The Null Hypothesis: It's How I Roll

By esiegel on January 9, 2012.

"If you go through a lot of hammers each month, I don't think it necessarily means you're a hard worker. It may just mean that you have a lot to learn about proper hammer maintenance." -Jack Handey

The most common type of question I get asked by people genuinely wanting to know more about the Universe goes something like, "Hey, I saw such-and-such-a-story about some fanciful-sounding-theory, and that could be the explanation for this-weird-thing-that-we-see. What do you think about that?"

Well, here's the thing.

Image credit: Contemporary Physics Education Project.

We've got a set of laws of nature, rules, observed and ordered phenomena, etc., that's the sum total of how we presently make sense of the world. It's pretty damn good, and it explains the vast majority of phenomena that we know. If we want to learn something new about the Universe, this is the standard we have to check it against!

In other words, that's what the null hypothesis is: a statement that all the observed phenomena we see can be explained by the laws we already know are true.

Image credit: xkcd. Not everyone understands the null hypothesis.

When the null hypothesis does the job, there's no reason to postulate any sort of alternative, or novel, hypothesis; there's simply no merit to it. Hyping an idea that makes predictions no different from the null hypothesis is not only silly, it's pointless. If you want to learn something new about the Universe, you need a hypothesis that leads to different quantifiable predictions -- even if you can't yet measure those differences -- than the things you already know.

And when the null hypothesis doesn't do the job, that's when it's clear that there's a gap in our understanding, and that's where science really gets interesting. Examples of this abound in both our past and present understanding of things.

Image credit: Russell Kightley.

Back in the 1800s, the "null hypothesis" about the motion of the heavens was that all the planets in our Solar System orbited the Sun according to Newton's Law of Universal Gravitation. And -- to the best of our measurements -- this was true for all of the planets (once Neptune was discovered, that is), except for Mercury! That observation was key, as the null hypothesis -- that our Solar System consisted of eight planets governed by Newtonian Gravity -- no longer held up.

Why was Mercury's orbit precessing at the rate observed? Three alternate hypotheses came up:

there was an inner planet to Mercury, which was causing the perihelion advance,
Newton's law of gravity needed to be slightly modified; perhaps instead of a 1/r² law, it was actually 1/r^{(2 + ϵ)}, or
Newtonian gravity needed to be replaced with a more complete theory of gravitation.

As you all know, it was this final option that turned out to be correct, as Einstein's General Theory of Relativity explained not only Mercury's advance, but also a host of other phenomena. But it was the observation of Mercury -- an observed violation of the null hypothesis -- that made the question worth asking in the first place.

Image credit: Sam Pitts.

And it's the question you always need to ask yourself. If you want to know whether these nebulae are within your own galaxy, like everything else you know and see, or beyond it, you need something that contradicts the null hypothesis. In the case of this particular spiral nebula, it was the observation of Cepheid variable stars that established this object's distance to be millions of light years distant, placing it far outside our own galaxy.

And this is true across the board, in all fields of science.

Image credit: the OPERA collaboration.

The null hypothesis would be that special relativity holds, and applies to all particles in the Universe. So when we get an observation that contends neutrinos travel faster than light, we are justifiably skeptical. So many observations have supported this null hypothesis over such a long period of time that, to overturn a null hypothesis this good, we'll require overwhelming evidence that these new experiments do, verifiably, contradict it! (And if they do, it's terribly interesting, but that wouldn't be my first guess!)

Image credit: ECFA/DESY and the IoP of the Czech Republic.

When someone claims that the new evidence for the Higgs supports Supersymmetry, we need to ask what the laws of nature without Supersymmetry predict: that's the null hypothesis. So far, the standard model with no Supersymmetry is just as good as it with Supersymmetry, so we go with the null -- i.e., non-SUSY -- hypothesis.

Image credit: 2dF Galaxy Redshift Survey.

And when we look at the Universe on the largest scales, from galaxy clusters and supercluster to the cosmic microwave background, we find that a Universe full of protons, neutrons, electrons, neutrinos, photons, and all the other known particles can't explain what we see. In other words, the null hypothesis is invalid, and so we need something else (i.e., dark matter).

The burden of proof is always on the new hypothesis, the one that postulates a new effect or new phenomenon. This is true in all types of science, from astro- and particle physics to chemistry, biology, psychology and the social sciences.

So when there are claims like this,

my first thought is, "well, how does that compare with the null hypothesis," i.e., what we currently know and accept? (In this case, the answer is, poorly.)

Sensationalized claims like this one almost always compare poorly to the null hypothesis, so please pardon me when I don't comment on every one of them. Most of them don't get very much attention, and I feel no need to draw extra attention to such claims by publicly spotlighting them just to compare them with the null hypothesis, and show how unfavorable it is.

Comparison with the null hypothesis is a great starting point for anyone who knows what the current state of affairs -- and hence what the null hypothesis -- actually is. It's also why I don't believe that -- as you can surely tell -- women are underrepresented because they're somehow inherently inferior to men as scientists and science professors. (The null hypothesis being, of course, that they're inherently and intellectually equal.)

Image credit: Unknown; this is Helen Quinn receiving the Order of Australia.

The contention normally goes as follows:

More men want to be scientists and science professors than women,
Men have an inherently better aptitude at math than women at the high end,
This aptitude is what determines whether they make good scientists/science professors, and
Sexism and gender discrimination is a negligible factor in explaining the existing gender gap in the profession.

If you want to make this contention -- that women are inherently inferior to men at this -- you need to establish all four of these over the null hypothesis. (It surprises me every time I see a study done on the second item on the list, as though that somehow settles the issue.)

As to my own personal experience, I've seen #1 appear to be true, but only after women encounter some form of sexism and/or gender discrimination. I've seen a large number of women just as competent (at the high end) in math and science skills as any of the men, yet who were treated differently by many (not all, but many) of the professors. And I've seen what can only be described as a total lack of correlation between item #2 and item #3 on that list. Being "good enough" at math to get your foot in the door is important, but that is hardly the determining factor as to whether someone makes a good scientist or science professor. And the existence of sexism and gender discrimination -- particularly in physics, my field -- is incredibly well-documented.

I'm not saying that the alternative hypothesis, that there might be some inherent differences between men and women, is necessarily wrong, but I am saying that until you can demonstrate that the null hypothesis is invalid, you've got nothing.

Once you get there, we've got to figure out what the new, correct explanation is, of course, and that's not only terribly interesting, it's how science advances. But if you can't prove the null hypothesis invalid, you're not even science yet; you're just hype.

More like this

I'm sure it's that simple. The problem is that the current laws are incompatible. There is the Standard Model (SM) and General Relativity (GR). There are quantum phenomena (q) that are explained by SM and macro phenomena (m) that are explained by GR. But q is inconsistent with GR, m with SM. So GR+SM is inconsistent.

Inconsistency in science is not a good place to be, but that is where we are. We don't expect different parts of the physical world to be explained by different sets of laws and then just fudge the difference.

Supersymmetry (SuSy) could lead to a new theory (M-theory) to supercede GR+SM that would explain both q and m.

--Excellent post!!

Hi Ethan,

related to rejection of hypothesis, which "compare poorly to the null hypothesis":

Please look at the example of Einstein's "idea", which throwed away all "what we currently know and accept" about gravitational forces, and replaced that with mathematically modelized geodesical zero-force paths.

This "idea" was totally different and very "poorly".

To your opinion this "idea" was not even worth to be taken "attention" on it??

What did I misunderstood?

Cheers.

I believe what you missed SCHWAR_A (Specifically from this blog post) was that Einstein's "idea" accurately matched observation where Newton's "idea" did not.
Specifically the orbit of Mercury.

That said it also made many testable predictions which were later shown to be correct.

I think you also missed the topic.

"When the null hypothesis does the job, there's no reason to postulate any sort of alternative, or novel, hypothesis; there's simply no merit to it"

But postulating a new type of stuff (Dark Matter and Dark Energy) isn't the right alternative, either.

It's avoiding attempting to find out whether the null hypothesis is wrong by substituting another hypothesis tangential to the one you have found wanting.

This is not in any genuine sense different than changing the null hypothesis by intent.

Philip @1, the null hypothesis of fundamental physics today is that we have a quantum set of laws for the weak, electromagnetic and strong forces, and a classical law -- general relativity -- for gravitation. You want to postulate something that goes beyond it, that's fine, but claiming that we don't have a quantum theory of gravity isn't a problem when we don't have any observations that contradict classical GR.

Schwar_a @3, I like what Trebor said, but to elaborate a bit, Einstein's idea didn't throw away Newtonian gravity at all, but in fact reduces to it in the limit of weak fields: small masses and/or large distances. So it made all of the predictions of the old theory in most regimes, but in some strange places it made some alternative hypotheses, which turned out to be correct.

But the point was that the null hypothesis, that Newtonian Gravity would explain Mercury's motion in the Solar System, was insufficient. Were there no such thing as Mercury, there would have been no impetus, or motivation, for GR.

Wow @5, it's okay to postulate "new stuff" or a new law or a new particle or a new interaction, etc., when the null hypothesis is demonstrably wrong. What's remarkable about dark matter is that it works to solve so many disparate problems where the null hypothesis fails. How would you approach it?

But postulating a new type of stuff (Dark Matter and Dark Energy) isn't the right alternative, either.

There is no a priori guarantee that postulating a new type of stuff is the correct solution to a disproven null hypothesis, but it is one of a few types of possible solutions allowed. Ethan has covered the dark matter case extensively in previous posts, so I will just summarize the argument. It was shown two or three decades ago that the following three statements are mutually incompatible: (1) all of the matter of the universe consists of baryons; (2) gravity works according to general relativity; and (3) galaxies exist in the universe. That is, if any two of those statements are true then the third must be false. We know that galaxies exist, so any alternative hypothesis that violates (3) is ruled out. That leaves (1) dark matter or (2) alternative theories of gravity. But whatever hypothesis you form will lead you to make other predictions about how the universe works. Dark matter passes all of these tests. Some alternative theories of gravity explain galaxy rotation curves as well or better than dark matter, but they fail every other test. So we conclude that dark matter is indeed the correct solution to this problem, and we are therefore justified in declaring it to be the new null hypothesis.

Dark energy is not quite as firmly established as dark matter, but I have not heard of any other viable hypothesis which explains the discrepancy from the null hypothesis that dark energy is supposed to explain. (This isn't my field, so there may be some non-crank proposal out there that I am not aware of.) Until and unless somebody comes up with a better idea, I'll stick with dark energy as the explanation for why the expansion of the universe is accelerating.

Yes, yes the null hypothesis is very important.

But I think some of your examples oversimplify. For example, dark matter theory will not hold until some dark matter is identified. I won't repeat my concerns with dark matter; but here is what Philip W. Anderson, nobel laureate in solid state physics, has to say.

"Let me make only one provocative suggestion: that when we are all done, it will turn out that there is no exotic form of "dark matter", merely a comedy of errors in a field where it is practically de rigueur to underestimate one's limits of error." Philip W. Anderson pg 109 of book More and Different, 2011, in the essay summing and titled 21st Century Physics.

Ouch, ouch. My point is not that Anderson is correct; but only that dark matter is far from a generally accepted physics theory.

Another excellent article by what is fast becoming one of the best science blogs around. Please keep up the great work.

I think the nomenclature of the Null Hypothesis is unfortunate and it is too easy to substitute a straw man null hypothesis and miss what it is you are trying to study (or should be trying to study). I try to use instead the term âdefault hypothesisâ, meaning the hypothesis based on the âconventional wisdomâ as it is known.

The default hypothesis (Newtonian gravity) can be known to be wrong (it doesn't explain the orbit of Mercury). But replacing Newtonian gravity with something that does explain the orbit of Mercury but doesn't explain the other things that Newtonian gravity does explain (such as MOND) is not using the proper ânull hypothesisâ.

Ethan, thank you for the clear explanation of what the Null Hypothesis is. Re your example on whether women are as good in science as men: you observe that even if Item 2 - Men have an inherently better aptitude at math than women at the high end - is correct, it does not necessarily lead to Item 3: This aptitude is what determines whether they make good scientists/science professors,...

Would your reasoning stay the same if the words "scientists/science" in Item 3 were replaced by "mathematicians/mathematics"? It would seem that, in this case, Item 3 follows from Item 2 by definition, no? If the "by definition" is too strong, how about a weaker "strong correlation"?

Assuming you agree with the above, is it not correct that mathematical physics, or at least some of it, is actually pure math, in its methods and the way it is practiced?

If yes, would your original statement on the lack of correlation have to be modified, at least for a particular branch of science? Which, in its turn, might excuse, to a certain degree, Dr. Summers (whose picture was included in the post for a reason, I assume)?

Finally, if the whole of the above seems a bit out of place in a blog like yours, what about your example?

Ethan, I know this is off topic, but I just realized that the Research Works Act that is being considered would require that arXiv.org be shut down.

I can't think of another single thing that could do more damage to physics.

"When the null hypothesis does the job, there's no reason to postulate any sort of alternative, or novel, hypothesis; there's simply no merit to it. Hyping an idea that makes predictions no different from the null hypothesis is not only silly, it's pointless."

Perhaps I'm being pedantic, but you can also reject the null hypothesis if a new hypothesis makes identical predictions but is simpler. The precopernican hypothesis that angels push the planets around the Earth can be contorted to match the observed orbitals with enough angels pushing. In reality, the geocentric model was able to make novel predictions because the scientists hadn't gotten around to deducing all the angles involved, but even if they had that null hypothesis would be rightly rejected.

In a more modern example, if an alternative theory to the Standard Model existed that made all the same predictions, but used a much smaller number of constants, I'd consider that a better model.

Michael @11, you are assuming that the same metrics we use to measure "mathematical aptitude" are the actual metrics that determine mathematical aptitude as applied to a career in mathematics. I would say that there is good evidence that our tests and those results are positively correlated, but not 100% so.

But I still don't excuse Larry Summers, especially because he still refuses to consider, looking back on the incident, what possible social ramifications his message/speech could carry.

daedalus2u @12, it seems like there's a new potential law to fight every few weeks, doesn't it? You know my stance, which I think would be totally applicable to this, on civil disobedience...

Paul @13, I'd still demand that it make somehow better/different predictions than what came before, not just be a more elegant explanation. Even fewer parameters wouldn't be compelling enough for me to switch to the new standard model; you'd have to do something else, like predict particle masses, the neutrino mass eigenstates, or something like that.

Have you seen the Journal of Articles in Support of the Null Hypothesis? (http://www.jasnh.com/) It collects research papers in psychology that were rejected by mainstream publications because they didn't find anything new... which is to say, they supported the null hypothesis. In social science (and medical research, I'm given to understand) there seems to be a bias towards publishing research that finds a correlation between things... which means that research suggesting that two things are in fact completely unrelated tends to go ignored. So in those fields it isn't that the null hypothesis is misunderstood... just that it isn't very interesting. Yet the results of "failed" experiments are potentially quite useful to other researchers.

How does that sort of thing get handled in physics? Does a similar bias exist in publishing, and if so, are there informal or back-channel ways of disseminating such results?

Making a prediction which is no different isn't silly if your method is simpler. I wouldn't be surprised if some people still believed in the epicycles while using the tools of Newton and Kepler to calculate the position of the sun, other stars, and planets.

Dear Ethan,
shouldn't the Null Hypothesis also be applied to counter sensational claims of "man-driven global warming"?

It has already had 170 years of null hypothesis applied to climate science that leads inevitably to AGW if we burn fossil fuels, nessuno.

At some point the sane person has to decide that the null hypothesis has been firmly rejected.

In the case of AGW, that was done by 1956.

Where have you been since then?

"I think the nomenclature of the Null Hypothesis is unfortunate and it is too easy to substitute a straw man null hypothesis and miss what it is you are trying to study (or should be trying to study)."

I believe you have this absolutely correct.

Many AGW denialists think that "the null hypothesis" is "It's natural". Except that that's neither a null hypothesis or even measurable.

An appropriate "null hypothesis" requires the proposal and then the null to check if the proposal is void. I.e.

Proposal: CO2 is driving temperatures
Null Hypothesis: CO2 does not drive temperatures

To test this hypothesis can then be done by seeing if the CO2 concentration over time and global temperature over time correlate and whether they correlate enough to preclude CO2 being the driver of temperature.

This has been done, as you can find over at Tamino's blog, and the correlation is extremely good, rejecting the null hypothesis above by better than 85%.

Given other evidence that disproves the null hypothesis (e.g. a causation: The greenhouse gas effect), and the null hypothesis is rejected to a better than 95% probability.

I.e. the chance of the null hypothesis "CO2 does not drive temperature" is less than 5% likely to be true despite the evidence.

But postulating a new type of stuff (Dark Matter and Dark Energy) isn't the right alternative, either."

I suppose I ought to have said "isn't necessarily the right alternative, either.".

It's just as much a non-null-hypothesis as MOND or others. Those who like the idea of DM/DE are asking how much and where this stuff is. AFAIK, nobody is asking (who has any chance of answering, so I'm well out of it by a couple of decades!) how it's made, why it's there and what it's doing.

"What's remarkable about dark matter is that it works to solve so many disparate problems where the null hypothesis fails. How would you approach it?"

Coby, there are other postulates to the observational issues.

However, you discard them as unpossible.

I would, at the very least, accept that there may be something there.

I would also point you to your position regarding FTL neutrinos. The same observational problems show the GR light speed limit wrong. Yet postulating a tachyon solves that problem and being neutrinos introduce none we were looking for.

So rather than reject FTL neutrinos, why not accept them as much a possibility as DM/DE?

Yes, I'm chiding you. It's done because I think you can do better, not to tell you you're wrong.

What about when empirical evidence clashes with hegemonic theory? http://www.youtube.com/watch?v=VymhJCcNBBc + http://www.youtube.com/watch?v=EtweR_qGHEc

Wow. That post there (I can't click on UTube links) sounded exactly like a Calvin and Hobbes cartoon lampooning New-Ageism.

Care to explain?

Dear Wow,
during the Medieval Warm Period (1000-1200) the temperature was higher than now, with glaciers melting more than now. Some centuries after it was possible to cross the Teodulo Col (3316 meters) between Italy and Switzerland without touching snow. This was clearly not driven by human activity. The Little Ice Age which came afterwards was also not driven by human mitigation measures against the warming. Where have you been since then?

nessuno:

Please provide references to your sources for your claims.

The Medieval Climate Anomaly has been shown by several reconstructions (including two referred to in this blog post to be a largely regional phenomenon. As a global event it does not stack up to today's warming in the slightest.

There in a nutshell you have wrapped up the gross flaw with the anthropogenic global warming hypothesis (AGW). Nothing observed so far violates the null hypothesis of natural climatic variation. On the other hand, reams of research results cannot be explained by AGW. As best known so far, neither the rate, magnitude, or maximum temperatures are any greater than what has occurred multiple times during this interglacial - and previous interglacial temperatures were hotter yet.

The perversion of science has been astounding and disgusting.

rational db8 #26 is why I don't like the terminology of the null hypothesis.

The default hypothesis isn't "nothing is happening", the default hypothesis is "physical reality corresponds to what we have learned about physics in the last 200 years".

The political question is what default should we base policy questions on?

The hypothesis that "nothing will happen when we dump a trillion tons of CO2 into the atmosphere"?

Or should the hypothesis be "what will happen when we dump a trillion tons of CO2 in the atmosphere is that the Earth will respond as we have learned that physical reality does respond consistent with what we have learned about physics in the last 200 years".

> Nothing observed so far violates the null hypothesis of natural climatic variation

Gosh, how wrong can you be!

The variation of the climate is +/- 0.1C per Century. We're well beyond that. So "natural variability" is disproven by the temperature record.

Non natural variability of climate causes are out too:

Sun caused it before, but we're in a cooling phase of the sun AND we're in a cooling phase of the orbital cycles.

Volcanic eruptions caused it before (massive outpouring of CO2), but we have no such massive super volcanic event.

Given that AGW is a natural result of the production of large amounts of CO2, natural climate is AGW. Except this time, rather than volcanoes producing it, it's our industrial output.

"during the Medieval Warm Period (1000-1200) the temperature was higher than now"

Wrong.

Did you know that large regions of the North Pole are now over 6.2C warmer than the 1961-1990 average?

"with glaciers melting more than now."

Wrong too. Since there are glaciers melting now that have survived 130,000 years and the MWP was much more recent than that, your position is proven false.

"This was clearly not driven by human activity."

Indeed. And lightning started fires in the Midwest millenia before mankind found a route there. Does this prove that arson is impossible?

No.

But you seem to think so. Why is that?

"As best known so far"

You mean "as far as I've been told by denier sites", yes?

"neither the rate"

Nope, the rate is far faster by orders of magnitude than any earlier change in climate.

"magnitude"

Well given we haven't stopped our AGW causing activities, this is hardly a point.

"or maximum temperatures"

double counting! Unless you're talking about a period of time when the CO2 concentrations were far higher than today. Which kind of proves that AGW is a problem: we can get far higher temperatures under "business as usual".

"are any greater than what has occurred multiple times during this interglacial"

Well we now have far hotter temperatures and a far faster rising mean and a higher maximum than at ANY TIME during the current interglacial, so your above points are 100% proven false.

"and previous interglacial temperatures were hotter yet."

Now, although MAXIMUM temps were much higher in the dim and distant past of the dinosaur age etc, the rate of change cannot have been any faster even by events that caused the extinction of 99.2% of the planets species. And during non-extinction events, those periods with higher temperatures had higher CO2 concentrations (and we're releasing the CO2 laid down during that time, so we're going to get or surpass those levels under BAU).

"during the Medieval Warm Period (1000-1200) the temperature was higher than now"

Wrong.

Did you know that large regions of the North Pole are now over 6.2C warmer than the 1961-1990 average?

"with glaciers melting more than now."

Wrong too. Since there are glaciers melting now that have survived 130,000 years and the MWP was much more recent than that, your position is proven false.

"This was clearly not driven by human activity."

Indeed. And lightning started fires in the Midwest millenia before mankind found a route there. Does this prove that arson is impossible?

No.

But you seem to think so. Why is that?

"As best known so far"

You mean "as far as I've been told by denier sites", yes?

"neither the rate"

Nope, the rate is far faster by orders of magnitude than any earlier change in climate.

"magnitude"

Well given we haven't stopped our AGW causing activities, this is hardly a point.

"or maximum temperatures"

"are any greater than what has occurred multiple times during this interglacial"

Well we now have far hotter temperatures and a far faster rising mean and a higher maximum than at ANY TIME during the current interglacial, so your above points are 100% proven false.

"and previous interglacial temperatures were hotter yet."

@27 and @26

First I'll discuss how the the null hypothesis works (e.g. in the case of dark matter). Then I'll talk the null hypothesis in AGW. (my interpretation is in rough accord with Ethan's but I defer to his.)

How the null hypothesis works (dark matter example):
When we look at the dark matter observation, astronomers and physicists check and double check. They cannot explain the observations in terms of the known theory. So they need a new hypothesis; hence the dark matter hypothesis is necessary; because the simplest hypothesis (i.e. the null hypothesis: meaning no new theory is needed) fails. Why because with current theories we cannot (yet anyway) figure out how to make them account for the dark matter observations. But the dark matter hypotheses (yes plural) are not yet an established theory (hence my remarks above @8); AND thus I don't apply the null hypothesis to the hark matter hypotheses; rather we continue to test each of the various dark matter hypotheses (as well as continue to try to extend current theory to account for dark matter observations without additional theory, e.g. Cooperstock's efforts).

How null hypothesis works re Anthropologic Global Warming (AGW):
10,000 yrs ago, there were 5,000,000 humans on planet Earth
200 yrs ago, there were 1,000,000,000 humans on planet Earth
Today,2011, there are 7,000,000,000 humans on planet Earth
Can known theories of physics, chemistry, meteorology and natural phenomenon known to influence climate account for the rapid climate change in the last few decades? The unanimous scientific view (versus political view) is No! Thus the null hypothesis had been applied. Thus scientist needed a new hypothesis to account for the global warming of the last few decades.

So scientists considered an a great many theories. And scientists reached a unanimous conclusion humans were causing global warming. Thus Anthropologic Global Warming became the accepted theory. But because AGW (like cigarettes causing lung cancer theory before it), was economically hazardous to certain business interest; the lobbying, marketing and public relations arms of business moved to squash the accepted theory of Anthropologic Global Warming on planet Earth.

But Anthropologic Global Warming is the accepted scientific theory that explains the warming of planet Earth that has become very obvious in the last few decades. Now if you want to disparage global warming without any new evidence; then this disinformation activity is not science; it is politics.

The pope was not able to disparage, torture, and intimidate scientists not accept Galileo's theory that the Earth circled the moon and that moons circled the planets. In fact, Galileo made over 700 telescopes (my memory may be incorrect) and sent them to kings and queens so that they could see for themselves the planets circling Jupiter. The papal inquisition politics didn't have a chance against science. Nor did the cigarette company politics of deception, dishonesty and disinformation have a chance against science. Nor will the oil, gas, automobile, chemical companies politics of deception, dishonesty and disinformation have a chance against science.

The smart companies, executives and politicians have moved on; they know from history that fighting an established scientific theory is a losing battle.

But going against the Anthropologic Global Warming theory is not an example of applying the null hypothesis (unless there are new observations of climate on planet Earth beyond those of AGW theory. But the theory that a population of 7,000,000,000 humans using 20th century cars, factories etc changes the planet Earths climate significantly (i.e. AGW)has been firmly and irrevocably established. And in that case of new observation AGW would still be valid within its limitations; just as Newtonian mechanics is valid within its particular range of limitations and phenomenon.

The Anthropologic Global Warming theory is the accepted scientific theory and that will not change. Just as cigarettes causing cancer will not change even if science learns how to prevent the disease of cancer by some intervention. For example, just because we can treat infections with penicillin doesn't mean that bacteria no longer cause infections, Just so, if we find a way to counteract the effects of Anthropologic Global Warming; that will not mean that AGW is wrong.

So without new observations, new evidence for new phenomenon not explained by the current theory (e.g. AGW, quantum mechanics or relativity); there is no need even to apply the null hypothesis.

But when there is new phenomenon (e.g. faster than light neutrinos) and when those observations are scrutinized for errors and validity then and only then the null hypothesis has been applied and it is time to begin testing various hypothesis to find a new theory. Buy new evidence new phenomena is needed before applying the null hypothesis.

Remember also the null hypothesis is just one way among thousands that scientist test the validity of current theories. Also remember that there are thousands of observations that are not accounted for by current theory; so much hypothesizing is normal. But no scientist argues against Newtonian mechanics within its range of validity or against AGW. Because within a current theory's range of validity, a new hypothesis is no better than current theory. So why bother? But if your new hypothesis does not account for previously unaccountable phenomena; well then yes do bother.

So looking beyond AGW what new phenomena does such a theory propose to account. If there is no new unexplained phenomenon, we aren't in the realm of science; we are in the realm of the politics of deception, dishonesty and disinformation.

"So they need a new hypothesis; hence the dark matter hypothesis is necessary;"

IMO, since there is very little knowledge about either DM or any of the other proposals of fixing the observation to models, I don't know we can actually GET a null hypothesis with the observational problems reconciling galactic dynamics to basic physics.

A null would be to find out if MD were right or whether it was MOND. Observations can then be made to decide which one agrees and which one doesn't.

With the weather, we know a lot more about all feasible forcings and the problem very much simpler. And we've already gone through the null testing whether it's CO2 or the sun, CO2 or volcanoes, CO2 or...

So far, CO2 is the only one that fits.

And Anthropogenic source of CO2 means that the natural warming of the globe from CO2 now has a human cause.

AGW.

Ethan, you are using strong language in your latest post - "... deception, dishonesty and disinformation." - that you probably would avoid speaking about, say, string theory. Obviously, for you AGW is an emotionally charged subject, and doubting it amounts to that nicely alliterative 3D above. You would expect it from a politician or just a plain ignorant person, not from a physicist of a world stature, right? How about Freeman Dyson then?

I remember very well his public lecture in Moscow (http://elementy.ru/lib/430802) entitled "Heretical Thoughts about Science and Society". One of the "heresies" of the title was exactly his doubting the AGW - both as established science, but even more so as a call to action. Now this is Dyson, not some Lomborg or a similar oil apologist. Whatever Dyson's politics (of which I know nothing), you would not expect him to doubt the multiplication table, no?

So what do you say of that negative 3D, that "damn doubting Dyson"?

"Ethan, you are using strong language in your latest post - "... deception, dishonesty and disinformation.""

They're completely accurate. Why are you so scared of the truth?

And how do you treat people who doubt that the Moon landings were real? Or doubt that the earth is, in fact, round?

Or doubt that AIDS is caused by HSV.

In the last case, that delusion kills people, just like your delusion that there's room for doubt about AGW.

Doubting science is what is required to doubt AGW.

@33 Wow

Yes, yes. But to pick a few nits.

"IMO, since there is very little knowledge about either DM or any of the other proposals of fixing the observation to models, I don't know we can actually GET a null hypothesis with the observational problems reconciling galactic dynamics to basic physics."

In My Opinion, the current accepted cosmic theory (despite my personal quibbles) is the Big Bang Model (i.e. some version of the Standard Cosmological Model, there are various tweeks). So the Standard Cosmological Model , along with all of quantum mechanics, the Standard model of elementary particles, special and general relativity, solid state theories of superconductivity and superflued etc, various field theories QED, QCD, etc.. Since we're talking about the universe, we have a lot of subtleties and may have to bring in any of these accepted theories. So the "cosmic null hypothesis" is the sum of these accepted theories; or more precisely the multiply interconnected web of these relevant accepted theories.

Now we get a collection of observations that I'll call the "dark matter observations". But the "cosmic null hypothesis" (as it is applied today) can account for the various observations. Thus various hypotheses are suggested; WIMPS, Axions, Cooperstock's interpretation of General relativity, Mond; but none of these hypotheses is accepted for even some of the collection of "dark matter observations."

OK, Wow, that's how I'm thinking qand that's my quibble. If you have quibble or a major flaw in my thinking please point out.

Yes, yes to your comments of climate.

@wow @okthen, both of you really need to read more of the actual science, rather than talking points from strongly pro-AGW sites. @Okthen, based on your first reply to me, I suggest you re-read this article on the null hypothesis to get a better grasp on this basic tenet of the scientific method.

Massive climate shifts have occurred during the Holocene (this interglacial) - look up the Younger Dryas. I don't have most of my links on this computer, but will give you some on these various issues. Even larger (and more rapid by far) shifts have occurred in the past. Even ice cores, the majority of them, clearly show that major temperature increases occur roughly 800 +/-200 years BEFORE CO2 levels begin rising (hum, that'd be about right for us to see CO2 level rising from the MWP, wouldn't it...and oceans warming from the Little Ice Age to boot...hum....). Then typically temperatures begin dropping well before the CO2 levels follow. Just to wet your appetite on the issue - if either of you are even open to considering all the science and not just that which supports your view: http://tinyurl.com/2nfjgf

The AGW hypothesis doesn't even rise to the level of a theory yet, let alone something that is unanimously believed by scientists. Any claim to 'unanimous' agreement of scientists is bogus on the face of it, especially with something as complex as our climate system. Science isn't run by consensus, but by empirical data (not climate model projections) that is falsifiable (look up the father of modern science, Karl Popper), verifiable, and repeatable. Currently the AGW hypothesis fails on all three counts.

As to scientists who do NOT concur with AGW, Freeman Dyson's stance mentioned accurately by Michael Hanes is a good example. Add eminent professor Harold Lewis (physics) http://tinyurl.com/2ab7uto or the 7 eminent physicists skeptical of AGW alarm, including a great video of Dyson himself on the issue: http://tinyurl.com/4zcrb5f

Try: **900+ peer reviewed research papers supporting skeptical arguments http://tinyurl.com/y9jrjaf

**100 prominent scientists including Nobel winners and IPCC lead authors who wrote the U.N. warning against 'Futile' climate control efforts http://tinyurl.com/yo7fcz

**31,000+ scientists disavowing AGW www.petitionproject.org

**Over 700 scientists worldwide disavowing AGW signed onto USA Senate report http://tinyurl.com/yaqd3fn

The list goes on and on. Try quibbling with the credentials of many of those eminent scientists. Anyone claiming that 'every scientist' supports AGW automatically sets off the 'bogus' alarm bells for anyone familiar with science.

So much more can easily be posted, but this ought to be more than enough to get you started - or at least disabuse you both of any notion that there is solidity behind the AGW hypothesis. The actual science simply doesn't begin to support such conclusions.

I just posted a bit lengthy post replying primarily to posts directed at me by "Wow" and "Okthen." It contained a number of links to supporting information that got an automatic page saying the post would be held for review by the blog owner - hopefully he will approve it shortly.

@39

Yep, one of my comments is being held as well.

Ethan informed me his filter is hyperactive today. So we'll be patient.

First, thanks to OKThen for the update on stalled posts from Ethan. Hopefully that will clear up soon.

Next -- oops, in skimming comments again, I realized that if Ethan does post my comment that's hung in the moderator que, I made an error - I was replying to both Wow and OKThen, but a comment I made suggesting a re-reading of Ethan's article was meant for daedalus2u.

Daedalus, the null hypothesis of natural variation, natural cycles, is anything but "nothing happens." Climate on Earth has always changed, often pretty radically - hot house to ice house and back again. Our interglacials aren't nearly as extreme, and are still relatively 'cold.'

This variation occurred on it's own for several billion years quite apart from us - and over the long term hasn't been well correlated with CO2 levels at all. Plus, what science has shown so far is that for the most part, major temperature increases began roughly 800 +/-200 years before CO2 began to rise. I'd made a few more comments on that issue in the comment that hopefully will post soon.

Note also that of course the null is actually a large number of null hypotheses, each for different aspects of the system, and also for aspects we don't know yet, but that we do know occurred before any significant CO2 generation by mankind or any other sources. Lumped together, however, it boils down to being far easier to say 'natural cycles.' This is no different than using the shorthand of the AGW hypothesis - it's also composed of a large number of variables.

For example, just one of many... water vapor is by far the biggest greenhouse gas in the atmosphere, to the point that CO2 pp volume are insignificant - the only way the AGW hypothesis works is based on assumed or claimed 'feedbacks' from CO2 that then affect water vapor which boosts the response of the entire system. That's according to the IPCC etc. (heading off any claims to the contrary).

Food for thought - this being the case, why aren't we talking about controlling our water use, and factors unrelated to CO2 that have a large impact on atmospheric water vapor? Really think about the concept for a little bit.

More importantly, the null hypothesis is a basic, key, integral tenet of the scientific method. You can't just wish it away because you don't like it, or you don't like conclusions based on it. If you try to, all you are doing is wishing away the scientific method itself, and I for one don't care to go back to the dark ages.

The null hypothesis is in part - a quite significant part - what has allowed us to get further away from emotionally based conclusions, and confirmation bias issues, and closer to a far better and faster method of understanding everything around and inside us. It's part of what has let us come father in the past few hundred years than in the many thousands of years previously.

Science isn't about deciding what we believe or wish for, then trying to find evidence to support it. Science on the contrary, is about finding things that are contrary to what previous research has 'told' us, developing an idea (hypothesis) that has scientific merit to explain both the previously supported aspects AND the contrary aspects - explains it all at the very least as well as the null hypothesis, then designing a falsifiable experiment to test the new hypothesis. Then presenting your results along with all data, methods, etc., to the scientific community at large in hopes that they will try their best to tear it apart and fail.

Usually they don't fail - occasionally they do, but then you are still nowhere near an accepted hypothesis even, let alone a replacement of the null. Nope, then it's a boatload of 'wash, rinse, repeat' by independent scientists. Only when they are able to repeat your results, using your identical methods, repeat your results using different ways of testing your hypothesis, multiple times by multiple researchers, it withstands the test of time, and the new h. fits all the evidence better than the null is the null replaced by the new.

Obviously the more established the null hypothesis (billions of years of natural major changes, and several hundred years of research supporting natural causes), and the more important the issue, the more rigorous all of this must be.

"both of you really need to read more of the actual science"

I did.

I went to, for example,

http://www.ipcc.ch

Whereas YOU went to:

Poptech's website, a blogger who is completely nuts: he REFUSES to remove papers that even eminent "skeptic" scientists believe are being misrepresented on his list.

A non-governmental lobby group where a few members of an institute abuse their association and pretend they're talking for the entire group.

A creationist "by-mail" university poll that includes "Dr Gerry Spice" "Dr Doom" and "Mickey Mouse, PhD".

Another political site for the USA denialists.

You need to stop going to political and blogroll sites and go to the science.

@37 Rational Db8

You say, "As to scientists who do NOT concur with AGW, Freeman Dyson's stance mentioned accurately by Michael Hanes @34 is a good example."

So let's hear Freeman Dyson speak for himself about Anthropologic Global Warming. Just a few Freeman Dyson quotes (fully referenced)from http://en.wikipedia.org/wiki/Freeman_Dyson

"the main causes of warming is the increase of carbon dioxide in the atmosphere resulting from our burning of fossil fuels such as oil and coal and natural gas."

"[H]eretics who question the dogmas are needed... I am proud to be a heretic. The world always needs heretics to challenge the prevailing orthodoxies."

"[m]y objections to the global warming propaganda are not so much over the technical facts, about which I do not know much, but itâs rather against the way those people behave and the kind of intolerance to criticism that a lot of them have."

"but itâs rather against the way those people behave and the kind of intolerance to criticism that a lot of them have."

Isn't that an intolerant method of dealing with criticism of AGW denial?

Because, you know, maybe "AGW is not happening" is actually incorrect.

But nobody seems to care about that possibility on the "skeptic" side. Not even Dyson gives a flying fig for it.

41 "I went to ipcc.ch". And you call that "science", Wow? That is a bunch of about 2000 persons, a great part of which utterly incompetent in any field, which are defining themselves as scientist, and which are actually payed (unfortunately with much too much money of tax-payer's around the world) only to "demonstrate", or better to make propaganda, that the warming trend of the last 120 years is driven by human activities. Luckily their credibility is rapidly fading out.

Note also that of course the null is actually a large number of null hypotheses, each for different aspects of the system,

More importantly, the null hypothesis is a basic, key, integral tenet of the scientific method. You can't just wish it away because you don't like it, or you don't like conclusions based on it.

Your use of 'null hypothesis' is rather idiosyncratic. What exactly do you mean by it?

Food for thought - this being the case, why aren't we talking about controlling our water use, and factors unrelated to CO2 that have a large impact on atmospheric water vapor?

Was this intended as a serious comment? Apart from the indirect effects through temperature of anthropogenic CO2 and aerosols, can you think of any human activity that has anything other than local effects on atmospheric water vapour?

This variation occurred on it's own for several billion years quite apart from us - and over the long term hasn't been well correlated with CO2 levels at all. Plus, what science has shown so far is that for the most part, major temperature increases began roughly 800 +/-200 years before CO2 began to rise.

Given that this is the first time in all those billions of years that humans have suddenly released vast quantities of CO2 into the atmosphere, I don't see that this has any relevance to the discussion.

Oh, so Db8 is saying that because the Medieval Warming period happened ~800 years ago, that it was caused by the CO2 rise that is happening now?

No - I think Db8 is saying that the increase in CO2 is a sort of delayed shock reaction by Earth to the Medieval Warm Period. ;-)

re post #41 where 'Wow' replies to my earlier post. Sorry to say it, but "Wow" that's a pathetic response. You brand yourself as a true believer, and not one who is actually interested in science of any sort.

Incorrect talking points right off the true believer's handbook, and outdated. First, it appears that you neglected to address both of the very large sets of independent scientists who wrote the UN or the USA congress. I'm sure that's because if one actually looks at their qualifications, it's pretty impossible to try to claim that they're anything other than top notch eminent scientists who've opinions carry a great deal of weight.

Then, in the order from your post: You note going to the IPCC website. Let's be clear - that's the InterGOVERNMENTAL Panel on Climate Change. Going to that site itself has nothing to do with reading the actual science. They're a bureaucracy, not peer reviewed science. Government bureaucrats have to approve each line, and they modify at will and afterwards the reports are never sent back to the scientists for peer review. A number of authors and even lead authors have resigned because of this. They use advocacy group's propaganda, grey literature, student papers, rumor, etc. in those reports.

Have you never bothered to look into the IPCC's Hymalayan glacier-gate, amazon rainforest-gate, Norway (or was it Denmark?) under water-gate, Africa crop-gate, Africa drought-gate, and all the other IPCC-gates? I said 'go read the actual science, not 'go read propaganda summaries supposedly representing science.'

As to the poptech site - had you bothered to go there and READ, with an open mind, you would discover that papers are posted based on their actual content, not the personal viewpoints of the authors. I've read a few of the papers from the site, and each had research results that could clearly be used as an argument for being skeptical of any significant amount of AGW. Science isn't about emotional belief, it's about actual research data, collected and evaluated using the scientific method properly.

Then you claim I linked to a non-gov. lobby group - you'd best look again, I did no such thing.

You then rip on the >31,000 scientists who've signed onto the petitionproject, using outdated incorrect claims. A few 'true believers' did try to kill the credibility of the list by falsely signing up bogus names - that happened many years ago, and many years ago the list was gone thru in it's entirety, hard copy signatures received from each person on it, the few bogus names removed, and qualifications of each signatory were verified.

You then try using the logical fallacy of 'guilt by association.' It doesn't matter one bit who hosts the servers that the petitionproject is on - what matters is that over 31,000 scientists have responded voluntarily because they don't believe that AGW is a serious concern.

Then you rip on the USA senate for heaven's sake. Worse, you again deny the credibility of independent scientists, not just from the USA either (as you claimed) - many of them incredibly credentialed - because they voiced their opinions to our national legislative body and the entire world? You have GOT to be joking.

Lastly, you might try noting that my links to reams of scientists speaking out as publicly as possible against the idea of significant or problematic AGW was in response to grossly incorrect claims that there was unanimous agreement among scientists that AGW was a serious problem. Quite clearly that is not the case. You might also try noting that one of my links pointed to over 900 scientific papers, with links to every single one of them. I believe that clearly qualifies as science - and that's simply one handy source I posted for others here. You try the logical fallacy of a biased sample or prejudiced induction, trying to make out as if the little I posted here (as if that weren't enough to falsify your claim from the get go), is supposedly all I have ever read.

Perhaps you could present more cogent, less biased arguments if you learn a little about logical fallacies so you can avoid them in the future: http://tinyurl.com/2rlnv

@42, OKthen - if you want to really hear and understand Freeman Dyson, why don't you do as I suggested originally, and go listen to the actual man at the video on the page I linked to? You can hear the man directly address the issue in his own words from a video of the man himself, for heaven's sake, not from out of context quotes that may or may not even be accurate.

As to wikipedia, that's a completely unreliable source. Have you never heard of William Connolley? You're trying to use a publicly written and edited source as supposedly being solid?? See: http://tinyurl.com/yllkqst Partial excerpt follows:

... All told, Connolley created or rewrote 5,428 unique Wikipedia articles. His control over Wikipedia was greater still, however, through the role he obtained at Wikipedia as a website administrator, which allowed him to act with virtual impunity. When Connolley didnât like the subject of a certain article, he removed it â more than 500 articles of various descriptions disappeared at his hand. When he disapproved of the arguments that others were making, he often had them barred â over 2,000 Wikipedia contributors who ran afoul of him found themselves blocked from making further contributions. Acolytes whose writing conformed to Connolleyâs global warming views, in contrast, were rewarded with Wikipediaâs blessings. In these ways, Connolley turned Wikipedia into the missionary wing of the global warming movement.

The Medieval Warm Period disappeared, as did criticism of the global warming orthodoxy. With the release of the Climategate Emails, the disappearing trick has been exposed. The glorious Medieval Warm Period will remain in the history books, perhaps with an asterisk to describe how a band of zealots once tried to make it disappear.

Wikipedia suffers from the same problem that climate science in general suffers from now. A few determined zealots have influenced the vast majority of the published information...

(read full article at link provided)

@43: ...But nobody seems to care about that possibility on the "skeptic" side. Not even Dyson gives a flying fig for it.

Posted by: Wow
~~~~~~

Amazing claim, Wow. I'd be willing to bet that the majority of skeptics would jump on the AGW bandwagon in a heartbeat if the existing science actually supported the idea of any significant problem with AGW. A huge number of skeptics actually believed in AGW, because they trusted the scientists were accurately portraying the real science. Once they began to look into the issue themselves, however, they quickly discovered that simply isn't the situation, and the science simply doesn't support the AGW hypothesis at this point in time. Many of us were horrified on discovering just how grossly inaccurately the situation was being portrayed by a small group of scientists and a huge number of advocacy groups behind them. It is a nasty stain on the general reputation of science - and that infuriates and disgusts many of us who are scientists.

re post by Richard Simons @45

Idiosyncratic? I'm afraid that's a bit ambiguous... what do I mean by null hypothesis? Read the article these comments are about, I think Ethan Siegal has done a fine job of explaining it (kudos Ethan!).

Yes, it was a serious comment - I suggested that folks think about the logic involved, I did not suggest that we actually try to control atmospheric water vapor (other than in our own buildings perhaps {g}). Do I think we affect atmospheric water vapor? People believe that our burning of fossil fuels affects the level of CO2, and yet all the watering we do of lawns, gardens, etc., water use for agricultural purposes, dust control, industry, evaporative cooling of power plants and other industrial concerns, water control of rivers, lakes, ponds, run off, and so on - you don't believe that affects the level of water vapor as much as we're affecting the level of CO2?? Just how much change in atmospheric water vapor is significant? Can you scientifically quantify it, and our contribution, from 7 billion people worldwide?

Besides, what all of this ought to have gotten you thinking about is what is believed to be the tiny change in global water vapor that can significantly affect temperature - and how clear it is that we don't know very much about the entire system yet.

You've ended by begging the question with circular logic - we're releasing stuff, therefore it must have an effect, therefore AGW is true. A "just so" story.

That's the sort of thing science is designed to help us avoid - and where so far, science hasn't been able to show that the CO2 we've released is actually having any significant effect. As it is, they keep having to revise the climate sensitivity downward, because the changes we've actually measured - the hard data - don't support the estimated/modeled sensitivity claimed by the IPCC et. al. as the smoking gun.

Only it turns out that gun prolly ain't smokin' after all. A few folks thought they saw smoke, and rushed to sell their story, when maybe it was just a bit of water vapor. ;-)

Rational Db8:
1. Much of the energy leaving Earth is in the infra-red.
2. CO2 absorbs in the infra-red.
3. CO2 in the atmosphere is increasing.
4. Therefore Earth's temperature can be expected to increase.
5. This will increase the amount of water vapour in the atmosphere. As this also absorbs in the infra-red, this will lead to a further increase in Earth's temperature.
6. Most, if not all, of the increase in atmospheric CO2 comes from human activity.
Where exactly do you take issue with this?

You've ended by begging the question with circular logic - we're releasing stuff, therefore it must have an effect, therefore AGW is true.

Not at all. I was trying to point out that, just because at times in the past global increases in temperature have resulted in increases in CO2 200 - 800 years later, this does not mean that the current increase in CO2 has anything to do with an increase in temperature 200 - 800 years earlier, (apart from anything else, how does Earth remember it through the Little Ice Age?) but could instead be due to something else, for example human activity.

Is the Oregon Petition still being trumpeted? I thought even denialists had given up on that long ago.

> Where exactly do you take issue with this?

I believe I can answer irrationaldb8's problem here.

His issue is with the conclusion: humans are changing the climate quickly and it's our big industries that are doing it.

His problem is that he's a market fundamentalist and therefore his problem starts at "business is doing something bad" (which is an anathema to a fundie) and goes through "governments are the only supra-organisation therefore they have to do something about it" (which is an anathema to a libertarian) and into "we have to change" which is antithetical to both the wealthy and libertarian and market fundamentalists.

He doesn't know the science, since it is devastating to his case.

> I'd be willing to bet that the majority of skeptics would jump on the AGW bandwagon in a heartbeat if the existing science actually supported the idea of any significant problem with AGW

I'd be willing to bet on that too.

Though this would be cheating, since this already happened around the 1930's-1960's.

However, denialists will never jump on the AGW bandwagon, even though the existing science supports the idea of a significant problem of AGW. You yourself are a case in point.

I note you now bring in the Invisible Choir to back you up, by the way. Stop pretending that you're anything more than the extremely extreme lunatic fringe of science.

> 41 "I went to ipcc.ch". And you call that "science", Wow?

Yes.

what do you call science?

A failed weatherman's blogroll?

An incompetent statisticians site?

A fake lord's word?

> That is a bunch of about 2000 persons

It's a bunch of about 3000 papers peer reviewed and widely accepted. Whereas you have just hate and denial.

Can you demonstrate the effect that stops CO2 from human causes causing warming just like CO2 did when it wasn't from human causes?

Or do you just have denial?

@52 Richard, you honestly believe it's that simple, when in fact the system is grossly complex?

I suppose it's massive miracle then that the earth didn't turn into one big smoking molten cylinder ages ago. /sarc (mostly)

Pray tell, how do you account for the fact that on multiple occasions in the past, CO2 levels have been 5 to 20 times higher than present day, while it was an iceball planet? Similarly, how do you explain the fact that on multiple occasions, temperatures plummeted from well above todays, to well below (several degrees C each direction, vastly more than the 20th century warming magnitude), all while CO2 levels remained steady? How do you account for the fact that in Earth's history, 'hothouse' planet times when there were palm trees above the arctic circle were also some of the most abundant and diverse in terms of life planet wide?

How then do rationalize research showing that up to 80% of the 20th century warming is likely because of soot? How do clouds affect the earth's albedo, and subsequently temperature? (hint, you can't answer that, because even the top 'climate scientists' who are the most adamantly pro-AGW admit they don't know). How do you ignore multiple research papers from several different groups showing that variation in cosmic ray levels may well cause significant changes in cloud cover? Or the various papers showing that biota respond to increased sunlight and/or CO2 by producing more aerosols, which act as a negative feedback, cooling things down?

By the way - you do realize that the CO2 absorbtion vs. concentration spectrum is lograthmic, and that we long ago entered the near plateau stage of the curve? That your number 6 is controversial (in science circles, that is)?

As to how the Earth 'remembers' previous changes - how do you figure the Earth managed to 'remember' each and every time that's been captured in the historical record going back hundreds of thousands of years as it is? Have you no understanding of lag times in complex systems? Or of what a huge heat sink the ocean is? Or that any number of variables could easily account for the lag, that it's not some magical anthropomorphic 'memory' that just ignores everything in between and pops out proper changes 800 years later? Until the system can be well explained for these historical changes that occurred long before man's industrial age began contributing CO2 to the system, it makes zero sense to say every time in the past it was 'something else' but this time, this time by gawd, it must be us!! (just because it must)

Finally, re the Oregon or Petition Project - when verified signatures of over 31,000 dissenting scientists magically become meaningless in the face of unsupported absurd claims of some major pro-AGW consensus , then I suppose folks will stop mentioning it. It is only the AGW catastrophists and true believers who continue with attempts to denigrate, demonize, and dismiss those scientists based on bogus or grossly outdated claims.

@53 Quite obviously Wow can't answer for me, and the conclusions presented are grossly incorrect, based on his personal agenda and biases in the fact of overwhelming evidence to the contrary.

The fact is the the argument is all about the science, and nothing else - and the simple fact that currently, the body of science simply doesn't support it. At this time, the body of science is very controversial on the issue and on pretty much every major aspect of the system. Even the most fervent AGW 'climate scientists' admit to huge doubts, contrary to what they proclaim in public, as can easily be seen in the climategate email threads.

It's about the integrity of the scientific method, "wow." About scientific conclusions then being accurately portrayed to the public - something which has most unfortunately not been occurring so far in this field - a fact that utterly disgusts real scientists, and utterly disgusts me. Science will win in the long run barring a complete breakdown in society - but in the meantime this nonsense is doing uncalculable harm with the resources and money that could be put to vastly more beneficial uses (how about dealing with starvation and malaria, both in terms of research and practical issues, for just two examples from the reams available?) rather than the bogus FUD of AGW that has actually significantly increased deaths from starvation and wasted billions if not trillions of dollars.

@54, more mud slinging and specious claims by commentator "wow," who keeps trying to throw in red herrings while ignoring anything posted that counters his true belief in AGW.

@55

A classic case of what is called 'projection' in psychology - where someone incorrectly sees or claims that others have what are in reality their own personal faults or problems.

> A classic case of what is called 'projection' in psychology

You know, just saying that doesn't make it so. Your application is incorrect.

I have no blogroll and I'm no weatherman (failed or otherwise). Anthony Watts is both, and this is a fact. So where is the projection?

But I guess you're just irrational.

> I suppose it's massive miracle then that the earth didn't turn into one big smoking molten cylinder ages ago.

No. What does this have to do with climate science? Nothing.

> Pray tell, how do you account for the fact that on multiple occasions in the past, CO2 levels have been 5 to 20 times higher than present day, while it was an iceball planet?

Pray tell when these ice ball conditions with CO2 even 2 times higher than the present day occurred.

Hint: they didn't happen.

> how do you explain the fact that on multiple occasions, temperatures plummeted from well above todays, to well below (several degrees C each direction, vastly more than the 20th century warming magnitude), all while CO2 levels remained steady

Pray tell us when these plummets happened with steady CO2 levels.

Hint: they didn't happen.

> How do you account for the fact that in Earth's history, 'hothouse' planet times when there were palm trees above the arctic circle were also some of the most abundant and diverse in terms of life planet wide?

How many men were alive in those days? How many species? How many species exist today? Or are you begging the question. Again.

> How then do rationalize research showing that up to 80% of the 20th century warming is likely because of soot?

That research is incorrect.

> How do clouds affect the earth's albedo, and subsequently temperature?

Pop along to the AR4 at http://www.ipcc.ch and check over for yourself. Chapter 7 IIRC is the one with attribution of the various forcings including clout effects in the earth's past and current climate changes.

Seems like you're the one who doesn't know what the science is...

> How do you ignore multiple research papers from several different groups showing that variation in cosmic ray levels may well cause significant changes in cloud cover?

There aren't multiple research papers saying this and the one that does talk about this say that they don't see any significant change brought on by cosmic rays. Even the head author has had to come out and refute people who misattribute his work like you just did there. All his paper says is that this is another way of causing clouds. Not a surprise. Hint: google "cloud chamber".

> Or the various papers showing that biota respond to increased sunlight and/or CO2 by producing more aerosols

Go look at chapter 7 in AR4 again. It's already accounted for in the science.

Just because YOU don't know something, doesn't mean it's not known by anyone.

> By the way - you do realize that the CO2 absorbtion vs. concentration spectrum is lograthmic

No, because it isn't. You can check for yourself with a program called HITRANS to check for yourself.

> and that we long ago entered the near plateau stage of the curve?

Look at Venus. No such state has occurred. Look up what "logarithmic" means. There is NO asymptote in a logarithmic curve. Seems you're incompetent at maths as well as science.

> As to how the Earth 'remembers' previous changes

We see the results of previous changes. It's how you can make your claims about the dim and distant past's climate to make your erroneous claims about it's temperature and CO2 levels, for example.

Or were you actually alive at the time of the Dinosaurs and took measurements?

> Have you no understanding of lag times in complex systems?

Yes we do. Seems you don't. Google "warming in the pipeline".

> Or that any number of variables could easily account for the lag

What lag?

> that just ignores everything in between and pops out proper changes 800 years later?

Yes, why do you ignore everything in between? If CO2 lags temperature, then where is the 800 year old temperature increase that's "causing" this CO2 increase? Can you explain where that temperature rise is? Can you explain where this CO2 is coming from, since we're already pumping out more than twice that amount from industrial activity and the oceans are gaining CO2 at the same rate as the atmosphere is?

Can you explain that?

Can you also explain why this makes any difference if your claim of "CO2 doesn't change the temperature" is correct? Can you explain your obsession with CO2 in the face of that?

> it makes zero sense to say every time in the past it was 'something else' but this time, this time by gawd, it must be us!! (just because it must)

Ah, a strawman. Well, you'll be glad to know that this isn't being said except by denialists. You see we're producing CO2. CO2 produces warming. We're causing warming.

Therefore the global warming we're seeing is from human origin.

AGW.

Arsonists would love to say that it's impossible for them to be jailed because fires occurred in the past without humans starting them, and that just because they had a can of gasoline and a box of matches and were dousing trees and setting light to them DOES NOT mean that they're causing forest fires (just because they must).

However, the sane proportion of humanity realise that this is bunkum.

> re the Oregon or Petition Project - when verified signatures of over 31,000 dissenting scientists

Even the promoter of the Oregon Petition says the list isn't verified. The list includes fictional characters, dental assistants and so on.

http://www.huffingtonpost.com/kevin-grandia/the-30000-global-warming_b_…

is why every other denier has given up on the OP. Why are you so much dumber than all those other idiots?