The Volokh Conspiracy

Climate Change, Cumulative Evidence, and Ideology:

Almost every time I post something on climate change policy, the comment thread quickly devolves into a debate over the existence of antrhopogenic global warming at all. (See, for instance, this post on "conservative" approaches to climate change policy.) I have largely refused to engage in these discussions because I find them quite unproductive. The same arguments are repeated ad nauseum, and no one is convinced (if anyone even listens to what the other side is saying). I have also seen nothing in these exchanges that would alter my current assessment of the scientific evidence.

Given my strong libertarian leanings, it would certainly be ideologically convenient if the evidence for a human contribution to climate change were less strong. Alas, I believe the preponderance of evidence strongly supports the claim that anthropogenic emissions are having an effect on the global climate, and that effect will increase as greenhouse gases accumulate in the atmosphere. While I reject most apocalyptic scenarios as unfounded or unduly speculative, I am convinced that the human contribution to climate change will cause or exacerbate significant problems in at least some parts of the world. For instance, even a relatively modest warming over the coming decades is very likely to have a meaningful effect on the timing and distribution of precipitation and evaporation rates, which will, in turn, have a substantial impact on freshwater supplies. That we do not know with any precision the when, where, and how much does not change the fact that we are quite certain that such changes will occur.

So-called climate "skeptics" make many valid points about the weakness or unreliability of many individual arguments and studies on climate. They also point out how policy advocates routinely exaggerate the implications of various studies or the likely consequences of even the most robust climate predictions. Economists and others have also done important work questioning whether climate risks justify extreme mitigation measures. But none of this changes the fact that the cumulative evidence for a human contribution to present and future climate changes, when taken as a whole, is quite strong. In this regard, I think it is worth quoting something Ilya wrote below about the nature of evidence in his post about 12 Angry Men":

People often dismiss individual arguments and evidence against their preferred position without considering the cumulative weight of the other side's points. It's a very easy fallacy to fall into. But the beginning of wisdom is to at least be aware of the problem.
The "divide and conquer" strategy of dissecting each piece of evidence independently can make for effective advocacy, but it is not a good way to find the truth.

Don't get me wrong. I believe that there is room to question the global warming "consensus," particularly as represented by activist groups and some in the media, and to challenge various climate scenarios and their policy implications. I am unpersuaded that climate change threatens civilization or justifies truly draconian measures. Nevertheless, I believe climate change is a serious concern. And as much as I wish it were not the case, I believe the threat of climate change justifies some measures that the libertarian in me does not much like. But that's the way it is.

Truth Seeker:
If you're not interested in more discussion of the evidence and the arguments then it sounds like you have taken a religious approach to AGW like many on the left. You're saying your faith will not be swayed by more evidence.
2.2.2008 10:58am
Jonathan H. Adler (mail) (www):
Truth Seeker --

That's not at all what I said. You may wish to re-read the post.

JHA
2.2.2008 11:05am
pgepps (www):
So you're saying that because aggregates of human behavior over large populations (global) over long periods (centuries) may affect the distribution of scarce resources (coastland, rainy days, fresh water, sunny days) in unspecified ways, we should ask the government to interfere to "correct" that distribution?

What could we not justify in this manner?
2.2.2008 11:08am
Dave Hardy (mail) (www):
I think his point was a little more like reiteration of the same arguments clogs the thread and does not increase persuasive value.

Personally, living in the Sonoran Desert, it would be hard to notice global warming. I consider wearing shorts in the winter and having a 110 day in the summer quite normal.
2.2.2008 11:13am
Loophole1998 (mail):
If the proposition were in fact true, would there not be evidence stronger than the mere accumulation of several questionable pieces (many offered by proponents have agendas apart from the search for truth)?

Would such evidence suffice in a civil trial? A defense lawyer is usually successful if he or she can call each piece of the plaintiff's evidence into question. Also, evidence in a trial won't even come before the jury unless it meets certain threshold tests of reliability (i.e., no hearsay). Maybe the rules of evidence should make an exception for cumulative bits of otherwise "bad" evidence?

Also, while it is difficult to prove a negative, should we not also consider the cumulative effect of the evidence against the proposition? (See http://tomnelson.blogspot.com/ for an "accumulation" of the skeptics position.)
2.2.2008 11:17am
Jonathan H. Adler (mail) (www):
pgepps --

No. I am saying that because the preponderance of evidence supports the conclusion that human behavior will affect the distribution of resources and cause other harms, policies that can provide a reasonable degree of protection against such harms, at a reasonable cost, are justified. I do not believe the set of policies that satisfy such criteria is all that large.

JHA
2.2.2008 11:20am
Houston Lawyer:
Global warming could possibly be an overall boon to us. Aren't liberals always claiming that change is good?

Why do we start with the premise that the world is at its optimum temperature at the present time? From unexamined premises flow flawed conclusions.
2.2.2008 11:25am
Jmaie (mail):
The following is an honest question, I will not state my opinion nor agree/disagree with yours. It is about method:

At what point does scientific opinion become consensus and when does it become important?

If 55% of a group of scientists believe one way and 45% posit the opposite, that will not probably sway too many people.

If it is 90% for and 10% against, that will probably sway most.

There are other issues rarely discussed which I personally would welcome, i.e.

1) How is the term "scientist" defined for the purposes of this discussion? My undergrad major was in Physics. This gives me familiarity with the scientific method, but certainly does not make me qualified to discuss cloud distribution, solar cycles, and many other relevant topics. I would guess that a large block of those quoted (on both sides) are not well qualified as good sources of reliable information.

2) Is consensus reliable? Depends on the topic - sometimes consensus can mean nothing (think Copernicus). With climate change we have no basic agreed-to framework as to what is important and what weight should be assigned to each portion of evidence. There are thousands of relevant topics and the tendency is to cherry pick what appeals to each individual.

3) It is unfortunate that there are so many players who's sole purpose is to sway opinion rather than determine the actual situation and produce reasonable responses. How does one cut through the noise? If 90% of the players are not really qualified to have an opinion, will it be possible to do so?

My fear is that none of this is important to policy makers who will make decisions based on political expediency.
2.2.2008 11:33am
Bender (mail):
How does human activity account for the warming trends on Venus and Mars, which roughly track those on Earth? Wouldn't Occam's razor suggest that changes in solar radiation might be the best explanation for a common trend on all three planets?
2.2.2008 11:40am
Beran Panasper:
People often dismiss individual arguments and evidence against their preferred position without considering the cumulative weight of the other side's points. It's a very easy fallacy to fall into. But the beginning of wisdom is to at least be aware of the problem.

Does this not also apply to the True Believers in AGW?

At what point does scientific opinion become consensus and when does it become important?


Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you’re being had.

Let’s be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world. In science, consensus is irrelevant. What is relevant is reproducible results. The greatest scientists in history are great precisely because they broke with the consensus.

And furthermore, the consensus of scientists has frequently been wrong. As they were wrong when they believed, earlier in my lifetime, that the continents did not move. So we must remember the immortal words of Mark Twain, who said, “Whenever you find yourself on the side of the majority, it is time to pause and reflect.”
2.2.2008 11:42am
Tern (mail):
Fair enough. For me, the preponderance of the evidence that I have seen indicates that anthropogenic global warming is likely false. That, combined with the exaggerated and distorted nature of what I have seen sets off my b.s. detector and leads me to suspect that the evidence I have yet to seen is of the same character. Nevertheless, I reserve final judgment on the evidence I have not seen.

Also, the pseudoreligious approach taken by many of the more hardcore activists creeps me out and leads me to further doubt their evidence. I don't want to have to believe in some other religion's priests - er, scientists. And their demand that we take the pronouncement of scientists without further thought and their attacks on people who look (admittedly doubtfully) more closely at the evidence smacks more of an inquisition than an open process of scientific discovery.

If global warming is real, let's have them put all the cards on the table, stop claiming that the two pairs are a full house, and invite all qualified comers to challenge their conclusions. If it holds up, I'll stop being an atheist and become a believer.
2.2.2008 11:46am
Chris Bell (mail) (www):
Well Jon, you've put your foot in it now....

Jmaie: I suspect we feel similarly. I often argue that we should defer to scientists on scientific questions (and doctors on medical questions, and plumbers on plumbing questions). It's not wholly an argument from authority, but a pragmatic realization that it takes years of study and expertise to understand the factors in play and only experts are likely to have valuable insight.

Scientific consensus, which can often be determined by statements from scientific organizations, are therefore very persuasive to me. To answer your questions:

1) "Scientists" should be restricted to the relevant scientific fields. In this case, Earth and Atmospheric Scientists. You often here that some small group of scientists oppose evolution; you almost never here that only the smallest handful of them are biologists.

2) Consensus is pragmatic. You mention Copernicus, but the point is that consensus is often the best we can do. Sure, Galileo was right and the consensus was wrong, but Galileo convinced the others and the consensus corrected itself. It's unlikely that an erroneous consensus will withstand prolonged scientific scrutiny. In any event, name something more reliable that is socially accessible.

3) I suggest focusing on expertise. Consider this page from the National Academy of Scientists, possibly the most elite Scientific body in the world.
2.2.2008 11:48am
Chris Bell (mail) (www):
Bender: The other 100 bodies in our solar system are NOT warming. Perhaps you should use Occam's razor and consider that the few objects that are warming have individual causes.
2.2.2008 11:50am
Truth Seeker:
All the evidence I can see with my untrained eye tells me the sun goes around the earth. God thing some bold and persequted scientists pressed the truth.
2.2.2008 11:54am
Taltos:
Bender: The other 100 bodies in our solar system are NOT warming. Perhaps you should use Occam's razor and consider that the few objects that are warming have individual causes.

Considering that Mercury has no atmosphere to speak of and the outer planets are significantly further from the sun than any of the inner planets, that statement is a bit silly. Not to mention the asteroid belt acting as a baffle for solar radiation to the outer planets.
2.2.2008 12:06pm
allwrits (mail):
That Global Warming is occurring is unassailable. That humans may be either causing or, more likely IMO, exasperating a natural process is -- in light of scientific consensus, probable. Do we not have a duty to mitigate any damage we ar cauding.

Even if the process is ENTIRELY natural, do we not have the same duty to mitigate the damage?
2.2.2008 12:11pm
Loophole1998 (mail):
If mitigation comes with significant costs but is not likely to have any effect on the actual warming, then it would be in our better interest to spend the money figuring out how to cope with a hot world.
2.2.2008 12:17pm
Jmaie (mail):
I do not mean that we should defer to scientists, because the term "scientist" is too broad.

Evolution was mentioned. Biologists are scientists and educated on this particular subject. Astronomers are also scientists but I would not look to them for guidance regarding evolution.
2.2.2008 12:18pm
Chris Bell (mail) (www):
But the consensus of Earth and Atmospheric Scientists is, I argue, the best source of expertise available when attempting to formulate public policy.

That's the statement I want to make.
2.2.2008 12:26pm
Wayne Jarvis:
But you must take into consideration that the available data might be biased or skewed. It takes while for a complete picture to emerge.

One problem here is that almost no one discusses is that doomsayers get a head start. That's how you get a funding for a grant. Scientists don't get grants to prove that everything is a-okay. Initially there will always be skewed data.

I spend 6 years in a lab studying infection diseases and I experienced this phenomenon first hand. If you are clawing for scare research money, you want to convince reviewers that your project is of paramount importance. Accordingly, I recall certain scientists making outrageous End Of Days claims.
2.2.2008 12:28pm
Chris Bell (mail) (www):
How long do you want to wait before you consider the scientific consensus? (And what are you going to rely on in the meantime?)

Countries were willing to sign Kyoto eight years ago. Global warming modeling based on CO2 emissions began in the 60s.
2.2.2008 12:46pm
Doc W (mail):
"I am saying that because the preponderance of evidence supports the conclusion that human behavior will affect the distribution of resources and cause other harms, policies that can provide a reasonable degree of protection against such harms, at a reasonable cost, are justified. I do not believe the set of policies that satisfy such criteria is all that large. "

That's your take on the "preponderance of evidence" and you're not interested in discussing it as a live question. So be it.

Just curious, and sorry if I should be consulting your other posts: what in your opinion does fall within the range of policies that satisfy your criteria?
2.2.2008 12:47pm
CiarandDenlane (mail):
I (mostly) agree with the post, and after reading the first 20 or so comments, I am tempted to say that a Q.E.D. would be justified at this point.

I don't mean by that any disrespect to the prior commenters. I don't have any expertise or striking insights to bring to the table. I wish that anthropogenic global warming were a fairy tale. Perhaps because I'm less of a libertarian than the conspirators, I tend to put the burden of proof on those who say that worlwide changes in land use and burning of oxygen will not have appreciable effects on climate.
2.2.2008 12:54pm
Chris Bell (mail) (www):
Taltos, please at least Google common GW claims before you defend/support them
2.2.2008 12:55pm
Harry Eagar (mail):
I missed Ilya's discussion of fragmented evidence, but there seem to be some serious problems with it as restated here.

First, one piece of solid evidence can indeed subvert a mountain of apparently contradictory evidence. Darwinism, for example, fails the moment somebody finds a reputable fossil out of sequence.

Second, piling up meaningless bits of information to extract meaning is a mug's game. Consider political polling in the United States.

The usual practice is to ask one person per two counties how he is going to vote.

Think about that. It is assumed that that response tells you something meaningful about those two counties. Obviously, it cannot.

Nevertheless, you pile up 1500 responses and, voila!, a meaningful conclusion.

That this does not work is proven by the poor record of political polls when matched against samples (ballot box) big enough to give meaningful assessments.

The reason we should be skeptical about claims of AGW is that all the bits of information so far advanced in its favor are like political polls.

It is even worse than that. Since there are no reliable global climate series that go back further than 28 years (and even that one is not very reliable), the problem is akin to trying to figure out what a Gallup Poll would have found if it had been taken in the summer of, say, 1908.
2.2.2008 12:57pm
Michael B (mail):
Reid A. Bryson Ph.D., D.Sc., D.Engr., Emeritus Professor of Meteorology, of Geography and of Environmental Studies. Senior Scientist, Center for Climatic Research, The Gaylord Nelson Institute for Environmental Studies (Founding Director), the University of Wisconsin, Madison, c. 2004

Extended excerpt, emphases added:

1. The atmospheric warming of the last century is unprecedented and unique.

Wrong.

There are literally thousands of papers in the scientific literature with data that shows that the climate has been changing one way or the other for millions of years.

2. It is a fact that the warming of the past century was anthropogenic in origin, i.e. man-made and due to carbon dioxide emission.

Wrong.

That is a theory for which there is no credible proof. There are a number of causes of climatic change, and until all causes other than carbon dioxide increase are ruled out, we cannot attribute the change to carbon dioxide alone.

3. The most important gas with a "greenhouse" effect is carbon dioxide.

Wrong.

Water vapor is at least 100 times as effective as carbon dioxide, so small variations in water vapor are more important than large changes in carbon dioxide.

4. One cannot argue with the computer models that predict the climate effects of a doubling of carbon dioxide or other "greenhouse gases".

Wrong.

To show this we must show that the computer models can at least duplicate the present-day climate. This they cannot do with what could be called accuracy by any stretch of the imagination. There are studies that show that the average error in modeling present precipitation is on the order of 100%, and the error in modeling present temperature is about the same size as the predicted change due to a doubling of carbon dioxide. For many areas, the precipitation error is 300-400 percent.

5. I am arguing that the carbon dioxide measurements are poorly done.

Wrong.

The measurements are well done, but the interpretation of them is often less than acceptably scientific.

6. It is the consensus of scientists in general that carbon-dioxide-induced warming of the climate is a fact.

Probably wrong.

I know of no vote having been taken, and know that if such a vote were taken of those who are most vocal about the matter, it would include a significant fraction of people who do not know enough about climate to have a significant opinion. Taking a vote is a risky way to discover scientific truth.

Then there's the rhetorical baseball bat to the head and shiv in the side approach used to help ensure ideological consensus/conformity is reached. A study unto itself, though one needing a sociological and psychological focus as much as anything else.

h/t to some blogger for the original link
2.2.2008 12:59pm
Wayne Jarvis:

How long do you want to wait before you consider the scientific consensus?


Considering that seems he last year has seen quite a few defectors in the scientific community: a while longer.
2.2.2008 1:05pm
Jonathan H. Adler (mail) (www):
Doc W -

I discuss some such measures in this essay. I've also discussed the implications of property rights for climate change policy here, here and here. I also am finishing an (overdue) paper on how greater use of water markets can facilitate adaptation to changes in fresh water supplies.

For some of my earlier, more climate skeptic-friendly work, see here.

JHA
2.2.2008 1:13pm
CiarandDenlane (mail):
"The reason we should be skeptical about claims of AGW is that all the bits of information so far advanced in its favor are like political polls."

That doesn't really advance the case against AGW, because polls are pretty good at what they purport to do/measure. It's news on the rare occasions when they're off. Politicians spend a lot of money on polls. Politicians may be stupid on some subjects and [insert derogatory adjective] on all subjects, but in figuring out how to get elected/re-elected, they are focused pros. That they choose to spend so much money on polls is a telling datapoint that polls can, if properly designed, provide insights into opinions. (Speaking of properly designed, are there really pollsters who take polls of 1500 people nationwide, which works out to one person for every two counties, and then opine based on that one person "something meaningful about those two counties"? I would think they would go for something meaningful about nationwide opinion. I smell straw burning.)

You may be right that trying to evaluate whether/the extent to which AGW is real is worse in some respects than the problems facing pollsters. But it's probably better in others. The earth (anthropormorphizing of the earth as Gaia notwithstanding) will not be making some subjective decision whether to warm up or changing its mind on Tuesday based on the latest spin or the momentum carried over from what Mars decided to do. It will be reacting to physical processes that(at least in theory) we are capable of trying to understand and therefore predict. And it's not as if there are 250 million earths and we have to worry about sampling errors. We have only one earth to get/keep right.
2.2.2008 1:23pm
Doc W (mail):
JHA--Thanks. I promise to check those out. Probably not in time to respond this time around, though. --Doc W
2.2.2008 1:25pm
Truth Seeker:
Jonathan H. Adler (mail) (www):
Truth Seeker --
That's not at all what I said. You may wish to re-read the post.
JHA


I know you're trying to sound intellectual and rational, but considering that the science does not exist to prove things one way or another, when you say you're convinced and don't want to hear it, you've gone over to the other side and made it your religion.

It's like a criminal trial and mankind is charged with harming the Earth. There is evidence on both sides but the evidence of guilt is circumstantial and we do not yet have a dna test to prove it. You are proclaiming guilt because we can't afford to let him loose IF he is guilty. The correct result is acquittal at this point. I say innocent until PROVEN guilty!
2.2.2008 1:27pm
Truth Seeker:
When there are hundreds of scientists on each side of an issue and you are not a scientist then the only rational side to take is agnostic.
2.2.2008 1:41pm
CiarandDenlane (mail):
"It's like a criminal trial and mankind is charged with harming the Earth. There is evidence on both sides but the evidence of guilt is circumstantial and we do not yet have a dna test to prove it. You are proclaiming guilt because we can't afford to let him loose IF he is guilty. The correct result is acquittal at this point. I say innocent until PROVEN guilty!"

If I were a space alien coming upon the ecological wreckage of earth a couple of hundred years hence and had an interest in apportioning justice upon today's mankind's children based an evaluation of the guilt of their ancestors, that might be my standard of proof.

But WE today are not the prosecutor in that hypothetical case. We're not even the defendant, at least not if the question isn't how much to beat breasts over what we've already done, but the more useful one of figuring out what WE do NEXT. Guilty beyond a reasonable doubt may be a good standard for assessing someone else's guilt over actions that are in any event now no longer preventable. But if I am told that MY proposed FUTURE actions that I can still change may cause harm in excess of the actions' benefits, under what moral standard (or prudential standard if I am still talking about a "we" of mankind doing harm unto ourselves) can I decline to make that change if there is merely, say, a strong preponderance of evidence that the harm will occur?
2.2.2008 1:42pm
Paul McKaskle (mail):
There is clear evidence that there has been some global warming over the past century. It is reasonably possible that the warming will continue or intensify. Finally, it is reasonably possible that past warming as well as future warming has been caused by human activity. There are contrary arguments which are also reasonably possible, both as to the possibility of continued warming and as to whether it is caused by human beings (as opposed, for example, by solar activity or some other non-human cause). Perhaps, judging from the head count of scientists speaking on the subject (some perhaps more qualified than others) the anthropogenic thesis is at least somewhat more probable. But even this doesn’t tell us very much about the expected amount of change and whether the change will, on balance, be harmful. I suppose in the next few decades we will have a better understanding of the issues.

If there is continued global warming it will have some undesirable effects. If the ocean rises even somewhat, countries such as the Maldives and Bangladesh will certainly be badly affected. But, just as the Dutch have done for centuries, I suspect that most low lying developed areas will be able to protect themselves by dikes or other devices–at a cost, of course, but not an overwhelming cost. (I think the Gore “prediction” of something like a twenty foot rise in sea-level is absurd, but if there is more warming there may be some rise--the IPCC predicts a rise in the range of a foot or two.) But there may also be advantages to a warmer climate–much more habitable land in places such as Canada and Russia, for example. (A great deal of the world’s land mass is fairly far north on the planet and is currently very lightly populated.) A recent study in the United States suggested that when elderly people move from the Northeast and Upper Midwest to warmer climes it adds several years to their expected life-spans. If significant climate changes occur there will be significant dislocation costs and these shouldn’t be minimized, but in the long run (or even in the medium term) I think it is hard to say whether the losses outweigh the gains. (Bjorn Lomborg, who agrees that there is global warming, has suggested in his recent book “Cool It”that the long term advantages may well predominate.)

I think there are two problems with the current fad for advocating extreme actions to combat global warming.

First, a pessimistic one, I think there is very little the United States or even a combination of the United States and Europe can do in the near future to significantly lower the world-wide amount of carbon dioxide being discharged into the air. By significant I mean to lower CO2 discharges enough that the worldwide levels stop increasing or even decline. The reason is simple, the discharges by China and India alone (let alone other emerging economies) by themselves are producing (or soon will produce) enough carbon dioxide to sustain at least some increase in worldwide levels of CO2. Perhaps at some point in the future China and India might themselves take ameliorative steps to reduce their carbon dioxide discharges by a significant amount, but I suspect this will occur, if at all, several decades in the future. If methods (industrial techniques) can be developed to make discharge of carbon dioxide more expensive than not discharging it, then I think India and China would adopt them, but I think it is highly unlikely that either will undertake drastic (and expensive) methods to reduce carbon dioxide discharges if it will substantially impair their economic development and there is zero chance that the Western World would be willing to use force to require such a result.

Second, another pessimistic problem, I think that the prospects of either the United States or Europe reducing discharges of carbon dioxide enough to stabilize or reduce the level of world-wide CO2 are dismal. Ten or twenty percent reductions would not do any good (other than slow the warming by a year or two). Probably only a reduction of carbon dioxide emissions in the neighborhood of eighty percent would. It would take a wrenching change in current living standards–steps to reduce immensely the number of automobiles, complete restructuring of urban life (e.g., rules requiring drastic reduction of residential square footage per family, forced use of public transportation), bans on any “non-essential” air travel, rationing of electricity and heating fuels, and much more. That is the only way that the Western World can, by itself, “solve” the problem of increases in world-wide levels of CO2.

Would the body politic be willing to do this? Europe failed miserably in its quest to live up to the Kyoto Protocols that it signed. The only two European countries that met the very mild restrictions in the Protocol were Germany (because it was in the process of shutting down the grossly inefficient coal power plants it inherited when East Germany was annexed) and Britain (because it converted its coal power plants to natural gas partly because it had recently discovered large sources in the North Sea and partly to destroy the militant coal miners union). I think it is significant that most resolutions (such as by the California legislature) to “reduce” CO2 emissions by certain percentages are always cast fairly far into the future (i.e., when those who voted for them will long be out of office). No politician is willing to vote for drastic restrictions which will take effect immediately. Even the recent highly-touted Energy Bill passed by Congress is, in substantial part, smoke and mirrors because the Michigan congressional delegation had to be appeased as to auto fuel efficiency standards.

Another source of pessimism on my part is that the few steps which we have taken are patently inadequate and are a gross waste of money and resources. The promotion of ethanol as a partial replacement of gasoline is an outrageous scam. One method to reduce CO2 emissions by a substantial amount is to increase reliance on nuclear energy to produce electricity. But nuclear energy is simply unacceptable to most extreme global warming zealots. Carbon credits, when not a complete scam, are very marginal in their effects and can have terrible side effects (such as converting subsistence farming land in Africa into forests–thus reducing the standard of living of very poor natives). Further they enable the very rich to continue their jet setting ways (producing massive amounts of carbon dioxide) with a faux clear conscience.

For all my pessimism, I don’t think all efforts to reduce carbon dioxide emissions are ill-founded. I think realistic attempts to make automobiles more efficient make sense, I think research into converting agricultural waste products or switchgrass into usable fuels makes sense, methods of sequestering power plant carbon dioxide discharges deserve more research, and in general promoting efficiency in use of energy resources makes sense. These (and other similar activities–including considering nuclear energy) will reduce (maybe only slightly) discharge of carbon dioxide but they might make us more energy independent, and it is possible that someday in the future supplies of our current energy sources will become more scarce. But I would hope politicians would make sensible cost-benefit analyses before embarking on promotion of such research or processes.
2.2.2008 1:52pm
Chris Bell (mail) (www):
When there are hundreds of scientists on each side of an issue and you are not a scientist then the only rational side to take is agnostic.

Intellectually, maybe, but not in real life. In real life, something must be done or not done about global warming. Saying "I'm not a qualified scientist; therefore, I'm agnostic" is essentially acting like you think the scientists are wrong.

In real life there comes a point when you realize you must sometimes rely on the opinions of others.
2.2.2008 1:56pm
Taltos:
Taltos, please at least Google common GW claims before you defend/support them

1.) I wasn't defending or supporting anything, I was pointing out that the statement you made was foolish. Distance from the source has a direct effect on the radiation recieved by an object.

2.) The post you link to merely points out that some other guys think that maybe changes in dust distribution could have altered the planetary albedo on Mars and resulted in warming. In other words you like that guy's theory instead of the other guy's theory.
2.2.2008 1:59pm
A. Zarkov (mail):
“Water vapor is at least 100 times as effective as carbon dioxide, so small variations in water vapor are more important than large changes in carbon dioxide.”

That’s true but misleading. Water vapor is generally not included as a greenhouse gas because it’s not a forcing. It’s one of the feedback loops in the climate system. As such it serves to amplify the effects of increased co2 concentration. But more water vapor (from increased co2) means more clouds. Does more cloud cover act as a positive or negative feedback? That’s one of the unanswered questions in the climate science debate. We still don’t understand the appropriate cloud physics enough to make an accurate calculation of the climate sensitivity factor (amount of warming for a doubling of co2). Note that the uncertainty in climate sensitivity has remained virtually unchanged since the 1970s. If we were making progress in our understanding of the physics of global warming, the uncertainty would be shrinking.

The basic argument from advocates of AGW goes as follows. We observe a warming trend. Our models predict the warming trend. We can think of no other mechanism to explain the warming trend, so go with the models as it’s on the only game in town. There are two problems with this argument. First the models are calibrated using empirical data, so in a sense they function as a complicated interpolator/predictor. In other words the data and the models really aren’t independent. If the models were developed from first principles and then compared against data, we would have little controversy. Second the climate modelers and AGW advocates essentially ignore competing theories such as solar wind and cosmic ray flux. None of this rebuts AGW. AGW could be true. It’s a matter of how you view the supporting science.

You can read about the science behind the climate sensitivity factor and the cosmic ray theory here.
2.2.2008 2:03pm
GaltLives:
I'm fascinated by the new information on sun spots that indicates a mini ice age is starting. Will the zealots then switch to saying "burn more coal" and "drive more Hummers" to save the planet?
2.2.2008 2:11pm
Chris Bell (mail) (www):
Tatos:

The link I provided at least cites scientists for its opinion. You should know that "Mars is heating up, so global warming is false" is a common argument that has been debunked multiple times. I just gave you one cite. Again, Google it and see.

And the idea is silly. If the sun is heating up, then all objects would receive more solar energy in relation to their distance from the sun. The only effect of atmosphere would be to trap in heat and accelerate the warming. Considering that Earth, Venus, and Mars all have completely different atmospheres and reflective properties, it's like comparing apples and oranges without factoring all those things in.

No one ever bothers to include in their statements the fact that several solar bodies are getting cooler.

and the asteroid belt helps block the sun? Please.
2.2.2008 2:13pm
Truth Seeker:
Chris Bell
...Saying "I'm not a qualified scientist; therefore, I'm agnostic" is essentially acting like you think the scientists are wrong.

In real life there comes a point when you realize you must sometimes rely on the opinions of others.


You're just completely ignoring the fact that there are two groups of scientists who have come to different conclusions. You have been brainwashed into believing that all scientists are on one side. Lots of scientists are saying that man has no effect on the climate.
2.2.2008 2:14pm
Chris Bell (mail) (www):
I've gotta go, so I won't be responding anymore for a while. This is my entire point (and my response to Truth Seeker).

Here is a statement signed by:
-Academia Brasiliera de Ciências, Brazil
-Royal Society of Canada, Canada
-Chinese Academy of Sciences, China
-Academié des Sciences, France
-Deutsche Akademie der Naturforscher, Germany
-Indian National Science Academy, India
-Accademia dei Lincei, Italy
-Science Council of Japan, Japan
-Russian Academy of Sciences, Russia
-Royal Society, England
-National Academy of Sciences, America

Collectively, these bodies represent the most prestigious scientists on the planet.

I'm not an expert on climate change and I'm not going to go spend the years it would take to become one. Therefore, I think the most rational course for me to follow is to trust what these guys have to say.
2.2.2008 2:21pm
Jonathan H. Adler (mail) (www):
Truth Seeker --

You're still misrepresenting my post. Yes I said I am convinced that human activity contributes to climate change, but I did not say I didn't want to hear contrary evidence. Rather, I said that none of the claims made in these discussions has convinced me to I should return to a more skeptical position. That's quite a difference.

I am glad you brought up the trial analogy, however. Indeed, I accept that analogy, but with one important qualification: The proper analogy is not to a criminal trial, but to a civil trial. A is claiming harm from actions taken by B, and would like compensation, mitigation, and other appropriate relief. No one is talking about imprisoning GHG emitters. The sorts of measures that are on the table (or at least those I would consider) are equivalent to the sorts of remedies that would be available in a civil trial -- payment of money and injunctive relief. Therefore, the burden of proof would not be "beyond a reasonable doubt" but the preponderance of evidence. Judged by this standard, the basic claim that human activity is contributing to a gradual warming of the earth easily passes muster.

Does this mean there is no doubt? No. Does this mean there is no room for debate? Of course not. But in my mind it establishes ample reason to consider which available policy measures are appropriate.

JHA
2.2.2008 2:29pm
Brian K (mail):
you have taken a religious approach to AGW like many on the left.

you've got to be joking. only people on the left take a quasi-religious view? you either don't read much on this topic or are ignoring evidence that doesn't fit your preformed opinion. neither of which speak well about your ability to come to a rational scientifically supported opinion about AGW.

I also love how some of the above posters seem to think that only pro-AGW people are distorting evidence or making doomsday predictions. I've seen the claim that even partially mitigating global warming would require us to live in caves and send our economy back to stone age made quite often.
2.2.2008 2:29pm
Brian K (mail):
When there are hundreds of scientists on each side of an issue and you are not a scientist then the only rational side to take is agnostic.

yes, if there the number of scientists on either side about equal by some meaningful and relevant measure. It would be very irrational to hold that belief if there hundreds of scientists on one side and 1 or 2 on the other side. the AGW position is much closer to the latter than it is to the former.
2.2.2008 2:32pm
Wondering Willy:
As a former research scientist who left the lab for the courtroom, I'd just like to point out that there have been many times in human history that the scientific "consensus" ended up being wrong. I also have a very difficult time understanding how global warming could possibly have anything to do with the composition of the earth. The earth does not radiate an appreciable amount of heat into space, and the "greehouse gases" do not make the atmosphere less reflective to photons raining down on us from the sun. Therefore, I have a very, very difficult time understand how either heat input or heat retention could possibly be caused by gas emissions on earth.

To the extent there is any anthropogenic global warming, it is likely caused only be increased exothermic processes caused by, simply put, human beings doing more stuff now than we used to. A human who drives and flies and watches TV and runs an air conditioner and refrigerator and heat pump puts out more heat than a human who sits in a cave and hunts for game and berries. But such a contribution could not possibly be particularly appreciable, and will not lead to some catastrophic "jumping off point" like something familiar to those who study differential equations.
2.2.2008 2:53pm
Truth Seeker:
One of the biggest problems with the AGW debate is that proponents almost always are using it to gain money or power. Politicians and leftists want power overpeople and the market and scientists want money for their work or their products.

JHA, from your comment above, you seem only to have come over to the believer side after you found a way to profit from it (academically or otherwise) as a legal expert in the niche area of water markets and property rights in a time of climate controls. It just isn't convincing.

Show me someone who believes it in spite of his contrary financial interest and I'll pay attention.
2.2.2008 3:02pm
Kazinski:
I'm a skeptic on global warming, but I am willing to defer to the scientific consensus. After all we've taken action before on issues where there was even less or no scientific consensus. As a conservative I see nothing wrong with conservation and conserving resources. The one thing I do vehemently object to is feel good actions, or those pushing solutions that match their political agenda's that will do little if any good.

So if we are going to reduce our carbon footprint by 80%, the first thing to be done is start a worldwide crash nuclear power plant construction program to replace coal fired power plants. That is where we could get the biggest bang for our buck with reducing CO2 emmissions, and reducing pollution in general.

Next up is banning recreational and most business travel. Outlawing private jets is also an early step to be taken. Mandatory quotas for work at home employee's for businesses.

I could go on and on, but the point is, there are absolutly NO serious proposals for addressing GW on the table. Most of the proposals are revenue enhancing (taxes), pork (grain based ethanol), or feel good proposals that just tinker around the margins.
2.2.2008 3:09pm
allwrits (mail):
One of the biggest problems with the AGW debate is that proponents almost always are using it to gain money or power. Politicians and leftists want power overpeople and the market and scientists want money for their work or their products.


The same is true on both sides of the debate, those most likely to be opposed, esp. rabidly opposed, are those in the carbon based industries. Indeed, once you begin to exclude "experts" with a substantial financial interest in opposing AGW the "proof" for at least some human influence in GW becomes much stronger.

However, even assuming there is no AGW (again the evidence suggests either a human activity causing or, IMO, amplifying naturally occurring GW)do we not have a duty to plan for, to mitigate and, hopefully harness the power of GW?
2.2.2008 3:16pm
PaddyL (mail):
See:

http://icecap.us/index.php/go/new-and-cool/environmental_
effects_of_increased_atmospheric_carbon_dioxide/

This is a review of the scientific literature involving experimental research about the consequences from increased carbon dioxide in the atmosphere on climate by Robinson, Robinson, and Soon. Not unsurprisingly, they found:

"There are no experimental data to support the hypothesis that increases in human hydrocarbon use or in atmospheric carbon dioxide and other greenhouse gases are causing or can be expected to cause unfavorable changes in global temperatures, weather, or landscape. There is no reason to limit human production of CO2, CH4, and other minor greenhouse gases as has been proposed."
2.2.2008 3:22pm
Nimrod:
I personally think that even if human greenhouse gas emissions are causing climate warming that the fact is humans won't be able to cut back for economic and political reasons anyway.

It seems like if there's really a coming disaster then we need a contingency plan for what to do if our CO2-cutting measures don't work. The fact that nobody seems to even be talking about one causes me to wonder how many people really truly believe in global warming. After all, if an asteroid were heading toward the planet, we'd no doubt try to divert it somehow, but we'd probably also have some sort of plan for what to do if we failed. (Start building self-sufficient colonies underground or something, etc.)
2.2.2008 3:30pm
Michael B (mail):
“Water vapor is at least 100 times as effective as carbon dioxide, so small variations in water vapor are more important than large changes in carbon dioxide.”
That’s true but misleading. A. Zarkov
Well, perhaps, but it's difficult to comprehend how a simple and unadorned statement of scientific fact is deemed to be misleading. (And don't misunderstand as I appreciate the tenor of your comment as a whole.)
2.2.2008 3:34pm
Doc Rampage (mail) (www):
Actually, there is a proposal that would make a big difference in net human CO2 production at very low cost and with other advantages. Global warming isn't the justification for Zubrin's proposal, but it would replace a large percentage of fossil-fuel burning (which produces new CO2) with agriculturally-created fuels, which are mostly CO2 neutral --when burning it, you only put out as much carbon as the plant originally took in from the atmosphere.
2.2.2008 3:35pm
Elliot123 (mail):
"I am convinced that the human contribution to climate change will cause or exacerbate significant problems in at least some parts of the world."

There is a huge difference between causing and exacerbating. Which is it? Exacerbate means human influence could add another .0001 degres to warming. Cause means a problem will exist only because of human action. Just tell us 1) the number of average warmimg degrees we can expect with no contrary action, and 2) what percentage of that is due to human activity. If you don't know, why bother posting? You are really not sayig anything.

Can we expect you will reply by saying such numbers are at best unrealiable, but in your gut you feel right?
2.2.2008 3:42pm
Doc W (mail):
JHA--I did look at those links and all I found was the idea of prizes for technological innovations and subsidies for certain R&D. If there's more, I'm still interested. I'm very sympathetic to property rights arguments for compensation or behavior mod on the part of those who cause damages. Nevertheless, it's not as though people in countries like Bangladesh don't burn any fossil fuels and wouldn't be burning a lot more if their governments didn't hamper their economic development. The discussion is interesting and I need to think more about it. I suspect we agree, however, that just siccing the taxman and bureaucrats on global warming, whether the warming is long-term or temporary, whether it is anthropogenic or natural, would likely have devastating effects of its own, on all we hold dear.

Wondering Willey--Over the long term, the Earth radiates energy into space at roughly the same rate that it absorbs energy from the Sun. Because the Earth is about 20 times cooler than the surface of the Sun, it emits this energy at infrared, rather than visible, wavelengths. Carbon dioxide is among those gases which are transparent to visible light but offer some significant absorption in the infrared. So it acts somewhat as a blanket to keep the surface warmer than it otherwise would be. And indeed, the Earth's surface is warmer on average by some tens of degrees than if there were no such "greenhouse effect." It doesn't have to do with exothermic processes.
2.2.2008 3:56pm
Jonathan H. Adler (mail) (www):
Truth Seeker --

How exactly am I profiting from my change in views? My occasional work on water rights and the like is anything but lucrative, and nothing I've done on climate was part of my tenure file or figures prominently on my C.V. If you're going to make such accusations, you might want to have some basis for it.

JHA
2.2.2008 4:46pm
Curt Fischer:
Kazinski has it exactly right. Err, almost. I don't quite agree with him, but he is at least moving the debate to a fruitful area.

No one know what policies (including the do nothing poicy) will best mitigate the effects of AGW. Can't we talk about that?

I'm very glad Prof. Adler made this post.
2.2.2008 4:49pm
eyesay:
I would have liked to have CO2 appear with the 2 as a subscript, but unfortunately, although allowed on Preview, the <sub> tag is prohibited on Posting. Why?

Wondering Willy wrote
As a former research scientist.... I also have a very difficult time understanding how global warming could possibly have anything to do with the composition of the earth. The earth does not radiate an appreciable amount of heat into space, and the "greehouse gases" do not make the atmosphere less reflective to photons raining down on us from the sun. Therefore, I have a very, very difficult time understand how either heat input or heat retention could possibly be caused by gas emissions on earth.
As a thinking human being, I have a difficult time understanding how Willy could ever have been a scientist.

Scientists don't say that global warming is caused by the composition of the earth. They say that global warming is caused by the composition of the earth's atmosphere.

A greenhouse is warmer than the surrounding area because sunlight passes through the glass on the way in, and heat is reflected to some extent on the way back out. Greenhouse gases such as CO2 work the same way.

Fact: In the past several decades, fossil fuels (laid down over millions of years) containing carbon have been burned at historically unprecedented rates.

Fact: In the past several decades, forest areas (where trees have grown for centuries and millennia) have been slashed and burned for fuel, for farmland, and for other purposes.

Fact: As a result of these, atmospheric CO2 has increased greatly over historic levels.

Fact: Increases in atmospheric CO2 lead to a reduction in radiation of the earth's heat into outer space.

Fact: Global warming is real and it is happening right now.

We don't know how much we need to cut back greenhouse gas emissions in order to avoid a critical tipping point. We don't know how much sea levels will rise if we take no action to reduce greenhouse gas emissions. But we do know that global warming is real.
2.2.2008 5:16pm
Engineer-Poet (mail) (www):
Quoth Tern:
the pseudoreligious approach taken by many of the more hardcore activists creeps me out and leads me to further doubt their evidence.
There's your mistake.  You're right to question the policy positions of those activists, but the evidence which is their support must be judged separately (I'm sure you'd support a different policy, and mine would be much closer to yours).  After all, the failure of autism activists to pin blame on thimerosal does not mean the syndrome does not exist or is not a matter of public concern.

Quoth Taltos:
Not to mention the asteroid belt acting as a baffle for solar radiation to the outer planets.
Can we nominate this for the 2008 Dan Quayle award for expertise in planetary science?

This is the sort of "knowledge" I expect to hear from soi-distant "skeptics".  A large part of what they think they know is flat wrong, but even a concerted effort to show them where they are wrong (with references) usually fails to convince them that they may not have a good picture, let alone that they are on the wrong side.
2.2.2008 5:58pm
Wondering Willy:
eyesay,

Exactly how does heat radiate into space? Heat conduction into space occurs through two mechanisms: mass interactions (i.e. through atoms and molecules and other particles) and radiation (i.e., light). There is no appreciable transfer of heat into space through a mass transfer mechanism because there is very, very little matter in space. Sure, you come across the occasional hydrogen or helium atom and some subatomics and exotics, but otherwise, there's no mass to transfer heat into from the earth.

Radiative transfers follow one of two mechanisms. Photons originating on earth fly out into space, and photons originating in space are reflected back into space. The first mechanism cannot be seriously suggested to have an impact on global warming; there is no earth-side source of photons that used to send lots of heat into space that is now being interfered with. The second mechanism likewise fails, because there is no appreciable difference between greenhouse gases and the standard atmospheric components and surface absorbers. Put simply, an atmosphere without CO2 is not appreciably more reflective than an atmosphere with CO2.

Further, my reference to "the composition of the earth" was intended to include the atmosphere. I did not use "earth" as a synonym for "dirt." Further, I appreciate the personal insult: "As a thinking human being, I have a difficult time understanding how Willy could ever have been a scientist." Your hateful comments towards me lend lots of credibility to your position.
2.2.2008 6:16pm
Truth Seeker:
Jonathan H. Adler (mail) (www):
Truth Seeker --

How exactly am I profiting from my change in views? My occasional work on water rights and the like is anything but lucrative, and nothing I've done on climate was part of my tenure file or figures prominently on my C.V. If you're going to make such accusations, you might want to have some basis for it.

JHA


Sorry if I misunderstood, but I based it on your comment uppost listing your work which started out skeptical, but then switched to legal writing that can be useful to pro-climate control types. Presumably if you are the first writing in this niche you will be much sought out when climate control gets stricter.
2.2.2008 6:18pm
Doc W (mail):
To eyesay's list of facts might also be added that global warmings and coolings have occurred over and over again throughout recorded history and apparently for millions of years before that, according to evidence from ice cores. And the ice core data demonstrate that CO2 levels rose with the increasing temperatures when it couldn't have been blamed on humans. Global temperature data for the past several years seem to indicate a leveling off of the temperature. There is also an apparent correlation of climate with solar activity--for example, an extremely cold period in the 1700s coincided with an almost total disappearance of sunspots.

As for claims of scientific consensus, I've never quite gotten over that statement by Stephen Schneider some years back, a still-prominent and oft-quoted climatologist who owned as to how scientists might need to serve up scary stories and downplay doubts in order to get folks to buy into their policy preferences.
2.2.2008 6:25pm
Wondering Willy:
Doc W,

My personal opinion is that solar activity is the real reason for climate change of any magnitude. With regard to your comment about the greenhouse effect and CO2's absorption of IR photons, that has never seemed to me to be a useful explanation of how heat remains through a "greenhouse" effect. The reason is this: the heat is eventually going to get rattled out into space somehow, it just has to go through more contortions to get there. It's an equilabrated system, so it doesn't seem to me that there is appreciably more heat remaining in the atmosphere because of Le Chatelier's principle applied to the earth-space heat transfer.
2.2.2008 6:33pm
Doc W (mail):
Heat radiates from the Earth's surface via thermal or (roughly) "blackbody" radiation. The power radiated is equal to the Stephan-Boltzmann constant times the fourth power of the absolute temperature times the surface area, times the emissivity. For the Earth's surface, at infrared wavelengths, the emissivity is fairly close to one as I recall. The peak wavelength is given by Wien's law. It is the absorption of outgoing infrared light by greenhouse gases, not any effect on reflectivity, that constitutes the greenhouse effect.
2.2.2008 6:35pm
Doc W (mail):
WW--sorry, our posts crossed in the ether. Yes, the same amount of energy has to get out into space at the same rate, over the long term, but the absorption by greenhouse gases requires the surface temperature to be higher in order to radiate at a sufficiently higher rate (than would otherwise be the case) to make up for the fraction absorbed. This stuff has been in physics and astronomy texts for many decades, including back in the days when people were fretting about global cooling. I happen to know this particular story real well because my grad work was in astrophysics and I've taught physics and astronomy for a long time.
2.2.2008 6:43pm
Eli Rabett (www):
Don't know if I am going to mix into this much, but I submit you captured the problem in your first sentence:
<blockquote>
Given my strong libertarian leanings, it would certainly be ideologically convenient if the evidence for a human contribution to climate change were less strong.
</blockquote>
A human contribution to climate change is neither good nor evil. People make the same mistake of assigning motives to markets.

If you are really serious about what you said one has to ask what is it about humans causing climate change that makes any necessary response difficult for a libertarian to contemplate. That is much more interesting in this forum.
2.2.2008 6:53pm
eyesay:
Doc W wrote "Global temperature data for the past several years seem to indicate a leveling off of the temperature."

Do you mean (a) the leveling off has already completed, or (b) the leveling off is occurring now over the course of the past few and next few years, or (c) the leveling off is expected to start at some point in the future? (I agree with (c); there is no theory that earth temperatures will rise without limit.) And please provide a source for this claim — preferably a source not associated with a right-wing think tank.
2.2.2008 6:55pm
Wondering Willy:
Sure, reflectivity has nothing to do with it, I was just, in my previous post, explaining how that was one potential mechanism that, in the end, doesn't end up being a possible mechanism. I just don't happen to believe that the fractional absorption by greenhouse gases creates an appreciably warmer surface, only a slightly warmer surface. Atmospheric absorption in the IR certainly has some effect, but it's likely to be miniscule.

My grad work was in nanochemistry, but my undergrad was in physics and chemistry (with a mathematics degree thrown in for good measure), so I have no doubt you are better versed than I am.
2.2.2008 6:58pm
Harry Eagar (mail):
CiarandDenlane, your faith in political polling is touching, but you need to look at it more closely.

In 1980, I was working at The Des Moines Register, home of 'the respected Iowa Poll' (which was respected because unlike Gallup and the rest it did not load up its surveys with junk), and when Iowans actually voted, the result was not close to the poll result, it was opposite.

There was much handwringing and gnashing of teeth among management, to my great amusement, since I already knew what was wrong, and there was serious consideration of killing the poll.

Closer to national elections, outfits like Gallup take much bigger samples than they do in their routine polls, and consequently the likelihood of guessing right increases somewhat. But polls are not reliable.

++++

'Fact: Increases in atmospheric CO2 lead to a reduction in radiation of the earth's heat into outer space.'

This is not a fact, just a conjecture. And even if it turns out to be correct, increases in carbon dioxide have to give diminishing returns in the ability to trap photons.

No gas can trap photons of all energies. This is what quantized particles are about.

Diatomic nitrogen also is a greenhouse gas, but adding nitrogen would not trap any more photons because there is so much nitrogen that all the photons N2 is capable of capturing are captured. Any excess of photons at those energies escapes.

Since water vapor is 100K times more important than CO2 at trapping photons (different energy levels but the heat consequences are the same), then an increase in CO2 from 2 to 3 (which is what we've seen) has the same effect as an increase in water vapor from 100,000 to 100,001.

Contra Zarkov, forcing has nothing to do with it.
2.2.2008 7:17pm
Doc W (mail):
eyesay--I googled something like "global temperature 2007" and checked the data on various official-looking, global-warming-touting sites. Apparently 1998 was the hottest year, or maybe tied with 2005. The points for the past 8 years or so don't appear to be following the steep trend from the decade before. Maybe it's just a pause. I used the word "seem" because that's how it seems to me, but I've also hear others (whom you presumably would dismiss as "right-wing") comment on the same thing.
2.2.2008 7:23pm
lucia (mail) (www):
Jonathan:

Ditto. The preponderance of the evidence supports the idea that the recent warming is due in a sufficient degree to humans. Though advocates for climate action often over reach, and deny all counter argument, there is still some counter evidence. But, yes, the preponderace points to change, and it's due to we homo-sapiens.

What to do about it? I don't know.

@Eli Rabette: The difficulty for a liberatian is obvious. Most proposed solutions call for collective actions imposed by a centralized governments. Generally speaking, libertarians believe these sort of solutions are unworkable, and are doomed to failure. So, it would be convenient if one could deny the balance of the evidence leaned against AGW. After all, who wants to believe everything is hopeless.

But it doesn't. (Even if there are some data inconsistencies and some people want to wave them away with smiley faces.)

@Bender-- Sorry.. but it just looks this way. Even with Venus and Mars heating. OTOH, I do supsect (possibly incorrectly) that sensitivity is on the low side of the range predicted, but still, the recent heating is due to us.
2.2.2008 7:29pm
GaryC (mail):
The global climate models make fairly specific predictions about the temperature anomaly patterns that will be produced by increasing levels of carbon dioxide and other greenhouse gases in the atmosphere. The temperature anomalies created by different changes show very different patterns in terms of temperature change versus latitude and altitude. The patterns are distinctive enough that they constitute a fingerprint for the different possible causes of global warming.

The Climate Change Science Program Report released in April 2006 shows the observed temperature changes as a function of latitude and altitude. This pattern is entirely inconsistent with the model predictions. To use the criminal trial analogy, imagine a fingerprint expert testifying that there is absolutely no similarity between the fingerprints on the murder weapon and those of the defendant.

The conclusion that I reach is that either carbon dioxide is not implicated in global warming, or that the computer models are so inaccurate that their predictions cannot be deemed reliable. The water vapor feedback is only one possible source of error.

Fred Singer is one global warming "denier" who is eminently qualified, and his article in the August issue of Imprimis is worth reading.


Professor Singer references the Climate Change Science Program Report 1.1
2.2.2008 7:46pm
Skyler (mail) (www):
Adler, that is the strangest arguement I've ever seen come out of an educated mind. You're saying that even if every detail of an argument is proven false, that if there are enough of these false arguments, then that is sufficient to prove the theorty true. What silliness. How profoundly anti-intellectual.

Beyond that, all the modern research is based on assumptions that have little basis in reality. They claim to be able to measure a worldwide temperature for a year within an accuracy of tenths of a degree.

Folks, you can't even measure the temperature in one small city like Austin on one day with that degree of accuracy. You can't even do it for one moment in that day. Temperatures vary in the area of a city by as much as five to ten degrees. If you could theoretically measure every location in one city for one moment, you still have the vast majority of the planet that is not being measured.

You can't conclude to a greater degree than the accuracy of your data. Especially for any time before the late 19th century (and even then for only a tiny part of the globe) it is absurd to speculate on any average temperature that doesn't have an error in ranges much much greater than tenths of a degree.
2.2.2008 8:20pm
pmorem (mail):
There's another name for an arguement where each piece of evidence is itself false or questionable:

The Big Lie.

"Weighting" false evidence is not useful. Either the evidence is valid, or it's not.
2.2.2008 8:21pm
pmorem (mail):
I'll put it another way:

For the past year, I've been running a series of experiments. Up until recently, every single test run was fouled. Those test runs do not supply meaningful evidence towards what I am trying to demonstrate. They only provide evidence of means by which a test can be fouled.

If I were to attempt to claim my fouled runs as evidence, my work could not be independently reproduced. Therefore, they can only be included as "potential causes for test failure".
2.2.2008 8:36pm
Adler Colleague:
Prof. Adler,

With respect, I still have not found a comprehensive analysis by you regarding the "convincing evidence" of man induced climate change. Your intellect is among the best I have known in my experience, and I am open to your view. However, saying you are persuaded by the "preponderance of the evidence" without detailed analysis won't do it. Please provide some direction. Also, could you please further expound on the collectivist measures that, while offensive to your libertarian sensibilities, are acceptable?

My research reveals that solar heating, subtle but detected changes in earth's magnetic properties and the well-documented cyclical nature of climate (among other natural factors) are far more influential precursors to any climate change; rather than the actions of humans. That said, I'm all for a clean environment, including the air, and believe we may need to abandon some of those libertarian principles to achieve the objective. I don't like to see a specious issue such as global warming being the government bludgeon to get there, however.
2.2.2008 8:47pm
Taltos:
Quoth Taltos:
Not to mention the asteroid belt acting as a baffle for solar radiation to the outer planets.
Can we nominate this for the 2008 Dan Quayle award for expertise in planetary science?


Asteroids = rocks, rocks absorb sunlight, ergo the amount of solar radiation reaching a point on the trailing edge of the asteroid belt necessarily will be less than that reaching an opposite point on the leading edge. Or have the global warming folks changed the laws of physics whilst I wasn't looking.
2.2.2008 9:29pm
William Oliver (mail) (www):
Actually, the big question is not whether or not human activity changes the climate. The big question is whether or not it will save us from the impending mini-ice age. The most amusing thing about all of this is not whether or not human activity does or does not add or subtract a couple of points from the temperature (and remember, the "scientific consensus" from all these same folk 20 years ago was that we were all going to freeze because of these very same effects). The amusing thing is that these same people think they can predict what the *major* climate pattern will be. They can't. And those who do are almost uniformly predicting that we are going to get much colder.

See:
http://www.britsattheirbest.com/001645.php
2.2.2008 9:58pm
Harry Eagar (mail):
There is an experiment you can do in your backyard to demonstrate that carbon dioxide does not trap (an appreciable amount of) heat.

It's a little trouble, but if it saves you THIRTY TRILLION DOLLARS, it might be worth it.

Dig a hole deep enough to protect the bottom from air currents. 4 or 5 feet will do, maybe less. Put a stryofoam cooler in the bottom. Put water in cooler. Wait for a clear, calm night. Sleep. Wake up at dawn. Look in cooler. Find ice.

The heat in the water, following the laws of thermodynamics, radiated toward space (effectively, a cold black body). The carbon dioxide in the atmosphere did not stop it.

The Egyptians knew this thousands of years ago, and it worked for me in Hawaii, which is warmer than almost anyplace VC conspirators are posting from, and warmer than even the alarmist AGW panicmongers are predicting it will be in 2050 where you are.

Which is a different issue from cumulative evidence, but sometimes you need only one piece of evidence.
2.2.2008 10:18pm
John Lederer (mail):
Before doing anything, donb't we need to answer some questions.

It has been warmer and cooler in the past before we had any input into the equation, and the rates of chnage have been as large as those at present. So:

1. What temperature would we like it to be?
2. How fast do we want it to get there?
3. How does the present natural (without man induced CO2 effects) trend go?

I don't think we can reach consensus on the first or second question -- here in Wisconsin I would like it a bit warmer, please, I suspect someone elsewhere might like it cooler.
2.2.2008 10:22pm
GaryC (mail):

Asteroids = rocks, rocks absorb sunlight, ergo the amount of solar radiation reaching a point on the trailing edge of the asteroid belt necessarily will be less than that reaching an opposite point on the leading edge. Or have the global warming folks changed the laws of physics whilst I wasn't looking.


Taltos, space is empty.

Really, really empty.

The amount of solar radiation blocked by the asteroid belt is infinitesimal, even if you only worry about the plane of the ecliptic, to which the planets are (roughly) confined.

Assume that there are 2 million asteroids that are 1 km in diameter or above. (Wikipedia gives 1.1 to 1.9 million.) Although there are a few large ones, most will be near the size limit, so let's assume that the average cross section is 4 square kilometers. That's is a total of 8 million square kilometers of asteroid surface absorbing sunlight.

That sounds like a lot, doesn't it? It's a little bit more than the projected surface area of the Earth, at 5.1 million square kilometers.

The main asteroid belt is between Mars and Jupiter, more than 2 astronomical units from the Sun. An astronomical unit is 93 million miles, or about 160 million kilometers. At a distance of 320 million kilometers, the surface area of a sphere is 1.3 x 10^18 square kilometers. The inclinations of the asteroids cover a larger range than those of the planets, but suppose that we only have to worry about a band that is 10 degrees wide. The surface area is reduced by an order of magnitude, to 1.1 x 10^17 square kilometers, so the fraction of sunlight blocked by the asteroids in this band is about 1 in 14 billion.

This has been a public service calculation by an astronomy geek. We now return you to the regularly scheduled comments by legal geeks.
2.2.2008 10:23pm
GaryC (mail):
Oops!

The projected surface area of the Earth is actually 256 square million kilometers.
2.2.2008 10:27pm
Chris Bell (mail) (www):

Harry Eagar: There is an experiment you can do in your backyard to demonstrate that carbon dioxide does not trap (an appreciable amount of) heat.

This is what I was talking about earlier.

I cited a document signed on behalf of every serious scientific academy on the planet, all of whom agree that global warming is real and needs to be dealt with.

Harry Eager dug a hole in his backyard and thinks he knows better.

Now maybe Harry just won the f*ing Nobel Prize here, but you think he would consider the fact that maybe his experiment doesn't show what he thinks it shows.
2.2.2008 11:25pm
Chris Bell (mail) (www):
Taltos, GaryC is right. When NASA sends explorers to the outer planets they don't even consider the possibility that they might hit an asteroid. (Well, the consider it, but they don't factor it into the flight plan.)

The asteroid belt looks impressive in illustrations, but for practical purposes space is just too empty for it to have any effect.
2.2.2008 11:28pm
eyesay:
William Oliver writes "and remember, the 'scientific consensus' from all these same folk 20 years ago was that we were all going to freeze because of these very same effects."

Mr. Oliver's memory is incorrect. He is remembering the nuclear winter scenario, in which a hypothetical nuclear war, between, say, the USSR and the U.S., kicks up so much smoke and dust into the atmosphere that, for a period of months to years, so much sunlight is reflected back and never reaches earth, that the earth's surface and atmospheric temperature is greatly reduced. The nuclear winter scenario caused by smoke, ash and dust is fully consistent with the global warming scenario caused by greenhouse gases; these two theories do not in any way contradict each other.
2.3.2008 2:44am
Oren:
Exactly how does heat radiate into space? Heat conduction into space occurs through two mechanisms: mass interactions (i.e. through atoms and molecules and other particles) and radiation (i.e., light).


Blackbody radiation has been known for 100 years. The earth is constantly giving of IR photons that are escaping into space. If space were also 300K, it would contribute back the same number and we would be in equilibrium however, space is 3K. This is the same principle that lights up incandescent bulbs, except they are much hotter and therefore radiate in the visible (Wein's Law).
2.3.2008 2:49am
eyesay:
Adler Colleague writes, "My research reveals . . . "

Sorry for this ad hominem, but when you were in third grade, it was OK to look stuff up in the encyclopedia and other sources and call it "research." But now that you are a grownup, you're not supposed to use the word "research" for looking up stuff written by others. Research is what actual scientists do. It's not just looking stuff up. It requires developing a background understanding of the field, development of a hypotheses, gathering and analyzing data, and more, culminating in the writing of scientific papers that are then peer-reviewed.

Tell us, Adler Colleague, where did you publish your research? I thought so.
2.3.2008 2:56am
Doc (mail):
Eyesay seems to have selective or inaccurate memory. The discussions of the coming ice age in the 1970s (see the Time and Newsweek covers of the period) were not at all in the context of "nuclear winter". That was a totally separate issue which was also discussed publicly at great length-- But the 1970s literature on the"coming ice age" had little to do with the "nuclear winter" scenario.
2.3.2008 3:12am
Kazinski:
I'm about 80% convinced that anthropocentric global warming is a crock of shit, but I'm past arguing that now. If it is a crock then it will come out in the next 4-20 years when the natural solar cycle reverses itself and the warming levels off or reverses itself.

With McCain as a AGW believer on the GOP side, and Hillary and Obama also as believers then we have to turn our focus to what the solutions are. Now we can be 100% certain, because politicians are in charge that the primary solution is going to be part 98% of a combination of pork and regulation, and about 2% of real solution. Its just a question of how much the politicians really believe the problem needs to be fixed and how much AGW is just going to be a trojan horse to push their own agendas.

I just think we need to hold their feet to the fire and make sure their is real accounting of the costs and a real accounting to the benefits. Take California's proposal to regulate automobile CO2 emissions, that will cost a lot more and do less good than if they replace all the oil and coal powerplants with nuclear.
2.3.2008 3:12am
Richard Aubrey (mail):
The original question had to do with the effect of a large number of pieces of evidence, all pointing in a given direction. That one or two, or perhaps more, are shown to be doubtful does not mean the conclusion drawn by looking at all of them is false.
I suppose one response might be that what we have is a large number of assertions, most of which are false or irrelevant.
There is another way to look at the process and that's who goes first.
The pro AGW folks went first, made large numbers of assertions and expect the number to overcome the demonstrable falsity of one or another. In fact, what we have is a proposition that the large number assertions overcomes a single case where one is wrong. This is asserted every time any assertion is demonstrated to be false or irrelevant. So, by the structure of the argument, it's always the large number of assertions versus a single contradicting fact. And the same with the next contradicting fact, and the next, and so on.

Now, suppose the anti-AGW folks had started this: They'd have made their large number of assertions and could point to their cumulative effect when faced with a single contradicting fact. And the next....

So the idea that an accumulation of doubtful assertions comprises a real truth depends largely on who went first, and who maintains control of the structure of the argument.

I have made some conclusions about my own life based on a number of data points. Each had half a dozen possible meanings. Each had a meaning which agreed with one of the meanings of another point. The other meanings pointed in all directions. By dragging the single meanings together and ignoring the other meanings, I came to a conclusion which seemed to be supported by the facts but which was, in fact, wrong. But I had the numbers!!
2.3.2008 8:31am
Michael B (mail):
"Mr. Oliver's memory is incorrect. He is remembering the nuclear winter scenario, in which a hypothetical nuclear war, between, say, the USSR and the U.S., kicks up so much smoke and dust into the atmosphere that, for a period of months to years, so much sunlight is reflected back and never reaches earth, that the earth's surface and atmospheric temperature is greatly reduced." eyesay

It was the mid to late 70's and into the early 80's, so his memory is fine (concerning global cooling scares).

Also, Wiki is decidedly not a good place to go for authoritative conclusions when it comes to these types of contentious issues since the editing fights that occur at Wiki largely reflect the PC vs. non-PC fights in any other on-line forum and elsewhere. They can be a place to begin some research and even that can be misleading if relied upon too heavily.

As to nuclear winter scenarios, using models, they essentially posited that an all-out nuclear war (using models where all or a very sizeable percentage of the world's nuclear arsenal is unleashed) would not be good for the environment. Or for people, one might be inclinded to add. As to modeling, an example pulled from the Kuwait oil fires after the first Gulf War may be instructive:

"During, and after Operation Desert Storm, various models were used to predict morbidity (illness), mortality (deaths), and cancer risks due to exposure to the oil well fire smoke. The predictions of these models differed greatly. The predictions of one of these models changed dramatically after real, rather than estimated, information became available. I will contrast the predicted illnesses, deaths, and cancer rates from this model used in the spring of 1991, with the predictions from the same model after a large number of measurements had been taken. In the spring of 1991, the model [using modeling estimates] predicted 27,839 illnesses, 1,883 deaths, and 10,273 cancers per 100,000 population for Al Ahmadi, a populated area near the oil well fires. In October 1991, after actual measurements were used in the model, it predicted only 17 illnesses, 4 deaths, and 0.3 cancers per 100,000 population for Al Ahmadi. The second scenario fits more closely with what PHS physicians and Kuwaiti governmental personnel have reported. It is important that models be validated continually so that the health professionals and the public are not confused."

Likewise, it should be emphasized that the more dire predictions concerning the Kuwait oil fires did not bear out.

Moreso, a single, localized phenomenon such as the Kuwait oil fires is vastly simpler to model than the earth's climate as a whole over a period of decades; indeed there is no comparison between the two given the multiplicity of evolving and indeterminable factors that can effect the climate as a whole over an period of decades.
2.3.2008 8:33am
Michael B (mail):
Btw, even the term "scientific consensus" itself is misleading. The better phrase to apply would be "a consensus of scientists" as it serves to highlight the fact that 1) individuals are involved and not science in the abstract or as an ideal and 2) the consensus itself is more of a gauge of median and mean proximations rather than scientific conclusions, for example in the pure/mathematical sense of the term.

I.e. some notable epistemic caution is in order, even prior to the policy debate that has the potential to leverage literally trillions of dollars.

(If you want a serious moral cause to go after, the global sex trade is a huge one and we positively know it's real and variously destroys massive numbers of young lives, many, many of them very young indeed. But there is little or no cause celeb fervor that can be associated with that trade and there is likewise little or no chance a quasi-religious fervor will be attached to that project.)
2.3.2008 8:57am
Harry Eagar (mail):
Chris, making ice isn't the only thing we know about radiation. It is one of the few demonstrations you can do with a shovel, though.
2.3.2008 9:31am
Engineer-Poet (mail) (www):
I'm going to post a bunch of replies to people as separate comments, to make it easier to track them.  I have consolidated bits of various comments from the same author for conciseness.

Quoth "Truth Seeker":
It's like a criminal trial and mankind is charged with harming the Earth. There is evidence on both sides but the evidence of guilt is circumstantial and we do not yet have a dna test to prove it. You are proclaiming guilt because we can't afford to let him loose IF he is guilty. The correct result is acquittal at this point. I say innocent until PROVEN guilty!
The failures of the legalistic mind are coming into sharp relief here.

This is not unlike refusing to put smog controls on any of the cars in Los Angeles until one can finger the driver whose emissions caused John Doe's bronchitis and Harry Roe's heart attack.  It is like refusing to inspect a bridge for cracks until it starts falling down.  It is like calling fire insurance a waste of money until you see the flames licking out the windows.  It is, in short, a complete repudiation of everything we know about prudent policy and risk management — which repudiation "Truth Seeker" would no doubt attack vigorously if his client stood to win a tort claim.

While "Truth Seeker" bloviates, research has linked the drying of the western US to climate change.  The chickens are coming home to roost, and the things we could have done about today's problems needed to have been started around 1985-90.  If we start today, we'll be seeing real results around 2025-30.  We can't do anything about today's problems; we failed to write that insurance check.

Our policy obviously cannot be "innocent until proven guilty beyond a reasonable doubt".  It cannot even be "a preponderance of the evidence".  We must act on precaution, to limit the untoward consequences.  This also means we should be looking for "no regrets" options.  Fortunately, we've got plenty of them.  Most moves to increase efficiency cut costs as well; I've saved a bundle with CFs since I started using them in the mid-90's.  If we cut the use of coal we eliminate the mining scars, ash dumps and mercury emissions too.  If we use wind power we at least have some powerplants which don't need to draw on shrinking supplies of water to cool condensers.

Policy isn't about what's innocent or guilty.  Policy is about what is prudent or foolish.  Our energy and environmental policies of Republican administrations since 1981 have been very, very foolish.
Show me someone who believes it in spite of his contrary financial interest and I'll pay attention.
Right here.  My primary source of income for the last 25 years has been the auto industry.  I am willing to sacrifice because I believe that the choice is between a clean, no-greenhouse, OPEC-free auto industry, or no auto industry.
2.3.2008 10:32am
Engineer-Poet (mail) (www):
Quoth Paul McKaskle:
I think there is very little the United States or ev