accommodation, language courses and so on during the six months that it takes Germany to decide whether or not someone qualifies for asylum, according to a comment on a recent post here)? And immigration restriction is made more difficult by the fact that border control is done at the national level. A country with low levels of redistribution can leave its border open in the expectation that most new arrivals will promptly depart for richer fields.

An alternative is to offer asylum on terms sufficiently unattractive so that only those fleeing real dangers will be inclined to take them—no welfare payments for five years, the current Czech policy for non-asylum migrants. That is the immigration policy that I recommended for the U.S., along with open borders, more than forty years ago in the first edition of The Machinery of Freedom.

Either policy might solve the immediate problem but  still leave a situation where rich E.U. nations with generous welfare policies can expect to attract poor people from poorer parts of the E.U.—who, under current law, have the same rights as existing residents. It will be interesting to see whether the result is to shrink the European welfare states or to shift redistribution one level up, converting the E.U. into something a little closer to a United Statues of Europe.

For those in favor of free immigration and opposed to redistribution, the optimum solution, within the E.U. and in the world more generally, is easy. Arguably, the same solution should be optimal for those who support redistribution for egalitarian motives. Open borders plus the abolition of transfer payments might increase inequality in the U.S. or Germany but would surely reduce inequality on a global scale, the poor of India and Egypt, who would benefit, being much poorer than the poor of the U.S. or Germany.

Intuiting the Kim Davis Case

I have to wonder: just how many of those supporting Kentucky clerk Kim Davis’s refusal to issue marriage licenses based on her religious objection to same-sex couples marrying would support a Quaker government official who refused to issue them gun permits based on a religious commitment to pacifism?—Lambda Legal Legal Director Jon Davidson
Davidson's hypothetical works if your objective is to show supporters of Kim Davis how her act looks from the standpoint of those critical of it, although it should include "and refuses to resign," since lots of people, probably including lots of those supporting Kim Davis, would approve of a Quaker who resigned rather than taking an action inconsistent with her religious views. For the reverse project, showing opponents of Kim Davis how the situation looks to supporters:
You are the only trash collector for your town. A recent change in state law has classified homeless people as trash and instructed all local trash collectors to kill homeless people and dispose of their bodies. You were  appointed by an elected official who opposes the new law, so cannot easily be removed. Should you obey the new law, resign your position, or hold the position as long as you can while refusing to kill anyone?

Sunday, August 30, 2015

Doing Something

A recent news story has a presidential candidate flirting with the idea of building a wall along the U.S. border—the northern border. His explanation:
Walker has long said that securing U.S. borders, especially the southern border with Mexico, is not only a deterrent to illegal immigration but also a way to ensure that terrorists and international criminals do not enter the country. 
The U.S. hosts about 75 million tourists each year, coming from a wide variety of countries. Does anyone seriously believe that we can filter out from that flood one, or ten, or a thousand bad guys? All a competent terrorist needs is a passport in a name that isn't on a list of people to keep out. I do not know what country in the world is currently the least expensive source of bogus passports, but I would be surprised if the price was high enough to discourage someone supported by ISIS or al Qaeda or ...  .

As in too many other cases, the underlying logic is:

Something must be done.

This is something.

Thursday, August 27, 2015

It Could Be an Interesting Election

A recent story claims that Bernie Sanders is planning to drop out of the Democratic race and run as an independent; he has denied it.  Donald Trump has said both that he would and would not consider running as an independent. If one runs and the other does not, that might well throw the election to the other side. The more interesting question is what happens if both run.

Sanders appeals to the left wing of the Democratic party, so the question is how many will vote their ideology at the risk of putting a Republican in the White House.  Trump is a more complicated case, with positions on the  right on some issues,  the center, even the left on others. His appeal, so far as I can tell, is not ideological but personal—he is a more competent demagogue than the other candidates, a point persuasively argued by Scott Adams of Dilbert fame. I would expect him to pull a significant number of votes from the Democrats although more from the Republicans.

If both run, how will the major parties respond? A Sanders campaign would pull Hilary left—arguably already has. A Trump campaign might give the Republican  an incentive to try to match his demagoguery, as some  are doing on the anchor babies issue. Or it might persuade the candidate that Trump's voters are a lost cause—and at least not voting Democratic. That could, to be unreasonably optimistic, improve the chances of Rand Paul or someone similar. And a Republican candidate Democrats only mildly dislike would reduce the incentive for Sanders supporters to vote for Hilary.

Commenters with better worked out ideas of the implications are invited to offer them.

Friday, June 12, 2015

Robert Heinlein, Cell Phones, and Police

Somewhere, Heinlein comments that predicting the direct effects of technological change is relatively easy. What is harder is predicting indirect effects. His example was the automobile. He argued that it had a substantial effect on sexual behavior by giving couples a place to make love out of sight of parents.

I am not sure how convincing that example is, but it occurs to me that we have another and clearer one. Did it occur to anyone, ten or fifteen years ago, that one effect of the development of cell phone technology would be, by providing practically everyone with a pocket video camera, to greatly increase public opposition to police beating people up? 

The closest I can think of is in David Brin's Transparent Society, where he argued that, in a future where everything is subject to surveillance, the transparency ought to go in both directions: The police can watch us, but we can also watch them.  I do not think it occurred to him how we would get there or that the essential change would be not in what you could see but in what you could record and offer for public view.

P.S. Judging by comments, I may have been unfair to Brin, working off my memory of one book, not all of his writing.

Wednesday, June 10, 2015

Medieval Myth

On an entirely different topic ...  

Given my historical interests, I have long been struck by how inaccurate popular conceptions of the Middle Ages are—summed up in the historically obsolete label of "Dark Ages." My usual example is the myth that medieval food was overspiced to hide the taste of spoiled meat, propagated by people who have never read a medieval recipe, let alone cooked from one, or spent as long as twenty seconds thinking about the consequence for a cook of routinely serving spoiled meat, disguised with expensive spices, to his boss. I also have a pair of accounts of scientific reasoning, one from a Norse saga and one from a 14th century North African.

I have just come across a delightful review of a recent book on the medieval foundations of modern science, written by a reviewer who shares my attitude towards popular confident ignorance on the subject.

Tuesday, June 09, 2015

Looking for an Honest Man

I believe I have shown that John Cook, lead author of the article commonly cited for the claim that 97% of climate scientists support AGW, has lied in print about his own work. My argument assumed that Cook et. al. 2013 was itself honest, but other people have offered good evidence that it is not.

It is not surprising if there are some dishonest people on one side, or the other, or both of the climate controversy. A more interesting question is whether there are any honest people. Can anyone point at a prominent supporter of action to prevent warming who has publicly rejected Cook et. al. 2013 or its author?

The same question can be asked of the other side. Are there prominent articles criticizing the campaign to prevent warming that are clearly dishonest, clearly enough so that someone with no commitment to either side of the controversy would recognize them as such? If so, have they been publicly rejected by anyone on that side?

Judging Outside Your Expertise

I have just been involved in a lengthy exchange on Facebook over my criticism of the claim that warming on the scale projected by the IPCC for 2100 can be expected to have large net negative consequences. The response I got was that the person I was arguing with was not interested in my arguments. He does not know enough to judge for himself whether the conclusion is true, so prefers to believe what the experts say.

Accepting the views of experts on a question you are not competent to answer for yourself, assuming that you can figure out who they are and what they believe, is often a sensible policy, but one can sometimes do better. Sometimes one can look at arguments and evaluate them not on the basis of the science but of internal evidence, what they themselves say. Here are three examples:

The widely cited 97% figure is based mostly on Cook et. al. 2013, which is webbed. It is often reported as the percentage of climate scientists who believe that humans are the main cause of warming and that warming will have very bad effects. Simply reading the article tells you that the second half is false. The article is about causes of warming and offers no evidence on consequences. Anyone who says it does is either ignorant or dishonest, and other things he says can be evaluated on that basis.

If you read the article carefully you discover that the 97% figure, which is a count of article abstracts not scientists, is the percentage of abstracts which say or imply that humans are *a* cause of warming (“contribute to” in the language of one example). The corresponding figure for humans as the principal cause, which is not given in the article but can be calculated from its webbed data, is 1.6%. That tells you that anyone who reports the 97% figure as the number of articles holding that humans are the main cause of warming is either ignorant or dishonest. One person who has done so, in print, is John Cook, the lead author of the article. John Cook runs skepticalscience.com, which is a major source for arguments for one side of the global warming dispute, so knowing that he is willing to lie in print about his own work is a reason not to believe things on that site without checking them. [My old blog post giving details]

One of the economists who has been active in estimating consequences of warming is William Nordhaus. He is, among other things, the original source for the 2° limit. A few years ago, he published an article in the New York Review of Books attacking a Wall Street Journal piece that argued that climate was not a catastrophic threat that required an immediate response. In it, he gave his figure for the cost of waiting fifty years instead of taking the optimal steps now—$4.1 trillion dollars—and commented that “Wars have been started over smaller sums.” What he did not mention was that that sum, spread out over the rest of the century and the entire world, came to about one twentieth of one percent of world GNP. He was attacking the WSJ authors for an argument which his own research, as he reported it, supported.

In a recent Facebook exchange on the consequences of AGW for agriculture, someone linked to an EPA piece on the subject. Reading it carefully, I noticed that the positive effects of warming and CO2 fertilization were facts, with numbers: “The yields for some crops, like wheat and soybeans, could increase by 30% or more under a doubling of CO2 concentrations. The yields for other crops, such as corn, exhibit a much smaller response (less than 10% increase).” The negative effects were vague and speculative: “some factors may counteract these potential increases in yield. For example, if temperature exceeds a crop's optimal level or if sufficient water and nutrients are not available, yield increases may be reduced or reversed.” The same pattern held through the article.

A careful reader might also notice that the piece referred to the negative effects of extreme weather without any attempt to distinguish between extreme weather that AGW made more likely (hot summers), less likely (cold winters), or would have an uncertain effect on (droughts, floods, hurricanes). It was reasonably clear that the article was designed to make it sound as though the effects of AGW would be negative without offering any good reason to believe it was true. One telling sentence: “Overall, climate change could make it more difficult to grow crops, raise animals, and catch fish in the same ways and same places as we have done in the past.” With most of a century to adjust, it is quite unlikely that farmers will continue to do everything in the same ways and the same places as in the past.

These are three examples of arguments for one side of the climate controversy by a source taken seriously by supporters of that side. Each can be evaluated on internal evidence, what it itself says, without requiring any expert knowledge of the subject. In each case, doing so gives you good reasons not to trust either the source or the conclusion.

Readers may reasonably suspect that I too am biased. But nothing I have said here depends on your trusting me. In each case, you can look at the evidence and evaluate it for yourself. And all of it is evidence provided by the people whose work I am criticizing.