CNN Meteorologist: ‘Definitely Some Inaccuracies’ in Gore Film (Rob Marciano)

CNN Meteorologist Rob Marciano clapped his hands and exclaimed, “Finally,” in response to a report that a British judge might ban the movie "An Inconvenient Truth" from UK schools because, according to “American Morning,” “it is politically biased and contains scientific inaccuracies.”

"There are definitely some inaccuracies,” Marciano added. “The biggest thing I have a problem with is this implication that Katrina was caused by global warming.”

The 1,000 lag between ocean warming and CO2 increase stands as a clear scientific result that settles the cause-and-effect link between the two.

Which is accurately described in my profile. The new result did not change how Milankovitch forcing initiates the transition between glacial and interglacial conditions, and how changing atmospheric CO2 concentrations sustains and continues the transition to completion, working in tandem with the changing extent of continental ice sheets. The lag between the initiation of the temperature increase at the beginning of a transition and the change in atmospheric CO2 concentrations does not refute that the change in atmospheric CO2 concentrations drives the temperature change.

Gore’s attempt to tie current CO2 AGW increases to these prior trends is laughably wrong, and skeptics are right on this - the science backs them up.

No, it is not wrong. The basic scientific fact is that changing atmospheric CO2 concentrations alter the radiative balance of the Earth. True during glacial/interglacial transitions and true now -- during a warm interglacial.

I will leave you to your own opinions of RealClimate and I will utilize the site as an informational resource when appropriate.

Regarding the adjustments to the temperature record, I will let ClimateAudit continue their exercise. John V's contribution is a needed perspective there. Given the correspondence of the temperature record to a wide variety of phenological data, I see no reason to believe that the global temperature records are substantially in error.

Wrong, its the average trend over all of the Antartic for 50 years... and “small” ... WELL, it’s greater than the US warming trend from 1930s to 2000s (which is admittedly miniscule).

insert wry smile here

So is ‘warming’ in US actually a small thing?

Not since 1975.

Funny, how come Gore neer admits that?

Do you have any specific quotes from Gore about temperatures in the United States?

This one data point is not a refutation of AGW as a whole, that wasn’t the point; its a refutation of Gore’s credibility,

I expect (and I hope) that some of the sites that address skeptical arguments about global warming will address the "inaccuracies" identified in the British court decision. I don't have the time. Some of them are dubious. I haven't seen the movie; I'd REALLY like to know what it actually says about the Gulf Stream. I'd like to know what it specifically says about the Antarctic ice accretion. And I know that it does not specifically indicate major Greenland ice cap changes by 2100 (despite the observations of significant change happening right now; see below).

most scientists do not at all predict the scenario Gore paints of the Greenland ice sheet melting away.

Really.

The Greenland Ice Sheet

Melting ice cap triggering earthquakes

Scientists warn of climate tipping points

Is the Greenland Ice Sheet in a state of collapse? (PDF)

Global Warming Impact on Polar Ice Sheets Confirmed

By the way, this last article includes this: "In Antarctica, the ice sheets had a major net loss of ice due to outflow from West Antarctica. These losses, which may have been going on for decades, outweighed the gains in snow and ice seen in the East Antarctic ice sheet and parts of West Antarctica."

He exagerrates entirely the current situation, the scale of the issue, the impact of our use of CO2, and neglects the many many mitigating facts of real science that would tend towards understanding AGW for what it is: A much more moderate and non-catastrophic issue than the alarmists want us to believe.

Obviously our opinions differ on this issue.

Thank you for proving my point ... again...

First, you link to the same hyping journalism to justify Gore’s own hyperbole; that is an exercise in circularity. They’ve all glommed on to this ‘consensus’ and it is truth by assertion. ... but read carefully and you find stuff like ...

Here’s the Guardian (so you link to a leftie Brit paper, whoo boy, but okay ...):
“According to the IPCC report, the melting should take about 1,000 years. But the study, by Tim Lenton of the University of East Anglia, showed the break-up could happen more quickly, in 300 years.”

Gore did *NOT* say that, ie., the ice sheets could melt in 300 to 1000 years from now, he said “NEAR FUTURE”:

http://www.freerepublic.com/focus/f-news/1909408/posts

Mr Gore’s assertion that a sea-level rise of up to 20 feet would be caused by melting of either West Antarctica or Greenland “in the near future”. The judge said this was “distinctly alarmist” and it was common ground that if Greenland’s ice melted it would release this amount of water - “but only after, and over, millennia”.

300 YEARS FROM NOW IS NOT “THE NEAR FUTURE”! And the claims that the ice sheets might melt within near future are based on unfounded and unjustified extrapolations - they are indeed alarmism.

The only way to get ice sheets to melt is to have warming of over 5C for a long period of time.

If you dont believe 5C, and there are very little reason to believe it ever WOULD happen, the ice sheets will never melt.

“Gore’s attempt to tie current CO2 AGW increases to these prior trends is laughably wrong, and skeptics are right on this - the science backs them up.”

I remain correct, justified by the science on this.

“No, it is not wrong. The basic scientific fact is that changing atmospheric CO2 concentrations alter the radiative balance of the Earth. “

Strawman!

This is not an argument over whether CO2 has any effect.
you are arguing a strawman. You seem to buy this phony idea that Gore is ‘justified’ if CO2 has any influence on the climate. The argument is not about that link - sure it is there, and doubling CO2 will likely increase temperatures, all other things being equal by as much as 1 - 1.5C. Most skeptics acknowledge there is a link but dispute the phony alarmism, question the data (Hansen’s bad data massaging), question the numbers, question the inability to acknowledge natural variability effects, etc.

“The lag between the initiation of the temperature increase at the beginning of a transition and the change in atmospheric CO2 concentrations does not refute that the change in atmospheric CO2 concentrations drives the temperature change.”

Which I already said is beside the point. you need to stop knee-jerk reciting the orthodoxy and listen to the valid critiques. I don’t think you even are listening/reading what is actually being said.

Q:
How much of the variability in US temp from 1950 to 1975 was man-made?

Another point: I suspect if you did a documentary on the topic, you would be more accurate and less alarmist than Gore was.

http://www.nytimes.com/2007/03/13/science/13gore.html
“But part of his scientific audience is uneasy. In talks, articles and blog entries that have appeared since his film and accompanying book came out last year, these scientists argue that some of Mr. Gore’s central points are exaggerated and erroneous. They are alarmed, some say, at what they call his alarmism.

“I don’t want to pick on Al Gore,” Don J. Easterbrook, an emeritus professor of geology at Western Washington University, told hundreds of experts at the annual meeting of the Geological Society of America. “But there are a lot of inaccuracies in the statements we are seeing, and we have to temper that with real data.””

...
“Criticisms of Mr. Gore have come not only from conservative groups and prominent skeptics of catastrophic warming, but also from rank-and-file scientists like Dr. Easterbook, who told his peers that he had no political ax to grind. A few see natural variation as more central to global warming than heat-trapping gases. Many appear to occupy a middle ground in the climate debate, seeing human activity as a serious threat but challenging what they call the extremism of both skeptics and zealots.”

...
In October, Dr. Easterbrook made similar points at the geological society meeting in Philadelphia. He hotly disputed Mr. Gore’s claim that “our civilization has never experienced any environmental shift remotely similar to this” threatened change.

Nonsense, Dr. Easterbrook told the crowded session. He flashed a slide that showed temperature trends for the past 15,000 years. It highlighted 10 large swings, including the medieval warm period. These shifts, he said, were up to “20 times greater than the warming in the past century.”

Getting personal, he mocked Mr. Gore’s assertion that scientists agreed on global warming except those industry had corrupted. “I’ve never been paid a nickel by an oil company,” Dr. Easterbrook told the group. “And I’m not a Republican.”

Biologists, too, have gotten into the act. In January, Paul Reiter, an active skeptic of global warming’s effects and director of the insects and infectious diseases unit of the Pasteur Institute in Paris, faulted Mr. Gore for his portrayal of global warming as spreading malaria.

“For 12 years, my colleagues and I have protested against the unsubstantiated claims,” Dr. Reiter wrote in The International Herald Tribune. “We have done the studies and challenged the alarmists, but they continue to ignore the facts.”

http://www.slate.com/id/2142319/
“As a motion picture, An Inconvenient Truth has a lot to say, but contains little imaginative cinematography that might have made global warming engaging at the suburban cineplex. The picture the movie paints is always worst-case scenario. Considering the multiple times Gore has given his greenhouse slide show (he says “thousands”), it’s jarring that the movie was not scrubbed for factual precision. For instance, this 2005 joint statement by the science academies of the Western nations, including the National Academy of Sciences, warns of sea-level rise of four to 35 inches in the 21st century; this amount of possible sea-level rise is current consensus science.

Yet An Inconvenient Truth asserts that a sea-level rise of 20 feet is a realistic short-term prospect. Gore says the entire Greenland and Antarctic ice sheets could melt rapidly; the film then jumps to animation of Manhattan flooded. Well, all that ice might melt really fast, and a UFO might land in London, too. “

he said “NEAR FUTURE”:

I promise not to get hung up on quantification of ambiguous phraseology if you don't.

300 YEARS FROM NOW IS NOT “THE NEAR FUTURE”!

It d*mn sure is for the Earth's environment. The PETM warm-up (accidentally encountered on Discovery Channel last night, in fact) took 10,000 years -- and the geologist being quoted called it "extremely fast".

The only way to get ice sheets to melt is to have warming of over 5C for a long period of time.

So you're the ultimate expert on ice sheet stability the world has been searching for?

You seem to buy this phony idea that Gore is ‘justified’ if CO2 has any influence on the climate. The argument is not about that link - sure it is there, and doubling CO2 will likely increase temperatures, all other things being equal by as much as 1 - 1.5C. Most skeptics acknowledge there is a link but dispute the phony alarmism, question the data (Hansen’s bad data massaging), question the numbers, question the inability to acknowledge natural variability effects, etc.

To start, 1-1.5 C is a lower-bound estimate, favored by skeptics like Patrick Michaels who have sufficient scientific acumen to realize that they have to be somewhat honest about this. 2.5 to 3 C is the midrange. Regarding Gore, the question that point #5 in my profile focuses on is the supposed temperature-CO2 lag observed in ice core data during glacial-interglacial transitions. The basic skeptical argument is that this refutes the forcing role of atmospheric CO2 on climate (i.e., that global temperature increase is the full cause of increasing atmospheric CO2 concentrations in a glacial-to-interglacial transition). This is, borrowing your phrase, laughably wrong. The reason for the close correlation of CO2 and temperature in the ice cores is that once the transition has been initiated by Milankovitch forcing, increasing atmospheric CO2 drives subsequent warming. The recession of the continental ice sheets is ultimately a larger forcing factor, but this also is driven by the CO2-induced warming. (And this gets back to the ice sheet stability issue in a roundabout way.)

So Gore is not wrong to tie the ice core temperature and CO2 record to current trends in both. That was my point. And the judge in the British case doesn't know enough about climate science to understand this point. Neither do 99.8% (being generous) of the American populace.

How much of the variability in US temp from 1950 to 1975 was man-made?

That depends on the size of the sulfate aerosol forcing in the models, I would think. Because I only understand that in a qualitative sense, I can't provide a quantitative answer to this question.

I suspect if you did a documentary on the topic, you would be more accurate and less alarmist than Gore was.

And I'd probably be even more boring -- imagine that. By the way, RealClimate has a couple of articles on how accurate Gore's treatment of science in the movie was; and they find errors. The funny thing is, the real errors are not listed in the 11 inaccuracies of the British court case.

The basic inconvenient truth is that the world is facing pressing environmental problems. Global warming is one of them. It can make other more critical problems worse in the longer term. None of that comforts me. For me, alarmism equates with inducing a panic. In a crisis situation, panic results minimally in error and inefficiency, and maximally in enhanced danger and potential disaster. So there's no place for alarmism. There is a place for clear-eyed, unbiased realism. The global "we" has to determine with cool-headed collectiveness what the effective risk reduction, risk mitigation, and risk elimination strategies are.

A few see natural variation as more central to global warming than heat-trapping gases.

They are incorrect.

It highlighted 10 large swings, including the medieval warm period. These shifts, he said, were up to “20 times greater than the warming in the past century.”

To which I respond: if the NAS assessment was correct regarding the Mann hockey stick, then Don Easterbrook cannot state this with any degree of quantitative certainty. Furthermore, the global warming of the past century was ~0.6 C. Yes, that's not large. Add 1.8 C this century, just above the 1-1.5 C range you quoted favored by skeptics, is 3 times that rate. 1.8 C plus 0.6 C is 2.4 C in two centuries. Is that still a "small swing"?

Finally, to finish this regarding sea level rise in coming centuries:

"Ultimately, global warming is a moral problem rather than a purely scientific or economic one. We are enriching ourselves by the use of fossil fuels in ways that degrade and imperil the future of our children, grandchildren and all future generations.The more I think about it, the situation is like that of the people who launched the anti-slavery campaign in the late 1700’s. One of the group’s leaders, William Wilberforce, is a great hero of mine. When they began their efforts, people were getting rich by degrading the lives of the slaves brought over from Africa to work on the plantations in the West Indies and America. It must have seemed hopeless at first, faced by the opposition of corrupt parliaments and wealthy merchants and planters. Yet, these Abolitionists changed the world by the force of their moral argument and I believe that moral argument will win the day and lead to solutions for global warming."

Gore pretended that ice sheet melting and other effects are so imminent that that it would impact the people watching the mockumentary, not our great-great-great-great-great-great-great-great-grandchildren.

“So you’re the ultimate expert on ice sheet stability the world has been searching for?”

I’m merely reporting what the real experts have concluded and say ... see below. No real expert is predicting imminent ice sheet melting, and as you know, the IPCC estimates of sea level rise is around 40cm max by 2100. My only claim is that I am more educated, informed and knowledgeable than Al Gore (I’m a PhD in Comp Sci).

http://www.abc.net.au/rn/science/earth/stories/s101703.htm
“Alexandra de Blas: Will the melting of Greenland have an impact in the next few hundred years?

Garth Paltridge: Not very much, no. For much the same reason as Antarctica. These ice sheets on Greenland and Antarctica, they have an input of ice from the snowfall, and an output of ice, if you like, as the ice falls off the edges in the form of icebergs and so on, into the sea, and melts. We think as far as Antarctica is concerned, that over the next 100 or 200 years, the input of snowfall will increase faster than will the melting of ice on the edges, and so Antarctica may actually increase in size slightly, the ice sheet. Greenland we’re not absolutely certain, but it won’t change much we believe over the next 100 or 200 years.”

“... The reason for the close correlation of CO2 and temperature in the ice cores is that once the transition has been initiated by Milankovitch forcing,”

...which is a forcing impact that Gore *never* mentions!
Geez, none are so blind that refuse to see. You keep arguing a strawman here, while defending Gore, who does *not* say what you are saying about the matter.

And you still have the uncomfortable set of facts due to the science on this:
1. Warming caused some CO2 release in the past.
2. Ice age was initially driven by forces other than CO2.
3. Other feedback effects like albedo were more important and earlier than the CO2 changes.

“So Gore is not wrong to tie the ice core temperature and CO2 record to current trends in both.” - he was wrong not to acknowledge the science that shows that ice-age warming came prior to the CO2 rise.

“So That was my point. And the judge in the British case doesn’t know enough about climate science to understand this point. Neither do 99.8% (being generous) of the American populace.”

The Judge is yet another person who has more education than Al Gore.

How much of the temperature change from 1898 to 1901 was due to natural variability?

How much of the temperature change from 1998 to 2001 was due to natural variability?

Camille Paglia riffs on Gore:

http://wattsupwiththat.wordpress.com/2007/10/10/camille-paglia-on-fancy-pants-speculative-climate-models/

Commenter: I too grew up in upstate New York. I am an environmental groundwater geologist (who almost majored in fine arts). Your take on the Al Gore/global warming pseudo-catastrophe was right on target. Anyone can read up on Holocene geology and see that climate changes are caused by polar wandering and magnetic reversals. It is entertaining, yet sad to read bloviage from Leonardo DiCaprio, who is so self-centered that he thinks the earth’s history and climate is a function of his short personal stay on this planet. Still he, Al Gore, Prince Charles and so on, ad nauseam, continue with their jet-set lifestyles. What hypocrisy!

Hanson

Camille Paglia: Thank you for your input on the mass hysteria over global warming. The simplest facts about geology seem to be missing from the mental equipment of many highly educated people these days. There is far too much credulity placed in fancy-pants, speculative computer modeling about future climate change. Furthermore, hand-wringing media reports about hotter temperatures in the Northern Hemisphere are rarely balanced by acknowledgment of the recent cold waves in South Africa and Australia, the most severe in 30 years.

Where are the intellectuals in this massive attack of groupthink? Inert, passive and cowardly, the lot of them. True intellectuals would be alarmed and repelled by the heavy fog of dogma that now hangs over the debate about climate change. More skeptical voices need to be heard. Why are liberals abandoning this issue to the right wing, which is successfully using it to contrast conservative rationality with liberal emotionalism? The environmental movement, whose roots are in nature-worshipping Romanticism, is vitally important to humanity, but it can only be undermined by rampant propaganda and half-truths.

http://www.guardian.co.uk/environment/2007/oct/11/climatechange?gusrc=rss&feed=8

Nine fallacies in Gore’s film:

· The film claimed that low-lying inhabited Pacific atolls “are being inundated because of anthropogenic global warming” - but there was no evidence of any evacuation occurring

· It spoke of global warming “shutting down the ocean conveyor” - the process by which the gulf stream is carried over the north Atlantic to western Europe. The judge said that, according to the Intergovernmental Panel on Climate Change, it was “very unlikely” that the conveyor would shut down in the future, though it might slow down

· Mr Gore had also claimed - by ridiculing the opposite view - that two graphs, one plotting a rise in C02 and the other the rise in temperature over a period of 650,000 years, showed “an exact fit”. The judge said although scientists agreed there was a connection, “the two graphs do not establish what Mr Gore asserts”

· Mr Gore said the disappearance of snow on Mt Kilimanjaro was expressly attributable to human-induced climate change. The judge said the consensus was that that could not be established

· The drying up of Lake Chad was used as an example of global warming. The judge said: “It is apparently considered to be more likely to result from ... population increase, over-grazing and regional climate variability”

· Mr Gore ascribed Hurricane Katrina to global warming, but there was “insufficient evidence to show that”

· Mr Gore also referred to a study showing that polar bears were being found that had drowned “swimming long distances to find the ice”. The judge said: “The only scientific study that either side before me can find is one which indicates that four polar bears have recently been found drowned because of a storm”

· The film said that coral reefs all over the world were bleaching because of global warming and other factors. The judge said separating the impacts of stresses due to climate change from other stresses, such as over-fishing, and pollution, was difficult

Let me make this point. I don’t really see that it matters if GW is occurring. Why?

1) If it is, and it is natural (IOW, not man), then we simply must adapt.

2) If it is, regardless of the cause, and it is happening as quickly as the doom sayers claim, then we are SOL.

3) If it is, and man is causing it, there is no way mankind can change enough things to the degree necessary to make any difference whatsoever.

4) If it is not, then 1 through 3 don’t matter anyway.

Disclaimer- I don’t believe anything of significance is happening, and that what is happening is inevitable anyway.

Nonetheless, what I believe in that regard is not even relevant because of my 4 points above.

“Furthermore, the global warming of the past century was ~0.6 C. Yes, that’s not large. Add 1.8 C this century, just above the 1-1.5 C range you quoted favored by skeptics, is 3 times that rate. 1.8 C plus 0.6 C is 2.4 C in two centuries. Is that still a “small swing”?”

The direct effect of CO2 forcing is only around 1C/doubling or so. the rest is positive feedback effects due to water vapor and clouds.

Do those numbers include the recent science that determined experimentally the cloud feedback effects from great water vapor? To wit:

http://www.uah.edu/news/newsread.php?newsID=875

Those estimates are not reliable if they do not. And as you know, cloud cover is the least reliable aspect of climate science... There is no reason to call 1.0-1.5C a ‘low range’ when in fact it may be the high range of actual 2000-2100 changes.
Further, the 0.6 warming is due to 40% increase in CO2, so a similar 80% increase in CO2 from 2000 to 2100 (viz 5.35 logC1/C0 effect) would only be another 1.2C, not 1.8C.

These swings of under 2C total are indeed smaller than the cited paleo-climate shifts observed by early man.

“By the way, RealClimate has a couple of articles on how accurate Gore’s treatment of science in the movie was; and they find errors. The funny thing is, the real errors are not listed in the 11 inaccuracies of the British court case.” LOL, again with the circularity of citing RealScience. That’s like citing the NYTimes ombudsman on whether the NYTimes is biased.

Sorry for the delay; and I likely won't be able to continue until Tuesday. (Maybe late Sunday, not sure.) So we can simmer or cease.

I'll be quoting extensively from this, because it provides information I did not have:

An 'error' is not the same thing as an error

Gore shows sea level rise scenarios if Greenland and WAIS significantly collapsed. The IPCC says:

"Recent satellite and in situ observations of ice streams behind disintegrating ice shelves highlight some rapid reactions of ice sheet systems. This raises new concern about the overall stability of the West Antarctic Ice Sheet, the collapse of which would trigger another five to six metres of sea level rise. While these streams appear buttressed by the shelves in front of them, it is currently unknown whether a reduction or failure of this buttressing of relatively limited areas of the ice sheet could actually trigger a widespread discharge of many ice streams and hence a destabilisation of the entire West Antarctic Ice Sheet. Ice sheet models are only beginning to capture such small-scale dynamical processes that involve complicated interactions with the glacier bed and the ocean at the perimeter of the ice sheet. Therefore, no quantitative information is available from the current generation of ice sheet models as to the likelihood or timing of such an event." [Similar things can be said about the Greeland ice sheet, which appears to be even more affected by warming polar temperatures.]

I previously provided other links about this issue. Because there is uncertainty about ice sheet dynamics, there is also disagreement about what might/could/will happen. As the saying goes, more data is needed. And there's no certainty regarding fast or slow ice sheet collapse likelihood. I wish there was.

which is a forcing impact that Gore *never* mentions! Geez, none are so blind that refuse to see. You keep arguing a strawman here, while defending Gore, who does *not* say what you are saying about the matter.

I haven't seen the movie. Gore does say, according the linked article:

"The relationship is very complicated. But there is one relationship that is more powerful than all the others and it is this. When there is more carbon dioxide, the temperature gets warmer, because it traps more heat from the sun inside" [the climate system or atmosphere, I presume -- unfortunate quote cutoff]

Which is correct. Which is what point #5 in my profile expands on. The complicating aspects are partly the triggering aspect of weak Milankovitch forcing. Gore's movie and Powerpoint weren't designed or intended to be rigorous scientific presentations. So saying "the relationship is very complicated" covers a lot of pertinent research findings.

1. Warming caused some CO2 release in the past.
2. Ice age was initially driven by forces other than CO2.
3. Other feedback effects like albedo were more important and earlier than the CO2 changes.

You characterize these as an "uncomfortable set of facts". And yet you know the approximate direct effect of doubled CO2 on global temperatures will be about 1 C, augmented by positive feedback processes, notably water vapor increase (just supported in a new publication, by the way). So they are not "uncomfortable" at all; they are part of the body of knowledge of how the climate system has worked in the past and how it is being affected by anthropogenic factors now.

The Judge is yet another person who has more education than Al Gore.

I'll certainly grant that regarding the nuances of British jurisprudence; given his interpretation of the science evinced in the decision (read the article I linked), I'll certainly not grant that regarding climate science.

How much of the temperature change from 1898 to 1901 was due to natural variability? ... How much of the temperature change from 1998 to 2001 was due to natural variability?

Quantitative answers to this question are impossible. There was less anthropogenic forcing present in the earlier time period than the latter. However, variability in the latter period was dominated by El Nino -- La Nina events in the Pacific Ocean. If that variability is removed, there is a consistent approximately 0.2 C per decade warming trend that is predominantly due to anthropogenic forcing factors since about 1975.

The direct effect of CO2 forcing is only around 1C/doubling or so. the rest is positive feedback effects due to water vapor and clouds.

Thank you. Yes, of course that's correct.

Do those numbers include the recent science that determined experimentally the cloud feedback effects from great water vapor?

My numbers (the lowball +1.8 C globally for this century) are based on the IPCC ranges we've discussed earlier. Since Spencer and Christy and cohort's paper is very recent, neither the robustness of their result or the effect on climate modeling/climate prediction has been evaluated, so the answer is no. But... Lindzen's Iris effect has been contradicted by other research, and I judge from cursory reading that this result is similar. It needs to be tested. Spencer was way off regarding his evaluation of Fu et al., so I hope he's more careful here.

There is no reason to call 1.0-1.5C a ‘low range’ when in fact it may be the high range of actual 2000-2100 changes.

My evaluation is based on comparison of that range to the IPCC scenarios. I know Pat Michaels likes 1-1.5 C, and given his bent and opinions, I figure he's going to advocate the lowest numbers as much as he can. So I went with a number between 1.5 and 2 C, the latter the low end of the IPCC scenarios (and conveniently 3x more than 20th century warming).

These swings of under 2C total are indeed smaller than the cited paleo-climate shifts observed by early man.

Checking back, Easterbrook's figure covered the last 15,000 years. That includes the final warming out of the last glacial period, the Younger Dryas, the 8200-year event, and the subsequent unusual stability of the Holocene. The first three events were larger than a 2.4 C warming over two centuries. The warming took a much longer time; the Younger Dryas entry and exit were very fast (due to ocean circulation mode changes), and the 8200 year event was similarly fast, it seems. Other than that, if you look at ice core records, there aren't any other bigger and faster shifts than 2.4 C in two centuries. Unfortunately, due to the reevaluation of the Hockey Stick, we don't know anything with quantitative accuracy about the MWP temperatures. Timing-wise, though, the rise to peak MWP conditions and the subsequent fall to peak LIA conditions appear to happen over 3-4 centuries, depending on what milestones are examined, rather than 1-2 centuries.

Thanks for a nice dialogue, despite our differences of opinion. I hope to be able to respond to you (if you care to respond to this) in a few days.

Skol!

My problem with Gore, to put it in blunt terse terms, is that he presents a highly unlikely worst-case scenario as an expected outcome if-we-dont-act-right-now.

This is what I call scaremongering.

Could it all happen? That’s the point you are defending and, yeah, sure it could happen - if a lot of things that I dont believe will happen end up happening. Given what I’ve learned of the carbon cycle and the vapor and cloud feedbacks, and the errors in the science (eg Mann’s hockey stick that is as much an artifact of statistical bias as it is a real record of temps), I have to conclude that ‘skeptics’ who think the effects are smaller than IPCC avg estimates are right. There has been too much incentive to skew the science in the IPCC to worst-case, and skeptics have noted how IPCC has cherry-picked some results.
IPCC raises concern, but doesnt mention that both measurements and models indicate no net loss of ice in antartica on balance, etc.

Yet even if IPCC is right, we are talking about a significant warming impact required to make this happen anytime soon, where ‘soon’ means 100 years or more.

BTW, I’ve posted previously about ‘deltoid’s’ own biases on things. he’s a Bush-basher among other things. You have a coterie of folks defending the orthodoxy here, and it doesn’t impress me to defend one member of the coterie with the words of another ...

Example: we get stuff from Deltoid like “Gore does not ascribe Katrina to global warming “ ... No, we get pictures of Katrina and the implicit connection tha global warming equals more katrinas ... “Katrina is used as an example of the damage that stronger hurricanes” ... yada yada yada. So Gore shows katrina and says that global warming causes stuff like that, and impressionable people don’t come out of the theatres thinking global warming causes Katrinas?
C’mon that is classic propaganda technique. Humans think in terms of associations. I could splice Hitler at Nuremberg and Hillary on the campaign trail and say nothing, and *of course* people would say I compared Hillary to Hitler. Rightly so. Same thing here.

Gore is peddling Global warming=katrina association. Which btw is not based on sound science despite Lambert’s protestations.

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