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The weirdest millennium

Filed under: — stefan @ 29 May 2007

Much research effort over the past years has gone into reconstructing the temperature history of the last millennium and beyond. The new IPCC report compiles a dozen reconstructions for the temperature of the Northern Hemisphere (including of course the original “hockey stick” reconstruction, despite opposite claims by the Wall Street Journal). Lack of data does not permit robust reconstructions for the Southern Hemisphere. Without exception, the reconstructions show that Northern Hemisphere temperatures are now higher than at any time during the past 1,000 years (Figure 1), confirming and strengthening the conclusions drawn in the previous IPCC report of 2001.

Fig. 1: Figure 6.10 (panel b) from the paleoclimate chapter of the current IPCC report (see there for details).

“Climate sceptics” do not like this and keep coming up with their own temperature histories. One of the weirdest has been circulated for years by German high-school teacher E.G. Beck (notorious for his equally weird CO2 curve). This history shows a medieval warm phase that is warmer than current climate by more than 1 ºC (see Figure 2). So how did Beck get this curve?


Fig. 2, modified from E.G. Beck (we added the green parts).

The curve is a fake in several respects. It originally is taken from the first IPCC report of 1990: a scan of the original is shown in Figure 3. At that time, no large-scale temperature reconstructions were available yet. To give an indication of past climate variability, the report showed Lamb’s Central England estimate. (Unfortunately this was not stated in the report – an oversight which shows that IPCC review procedures in the early days were not what they are now. We will post in more detail on the history of this curve another time.)


Fig. 3. The past millennium as shown in the first IPCC report of 1990, before quantitative large-scale reconstructions were available. This curve was based on Lamb’s estimated climate history for central England.

But Beck did not stop at simply using this outdated curve, he modified it as highlighted in green in Figure 2. First, he added a wrong temperature scale – the tick marks in the old IPCC report represent 1 ºC, so Beck’s claimed range of 5 ºC exaggerates the past temperature variations by more than a factor of three. Second, the original curve only goes up to the 1970’s. Since then, Northern Hemisphere temperatures have increased by about 0.6 ºC and those in central England even more – so whatever you take this curve for, if it were continued to present, the current temperature would be above the Medieval level, as in the proper reconstructions available today. As this would destroy his message, Beck applied another fakery: he extended the curve flat up to the year 2000, thereby denying the measured warming since the 1970s. With this trick, his curve looks as if it was warmer in Medieval times than now.

When approached directly about these issues, Beck published a modified curve on a website. He changed the temperature range from 5 ºC to 4.5 ºC – but he shortened the arrow as well, so this was just cosmetics. He also added instrumental temperatures for the 20th Century at the end – but with his wrong temperature scale, they are completely out of proportion. (In fact his version suggests temperatures have warmed by 2 ºC since 1900, more than twice of what is actually observed!)

Beck goes even further: in a recent article (in German), he has the audacity to claim that his manipulated curve is right and the more recent scientific results shown by IPCC are wrong. And for years, he has offered his curve on an internet site (biokurs.de) that distributes teaching materials for schools, with support from German school authorities. It is quite likely that his fake curve has been shown (and will continue to be shown) to many school children.


507 Responses to “The weirdest millennium”

  1. 151
    Tavita says:

    Here’s a bit more data concerning the Southern Hemisphere. It doesn’t bode well for Beck as it seems to show that the medieval warming period wasn’t so warm there and the little ice age wasn’t so cool.

    Here’s the abstract:

    Pacific archaeologists, geographers, and other social scientists have long used a model of Late Holocene climate change based largely on other regions of the world. In high-latitude regions, two major climate periods have been recognized: the Medieval Warm Period, dated to ca. AD 9001200, and the Little Ice Age, dated to ca. AD 15501900. However, new evidence from long-lived Pacific corals, along with more general climate modelling, suggests that while the rest of the world was experiencing the Medieval Warm Period, conditions in the tropical Pacific were cool and possibly dry. Similarly, during the Little Ice Age the central Pacific was comparatively warm and wet and stormy conditions more common. A significant body of new evidence points to substantial climate variability in the central Pacific over the past millennium. Changing background climate, El NiñoSouthern Oscillation variability, and the potential for regional variation are here considered with an eye to understanding the potential influence of climate on prehistoric human populations in the central Pacific region.

    Here’s the link:

    http://www.journals.uchicago.edu/cgi-bin/resolve?id=doi:10.1086/504168&erFrom=-2591966302784330799Guest

    I thought you all might find it of interest.

  2. 152

    No. I am not a denier. I just don’t think that the evidence is conclusive, at least not to a layman.

    And until you tell us why you think the evidence is inconclusive, by providing your own evidence which justifies its inconclusiveness, then you are firmly in the denier camp. Those are the facts, you just can’t say you are skeptical without providing evidence, and maintain your credibility at the same time. Skepticism without evidence, and credibility, are mutually exclusive, get it?

  3. 153
    Rod B says:

    “That makes you a denier. A skeptic must present evidence to back up their claim of skepticism.”

    That’s just bass ackwards. A skeptic is one who sees the arguments but still has valid questions about its veracity. He may have the capability to question the science but not have contrary scientific evidence. Or he can have reasonable doubts with the process, which logically taints the process’ conclusion. [99% of financial analysts say the market will go up -- usually is a sure sign it's going down.] It’s the denier that ought to have some evidence of refutation.

  4. 154
    Hank Roberts says:

    I think that’s not helpful, Mr. Elifritz. Kroganchor has asked some good questions; we can’t guess his age or education or background from them but so far they’ve been quite basic ones (like why is the ocean so cold since the core of the planet is hot and so is the air —- a question that takes a bit of physics to decide or believe). The Contributors here are good at figuring out where to start, with someone, after a while, and set a good example for visistors like you and me who. Take some time to try to get to know people when they arrive declaring themselves, see who’s willing to learn how to learn. Curiousity furthers.

  5. 155
    Timothy Chase says:

    Kroganchor (#145) wrote:

    No. I am not a denier. I just don’t think that the evidence is conclusive, at least not to a layman.

    Well, I could outline the basics within a single post.

    We know that given the distance of the earth from the sun, if it weren’t for the greenhouse effect, the earth would be below freezing – approximately 0 F. However, the atmosphere is able to diminish the rate at which the earth would radiate heat back into space. The process works in the following manner.

    1. For the earth to be in thermal equilibrium, with its temperature neither increasing nor decreasing, the amount of thermal energy entering the system has to be equal to the amount of thermal energy leaving the system, where the system consists of the ocean, the atmosphere and the ground. We know this because energy must be conserved.
    2. Humans have been putting more carbon dioxide into the atmosphere than can be absorbed by various natural processes. (We know that it is our carbon dioxide which has been entering the atmosphere because of isotopic analysis – the carbon we put into the atmosphere has an extra neutron – making it heavier. This is one of the “smoking guns.”
    3. Now sunlight enters the system, some of it striking either the ocean or the land. At this point we should note that the amount of sunlight entering the system is roughly constant.
    4. When it strikes either ocean or land, some of the energy is absorbed, causing them to heat up.
    5. When objects heat up they emit thermal radiation.
    6. Some of this thermal radiation is absorbed by the atmosphere, causing it to heat up, then re-emitted.
    7. We know the reason why it is absorbed by the atmosphere. Various gasses are opaque to thermal radiation at various wavelengths. Moreover we are able to study this in the lab.
    8. When such thermal radiation is re-emitted by the atmosphere some of it is absorbed by either the ground and water, and some of it leaks to space. The amount of each is roughly half because either it goes up to space or back down.
    9. As it is absorbed by the ground or water this causes the ground or water to heat up more, rising in temperature, emitting more thermal radiation, which is then either absorbed by the the atmosphere or leaks into space.
    10. As the water heats up, some evaporation takes place, adding to the amount of water vapor in the atmosphere, and water vapor will also absorb thermal radiation at specific wavelengths, causing the atmosphere to heat up further and emit more thermal radiation. As such, this is a positive feedback. Moreover, water vapor is a much more effective greenhouse gas.
    12. However, unlike carbon dioxide, water vapor tends to remain in the atmosphere for a much shorter period of time because it will tend to condense into clouds, falling as precipitation either in the form of rain or snow.
    13. Since carbon dioxide tends to remain in the atmosphere for a much longer period of time, the amount of carbon dioxide which is in the atmosphere will regulate the amount of water vapor is in the atmosphere.
    14. Given the greenhouse gasses which are in the atmosphere, the temperature of the system will ultimately rise to the point at which the thermal radiation leaving the system is equal to the amount of thermal energy leaving the system.

    However, there are various feedbacks involved.

    A few are:

    1. Convection. Where hot air rises, shortening the distance that thermal radiation has to travel in order to leak into space. When this happens there will be less re-emission and absorbtion occuring between the atmosphere and itself. As such, this will increase the rate at which thermal radiation leaves the system. As the temperature rises, more convection takes place, therefore this is a negative feedback.
    2. The albedo effect. When thermal energy is absorbed by ice or snow, some of it will melt, reflecting less light back into space and permitting more thermal radiation to enter the system when light is absorbed by either the dark ground or dark ocean, but as the system warms, resulting in positive feedback.
    3. The reduction in the capacity for the ocean to hold carbon dioxide. As the the ocean heats up, it is less able hold either carbon dioxide or oxygen, and therefore the amount of carbon dioxide which remains in the atmosphere will increase. Currently the ocean is still absorbing most of the carbon dioxide which we emit, acting as a sink, but it absorbs less and less each year. At some point it will have warmed enough that it will start releasing the carbon dioxide which it already has, becoming an emitter.
    4. The melting of the permafrost. When permafrost melts, the organic material which was frozen will decay, releasing methane and carbon dioxide into the atmosphere. Since both methane and carbon dioxide are greenhouse gases, this is a form of positive feedback.
    5. Heat stress in plants. The more the temperature rises, the less effective they will be at absorbing carbon dioxide.
    6. Stress on plants due to drought. The more the temperature rises, the more quickly water will evaporate, reducing the amount of water which will be available to plants and thereby reducing their capacity for absorbing carbon dioxide.

    Currently the net effect of the feedbacks is positive as the earth has moved away from the equilibrium which it was in and has to find a new equilibrium. Moreover, as we put more carbon dioxide into the atmosphere, the net effect is to push us further from equilibrium, increasing the temperature which the earth has to reach before it is able to radiate enough thermal energy to balance the thermal energy which is entering the system. As positive feedbacks, the more carbon dioxide which enters the system, the worse they will get.

    At each step, we are able to quantify what is going on, and there have been a great many empirical studies. Enough to convince the vast majority of scientists, and every major science organization which has seen fit to take a position on this. What few reasonable alternative explanations may have existed at one time for the increasing temperature of the earth have been eliminated, i.e. they are no longer reasonable and are kept alive only by special economic or ideological interests which are playing people for fools. However, this does not change what is happening to the earth, or the extent of the threat which faces humanity as it continues to emit more carbon dioxide each year.

  6. 156
    Jim Eager says:

    Re 142 Krogancho: “I am a skeptic. Not being sufficiently educated to understand the science, I must form an opinion from the conclusions of others.”

    Then perhaps you might want to educate yourself about the science more so that you can understand it better. And in the mean time, I suggest that you choose your ‘others’ very carefully. Make sure that they actually have at least as good an understanding of the science as do the scientists whose research is presented here and through the IPCC. Most important, be equally skeptical about their arguments, and make sure that their ‘evidence’ is not easily debunked by the facts and data and by well understood scientific principles.

  7. 157
    Tim Jones says:

    James Hansen must be particularly annoyed with Mr.Griffin’s backstabbing when on May 29th this was published:

    NASA: Danger Point Closer Than Thought From Warming
    http://abcnews.go.com/Technology/story?id=3223473&page=1

    ‘Disastrous Effects’ of Global Warming Tipping Points Near, According to New Study
    By BILL BLAKEMORE
    May 29, 2007 �

    Even “moderate additional” greenhouse emissions are likely to push Earth past “critical tipping points” with “dangerous consequences for the planet,” according to research conducted by NASA and the Columbia University Earth Institute.

    With just 10 more years of “business as usual” emissions from the burning of coal, oil and gas, says the NASA/Columbia paper, “it becomes impractical” to avoid “disastrous effects.”

    The study appears in the journal Atmospheric Chemistry and Physics. Its lead author is James Hansen, director of NASA’s Goddard Institute for Space Studies in New York.

    The forecast effects include “increasingly rapid sea-level rise, increased frequency of droughts and floods, and increased stress on wildlife and plants due to rapidly shifting climate zones,” according to the NASA announcement.

    Recent Climate Reports Underestimated How Soon

    By heralding the new research paper, NASA is endorsing science that places considerably more urgency on the need to reduce emissions to avoid “disastrous effects” of global warming than was evident in the recent reports from the world’s scientists coordinated by the Intergovernmental Panel on Climate Change.

    The new NASA release emphasizes the danger of “strong amplifying feedbacks” pushing Earth past “dangerous tipping points.”

    Scientists have been warning for several years that such tipping points are the greatest threat from manmade global warming and what makes it potentially catastrophic for civilization.

    ‘Potentially Uncontrollable’ Feedback Loops

    As the tipping points pass, “there is an acceleration, potentially uncontrollable, of emissions of vast natural stores of greenhouse gas,” according to Hansen, who reviewed the study for ABC News today.

    Hansen explains that dangerous feedback loops are being tracked in various regions of the planet.

    Many studies have reported feedback loops already observed in thawing tundra, seabeds and drying forests.

    Hansen also points out that dark and therefore heat-absorbing forests are now expanding toward the Arctic, replacing lighter-colored areas such as tundra and snow cover.

    The NASA research also reasserts the importance of the disappearing Arctic sea ice and snow, whose reflectivity has helped cool the planet by bouncing warm sunlight straight back into space.

    The disappearance of that bright sea ice and snow is uncovering more and more dark water and bare ground creating another dangerous feedback loop.

    These feedbacks all produce more heat, thus all reinforcing each other, leading to evermore thawing and thus releases of natural greenhouse gases (including CO2 and methane) in a viciously accelerating circle.

    450 Parts Per Million

    The recent IPCC summaries entertained “scenarios” of CO2 concentrations in the atmosphere ranging from 450 parts per million (ppm) up through 550 ppm and 650 ppm.

    This new research says “C02 exceeding 450 ppm is almost surely dangerous.”

    Hansen told ABC News today he believes the upper limit for avoiding dangerous climate change “could well be much lower” than 450 ppm.

    In the NASA announcement, Hansen said, “‘business as usual’ emissions would be a guarantee of global and regional disaster.”

    Earth’s CO2 concentration is currently 383 ppm, up from 280 ppm at the start of the industrial age.

    Studies released earlier this month report human-made emissions now spiraling upward at an accelerating rate much faster than scientists expected only a few years ago.

    The NASA release points out that a 1992 treaty was “signed (and ratified) & by the United States and almost all nations of the world,” which “has the goal to stabilize atmospheric greenhouse gases ‘at a level that prevents dangerous human-made interference with the climate system.’ ”

    NASA says this new study thus helps “define practical implications” of that 1992 treaty the United Nations Framework Convention on Climate Change.

    The study says that “only moderate additional climate forcing (which would mean only moderate additional warming from such emissions) is likely to set in motion the disintegration of the West Antarctic ice sheet” dubbed WAIS by polar scientists.

    Many scientists say a disintegration of WAIS would mean catastrophically rapid sea-level rise.

    The NASA/Columbia study is co-written by 48 scientists in the United States and France.

    end quote

  8. 158
    Mark A. York says:

    Boy, you can’t make this stuff up. Well, they can. Amazing what some will do, but they make nice archetypes for antagonists.

  9. 159
    Jim Eager says:

    Re 150: For the most part I agree with John Mashey’s comments about different motivations and degrees of skepticism and denial, and that they need to be addressed differently.

    In my experience when discussing climate change on general public message boards there are outright deniers who have already decided what their position is and who will seize on any and all arguments that seem to support their position or undermine its opposite, no matter how ludicrous the idea or how poorly they understand what their ‘evidence’ means or does not mean. It doesn’t really matter if they are from John’s type a group and bent on actively and deliberately sowing doubt and confusion, or from the type b1 group and simply repeating the type a arguments through ignorance or ideological loyalty. It is simply a waste of time responding to this sort of denier directly, beyond posting a brief message demonstrating how their particular assertion is simply wrong, with a link to evidence if possible, and even then mainly for the benefit of others reading or participating in the thread.

    However, I have found that it is possible to carry on a civil and intelligent conversation with honest skeptics who fall into John’s type b2 group. Indeed, it is even possible to convince some of them one step at a time using the arguments and information posted here at RealClimate and other science sites. In the process you also better educate others reading or participating in the thread. Frankly I’m often as appalled by the lack of knowledge of some of those who accept the idea of AGW as I am by that of skeptics. Simple stuff, like the fact that water vapor is a greenhouse gas, or that historically CO2 rise has followed temperature rise, or that the sun really does drive climate, even with the greenhouse effect. In fact, I’ve found that correcting these misconceptions increases your credibility with skeptics, which may in part be why they become more amenable to understanding the science better as they discuss it.

  10. 160
    Timothy Chase says:

    Thomas Lee Elifritz (#152) wrote:

    Skepticism without evidence, and credibility, are mutually exclusive, get it?

    In the case of someone who is simply uninformed (which he self-admittedly is not), there is one other possibility: that they simply do not wish to know more due to lack of interest.

    They either can’t see the consequences of action or inaction, the lives which are at stake or the implications for the economy if we continue with business as usual vs the implications for the economy if we try to reduce the carbon emissions. However, if this is due to difficulty understanding the science, it can be explained at an even simpler level than I have just done, even at the level that a ten year old could grasp the principles involved. If it is due to their no being convinced by the science, they should be willing to learn more – given the stakes. If it is due to lack of interest, then there is no reason to expect them to participate in the debate.

    They can propose alternative explanations – and as those alternative explanations have been dealt with, we should be able to point them to the relevant literature. They can argue that a particular mechanism does not work. We can show them otherwise. They can argue that the empirical evidence is not strong enough. We can demonstrate otherwise.

    In logic the alternatives are quite limited.

  11. 161
    John Mashey says:

    #145, #152:
    it’s been years since I managed cognitive psychologists, but we could probably some here, as expertise in studying learning and belief systems would be helpful in a blog whose goals include education.
    Google: cognitive psychology beliefs inventory

    Thomas: do you think your approach will actually convince Kroganchor?
    100%-NOT (denier) and NOT-PROVEN are at least sometimes different viewpoints.

    Kroganchor: you seem at least open to data (you write of next decade confirming/disconfirming AGW, whereas for a real denialist, NO data will ever confirm AGW (or more precisely, doing anything to lessen fossil fuel use). Note that AGW’s existence/non-existence should be a science question, whereas “and we should do something about it” is a policy question, i.e., not for RC.

    But briefly, in the way of beliefs inventory, help us understand where you’re coming from:

    a) How long have you been following AGW?

    b) How much have you read/seen, and do you have a couple specific favorite sources that you find credible and understandable?

    c) Where are you located? [Since it is clear there is a strong geographic component to AGW beliefs. Amongst US states, Californians and Floridians(~80%) think AGW is real, and will cause trouble, whereas people in some states are less concerned. Likewise, in Canada, I think the overall average is about the same, but Albertans are noticably less concerned. Alberta has lots of fossil energy and no coasts.] I won’t ask political affiliation, but it is notable that people’s opinions about a scientific question are somewhat correlated with their political affiliation, i.e., a higher percentage of Democrats & Independents think AGW is real than do Republicans.

    d) For instructive comparison, how familiar are you with the history of the tobacco industry and its approach to science, i.e., smoking/cancer linkage? {That may seem a weird question, but it isn’t.]

  12. 162

    A skeptic is one who sees the arguments but still has valid questions about its veracity.

    Of course, but that’s a circular argument, because the question must to be based upon evidence, which implies a familiarity with the subject, and most importantly, questions must be asked. To just come into an open forum and state ‘I am a skeptic’ without any justification or inquiry, is denialism.

    Evidence in science is like energy in physics. It can take many forms, it evolves, yet it is still conserved.

  13. 163
    Timothy Chase says:

    Thomas,

    My apologies.

    Looking over what I posted (#160), I noticed that we had actually said they same thing, only I had been more wordy. I am afraid that my enthusiasm sometimes gets the best of me.

  14. 164
    Kroganchor says:

    RE #156
    Thanks, I am too old and dumb get a degree in physics. I appreciate the other comments responsive to my post. In the last year I have gone from being AGW 20/80 to AGW 80/20% as a result of reading RC and other sites.

  15. 165
    Figen Mekik says:

    Perhaps being an educator myself, it bothers me when people try to pigeon hole others as “understands the science,” or “skeptic” or “denialist.” Judging people based on what category we think they belong educates no one and serves no constructive purpose. People’s ideas and perceptions evolve with how much they know and come to realize. And this goes for everyone. Even your most accomplished nuclear physicist probably has plenty to learn about physics. Any one who doesn’t appreciate that, doesn’t appreciate scientific curiosity and progress. Sorry to sound like a Greek philosopher but realizing what you don’t know is what drives scientific knowledge forward, not grouping people into categories, taking an “us vs them” attitude or trying to one-up each other with rhetoric.

  16. 166
    ray ladbury says:

    Kroganchor and other skeptics, can you see why I as a physicist, confronted with a system with increasing energy, pretty much have to believe in anthropogenic causation? I mean something must be increasing the energy of the system, right? We can quickly dismiss the #1 source of energy for climate, since solar irradiance has not increased enough to come even near explaining the increase in the energy of the climate. As a physicist, my next move is to look at the nest most important energy source for the climate–the greenhouse effect. The most important greenhouse gas is H2O. Could this be the culprit? Right away, I notice problems. H2O content varies considerably both spatially and temporally, and its residence time is measured in days–not really the characteristics you’re looking at when trying to explain an effect that persists over many years. It also hasn’t increased nearly enough, since further increases, increase warming only logarithmically. The next most important greenhouse gas is CO2. Hmm. A 40% increase over the period where we have experienced the warming. And the upper troposphere and stratosphere are dry compared to the lower troposphere where the effects of water are dominant. Could CO2 be playing the role of a second blanket over the bed on a cold night? Very plausible. And notice that not once have I consulted a computer model–all I’ve done is look at the known physics. Is there any other contributor that is likely of comparable magnitude to this. Well other greenhouse gases are much less important, have much shorter dwell times in the atmosphere, and contributors other than the greenhouse effect are small. Only now do we consult computer models of the global climate to find out if the possible effect of the CO2 is big enough to explain what we are seeing, and lo and behold, it is.
    Now we ask whether there might be reason to be concerned. Well, yes, anthropogenic greenhouse gas emissions increase exponentially, and they are nowhere near saturated and are expected to increase logarithmically for some time to come. Certainly, such warming will be sufficient to melt much of the polar ice, causing sea levels to rise. More than 20 years of data confirm that if anything, this trend has been underestimated! There are other reasons for concern. We are seeing strange weather patterns that persist longer than we would tradiationally expect–e.g. drought in Australia and the western US. Extinction rates among sensitive species such as amphibians are rising. None of these things by themselves would have the finger print of global climate change, but so many things happening globally while we see behavior consistent with such oddities in the climate models. And there is more. Paleoclimate records show the past 10000 years to be a time of exceptional climatic stability. It also happens to be the time when we have developed all of human civilization. There is certainly evidence that many of our crops could have trouble in a warmer drier world, while many invasives, weeds and pests would do quite well. There is certainly evidence to believe that many human activities could be harmed–perhaps greatly so.
    Now I do not like the implications of this theory that humans are altering the climate. Nevertheless, as a physicist and a scientist, what choice do I have but to act in accord with the evidence available to me? I would have to throw out everything including my belief in conservation of energy to do otherwise. So do you see why the overwhelming majority of scientists familiar with climate studies are concerned?

  17. 167
    Timothy Chase says:

    Re Kroganchor (#164)

    On a personal level…

    Undoubtedly there will be a great deal I will never fully understand. Quite honestly, I think it is probably just a little larger than any one mind can handle. And I am no expert.

    But I have seen the diagrams. I have seen a fair number of the scientific studies. And I know that the question isn’t whether or not anthropogenic climate change is taking place, but “How bad is it going to get?” Part of the answer to this question involves the positive feedbacks, some of which we know about others that we don’t. For example, we know that the ocean is already losing its ability to absorb much of the carbon dioxide that we put out. We know the permafrost which has been frozen for centuries is melting – and in the process beginning to release methane and carbon dioxide. And it appears that plants are already losing their capacity to absorb much of the carbon dioxide that we put out, at least during the warmer, drier years.

    I have also seen plenty of photos of what is happening to the glaciers and motion images of how the arctic polar ice has been melting over the past several decades – with the way it swirls around throughout the year, it looks like it is going down the drain, and it is disappearing much more quickly than they expected. Nearly every time I see something new about climate change, it is about how scientists have been too conservative in their projections, how they have underestimated the problem we face and how rapidly the positive feedbacks would kick in so that the process will take on a life of its own. They are worried – and that worries me. Our best minds and best models are telling us that we can’t wait ten more years for more evidence – and we have already waited twenty only to see that the best model we had (scenario B – the one that Hansen argued was the most probable at the time) from back then with the computer power they had at the time – was pretty much right on target.

    But the width and breadth of evidence available has grown a great deal since then, the methods have become more sophisticated, and the computers far more powerful. For just one chapter alone of the IPCC WG1 AR4 cited well over six hundred peer-reviewed studies backing up its conclusions. Just a few years ago, the NEC Earth Simulator was doing a trillion calculations a second. We could wait a little longer just to be a little more certain, that we have just a little more computer power, and have even more evidence than we do now, but to what effect? The longer we wait, the more difficult it will be to adjust course – and the more we will need to adjust course. And at this point our best minds are saying that if we don’t start adjusting our course now, that if we wait another ten years, we are going to be locked into a trajectory they would very much like to see us avoid.

    Whether one is looking at this in terms of the effects upon our water supply agriculture, the disintegration of the base of the ocean ecology and its effects upon fish harvests, the larger algae blooms which are already being swept into the coast lines just as our models said they would, the dying coral reefs or the effects upon the economy in the coming decades, this is something we need to start working on now, not ten years from now. They are saying that the longer we wait, the harder it is going to be, and in my personal judgment, given what I know, I know that they are right.

    Anyway, like you there are limits to what I can understand, and I also suspect that there is a great deal to this that I won’t be around to see, probably even the fair majority of this century. But I know this is going to be really tough on a lot of people. And if I can do any thing in my power to help, I am going to try to make sure that it won’t be any tougher on them than it has to be.

  18. 168
    Timothy Chase says:

    PS

    To my recent post to Kroganchor…

    In all honesty, having been opposed to doing something about climate change, although probably a great deal less than I was a while back, I think you are probably in a much better position than many to do something about it. You have some understanding of why people might be opposed to doing what must be done. I suspect you will stand a much better chance of explaining to them what they need to understand in terms that they will understand so that they can make the right choices.

    Something worth thinking about, perhaps.

  19. 169
    iswad says:

  20. 170
    Craig Allen says:

    The politicians are dodging and weaving around climate change denialism/realism everywhere at the moment it seems.

    In Australia in the build up to our federal election later this year, the head-kicking, dodging and weaving has started to get frenzied. Our economy is humming along. We’re rolling in money. And an unprecedented drought has been giving us grief for years. So climate change and the environment are front-and-center in the national debate.

    The following news articles give you the low down of where we are at right now.

    * Australian government finally concedes to that climate change is real and begins to makes plan to catch up with public opionion, opposition and state government policy by implementing a carbon trading scheme.

    * Opposition 20 points ahead in the polls, with climate change a major driver of opinion.

    * Having given up on the federal government, Australian state governments proceed with national emissions reporting by June 2008, for all companies which emit more than 25,000 tonnes of greenhouse gas emissions per year.

    * Meanwhile the record breaking trends to higher temperatures and lower rainfall continue.

    My conclusion: leaders can only deny the bleeding obvious for so long on climate before it begins to sully their credibility and they are forced to play catch-up.

  21. 171
    Kroganchor says:

    #161: John Mashey,
    I agree with you pretty much. AGW is a science question. My doubts are in the area of
    1) The mechanism of CO2 re-radiation, altitude, and can the effect be lab tested?
    2) Does the measured tempurature record match that calculated given the increase in atmospheric co2 ?
    3) Is the 20th century measured temperature rise within “normal” fluctuations?
    It seems to me that there is disagreement among real scientists on these questions.

    a) How long have you been following AGW?
    With serious thought, about a year.
    b) How much have you read/seen, and do you have a couple specific favorite sources that you find credible and understandable? No. RC is better than most.

    c) Where are you located? Washington State.

    I won’t ask political affiliation, but it is notable that people’s opinions about a scientific question are somewhat correlated with their political affiliation. My beliefs are libertarian, I vote Republican.
    d) For instructive comparison, how familiar are you with the history of the tobacco industry and its approach to science, i.e., smoking/cancer linkage? {That may seem a weird question, but it isn’t.]
    I am not familar. I don’t doubt that the Tobacco Cos “buy” their science.

    There is no doubt that a persons beliefs are influenced by perceived self interest. Isn’t this effect independent of the correctness of those beliefs?

  22. 172
    Timothy Chase says:

    Figen Mekik (#165) wrote:

    Perhaps being an educator myself, it bothers me when people try to pigeon hole others as “understands the science,” or “skeptic” or “denialist.” Judging people based on what category we think they belong educates no one and serves no constructive purpose.

    Although it may not be that relevant to the current situation, speaking from both personal experience and perhaps more personal observation, I would say that pigeon holing others is usually less of a problem than pigeon holing oneself.

    But within this context, it might also pay to remember that Exxon has just recently renewed its campaign – and while it may just be a coincidence, some of what we got yesterday sounds a bit like what was coming out of Exxon just a day or so ago, especially in the case of #140. In fact, the author seemed like some sort of absurdist, one-line, post-and-poof caricture of any position someone might even pretend to take.

    People’s ideas and perceptions evolve with how much they know and come to realize. And this goes for everyone. Even your most accomplished nuclear physicist probably has plenty to learn about physics. Any one who doesn’t appreciate that, doesn’t appreciate scientific curiosity and progress. Sorry to sound like a Greek philosopher but realizing what you don’t know is what drives scientific knowledge forward, not grouping people into categories, taking an “us vs them” attitude or trying to one-up each other with rhetoric.

    The “us vs them” is a problem – particularly when it causes one to fixate on winning an argument and each and every point rather than fixing on the discovery of the truth. The latter generally implies being willing to learn from the insights of others even when one disagrees with much of what they have to say. But somehow I think that the fixation on winning irrespective of the evidence is typically more of a problem for those who are unwilling to acknowledge either anthropogenic climate change or the magnitude of what faces us.

    However, I agree that to some extent the “us vs. them” is a problem for those who recognize both. Some people will wander in here at times, with far less experience in this sort of thing, possibly even sporting a nice looking bullseye on the back of their leather coat, and a few may be trigger happy enough to start something reminiscent of the OK Coral. Somewhat understandable given the circumstances, but best avoided while getting a little clearer view of what one may be shooting at. It might help to see whether someone actually wishes to engage in a discussion or simply create the appearance of a legitimate disagreement.

    My apologies if my own rhetoric seems a bit over the top at times (and as a matter of fact, I know it has on at least one occasion), but I sometimes feel like we are getting to the point at which we are being asked to debate whether the earth is flat – while enjoying a panoramic view of it from geosynchonous orbit. Undoubtedly others feel the same way, although perhaps with more justification.

    At the same time, I know that what is obvious to some may not be at all obvious to others. A friend of mine who had difficulty with simplifying fractions had fallen seriously behind while taking a course in calculus. No small part of the problem in lay in the fact that her professor would see step two through nine as obvious and skip from one to ten. Another part appeared to involve her use of prepositions. But she was able to pick things up if she was walked through step by step. With only a few hours of preparation, she went from failing the three previous tests to acing the next.

    Here is a thought: when someone comes in and states that they don’t believe that the evidence is strong enough, or that they don’t believe that the “theory” is sound enough or what have you, but without being specific in any way whatsoever, we could respond in the following fashion.

    If they appear to be unclear about what principles are involved, we could explain those principles to them, preferably in our own words, or for that matter, the evidence, the trends and the support – but more or less at a schematic level – so that they get the lay of the land. Then we could ask them what specifically doesn’t seem strong enough to support the claims which have such widespread support within the scientific community and have a great deal of evidence in their favor, then go on from there.

    Alternatively, if they believe that there is some alternative explanation for climate change, it should be easy enough to respond to that. Very few alternatives have been proposed, and all have been shown to be “problematic” to say the least. It may also help if we can discover what their genuine concerns are when it isn’t something they are immediately open about, but much of the time this isn’t the sort of thing which they seem willing to share.

    It is an imperfect world. But admittedly there is room for improvement, and I believe ways of making things better.

  23. 173
    Hank Roberts says:

    K., have you read the AIP History? It’s the top link under Science, right side of page. It’s exhaustive, maybe exhausting too; the author knows some parts are difficult and has one point where he asks you how he’s doing (you’ll find it, if you work through). No math needed, and it doesn’t go past the late 1980s or so, so you won’t be trouble too much by current events. It will answer some of your questions. Note the carbon dioxide (infrared) laser uses the same physics that describe how CO2 behaves in the atmosphere, that sort of practical application of theory may help believe the science there.

  24. 174
    John Mashey says:

    re: #171, #173: Kroganchor:
    Hank’s pointer is; http://www.aip.org/history/climate/index.html
    That’s a fine discussion: good theories rarely spring into existence full-blown (like Minerva from the brain of Jupiter), but are often presented that way, which eliminates the history.

    Kroganchor asks:
    “1) The mechanism of CO2 re-radiation, altitude, and can the effect be lab tested?
    2) Does the measured temperature record match that calculated given the increase in atmospheric co2 ?
    3) Is the 20th century measured temperature rise within “normal” fluctuations?
    It seems to me that there is disagreement among real scientists on these questions.

    For 1) and 2): http://www.aip.org/history/climate/co2.htm
    1) I think the sections you want is “The Speculation Vindicated (1950-1960)”
    It explains the differences between sea-level labs and high atmosphere.

    2) I think the section is “Carbon Dioxide as the key to Climate Change (1960s-1980s)”, looking especially for “Vostok”, and then go into “After 1988″.

    http://www.aip.org/history/climate/aerosol.htm is also worth reading, for the aerosol dimming/cooling effect .

    It may also be worth looking at http://www.ipcc.ch/SPM13apr07.pdf, especially Figure SPM.2, which shows the various forcing effects, including (very important) error bars and level of scientific understanding. That is a great chart, especially since it gives numbers and bounds, and immediately makes clear factors like current jiggles in solar irradiance, contrails, etc.

    3) This has been discussed plenty, and others may summarize it differently, but I’d say the evidence is rather strong that:
    - the rise from ~1850-1950 very likely had some rising solar irradiance, helped out by rising CO2, CH4, etc.
    - since solar irradiance has been almost constant at a high level since then (modulo 11-year sunspot cycles), and since Milankovitch-cycle effects are slow,
    and modulo the usual jiggles:
    - spike down and up from volcanoes (like Pinataubo)
    - spike up from big ENSO (1998)
    what’s left is anthropogenic effects and their feedbacks:
    - down/flat from aerosols, until Clean Air Acts
    - up from CO2

    Do you call the last 1M years “normal”? Based on orbital cycles, this is what we’d expect for quite a while, i.e., glaciations, with interglacials of various lengths. Of course, if you keep going back, you can find a planet with radically different conditions, continents in different places, higher temperatures&oceans, much higher CO2 [before ocean absorbed as much, and plants put it into the ground as oil, gas, and coal.] Those conditions are, hopefully, irrelevant.

    We might or might not be at the same temperature as around 1000AD, and we’re likely not up to where we were 8,000-10,000 years ago … but from orbital cycles, it *should* be a little cooler now than then, and flat, or slowly falling, but instead, it’s going up exceptionally fast.

    I don’t care that much about the exact current temperature, I care more about it’s first and second derivatives: the first is clearly positive, and I don’t think the second is negative, which means the temperature is going up for a while, based on simple physics.

    Back to the IPCC SPM forcing chart:
    With the current level of CO2, it will keep getting warmer, because the forcing in the chart is from the *current* level of CO2 in the atmosphere, not our rate of emissions, which is more like the first derivative of the level of CO2. Given its long atmospheric life, if we stopped emitting CO2 tomorrow, it would take many decades for enough CO2 to get absorbed to bring that forcing back to zero. When the IPCC does the next report, I’d expect CO2 (and its forcing) to be higher, not less .. and the second derivative may be positive as well.

    Over in the RC thread “Glacier Mass Balance…”, you might want to look at Prof. Pelto’s nice discussion of glaciers, including Washington’s North Cascades, and his website: http://www.nichols.edu/departments/glacier/intro.htm

    To go further back, in that thread, see #15 and #55, where I put together some glacier information, using the longest Swiss glacier, going back 3500 years. Basically, that glacier is retreating up the mountain at an unusual rate, and is heading off the 3500-year chart in a few decades.

    I always recommend Ruddiman’s very readable “Plows, Plagues, and Petroleum”, which has a really nice description of climate history and the detective work that goes on.

    Is there serious disagreement from real scientists? From my outside viewpoint, not much.

    Richard Lindzen often proposes theories (like IRIS) to explain why Co2 warming will be canceled by certain atmospheric effects, but they haven’t been that convincing or well-supported. It would be wonderful if they were true! But I doubt it. Everybody agrees we need to understand clouds an aerosols better.

    There are a few others, and there is a stream of hypotheses that just don’t make sense, or lack mechanisms to explain why they should be true, so I usually apply Occam’s Razor, knowing that the science behind CO2 forcing is rock-solid. If there’s a CO2 elephant running around my living room, I don’t really need cosmic rays, or random gremlins, or cycles-conjured-out-of-cherry-picked-data, or weird solar effects … to explain why the floor is shaking.

    This is like:
    You are hot. A bunch of world-class doctors come in with various thermometers, and they get 100 +/- 1.0, so they argue a lot about the measurements differences. They keep improving thermometers, and a while later, they get 101 +/- .5. They still argue about the differences. The next batch of thermometers arrives, and they get 102 +/- .1. They still argue about the +/- .1, but they agree that the scinece is settled that you have a nasty heat stroke, getting worse, and it would be really good to get you in an ice bath SOON.

    Meanwhile, random scientists (not doctors) and others (not even scientists) visit you. Some just look at you, taking no measurements, and say you look fine, so no action needed. Some say you’re getting warmer, but it’s just the natural day/night cycle. Some say it’s better for you to be warmer than colder. Some say that it’s an exceptionally warm July. Some say the doctors are still arguing, and therefore more study is needed, so take no action before that. At 102, you’re still OK, and you probably shouldn’t leap into a freezer, but if you don’t do something, you will not be in good shape, pretty soon.

    ========
    Regarding the relationship of smoking to AGW, and the question about how long you’ve been watching, it sometimes takes a while to assess credibility of sources, because you have to watch how positions change (or don’t change) as new data arrives. It took me several years, but might be easier now.

    If you haven’t already, you might take a quick look at the George C. Marshall Institute (Frederick Seitz) and SEPP (Fred Singer).

    Seitz was (very long ago) a famous solid-state physicist, was President of the US National Academy of Sciences (1962-1969), and then President of Rockefeller University. Singer was first Director of the National Weather Satellite Service (1962-1964), and has written several books on GW. Those are good-sounding credentials! However…

    If you go look at their websites, you will find there is a clear viewpoint, and you may find originals/copies of much of the anti-AGW information that echoes around. You might check the contact address of GMI, which will may be informative if you follow Washington, DC.

    If you look them up in http://www.sourcewatch.org and Wikipedia, you can learn about funding, and the connection with smoking & tobacco companies for both of them …

    Re: Washington: if you haven’t, you may want to check http://seattlepi.nwsource.com/business/299234_climateecon11.html.
    You have some of the same issues as here in California, although probably not as bad. We have the problem that most of our precipitation comes in 5 months of the year, with 5 other months where snowpack is rather crucial.

    Finally, regarding beliefs and self-interest: I think rational self-interest is a good thing, and I much prefer systems designed to align self-interest and shared interests, so that good things happen because people decide it’s good for them.

    But, I don’t think long-term good comes from distorting science via politics or special economics interests.

    There is no doubt that it has *never* been in RJ Reynolds’ interest to have the smoking/cancer link get proven, and they were were very effective in delaying that, and then appealing to individual rights of adults (highly libertarian on the surface), and then coopting state governments with money. Since ~90% of adult smokers started when they were younger than they were 18, and since nicotine exposure during the teen/pre-teen years is far more effective in creating addiction than later exposure [due to specific brain changes going on in the earlier years], it was certainly in RJ Reynolds’ interest to do “Joe Camel” and candy-flavored cigarettes like Twista Lime. [They still can sell the latter, just without the delicious name.]

    [If you get interested in that, as there are many parallels with the tactics of anti-AGW arguments, Allan Brandt's "Cigarette Century" is a good recent book]. I think AGW is much more complicated than smoking, but there are far more powerful interests involved, and there may well be similar disinformation.

    I would love to believe that AGW is a hoax and is going away; it would simplify my life, but…

    Hopefully some of this is useful.

  25. 175

    Re: Kroganchor…Yep! there are non so blind as those who do not ‘wish’ to see. None of wants to believe the world is in trouble, but those of us with eyes and common sense can see the situation unfolding and instead of sticking our heads in the sand and hoping it was all a big mistake and will go away; instead we all have to do everything we possibly can to at least try and avert what is ahead…for your family and childen sake as well.

  26. 176

    K. wrote “There is no doubt that a persons beliefs are influenced by perceived self interest. Isn’t this effect independent of the correctness of those beliefs?”

    The answer is YES! It is not just the sceptics who don’t want to believe that CO2 is driving climate change and that they will have to give up their sexy SUVs and 4X4s. The scientsts too, don’t want to believe that global warming is as bad as it is. They don’t want to accept that within ten years the Arctic ice will have gone, along with most of the NH glaciers. Apart from anything else, it means those specialists will be out of work. There won’t be any ice in the northren hemisphere for them to investigate, and all the best remaining jobs are already taken by the Antarctica specialists.

    The top scientist at the head of NASA denied global warming was a problem, because it might mean an end to his pet project of sending a man to Mars. But worse than that, although the climate models do not work, the modelers insist that they do, because to admit they are wrong would mean losing face!

    I shouldn’t be skeptical about climate models without providing some evidence so I will just remark that the current models are based on the concept of local thermodynamic equilibrium (LTE.) The second hit from a Google search for “local themodynamic equilibrium” is from the prestigous “Eric Weinstein’s World of Physics” where it says -

    Real atmospheres are not in local thermodynamic equilibrium since their effective infrared, ultraviolet, and visible brightness temperatures are different. http://scienceworld.wolfram.com/physics/LocalThermodynamicEquilibrium.html

  27. 177

    Our economy is humming along. We’re rolling in money.

    And where, pray tell, do you think that wealth comes from?

    You are burning fossil fuels, and extracting it from the environment.

  28. 178
    Timothy Chase says:

    Thomas (#174),

    He wasn’t trying to argue that there is no need to cut emissions.

    He was explaining why the politicians are finally beginning to situp and take notice of the situation. From what he says, Australians have wanted to do something about greenhouse emissions for some time, particularly with the extended droughts they have been experiencing which have been creating water shortages the likes which they have never seen before, but the conservative party wasn’t. Now the conservative party is at least beginning to acknowledge there is a problem and a need to act – which he considers a good thing. You don’t need to convince him any more than me.

    Anyway, Australia is looking into some fairly important things. Desalination plants driven by solar energy – which could conceivably act as a prototype for other parts of the world where water is scarce. AgriChar – which would be a non-intensive way of greatly increasing the productivity of agriculture while sequestering carbon for centuries – and which could easily be adapted to Third World countries.

  29. 179
    Timothy Chase says:

    A few thoughts about convincing skeptics…

    When people come in here and seem especially skeptical of the science, I suspect that a large part of it has to do with how they are worried about the effects of doing something about climate change on the economy – although I have noticed other concerns. Another has to do with their worrying about creating some sort of world government.

    I can understand a bit of both concerns, maybe even more than a little bit.

    I know that I am worried about the world economy. In fact it is a big concern for me as the state of the economy will determine how many resources we have for dealing with the enormous problems that climate change will create for humanity. A great deal is riding on it being in good shape. But if we don’t do something about climate change, there is every reason for thinking that the world economy will be wrecked by it. And it is worthwhile to keep in mind that a former chief economist for the World Bank has argued that by the end of this century, the world could be facing something as severe as the Great Depression – which is likely an underestimate.

    As far as the United Nations goes, I of course realize that it is anything but a world government. Nevertheless, I would rather not see it turn into one, especially if it is handed too much power. Likewise, I would rather not see governments handed too much power. But the longer we wait before doing something about climate change, the harder it hits us, and the more likely people will become desperate enough to sacrifice their freedom to some demagogue – who will then in all likelihood be concerned with maintaining power than doing something about climate change.

    A real nightmare scenario for me is a centralized world government with control of a single currency which attempts to finance its programs for dealing with all of the problems resulting from severe climate change by hyperinflating its currency. It could very well be 1920s Germany on a world scale – without the benefit of an outside world economy needed for economic recovery. In my view, this could set us back a great deal – more than I suspect most could imagine. But this becomes far more likely the longer we wait to do something about climate change.

    Maybe if we learn to address some of these concerns earlier rather than later in a discussion, and if we point out that given their concerns, they should also be concerned with climate change, then we will actually stand a better chance of getting them onside. Sometimes I get the feeling that we oftentimes do a better job of convincing ourselves than convincing those who actually need the convincing. If we get them onside, it could really help – particularly since they will stand a far better chance of convincing others who are opposed to even acknowledging that there is a problem than many of us could do ourselves.

  30. 180
    Eli Rabett says:

    Kroganchor #171. Yes, re-radiation from CO2 has been observed both in the atmosphere and in the lab. The principle is called Kirchhoff’s law which holds that at thermal equilibrium a body will emit an equal amount of energy as it absorbs.

    Now you are not the first to doubt this happens (there are even papers that snuck into print), but it is still wrong. Re-radiation in keeping with Kirchhoff’s law and our ability to model what happens was demonstrated in Applied Optics 35 1519 (1996) by Evans and Puckrin. (And yes I know about convection, but you just have to account for the additional energy flows)

    The experiment was simple enough and it is elegant (IMHO) in the parsimonious way that it answers a complicated question.

    They used a standard IR spectrometer and instead of turning on the glowbar light source placed a gold mirror at 45o above liquid nitrogen in a dewar, so that the detector looked through the spectrometer at the LN2 surface at 77K. They then placed a sample (they used a CFC, but the principle is what they were afterin the light path and measured the emission. Because the temperature of the “source” is so low, 77K, the
    spectrometer is looking at a source of very low (almost no) emission and will not see any absorption of the light launched into the system, but only emission from any gas in the light path.

    Evans and Puckrin showed that the radiative transfer codes based on spectroscopy and Kirchhoff’s law could perfectly reproduce the measured emission spectra.

    This means that not only do you SEE the effect of that 0.03% CO2 in the IR emission spectrum, but you can, from first principles, calculate what it looks like.

    On the other side, emission from CO2 has been seen in the atmosphere, again, in good agreement with the radiative codes.

    To quote them:

    “In atmospheric radiation codes such as FASCDIP, the absorption spectra of gases are used to calculate emission spectra. These emission spectra actually determine the atmospheric greenhouse radiation; any increase in this radiation will affect the surface energy balance and will cause global warming.

    In large climate models and most radiation codes, Kirchoff’s law is assumed to be valid without any caveats. However, there have been questions raised recently by Barett as to the validity of Kirchoff’s law in the atmosphere. Hence an experimental verification of Kirchoff’s law for laboratory cells containing greenhouse gases which shows the validity of the radiation codes should be beneficial in answering such criticisms of the global warming theory. In this paper we have demonstrated that radiation codes predict the correct emission spectrum of CFC-12 from a laboratory gas cell even though the cell is not in a blackbody cavity. These laboratory measurements will also assist in the measurements of absolute greenhouse fluxes……”

    As Ray Ladbury made clear, sensible physicists had no doubt about Kirchhoff’s law applying. The Evans and Puckrin paper did not raise any fuss because it confirmed the obvious, but still one constantly encounters the equivalent of Barretts denialist driven misreading of the science. When you are trying to beat back a pail full of spaghetti that is being thrown against the wall, some will get through and pollute the atmosphere. Witness the silly recent paper by Beck, and much more.

  31. 181
    DocMartyn says:

    Eli Rabett, you say that “Kirchoff’s law is assumed to be valid without any caveats”, however, is this how the various models are run.
    Let me ask you a couple of simple questions, at one of the wavelengths of you choice, what is the relationship between absorbance of a photon by CO2 and :-
    A) A doubling of the CO2 concentration. So that at 380 [CO2] ppm; 50% of photons are absorbed, it follows that at 760 [CO2] ppm then X% of photons will be absorbed.

    B) The attenuation of absorbance through the atmosphere at 380 [CO2] ppm, so that overall there is an absolute absorbance of 50% of the photos at a particular weavelength. What is the relationship bettwen distance from the earths surface and the absorbance?

  32. 182
    wade shatara says:

    What is a “climate Skeptic”? Please define this term, as this is not a trivial request. The entire so called global warming debate is being conducted with out basic terms defined. The IPCC definition of climate change is “Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity”. So are there 730 climate changes a year from an inter-day temp range or are 4 climate changes a year from the seasons, or one week there is a blizzard and the next week sunny and 75. What is climate change?

  33. 183
    Timothy Chase says:

    Jim Eager (#159) wrote:

    Frankly I’m often as appalled by the lack of knowledge of some of those who accept the idea of AGW as I am by that of skeptics. Simple stuff, like the fact that water vapor is a greenhouse gas, or that historically CO2 rise has followed temperature rise, or that the sun really does drive climate, even with the greenhouse effect. In fact, I’ve found that correcting these misconceptions increases your credibility with skeptics, which may in part be why they become more amenable to understanding the science better as they discuss it.

    I know that I was “skeptical” only a few weeks ago about water vapor being a greenhouse gas. But the fact is that it is a far more effective greenhouse gas than carbon dioxide. Some of what the skeptics get fed is true but it is fairly selective, and as one nineteenth century thinker wrote, “the true is the whole.” Water vapor is a far more effective greenhouse gas, but it remains in the atmosphere for only a short time before it falls out as rain or snow. In contrast, a great deal of carbon dioxide remains in the atmosphere for centuries – and it determines how the equilibrium level of water vapor.

    Similarly, skeptics will sometimes point out that carbon dioxide has very little effect at near the surface. This is true. But carbon dioxide is quite effective in the stratosphere – which is quite dry.

    Skeptics may point out that the stratosphere is becoming cooler. This is true. With increased water vapor, some of it is actually managing to make it to that part of the stratosphere which is high in ozone – and ozone is an effective greenhouse gas. The water vapor destroys ozone which leads to the cooling of the stratosphere. But the cooling of the stratosphere leads to an increased temperature differential between the surface and the upper atmosphere. This increases convection, winds near the surface of antarctica, the churning of the upper layers of the ocean which is rich in organics – leading to higher levels of carbon dioxide and methane being released into the atmosphere.

    *

    There is a tendency – even among the honest – to debate and disagree with every point being made by those who they disagree with. This is called “complementary schismogenesis,” and I have seen it marital ping pong and I seen it at the level of 20th century epistemology where schools of thought were divided between those who argued for the hierarchical nature of knowledge where it builds from a foundation of some sort (the foundationalists) and those who argued for the interdependence of the elements of our knowledge (the coherentialists). After a while they were each arguing against strawman versions of the other’s position.

    *

    I went to St. John’s college. It was devoted to the Great Books of western civilization, beginning with ancient greek philosophy, reading the original Origin of the Species and working through proofs in Lobachevskian hyperbolic geometry. Despite my student loans, it is an experience which I wouldn’t trade for anything.

    One of the points which they emphasized was being able to hold discussions with those who have different views, that this would often reveal a great deal more of any given work than if one were simply studying it by oneself. Sometimes all this would result in were bull sessions, particularly when people hadn’t done their reading. But on occasion, it would work beautifully. It was almost as if the linear text on the two-dimensional pages had risen into the air forming some sort of three dimensional structure. At such times, even the dullest among us seemed capable of deep insights, and when you finally walked out of class, you would feel like you were six feet off the ground in a near dazed state for the next hour.

    But what was the principle behind this?

    Well, it was largely mathematical. If you have one individual with three insights, they are able to make only three connections between any two of them. But if you have two people with three insights each, the number of connections becomes fifteen. By the time you have five people, a hundred and five connections are possible. By the time you have twenty people actively participating, you probably have a cacophony of confusion. Too many cooks, I suppose.

    But the principle is real.

    And even when you are having a conversation with someone who is unwilling to acknowledge any of the insights you have brought to the table, you can still walk away with more than you had when you first arrived. But if you are willing to acknowledge what is true in what they have brought to the table, then show how it all fits together, at least among those who are more honest, they are more likely to start listening – because they will realize that you are listening. They will be less likely to fall into the trap of viewing everything in terms of “us vs. them.” There will undoubtedly be a great many people that this won’t work with, but it will work with some. And those who it works with will likely be able to reach people you can’t.

    Anyway, I figure this is part of what Figen Mekik was getting at back in #165.

  34. 184
    Steve Reynolds says:

    Timothy Chase 179> A few thoughts about convincing skeptics… Maybe if we learn to address some of these concerns earlier rather than later in a discussion, and if we point out that given their concerns, they should also be concerned with climate change, then we will actually stand a better chance of getting them onside.

    That is a very good point. I am sympathetic to reducing the negative effects of AGW, but most of what I see politicians and governments actually doing (such as carbon trading) is creating opportunities for corruption:

    http://business.guardian.co.uk/story/0,,2093816,00.html
    …reveals major flaws in the global system designed to reduce emissions

    As most economists recommend, a carbon tax (which could replace other taxes), would give everyone clear incentives to conserve and develop new technology to replace fossil energy. Of course, it does not give politicians the opportunity to directly pick winners and losers…

  35. 185
    Neil B. says:

    One of the counter claims by GW skeptics is that evaporation feedbacks against warming, so we don’t have so much to worry about after all. How credible is that? It would be easier to deal with the whole picture if all sides would let go their singular obsession over just temperature changes. If more water evaporates to help compensate for the warming forces, then we’d expect dew points to rise, not just (or even, instead of) temperatures. I suspect that they have, but I don’t see enough about that – what’s the story?

  36. 186
    Timothy Chase says:

    Making connections

    Sorry to post this again.

    Hopefully someone will be kind enough to delete the earlier version. A few of the sentences were bizarre hybrids of alternate ways of expressing the same thought. Somehow I suspect this would be distracting if not outright confusing.

    Jim Eager (#159) wrote:

    Frankly I’m often as appalled by the lack of knowledge of some of those who accept the idea of AGW as I am by that of skeptics. Simple stuff, like the fact that water vapor is a greenhouse gas, or that historically CO2 rise has followed temperature rise, or that the sun really does drive climate, even with the greenhouse effect. In fact, I’ve found that correcting these misconceptions increases your credibility with skeptics, which may in part be why they become more amenable to understanding the science better as they discuss it.

    I know that I was “skeptical” only a few weeks ago about water vapor being a greenhouse gas. But the fact is that it is a far more effective greenhouse gas than carbon dioxide. Some of what the skeptics get fed is true but it is fairly selective, and as one nineteenth century thinker wrote, “the true is the whole.” Water vapor is a far more effective greenhouse gas, but it remains in the atmosphere for only a short time before it falls out as rain or snow. In contrast, a great deal of carbon dioxide remains in the atmosphere for centuries – and it determines the equilibrium level of water vapor.

    Similarly, skeptics will sometimes point out that carbon dioxide has very little effect near the surface. This is true. But carbon dioxide is quite effective in the stratosphere – which is quite dry.

    Skeptics may point out that the stratosphere is becoming cooler. This is true. With increased water vapor, some of it is actually managing to make it to that part of the stratosphere which is high in ozone – and ozone is an effective greenhouse gas. The water vapor destroys ozone which leads to the cooling of the stratosphere. But the cooling of the stratosphere leads to an increased temperature differential between the surface and the upper atmosphere. This increases convection, winds near the surface of antarctica, the churning of the upper layers of the ocean which is rich in organics – leading to higher levels of carbon dioxide and methane being released into the atmosphere.

    *

    There is a tendency – even among the honest – to debate and disagree with every point being made by those who they disagree with. This is called “complementary schismogenesis,” and I have seen it in marital ping pong and I seen it at the level of 20th century epistemology where schools of thought were divided between those who argued for the hierarchical nature of knowledge where it builds from a foundation of some sort (the foundationalists) and those who argued for the interdependence of the elements of our knowledge (the coherentialists). After a while they were each arguing against strawman versions of the other’s position.

    *

    I went to St. John’s college. It was devoted to the Great Books of western civilization, beginning with ancient greek philosophy, reading the original Origin of the Species and working through proofs in Lobachevskian hyperbolic geometry. Despite my student loans, it is an experience which I wouldn’t trade for anything.

    One of the points which they emphasized was being able to hold discussions with those who have different views, that this would often reveal a great deal more of any given work than if one were simply studying it by oneself. Sometimes all this would result in were bull sessions, particularly when people hadn’t done their reading. But on occasion, it would work beautifully. It was almost as if the linear text on the two-dimensional pages had risen into the air forming some sort of three dimensional structure. At such times, even the dullest among us seemed capable of deep insights, and when you finally walked out of class, you would feel like you were six feet off the ground in a near dazed state for the next hour.

    But what was the principle behind this?

    Well, it was largely mathematical. If you have one individual with three insights, they are able to make only three connections between any two of them. But if you have two people with three insights each, the number of connections becomes fifteen. By the time you have five people, a hundred and five connections are possible. By the time you have twenty people actively participating, you probably have a cacophony of confusion. Too many cooks, I suppose.

    But the principle is real.

    Even when you are having a conversation with someone who is unwilling to acknowledge any of the insights you have brought to the table, you can still walk away with more than you had when you first arrived. But if you are willing to acknowledge what is true in what they bring to the table, then show how it all fits together, at least among those who are more honest, they are more likely to start listening – because they will realize that you are listening. They will be less likely to fall into the trap of viewing everything in terms of “us vs. them.” There will undoubtedly be a great many people that this won’t work with, but it will work with some. It might even help with those who aren’t participating in the conversation at the time – but who are listening.

    Anyway, I believe that some of this is part of what Figen Mekik was getting at in #165.

  37. 187
    Neil B. says:

    Timothy Chase:
    Yes, water vapor is a greenhouse gas. Then, wouldn’t it be even worse for any other effect to increase water evaporation?
    PS – I have heard great things about the “barefoot St. Johnies.”

  38. 188
    Timothy Chase says:

    Neil B (#185) wrote:

    One of the counter claims by GW skeptics is that evaporation feedbacks against warming, so we don’t have so much to worry about after all. How credible is that? It would be easier to deal with the whole picture if all sides would let go their singular obsession over just temperature changes. If more water evaporates to help compensate for the warming forces, then we’d expect dew points to rise, not just (or even, instead of) temperatures. I suspect that they have, but I don’t see enough about that – what’s the story?

    Evaporation will certainly lead to a cooling of the surface of the ocean, but it would also lead to an increased temperature in the atmosphere. So that would be first effect. However, water vapor in the lower atmosphere is a highly effective greenhouse gas, so it will lead to greater absorbtion of infrared, heating the lower atmosphere, and given the feedback of absorbtion and re-emission between the atmosphere and the surface (including the ocean) it will actually tend to raise the temperature of the ocean over time.

    Additionally, the atmosphere will be able to hold more water vapor only by achieving a higher temperature – and as it becomes saturated with water vapor, this will tend to reduce the amount of evaporation which can take place. So for a given temperature, there will be an equilibrium level of water vapor, and the higher this level is, the greater water vapor is contributing to the greenhouse effect.

    Now of course water vapor will also condense into clouds and clouds have an albedo effect where they scatter sunlight back into space. This will reduce the amount of sunlight which gets absorbed at the surface, and thus reduce the thermal energy which enters the system. In this sense, they lead to a negative forcing.

    However, clouds will also tend to trap infrared radiation which might otherwise escape at night. This is why you will notice that overcast nights tend to be warmer than clearer nights. It is actually nightime which concerns us most when it comes to the greenhouse effect – because it is at this time that thermal energy tends to be lost into space.

    There are other effects, of course, but this is a good start.

    *

    Incidently, unlike water vapor, carbon dioxide itself isn’t that effective a greenhouse gas. But it is effective in the sense that it will tend to stay in atmosphere much longer than water vapor. With a relatively small initial rise in average temperature, it starts a positive feedback loop where water vapor raises the temperature leading to more water evaporation. This raises the water vapor content of the atmosphere until a new equilibrium is established – with the level of carbon dioxide being the determining factor – at least until you get to the positive feedback loops associated with the carbon cycle.

  39. 189

    The situation with water vapour is that its atmospheric concentration depends on the surface temperature. The hotter the surface the more water vapour is evaporated and the greater is its greenhouse effect.

    Carbon dioxide is also a greenhouse gas and is dominant when the there is little water vapour. This is true in deserts, but also above ice covered surfaces. Thus the altitude of the snow line is not only set by latitude, but also by atmopheric CO2 concentration. This is why the glaciers are melting globally.

    Carbon dioxide sets the base greenhouse effect and water vapour amplifies it. The problem is that we do not know how much this amplification (climate sensitivity) is. But I can give you one clue.

    Saturated water vapour density increases almost exponentially with temperature over the range 0 to 100 C. The higher that the base temperature is set by CO2, then the higher will be the rate of increase in water vapour. In other words, as the base temperature is raised by us pumping more CO2 into the atmosphere, then the climate sensitivity will increase (exponentially?) Think about it!

    However, there is another big player in the greenhouse effect stakes and that is clouds. More water vapour, more clouds, less sunshine and then we have to sweat it out under a cloudy sky which not only hides the sun but heats us up with its greenhouse effect.

  40. 190
    Timothy Chase says:

    Neil B (#187) wrote:

    Yes, water vapor is a greenhouse gas. Then, wouldn’t it be even worse for any other effect to increase water evaporation?

    Certainly.

    For example, methane is (I believe) about forty times more effective, gram to gram, as carbon dioxide. But it tends to remain in the atmosphere for only a few decades – before being converted into carbon dioxide. Increased sunlight would obviously be effective. So is nitrous oxide – a product of the combustion of many biofuels. But the central question, as I understand it is, “How long?” In a simple world with just carbon dioxide and water, once you remove the carbon dioxide, the system will begin to return to its original equilibrium. The same is true of any other forcing.

    But of course the world isn’t quite so simple. There is, for example, the positive feedback from the melting of the arctic cap lowering the albedo, increasing the absorbtion of solar energy and thus the amount of thermal energy entering the system.

    PS – I have heard great things about the “barefoot St. Johnies.”

    I don’t know the origin of that expression, although it might have something to do with the Greeks. Socrates was in essence the school mascot. I will have to check with Moira – she was both undergrad and grad, and she spent time at both schools. One is in Santa Fe where I was at, the other in Annapolis. But a little bit of news gets back and forth. For example, from what I understand, the Johnies at Annapolis often got the Naval Academy’s goat. Something of a tradition, I believe.

  41. 191
    yartrebo says:

    Re #189:

    “Saturated water vapour density increases almost exponentially with temperature over the range 0 to 100 C. The higher that the base temperature is set by CO2, then the higher will be the rate of increase in water vapour. In other words, as the base temperature is raised by us pumping more CO2 into the atmosphere, then the climate sensitivity will increase (exponentially?) Think about it!”

    Luckily for us, the greenhouse forcing from a given amount of H20 is logarithmic. ln(e^(x)) works out to simply kx (a linear function), so an exponentially increasing amount of water vapor will only increase climate forcing linearly. The end effect is that water vapor will multiply the CO2 forcing by a constant.

    My understanding is that climate models are quite effective at simulating the direct (greenhouse effect, not clouds) feedback from H20 and it’s well incorporated into global warming projections.

  42. 192
    DocMartyn says:

    The reason many skeptics are skeptics, is because of comments like this:-
    â��Additionally, the atmosphere will be able to hold more water vapor only by achieving a higher temperature – and as it becomes saturated with water vapor, this will tend to reduce the amount of evaporation which can take place. So for a given temperature, there will be an equilibrium level of water vapor, and the higher this level is, the greater water vapor is contributing to the greenhouse effect.â��
    Timothy Chase
    �The situation with water vapour is that its atmospheric concentration depends on the surface temperature. The hotter the surface the more water vapour is evaporated and the greater is its greenhouse effect.�
    Alastair McDonald
    Don�t you realize what system you are describing? The Earth rotates once every 24 hours. The system is never at equilibrium, the system can be better described as a steady state, but even then only over a yearly time scale. If you are trying to describe changes in the Earths climate you need to understand the transfer of Heat. The idea that you can pack more and more water vapor into the atmosphere, for very small increases in energy input, is nonsense. If you really want to persuade skeptics, you need to decend from the moral high ground you inhabit and produce data, or at least models supported by data.

    So what happens to the water vapor pressure in 24 hours ?
    How is heat transferred from water vapor during the gas/liquid state transition that occurs during the night ?
    What happens to the concentration of water soluble gases, like N2, O2 and CO2, when water undergoes this phase transition ?
    How does CO2 affect the rates at which the phase transition occurs?
    How does CO2 affect the direction of IR emission?
    What are the albedo values for different loacalities (e.g. ocean, grassland, snow, sandy desert) for reradiated IR?

    [Response:The system is very complicated but to first order all the signs are that relative humidity stays roughly constant; so warmer air means more water vapour in it - William]

    Finally, why do you insist that CO2 has such a long half-life?

    [Response:http://www.realclimate.org/index.php/archives/2005/03/how-long-will-global-warming-last/ - William]

    What has happened to the C14 generated by atmospheric H-bomb testing, it is gone. The linger time of C14O2 in the atmosphere indicates that the half-life of CO2 in the atmosphere is between 9-15 years. (I know the radioactive halflife of C14 is 5600 years).

  43. 193
    catman306 says:

    “Re: Kroganchor…Yep! there are non so blind as those who do not ‘wish’ to see. None of wants to believe the world is in trouble, but those of us with eyes and common sense can see the situation unfolding and instead of sticking our heads in the sand and hoping it was all a big mistake and will go away; instead we all have to do everything we possibly can to at least try and avert what is ahead…for your family and childen sake as well.”
    Comment by Lawrence Coleman

    This RC website is evidence for a thirteenth tipping point in climate change.

    http://www.motherjones.com/news/feature/2006/11/13th_tipping_point.html

  44. 194
    deanj59 says:

    Is there a reason for the variablity of data sets in the graph (1) above in the time periods between 800-1800?? It seems as though all of the data in more recent years is much more uniform. Why is this? For example DWJ2006 and ECS2002 appear to vary in measurements by as much as .5C or more in some cases versus JBB1998 and MJ2003. Even if they are using different models why would they all begin to move in lock step as time moves closer to present? Is the data set just more accurate now?

  45. 195
    Timothy Chase says:

    yartrebo (#189) wrote:

    The end effect is that water vapor will multiply the CO2 forcing by a constant.

    Yep. Approximately 2.8 degrees Celsius, judging from a recent paleoclimatological study. But it should be remembered that when we speak of a constant climate sensitivity, we are generally thinking equilibrium level – and it takes a while to get there.

    Please see:

    Climate sensitivity constrained by CO2 concentrations over the past 420 million years
    Dana L. Royer, et al
    Nature 446, 530-532 (29 March 2007)
    Abstract Only: http://www.nature.com/nature/journal/v446/n7135/abs/nature05699.html

    My understanding is that climate models are quite effective at simulating the direct (greenhouse effect, not clouds) feedback from H20 and it’s well incorporated into global warming projections.

    Clouds and their albedo effects are included in the models. However, there is still considerable room for improvement – and it is quickly being made. For example, HADGEM1′s clouds tended to be too thick (vertically) but too narrow. This no doubt resulted in an underestimate of the albedo effect, but it would have also resulted in an underestimate of the thermal radiation being trapped by clouds at night. However, HADGEM3′s clouds are far more realistic.

    It is also worth noting we have recently detected a twilight zone around clouds, invisible to the eye, but extending for kilometers. The effects of the twighlight zone no doubt will soon be incorporated into the models – and given us a sharper image of what is going on.

    For more on this, please see:

    Widespread ‘Twilight Zone’ Detected Around Clouds
    May 3, 2007
    http://www.nasa.gov/centers/goddard/news/topstory/2007/twilightzone_particles.html

  46. 196
    Hank Roberts says:

    >181, the answer would be “it depends on the air pressure”

    I’m not a physicist, I”m just reading this stuff —- but I recognize the questions having read some history.

    You should read the AIP History section on radiation physics; it’s the first link under Science, in the sidebar.
    Your questions in 181 are like those the researchers were posing back the 1930s, and you can read the history to see how they got past those.

    It took World War II and the development of the first computers to do enough math to get to the 1950s level where they understood what happened with radiation physics, particularly how CO2 behaved at the very low air pressure in the upper region of the atmosphere.

    Remember, an emitted photon can go off in any direction; only those emitted at the edge of space that happen to go outbound have a fair chance of actually carrying energy away from the planet.

  47. 197

    [[The idea that you can pack more and more water vapor into the atmosphere, for very small increases in energy input, is nonsense.]]

    Google “Clausius-Clapeyron law.”

  48. 198
    Lawrence McLean says:

    Re #192, to William…
    I had assumed that as the atmosphere is heating faster than the oceans, that worldwide, the average relative humidity was is the decline. The analogy is a bathroom… in order the get a bathroom less “steamy” (without getting rid of the water) is to heat the room (not the water). I assumed this is the reason that the tendency to drought is becomming widespread.

    William, am I wrong?

  49. 199
    Timothy Chase says:

    wade shatara 182 wrote:

    What is a “climate Skeptic”? Please define this term, as this is not a trivial request. The entire so called global warming debate is being conducted with out basic terms defined. The IPCC definition of climate change is “Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity”. So are there 730 climate changes a year from an inter-day temp range or are 4 climate changes a year from the seasons, or one week there is a blizzard and the next week sunny and 75. What is climate change?

    For “Climate” and “Climate Change,” I would suggest the following:

    Climate – Climate in a narrow sense is usually defined as the average weather, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is 30 years, as defined by the World Meteorological Organization. The relevant quantities are most often surface variables such as temperature, precipitation and wind. Climate in a wider sense is the state, including a statistical description, of the climate system. In various chapters in this report different averaging periods, such as a period of 20 years, are also used.

    Climate change – Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use. Note that the Framework Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: â??a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periodsâ??. The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition, and climate variability attributable to natural causes. See also Climate variability; Detection and Attribution.

    (emphasis added)

    IPCC WG1 AR4 (2007) Glossary pg. 942-943
    http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_Annexes.pdf

    from:

    IPCC WG1 AR4 (2007)
    http://ipcc-wg1.ucar.edu/wg1/wg1-report.html

    Typically, when I use the term, “climate skeptic,” I simply assume that someone who labels themselves a “climate skeptic” is a climate skeptic. In this sense, it would be a matter of self-labeling. But what I take this to mean is that they deny that the scientific case for anthropogenic climate change has been made when it is accepted by the vast majority of scientists. By this, they will typically mean that they do not believe that the scientific case for one of the following has been made:

    1. Carbon dioxide absorbs infrared radiation and therefore traps thermal radiation in the atmosphere, raising the temperature above what it would be otherwise.
    2. Humans have been responsible for substantially raising the level of carbon dioxide in the atmosphere.
    3. The extent to which we have raised the level of carbon dioxide in the atmosphere has had a significant effect upon the average temperature of the earth as a forcing where the level of water vapor is raised by means of a positive feedback loop.
    4. The level of carbon dioxide is now well above what it has been for the past 500,000 years.
    5. The level of carbon dioxide in the atmosphere is now high enough that it will cause substantial climate change.

    However, “skeptic” often has a positive connotation – which is part of the reason why they will use the term. But it is useful to keep in mind that there are also evolution skeptics, big bang skeptics, relativity skeptics, and heliocentric skeptics (yes – they are still around). I myself might prefer the term “contrarian” as it is more neutral while implying that their position is at a variance from the accepted scientific consensus – but this is often taken to imply that they actually deny one or more of the above propositions.

    In any case, you might want to look at the following:

    How to be a real sceptic
    19 Dec 2005
    http://www.realclimate.org/index.php?p=210

    *

    If someone wants to be properly skeptical of the case for the propositions numerically listed above, I would suggest that one begins by asking what the scientific case for one or more of those propositions is. Then within the context of a discussion, it is possible to examine how strong the scientific case for each of those propositions is and whether skepticism is warranted.

  50. 200
    Bob Gardiner says:

    It states on front page: â??Climate scepticsâ?? do not like this (graph showing temperature rise) and keep coming up with their own temperature histories.

    Climate sceptics invariably do not question the rise in temperature just the cause being put down to the wrong light bulbs being used, etc.


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