Confirmation bias

This demonstrates Lindzen's own confirmation bias. He saw a difference between two datasets, and rather than investigating whether the two represented different kinds of data (clearly stated, apparently, in the datasets themselves), he leapt to the conclusion that NASA had manipulated the data.

I like the heading of the apology:
"Apology From Prof. Lindzen for Howard Hayden's NASA-GISS Data Interpretation Error"

No attribution in the original slides. I wonder if he asked or just lifted it from JunkScience?

Hayden's NASA-GISS Data Interpretation Error

that would be misdescribed, wouldn't it?

Hayden's Data Error and Misinterpretation of NASA-GISS, eh?

No NASA-GISS error there, neither data nor interpretation.

Why do people keep going on about this one NASA-GISS graph for which Lindzen has apologised (while continuing to abidcate responsiblity for his mistake)...

As many have pointed out, there were numerous erros, and evidence of hypocrisy, ofuscation, and misdirection on just about every slide.

Finally there is the case of the "missing" slide with a Keeling v Temperature graph on it, which Lindzen has now re-inserted into the PPT/PDF. However, all this demonstrates is that Lindzen doesn't realise why it is meaningless (and misleading), in which case he is either incompetent or deceitful.

What offended me was Lindzen's comment that it was an "innocent" error.

Ignorance of scientific rigour is no defence.

He made a mistake and apologized. What's the beef?

[You are very forgiving, when it suits you. I think your response is going to be typical of the "skeptics" - or at least, of those who ever hear of the apology and who know of the error. Most won't -W]

It isn't like GISS doesn't have a record for fiddling with temperatures decades after the fact:

http://climateaudit.org/2007/08/08/a-new-leaderboard-at-the-us-open/

http://wattsupwiththat.com/2009/12/11/giss-raw-station-data-before-and-…

[Don't be silly. Quoting WUWT as fact is just trolling. And the CA stuff is deliberate misrepresentation. If you don't understand why it is, say so, and I can help you -W]

So yes, I think, and have long said, there is a serious case of confirmation bias going on at GISS. In particular, I suspect either the 1940's-1970's may have been cooler than they now calculate or it was warmer around the 1930's.

Keep in mind, as you may recall, back in 2001 even Hansen said UHI's could still be accounting for one-sixth of the warming trend:

http://www.giss.nasa.gov/research/news/20011105/

Doubling that estimate to account for one-third of the trend is not unreasonable considering his rather crude method and clear bias.

[Why would you take an obsolete estimate, that is now known to be too high, and then increase it still further? Unless you were desperate to manipulate the record, that is. Anything from 2001 is superseded by Peterson and Parker stuff since then. Again, if you're unfamiliar with the literature, I can point out references, but you already know the answer: just read the IPCC reports -W]

of course Lindzen's approach is way outside the far extremes of "confirmation bias", a creepy place where one preselects an appealing interpretation and then finesses "evidence" in support of this accompanied by assertions of authority.

He's been doing this for some time. In the 1990's he asserted wthout evidence that the small atmospheric warming from enhanced [CO2] would result in the "drying" of the uppper troposphere and thus give a negative feedback. Writing in the august pages of the Cato institute, Lindzen asserted:

"If, however, one asks why current models predict that large warming will accompany increasing carbon dioxide, the answer is mostly due to the effect of the water vapor feedback. Current models all predict that warmer climates will be accompanied by increasing humidity at all levels. As already noted, such behavior is an artifact of the models since they have neither the physics nor the numerical accuracy to deal with water vapor."

Of course a large body of evidence shows that the tropospheric response to greenhouse warming is an increase in absolute humidity much as models predicted - it isn't an "artifact of the models" at all. This is beyond dispute.

An honest scientist would likely say at that point something like "O.K. my assertion was way off base and the dominant source of positive feedback actually seems to exist in the real world. I need to readjust my view on this in line with the evidence." Lindzen simply planted his flag beside a different unevidenced notion "Iris hypothesis", and as seen in his pretty disgraceful paper with Dr Choi in 2009, now thinks nothing of fraudulent selection of analysis time periods to create the pretence of enhanced outward radiation in response to warming fluctuations in surface temperature.

"Confirmation bias" this ain't!

"[You are very forgiving, when it suits you. I think your response is going to be typical of the "skeptics" - or at least, of those who ever hear of the apology and who know of the error. Most won't -W]"

Well, I'm still waiting for Gleick to apologize for fabricating the Heartland strategy memo. If he did I don't think Heartland should sue him for damages and I'd email them suggesting such action. If he waits until he is caught then forgiveness is less likely.

I do recognize that some things are clearly unforgivable, but this is not such a case.

"[Why would you take an obsolete estimate, that is now known to be too high, and then increase it still further?"

Because about 3% of the land is urbanized and urban heat islands can cause a bias up to 10 degrees F. The surface stations, by their nature of being man-made, are going to tend to show up near or in these urban areas.

[That is a non-sequitur. I didn't ask "why do you personally think the UHI is large", I asked "why would you use an obsolete estimate"? -W]

I believe Hansen has shown himself to be incredibly biased and that it is quite difficult to properly account for UHIs in the surface station record.

"Unless you were desperate to manipulate the record, that is. Anything from 2001 is superseded by Peterson and Parker stuff since then. Again, if you're unfamiliar with the literature, I can point out references, but you already know the answer: just read the IPCC reports -W]"

If you could email or link the full text of the Peterson/Parker paper(s) that would be great.

[I'll look for them, if you do two things first: 1) tell me which scientific papers you've read about the UHI that made you come to your conclusion that "it is quite difficult to properly account for UHIs in the surface station record". Or, failing actual sci papers, what your sources are; and 2) find the Parker and Peterson refs in the IPCC report and tell me (or just link to the right page) that gives an up-to-date estimate of the UHI effect on global temperatures -W]

that's pretty illogical TheGoodLocust. This thread's about apples and you talk about oranges. Whatever one thinks of Gleick's actions he isn't someone that misrepresents the science under the guise of priviliged authority.

And you've learned enough about the UHI to link to a 2001 NASA Giss site, without apparently having any clue about the science that informs us on this subject. Very weird! Here's a couple of papers/reports.

http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3730.1

http://berkeleyearth.org/pdf/berkeley-earth-uhi.pdf

Note than in addition to work of Parker (linked; his recent paper in WIRES Climate Change doesn't have a free url unfortunately, but also demonstrates that the UHI has little contribution to the surface temperature record), and Peterson (cited in linked article), not to mention a number of other studies that demonstrate that the global temperature record is essentially unchanged if one eliminates all of the urban records altogether, the recent Berkeley temperature analysis also indicates that the UHI effect is negligible (see second link above).

Surely you know that already Locust, old chap! You seem at least to pretend to know about this stuff...perhaps you're simply trying to divert focus from the subject of this thread...

GoodLocust states in an evidence-free assertion:

"I believe Hansen has shown himself to be incredibly biased..."

Amongst the admirable characteristics of Dr. Hansen are (i) that he presents his case honestly and in good faith, and (ii) his presentations are strongly evidence-based.

In 1991 Hansen and Andrew Lacis engaged in a correspondence in the pages of Nature [Nature 349, p. 467 (1991)] with a certain R. S. Lindzen in which the latter reasserted his notion of a drying of the upper troposphere in response to greenhouse warming, and Hansen and Lacis pointed out that this was incompatible with the evidence even then.

Of course we now know that Hansen was/is correct and Lindzen was/is incorrect.

Seems that the evidence demonstrates that it's R.S. Lindzen that is "incredibly biased" whatever you "believe" GoodLocust. Your "beliefs" don't seem very well-founded in fact...

Oh dear! now that I've reminded myself of the very recent Berkeley temperature analysis, I can't help noticing another example that contradicts TheGoodLocust's ill-evidenced belief, a.k.a.:

""I believe Hansen has shown himself to be incredibly biased..."

For the Berkeley temperature group have come essentially to the same conclusion as Dr. Hansen by a rather different route, namely that the UHI has rather little influence on the temperature record.

http://berkeleyearth.org/pdf/berkeley-earth-uhi.pdf

It's difficult to agree with TheGoodLocust's belief that Hansen is "incredibly biased", when his work is repeatedly reproduced/verified by others. That's hardly the characteristic of "bias"! It's surely an indication of careful consideration of the evidence and robust and faithful treatment of data.

In contrast R.S. Lindzen's notions have repeatedly been shown either to be incorrect (see my posts #7 and #10 above) or incompatible with the evidence. And Lindzen has even gone so far as to preselect "convenient" time periods for comparing sea surface temperature and outgoing radiation from ERBE data to insinuate evidence of a negative feedback: See Fig 1a of:

http://www.agu.org/pubs/crossref/2009/2009GL039628.shtml

...who's biased GoodLocust....?

I'm just wondering what went on in Lindzen's head these days...

Let's see, Hayden at 'junkscience.com' sends me a graph, showing "NASA/GISS Data Manipulation". Now that's a pretty heavy accusation, so should I first check if that graph is valid before I present it to the UK House of Commons ? Nah, let's just put it in, and crank a joke about it so I get some laughers on my hand.

What the heck was he thinking ?

And then his slide 4 which asserts that "actual warming is
consistent with less than 1C warming for a doubling", which completely ignores influence of aerosols and the fact that Earth has heat capacity (oceans). How careless !

All this after the fundamental mistakes in his Lindzen and Choi 2009 paper, that he himself called "embarrassing".

You gotta give the 'skeptics' credit having "blind faith" in this apostel of the 'skeptics' gospel.

Lindzen is an interesting fellow. He's very, very smart. People who know him well also say he does not suffer from low self-esteem. A common view of those inside the profession is that he's twice as smart as the rest of us, but half as smart as he thinks he is.

So this might explain why he does these things that seem so odd for someone of his intellect and professional stature. Isaac Held (who I belive worked with Lindzen some years ago, and is genuinely a nice guy) put it in a news story: "There're people like [Lindzen] in every field of science. There are always people in the fringes... It may be as simple as, how do you prove you're smarter than everyone else? You don't do that by being part of the consensus."

Is that a deliberate spelling error in the title?

[Just a little test ;-). I've corrected it now -W]

What is interesting over at WUWT is watching the confirmation bias on top of confirmation bias. There people refused to even entertain the possibility that Lindzen might be wrong ( http://wattsupwiththat.com/2012/03/10/moncktons-schenectady-showdown/#c… ). I am actually surprised Lindzen owned up in any way to his mistake given that he could just refuse to admit he was wrong and all of his followers would steadfastly believe him.

http://3.bp.blogspot.com/-Hh-ZT9W2cYo/T15GNXRxhKI/AAAAAAAAAsU/uDNDmUA7t…

Just asking; I myself, by accident, once wrote "comformation bias", and then realised that confirmation bias can indeed come from a desire to be comforted (it ain't bad! Really, it ain't!).

Call it an epiphany (I was still young).

"He is being weaselly..."

This criticism from a man that has chosen a stoat as his mascot?

[I forgot to add the "[*] Not that there is anything wrong with weasels, of course" -W]

@WMC "[That is a non-sequitur. I didn't ask "why do you personally think the UHI is large", I asked "why would you use an obsolete estimate"? -W]"

Because I was already familiar with it. Besides, if this is settled science I wouldn't think a paper from 2001 would be considered "obsolete."

[Sorry, this won't do as an answer, not if you're actually interested in the science. 2001 is more than a decade ago, and "if this is settled science" is just facile. If you want to talk seriously, you need to stop saying things like that -W]

"[Just a little test ;-). I've corrected it now -W]"

Was it a test to see if people would spell it that way in comments? I don't generally correct people on spelling considering how often I forget to proof-read.

@Chris "http://journals.ametsoc.org/doi/pdf/10.1175/JCLI3730.1"

An interesting paper, my concern, and I'm just going off the top of my head, is that UHIs would affect both wind strength, wind direction and temperature, especially at night, which would throw off this analysis.

"http://berkeleyearth.org/pdf/berkeley-earth-uhi.pdf"

Seems to be a bit better than the Hansen method, but I've always been worried that very small man-made structures and concrete could significantly affect stations and yet still be classified as "very rural."

An individual rating of the stations would be needed, ideally with construction records, but this isn't as easy as looking at satellite images.

In any case, I admit I may be wrong about UHI.

"Surely you know that already Locust, old chap! You seem at least to pretend to know about this stuff...perhaps you're simply trying to divert focus from the subject of this thread..."

I know more than your average bear, but I'm always learning. I've learned from this little exchange which was nice.

"It's difficult to agree with TheGoodLocust's belief that Hansen is "incredibly biased", when his work is repeatedly reproduced/verified by others."

I was speaking about his arrest record, protests, speeches and tangentially some rather unethical/unprofessional behavior of his which isn't publicly known (to my knowledge).

The BEST work is very similar to his work - same/similar stations and using satellite images to attempt to correct for UHI. I don't have a lot of faith in such methods.

If I misinterpreted the BEST method then please correct me.

"In contrast R.S. Lindzen's notions have repeatedly been shown either to be incorrect (see my posts #7 and #10 above) or incompatible with the evidence."

I'm sure he may have made some mistakes in the past. Most people have. From listening to both him and Hansen he seems to me, by far, a more credible personality.

...a more credible personality

Personality is not an adequate measure of scientific credibility or achievement!

See Notes Rec. R. Soc. Lond. 49:1-56 (1995).

TGL, I am afraid you consider Lindzen's personality "credible" because he tells you things you like to hear.

And FIY: I don't like want Hansen tells me; I'd prefer Lindzen to be right, but still I find Hansen much more credible than Lindzen. Simply because the facts are so much more often on Hansen's side...

@Marco Well, Lindzen hasn't told me that the Earth's oceans will boil and then end up in the atmosphere - Hansen has said that.

Hansen has called trains that ship coal "death trains" (Death trains is another term for holocaust trains in WWII) and coal plants "factories of death."

That is not how a scientist speaks. It does not make him credible in my mind.

[Why is WUWT currently censoring my comments? -W]
[Update: no, they aren't, they've just hopelessly f*ck*d their wordpress-based comment system. Not your fault, but they are bozos -W]

@TGL
"@Marco Well, Lindzen hasn't told me that the Earth's oceans will boil and then end up in the atmosphere - Hansen has said that. "
No, he actually did not. Read the actual transcript: http://bigthink.com/ideas/17894

"Hansen has called trains that ship coal "death trains" (Death trains is another term for holocaust trains in WWII) and coal plants "factories of death."

That is not how a scientist speaks. It does not make him credible in my mind."

Assessing scientific credibility, you're doing it wrong.

TGL, Hansen has stated that a Venus-type outcome is possible *if* we burn all the fossil fuels. Of course we can't, if for no other reason than that the early effects would kill us before we could finish the job, but I think there is value in pointing out that the Earth system is capable of something so extreme. Note that there's a technical argument about whether a complete runaway could happen due to the Earth's greater gravity/magnetosphere/distance from the sun keeping hydrogen from escaping easily enough, but also that a failed runaway (various flavors available) would be quite bad enough. But Hansen's main concern is with climate states analogous to geologically recent extremes, as yours should be. A too-rapid transition to a mid-Eocene-like climate state (probably the path we're on now), or even a mid-Pliocene-like one (to which we may already be committed), would be no bed of roses.

[Personally, I don't think Venus-like is likely, or even plausible, if we do burn everything. But I agree that other consequences by then would have been pretty severe anyway -W]

TGL, I think Beaker already captured it well. You are assessing scientific credibility the wrong way.

Moreover, Hansen provided an explanation for saying this. So far, I have not seen anyone refute his argumentation; rather, it's all about the tone.

In contrast, I have on frequent occasions heard Lindzen claim his fellow climate scientists lie. His argumentation? Well, surely, no argumentation is needed!

@WMC "[Update: no, they aren't, they've just hopelessly f*ck*d their wordpress-based comment system. Not your fault, but they are bozos -W]"

It appears that it was a recent update on wordpress' end - not on WUWT's.

http://en.forums.wordpress.com/topic/you-must-be-logged-in-to-comment?r…

@Beaker "No, he actually did not. Read the actual transcript: http://bigthink.com/ideas/17894"

He didn't? Here are some exerpts:

"In the long run, if that really happened, as I point out in the book, over centuries, we could actually get a runaway greenhouse effect, and then that's it for all the species on this planet."

And a bit later he says:

"A runaway greenhouse effect means once the planet gets warmer and warmer, then the oceans begin to evaporate. And water vapor is a very strong greenhouse gas, even more powerful than carbon dioxide. So you can get to a situation where it just -- the oceans will begin to boil, and the planet becomes so hot that the ocean ends up in the atmosphere."

So he says we could get a runaway greenhouse effect here - and he then describes a runaway greenhouse effect as including "boiling oceans."

In any case, if you still disagree, then I'll take his statement that all species are going to die on this planet due to global warming as proof that he isn't credible.

There is just so much to choose from his statements that impugn his credibility.

For example:

"And one of the things I write about in my book is the effect that will have on storms, because as Greenland begins to release more fresh water, cold fresh water, and Antarctica does, what it does is cool the North Atlantic Ocean and the southern ocean, and that increases the temperature gradient between low latitudes and middle and high latitudes. And that will increase the strength of storms that are driven by horizontal temperature gradients. So our children can look forward to increasing storms."

So basically, and correct me if I'm wrong, he is saying global warming will cause the low/high latitude areas to cool, increases the temperature gradient and therefore storms.

And yet, global warming is supposed to warm the polar areas faster. How can "climate change" cause problems by both warming and cooling the same areas?

Besides, even if he was right, such an increase in storms would be temporary (only so much ice can melt), and there would be less of a temperature gradient, which would reduce storms.

He contradicts himself because it sounds scarier - and doesn't give complete answers. Again, he isn't credible.

"In any case, if you still disagree, then I'll take his statement that all species are going to die on this planet due to global warming as proof that he isn't credible."
I see you have a problem with understanding verbs. He talks about things that "could" happen, over a very long timespan. You interpret that as him saying that these things "will" happen, which he does not say. He is illustrating extreme cases, without saying that these also will arise. Is English not your primary language?

And adding to that, assessing scientific credibility, you're doing it wrong again. You assess scientific credibility by looking at how well his theories fit the facts, how well they stood the test of time and if he was wrong, how soon he realized this. You apply none of these tests.

"So basically, and correct me if I'm wrong, he is saying global warming will cause the low/high latitude areas to cool, increases the temperature gradient and therefore storms."
He states that sea temperatures in the low latitudes will go down because of the low temperatures of the melt water. Seriously, you should read for understanding, not to solely try to find flaws. After you understand what he is saying, you can start to find flaws, not sooner. So do that first.

"And yet, global warming is supposed to warm the polar areas faster. How can "climate change" cause problems by both warming and cooling the same areas?"
The way Hansen states, it could do this by warming the ice mass, but increasing the cold water mass. It is not warming and cooling the same area. It is warming the ice mass, after which the melt water cools the water mass. According to Hansen, there are multiple processes at work here.

"Besides, even if he was right, such an increase in storms would be temporary (only so much ice can melt), and there would be less of a temperature gradient, which would reduce storms."
Where does he say this increase in storms would be permanent?

"He contradicts himself because it sounds scarier - and doesn't give complete answers. Again, he isn't credible."
He gives a more complicated answer than just "it gets warmer".
He does, in fact, give a complete answer. Apparently however, this confuses you. Why? Why do you think a complex natural system such as we have on earth would only have single direction effects?

I'd say you misunderstood both of those points very well, TGL. But thanks for making it clear (yet again) you're not worth discussing them with.

Thanks TGL. You've gone from claiming "the Earth's oceans will boil and then end up in the atmosphere - Hansen has said that" to "he says we could get a runaway greenhouse effect here" (emphasis added). The difference between "will" and "could" is subtle enough that perhaps not everyone caught it.

Correcting your error (even while declining to acknowledge it) is a positive step.

I am very glad to see Hansen v Lindzen being discussed.

Hansen has been telling anyone that would listen for over 20 years that we have a significant problem that we simply must tackle or it will kill us all (in about 200 years).
http://lackofenvironment.wordpress.com/2011/10/27/how-does-james-hansen…

Lindzen has been telling anyone that would listen for over 20 years that we do not have any problems that we cannot simply ignore and hope they will go away.
http://lackofenvironment.wordpress.com/2012/03/16/lindzens-litany-of-la…

Lindzen is an ideologically-prejudiced fool; one who is clearly not going to change his mind no matter how much evidence accumulates to indicate that he is under-estimating climate sensitivity by a factor of 150%.

[I think you're not correct on Lindzen. http://scienceblogs.com/stoat/2011/06/lindzen_goes_emeritus.php perhaps -W]

Meanwhile, unless or until he - and all his denialist chums (Carter, Curry, Michaels, Spencer, etc.) - is silenced, his/their lies will continue to be repeated ad nauseaum by uncritical, non-scientific idiots in the media.
http://lackofenvironment.wordpress.com/2012/02/20/peddlers-of-doubt/

For those of you, who have not heard of me before, my blog is hopefully explained by its being on "...the politics & psychology underlying the denial of all our environmental problems" but if not try this:
http://lackofenvironment.wordpress.com/2012/03/12/a-brief-history-of-mi…

@Beaker "He talks about things that "could" happen, over a very long timespan."

He was asked what would happen if carbon emissions continued to grow. He said within "centuries" (not that long really) we "could" have a runaway greenhouse effect which would kill every species on Earth.

He said a runaway greenhouse effect involved "boiling oceans."

So yes, insults from your end notwithstanding, it is crystal clear what he is saying and it is equally clear that such predictions have zero basis in reality.

If you have a problem with "could" then let me make it clear for you - it cannot happen. His "could" is an impossibility. It is impossible for our carbon emissions to kill every species on this planet within centuries - or any time frame. It is impossible for our carbon emissions to cause the oceans to boil - in any time frame.

"Seriously, you should read for understanding, not to solely try to find flaws."

No, I understood it perfectly, had a slight typo (that I can see) and didn't communicate my understanding properly to your satisfaction.

"The way Hansen states, it could do this by warming the ice mass, but increasing the cold water mass. It is not warming and cooling the same area. It is warming the ice mass, after which the melt water cools the water mass."

So presumably, in the case of Antarctica/Greenland, it is warm air temperatures melting the ice and cooling the seas. I'm assuming the temperature gradient/storm theory is relying on air temperatures and the warm air melting the ice in Antarctica would decrease the temp gradient and therefore decrease storm strength/frequency.

This means defending Hansen's theory gets even fuzzier and more ridiculous.

Of course, as the ice melts from Greenland/Antarctica (not that I think it will) then that would decrease the albedo in those areas and throw another wrench in this theory.

"Where does he say this increase in storms would be permanent?"

Where does he say they'll be temporary? As I said, giving incomplete answers that increase fear does not make him credible.

Am I to assume the man talking about us killing all life on the planet is talking about a temporary increase?

"He does, in fact, give a complete answer."

And yet we can now both agree that he didn't since he didn't mention anything about the duration of "increased storms" - but still had time to talk about how we could get boiling oceans.

@Bishop "The difference between "will" and "could" is subtle enough that perhaps not everyone caught it."

Perhaps defending him based on minor semantic "errors" means your position isn't that strong. Read my first paragraph in this post and get back to me.

[Personally, I don't think Venus-like is likely, or even plausible, if we do burn everything. ... -W]

Yep, that's the consensus-of-sorts on this subject; Locust, do you notice how guarded this statement is?

William's and colleagues' position is based on physical modelling only, and they are well aware of its limitations (as are you, when it suits you). There is no analogue in the real world to this. (In fact, the closest analogue is Venus; and it isn't analogue enough. Or Earth a billion years from now, as the Sun gets brighter -- not helpful either.)

Locust, you never studied climatology as a science. You never ran general circulation models. But -- somehow, given how little it is based on, I must admire your calm confidence, expressed in repeated boldface above, of knowing better than the folks who do do these things...

22
That's odd- WUWT haven't stopped censoring mine.

[I'm not at all sure I trust their assurances of no-censorship. They like their echo chamber and aren't happy with people disturbing it -W]

@Martin "Yep, that's the consensus-of-sorts on this subject; Locust, do you notice how guarded this statement is?"

Yes, I thought he was being nice, but don't think our statements differ significantly.

"Locust, you never studied climatology as a science. You never ran general circulation models. But -- somehow, given how little it is based on, I must admire your calm confidence, expressed in repeated boldface above, of knowing better than the folks who do do these things... "

And theologians have told me the same thing. That I haven't studied theology or the Bible properly so my opinion on the existence of divinity is uninformed due to lack of expertise.

Despite that I can still confidently laugh at their claims that the eye couldn't have evolved without divine intervention and that the banana is proof of the existence of god.

The argument doesn't work when you use it too.

If you want to prove that the oceans can boil within centuries, that all life on this planet can go extinct during that time, all due to human carbon emissions, then convince me with evidence and reason.

You could start by explaining the mechanism to me - or perhaps by how many ppm of carbon dioxide is necessary to start boiling the oceans.

TGL, what probability of a Venus type outcome would you consider high enough to merit Hansen's "could"?

@Blueshift Not just a Venus outcome, but a Venus outcome within centuries due to carbon dioxide emissions.

I suppose there could some infinitesimally small chance of the oceans boiling away on Earth if a small black hole grazed our atmosphere to strip it down to some incredibly low pressure so the remaining oceans could boil.

Perhaps our magnetosphere decides to take a break and an enormous set of solar flares strips away our atmosphere to the point where our oceans can boil (doubt they'd be gone in centuries though).

But none of those ridiculous notions are man-made.

Tell me how many ppm of CO2 we need for boiling oceans. Use any feedbacks you like. I don't believe it is possible for us to put enough CO2 in the atmosphere to create such an outcome.

> And theologians have told me the same thing

And there we are... the old "AGW believers" denialist smear. I knew the mask would sag.

> If you want to prove that the oceans can boil

You need to prove mate. That it cannot happen if -- Hansen's assumption -- we burn up all the fossil fuel we can lay our hands on. That Pierrehumbert and the other modellers haven't overlooked something -- with certainty. Again, all we have are the models, and no real way to test them in this regime.

And if it happens (and I agree it is unlikely), expect it to happen within centuries. Just like those other climate runaways that did really happen on Earth, like coming out of Snowball Earth which took some 20 centuries to completion.

That's odd- WUWT haven't stopped censoring mine.

[I'm not at all sure I trust their assurances of no-censorship. They like their echo chamber and aren't happy with people disturbing it -W]

Anthony has admitted that my posts undergo an extra level of moderation. He does let almost all of them through...although there are a few areas of sensitivity where a post will never see the light of day. One is too strident criticisms of the poster who goes by the moniker of "Smokey" (and especially any suggestions that perhaps he might call "Smokey" out for hiding under a pseudonym when Anthony is calling out a commenter he doesn't like for using a pseudonym), making me wonder if Smokey might be someone who is helping to bankroll Anthony's site.

[I've had similar. Watts is terribly sensitive about anyone calling him out for his lies, which isn't perhaps too surprising, but even milder inquiries regarding his veracity don't fare well -W]

@Martin "And there we are... the old "AGW believers" denialist smear. I knew the mask would sag."

Perhaps you should wonder why an atheist like myself, who has had many debates with theists, notices such similarity in arguments.

"You need to prove mate. That it cannot happen if -- Hansen's assumption -- we burn up all the fossil fuel we can lay our hands on."

Actually you have it backwards. The burden of proof is on you to proof that the oceans can feasibly boil within centuries - without such proof I'll treat it like I would any other ridiculous claim. Similarly, theists always ask atheists to "Proof god doesn't exist" when the burden of proof has always been on them to proof existence.

http://en.wikipedia.org/wiki/Philosophic_burden_of_proof#Holder_of_the_…

TGL, you didn't actually answer my question. Would a 1% chance of climate sensitivity being high enough that burning all the fossil fuels leads to a Venus type outcome be enough for "could"?

Locust, the only feasibility proof I could offer would start from the validity in principle of physical modelling, which you equate to phrenology. Why should I bother?

Now, it would be fun to see you defend Raymond Pierrehumbert's modelling work...

(Philosophically, no, you have it backwards. The 'existence proof' that should be provided is that of reliable physical climate modelling in a regime where no empiry exists. Your problem, not mine. Venus-style runaway does exist: it happened on Venus :-) )

@Blueshift Yes, but I don't think you can model a 1% chance for something that we've never seen happen.

Now please tell me how many ppm of CO2 are needed for such an outcome within centuries.

@TGL, well *I* certainly don't know that answer. Given current knowledge we can't exclude climate sensitivity greater than 4.5C per doubling and if we burnt up all the oil and all the coal we'd have a few doublings. In this scenario, it's pretty easy to see how the ice sheets disappear, the methane clathrates thaw, and the biosphere switches from a carbon sink to a carbon source.

But let's go back to why we are discussing this in the first place. You said that Hansen was not credible because he said "that the Earth's oceans will boil and then end up in the atmosphere". On reflection, you amended this to him saying that it could happen over several centuries. (A far more accurate paraphrase.)

That is, you put forward an argument that depended on a Venus type outcome being patently impossible over the next several hundred years. But what is your evidence that it is impossible? That we can't accurately model something that far outside the parameters we have been able to observe? That we don't know precisely what forcing would be required, or how long it would take?

If so, then you are arguing that our inability to know the constraints on the response imply that we know the response won't be on the extremes.

TGL, blueshift: Held and Soden 2000 is pertinent, see esp. page 449 second paragraph. And overall a great read.