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  1. That’s some very nice work by Salzer. Nothing like increasing the amount of data to get rid of troublesome issues like the growth factor.

    Two other reactions
    1. Could you give a graph that doesn’t look out-of-focus?
    2. What medieval warm period? :-)

    Comment by GFW — 17 Nov 2009 @ 3:33 PM

  2. So that particular issue has apparently had people barking up the wrong tree…

    Multivariate puns, the best kind.

    I think Schulman, or maybe it was Douglas, used strip-barked bristlecones extensively in developing chronologies, for the very reason that they were less susceptible to size effects. No detrending needed.

    Thanks for the heads up Ray.

    Comment by Jim Bouldin — 17 Nov 2009 @ 3:38 PM

  3. I am not quite sure what this shows. If this rise took place in 1300BC then that means it has happened before. Is there any data or studies to reflect the CO2 content of the atmosphere during the last upswing?

    Comment by Richard K — 17 Nov 2009 @ 3:42 PM

  4. To elaborate on my MWP comment, the MWP actually does show up as a warming from the couple hundred years previous, but the LIA is less apparent – it appears as a couple out outliers, although strong ones. Still, this particular reconstruction has the LIA as on average warmer than say, 850 AD. OTOH, this reconstruction is only relevant high on mountainsides, so the climatic patterns experienced by most humans in the MWP and the LIA probably better conform to other reconstructions. Can’t argue with the clear signal that what we’re doing to the planet right now is far in excess of what the MWP was like though.

    Comment by GFW — 17 Nov 2009 @ 3:42 PM

  5. Wouldn’t the difference between the current relative growth rates also indicate that if a tested tree was not in the higher part of the grove at the time of the warming, evidence of the warming might not have been recorded? Have the heights of the groves varied enough over the last couple thousand years to make a difference?

    Thanks

    Comment by arch stanton — 17 Nov 2009 @ 3:49 PM

  6. Would it be possible for the rings now ‘wide’ to constrict in width in, say, 100 years, as more growth occurs?

    It seems there may be a lot of liberty taked to assign fixed characteristics to factors that may show a lof of deviation over time.

    Comment by Rolan O. Clark — 17 Nov 2009 @ 4:03 PM

  7. The data appears to show that climate was nearly as warm in the second millenium b.c.e. as now. Who can say why, and do we have corroborating evidence of melting glaciers and sea level rise rate that was higher during that time period?

    [Response: Keep in mind that the evidence is regional, and not necessarily indicative of hemispheric or global mean temperatures (though there are a number of studies that suggest that western North America is about as good as any single region if you’re trying to estimate larger-scale temperature trends). As for the other evidence available for corroboration, we reviewed this recently. As shown in that review, (a) it is only possible to reconstruct global or hemispheric mean temperatures from glacier records for the past 400 years or so (sea level is even trickier on these timescales!), and (b) existing reconstructions of extratropical Northern Hemisphere mean temperatures using the various available proxy data, only go back about 2000 years. In the latter case, the long-term trend is indeed one of cooling, prior to the industrial era, and the authors (Kaufman et al, 2009) interpret that trend as consistent with the expected response of extratropical temperatures (during summer, but this also applies more weakly to annual mean owing to land surface feedbacks) to the long-term earth orbital-related decline in extratropical northern hemisphere summer insolation. This interpretation would also seem to apply to the observations from the present study, recognizing that (i) there is likely to be substantial century-scale variability related to other forcings (solar and volcanic) about the longer, multi-millennial orbitally induced temperature trend, and (ii) this variability (and any internal variability) is likely to be more pronounced at the regional scale of the present study. – mike]

    Comment by Geno Canto del Halcon — 17 Nov 2009 @ 4:21 PM

  8. This tree ring study is a very interesting indirect way (proxy?) of proving the theory of global warming. The following could be considered off topic but I think it is in the same spirit of showing indirectly the effects of global warming. This is (perhaps) a new suggestion to accomplish the same thing.
    I live in the foothills of the rocky mountains at latitude 51 north. The layout of the land coming from the east is low prairie, elevated prairie, rolling hills and finally foothills and the mountains. In other words the terrain gets more mountainous with steeper terrain as one travels from east to west towards the rocky mountains.
    I go on daily hikes with my 2 dogs and look at various things in nature. There are 4 artesian wells which I have gone by regularly for the last few years because my dogs like to drink from them. I have never before seen these wells run totally dry. Even in midwinter with temperatures down to minus 20 or 30 these wells keep running sometimes building nice ice terraces etc. I mean they always provide a relatively copious amount of water.
    Indeed, such wells are commonly used here by people who raise cattle, horses or sheep etc. as a hobby or a sideline. People will install a drinking water trough or just create a dugout so the water can be collected for the animals.
    This is the first time since I moved here 9 years ago that these wells have gone either totally dry (2 wells) or almost stop running i.e. just a drip of water .
    The climate here is essentially dry because we are in the precipitation shadow of the Rockies. After July it rains very little if at all until late next spring. The snows usually come late in the year after the ground has been frozen (november,december)and again in the early spring before the ground thaws out.
    I therefor tend to think that these wells get their water from the mountain snow and ice melting all through the summer and that there is not enough snow and ice left in the mountains late in the season to keep these wells properly fed with water. I know that all attention is directed towards the large glaciers who are slowly or rapidly melting away. But there must be hundreds if not thousands of small valleys or depressions in the mountains filled with snow and ice which have no natural creek to discharge in and the water can only percolate through the ground and run down the mountains under the ground only to surface in the artesian wells along the foothills.
    I wonder if a survey could be done to determine if this decrease in flow of artesian wells is a common occurrence in the foothills along the length of the Rocky mountains.
    I know also that it may be better to keep quiet etc. as per Mark Twain. Based on some of the reactions to other suggestions I have read on this website I should probably look for cover.

    Comment by Joseph — 17 Nov 2009 @ 5:12 PM

  9. These rings give annual records, don’t they? I’m curious about the sharp dip at 1450 AD, and how it might look with a 20 year mean, instead of 50.

    Are there analogous trees in the Southern Hemisphere? It seems to me that more SH proxies would be especially helpful, to establish a better global reconstruction.

    Richard K, reply 3: Not all temperature rises have to be caused by the same thing. And any feature you see on the plot could only be regional; you have to combine these results with results from other places to get a global view.

    Comment by tharanga — 17 Nov 2009 @ 5:21 PM

  10. Joseph, you might ask around in your own area — there will be a county agricultural office, or something of the sort, there. And just a quick Google turned up quite a few recent references discussing what’s going on with water in Colorado.

    There’s almost certainly a document somewhere listing artesian wells that you can find for your area.

    I’d be very surprised if there isn’t serious attention being given to water flows — particularly because for example pumping water out of an aquifer can reduce pressure so artesian wells elsewhere quit running, and this raises legal questions.

    One quick example from one search — you can do better I’m sure:
    http://scholar.google.com/scholar?hl=en&q=artesian+wells+colorado&btnG=Search&as_sdt=2001&as_ylo=2004&as_vis=1

    Comment by Hank Roberts — 17 Nov 2009 @ 6:13 PM

  11. RichardK,
    > it has happened before. Is there any data or studies
    > to reflect the CO2 content …
    Yes. The “Start Here” button at the top of the page is a good place to start. Also click the first link under Science in the right sidebar.
    For pictures that are a good lead-in to reading, have a look here:
    http://www.globalwarmingart.com/wiki/Temperature_Gallery
    http://www.globalwarmingart.com/wiki/File:Carbon_Dioxide_400kyr_Rev_png
    Also have a look at this thread (Ruddiman’s work):
    http://www.realclimate.org/index.php?p=223

    Rolan,
    > Would it be possible for the rings now ‘wide’ to
    > constrict in width in, say, 100 years

    No. The wood inside the thin outside growing layer of a tree is dead and stable; trees don’t shrink in diameter over time.

    Comment by Hank Roberts — 17 Nov 2009 @ 6:25 PM

  12. Geno Canto del Halcon (7) — As Mike’s response indicates, that temperature high about 4000 years ago amy well have been but regional. However, something similar is found in the temperature proxies from GISP2, suggesting a somewhat similar warm period in the North Atlantic region around then. This might just be happenstance, but you could consider W.F. Ruddiman’s early anthropogenic hypothesis, as presented in his popular “Plows, Plagues and Petroleum”, in light of it. He has more in his professional papers, available from his web site; do note his hypothesis is not universally accepted.

    Comment by David B. Benson — 17 Nov 2009 @ 6:39 PM

  13. wrt #3: The lack of standardization means that the juvenile growth is likely in samples that go back to the center of the tree. This definitely is not at play in the 20th century. It is however possible in late second millennium BC.

    wrt #4: This paper isn’t a temperature reconstruction but a report on widths of tree rings and their possible causes. This is quite different than a formal paleoclimate reconstruction.

    wrt #9: Look at the paper and see figure 4. the paper is open access and viewed by anybody. The 1450 dip is clear at three different high elevation sites.

    Comment by DrCarbon — 17 Nov 2009 @ 6:39 PM

  14. re #7:

    In addition to what Mike has said, read the section on pg 4 titled “Ring width and tree age, with emphasis on the final sentence therein. The point is that the analysis may well be conservative wrt to temperature increase, in the sense that the pre-1900 ring widths may be somewhat inflated, relative to post-1900, by tree age (actually size) effects, given that the individual series were not detrended.

    Comment by Jim Bouldin — 17 Nov 2009 @ 6:53 PM

  15. Couldn’t local weather records also verify whether ring widths expand in warm years at treeline? I know the University of California has a research station in the White Mountains, so I assume they’d have pretty good data.

    Comment by Brian Schmidt — 17 Nov 2009 @ 7:07 PM

  16. Brian, the White Mtn station data are almost certainly incorporated into the PRISM data, which is a complex station data interpolater, and which is much the better data to use here because of its ability to estimate temps at all 3 sites, and its ability to account for topographic and elevational effects.

    tharanga: http://www.conifers.org/cu/fi/

    Comment by Jim Bouldin — 17 Nov 2009 @ 7:45 PM

  17. Increased growth may not indicate future survivability, or we wouldn’t be seeing dead pine trees all over the West. Bristlecones are a high desert species, similar to joshua trees and, to a lesser extent, pinon pines. Joshuas are predicted to become extinct in Joshua Tree National Park, because their seeds will not germinate at the predicted temperature levels of 50 years from now.

    It’s quite likely that similar problems will beset the ancient bristlecones. They inhabit an even narrower geographic range, also at arid higher elevations. I’m from California, and rarely see them anywhere outside their small habitat east of Bishop in the Sierras, at I would guess a 5,000 foot elevation. A 2C or more increase may doom them, though it may be tough to find dendro evidence to that effect. Besides germination problems, other factors could be shorter, milder winters, leading to increased pest colonization, or changes in the hydrological cycle. I welcome knowledgeable speculation on this subject. It will be tough for them to move upslope as the climate warms, because the mountains in their range are not very high.

    Comment by mike roddy — 17 Nov 2009 @ 8:37 PM

  18. They may be showing a decent increase in temperature over the last century – but how does that correlate with the raw temperature record from nearby weather stations in rural locations? I don’t recall information on that anywhere.

    Comment by Richard — 17 Nov 2009 @ 10:16 PM

  19. It’s pretty damn funny watching bender get all unhinged over this paper over at CA. Saying (this is a paraphrase): “strip-bark vs. whole bark was never the issue: six sigma trees!! NAS just dodged six sigma trees”. In another thread he says that the only thing that matters is sensitivity to precipitation but that Saltzer, et. al., just “dodged the issue”. Of course they didn’t dodge the issue and you can see the analysis in figure 3(c).

    It seems pretty clear that the crowd over there hasn’t come up with a good line of attack that might make one think for a second before answering their unfounded claim. CA needs a better class of denialist.

    Comment by Rattus Norvegicus — 17 Nov 2009 @ 11:38 PM

  20. 1) All this is a nice example of the general case of Liebig’s Law of the Minimum.

    2) I certainly recommend a visit to Bristlecone Pine Forest in the White Mountains and actually see these things live.

    3) And finally, Edmund Schulman and the “Living Ruins” – Bristlecone Pines, Tree Rings, and Radiocarbon Dating, by Donald J. McGraw, is a nice book on some of the history of this. McGraw was actually there signing books the day we visited. I hadn’t seen the time ‘cosmic schwung’ before, so it’s always nice to add to one’s vocabulary.

    Comment by John Mashey — 18 Nov 2009 @ 12:01 AM

  21. Oops, that was figure 4(c).

    Comment by Rattus Norvegicus — 18 Nov 2009 @ 12:29 AM

  22. Re Geno Canto del Halcon and Mike’s response.

    “The data appears to show that climate was nearly as warm in the second millenium b.c.e. as now.”

    Is it possible that this is an artefact? The ring widths were merely averaged, not corrected for the “growth function”, but as the article suggests, “as trees get older and the diameter of a tree increases, annual ring widths decline in thickness.”

    The point of averaging is to average over the effects of the age of trees, but most of the trees from which rings can be measured for 3500-4500 years ago would have been relatively “young” at that time. This may be a “boundary effect”.

    To put it another way, the population being sampled for the 3500-4500 year estimate would have a much younger age distribution at that time than those sampled later.

    Comment by Bruce Tabor — 18 Nov 2009 @ 2:10 AM

  23. Couple of observations. You can see that each grey dot represents 50 years of time on the horizontal axis.
    The latest upward trend appears to start around 1830. So what could have caused the start of that trend that seems to continue to the end?
    Why do the data end around 1950? This is a long time ago in terms of current CO2 trends.

    Comment by oakwood — 18 Nov 2009 @ 2:31 AM

  24. Could you relabel the date axis please. ” wide rings are formed in cool, wet years, and narrow rings in warm, dry years” So the downward trend since the year 200 means the climate is getting both warmer and drier or warmer or drier. It is easy to see this upside down if you don’t read carefully. I’m not sure where you are starting your trend line since it isn’t on the graph. The effect is subtle but a good confirmation.

    Is there a meaning to the sawtoothiness?

    Thanks for showing exactly how the climate change operates on these trees.

    Comment by Edward — 18 Nov 2009 @ 3:01 AM

  25. I sort of expected error bars on the graph. Is that an omission or isn’t it supposed to have those?

    Comment by Anne van der Bom — 18 Nov 2009 @ 3:49 AM

  26. It sounds as if Salzer is trying to take the simplest possible reconstruction method to get an idea of the climate. I think that is a good approach to the whole RCS discussion. I have done something somewhat similar to the Yamal dataset.

    Comment by Aslak Grinsted — 18 Nov 2009 @ 5:06 AM

  27. I was watching a doco about the battle of Hastings 1066.
    The deployment of troops made no sense if one took the geography to be the same as today. When sea levels were increased the reasons for the battle formations became clear. South England is supposed to have been sinking since the last ice age so if the sea level was much higher in 1066 then the climate would likely have been warmer than today, and/or for some time, around that date.
    The programme was, I would say, completely untainted by the current controversy.
    There may be more direct evidence available than these seemingly problematic tree rings.

    Comment by Jon — 18 Nov 2009 @ 5:59 AM

  28. Somebody uner post 11 Hank Roberts says

    “No. The wood inside the thin outside growing layer of a tree is dead and stable; trees don’t shrink in diameter over time.”

    There is exrtensive literature on the curing of trees for lumber and violin making (to give just 2 leads) that indicate that water submersion can densify tree wood. Since many dendro studies use old dead trees preserved underwater, I guess one should express some doubt about that comment.

    Comment by Geoff Sherrington — 18 Nov 2009 @ 6:04 AM

  29. #7: “The data appears to show that climate was nearly as warm in the second millenium b.c.e. as /now/.”

    I’ve not read the paper, but the graph’s last point is 1950. I’m not sure we can take the last data point to mean ~2000. The global temperature has increased by ~0.5degC since the middle of the last century: So most of the human-caused global warming wouldn’t really show up on the graph…

    http://en.wikipedia.org/wiki/File:Instrumental_Temperature_Record.png

    Comment by Mike Smith — 18 Nov 2009 @ 6:59 AM

  30. thanks for the great info. I just found this site. To me looking at the figure 1. we are about the peak as were years ago. To me it see cyclic. keep up the good work.

    Comment by shannon — 18 Nov 2009 @ 7:33 AM

  31. Geoff #29:

    During what period are you hypothesising the trees in this study were submerged?

    Comment by Chris S — 18 Nov 2009 @ 8:52 AM

  32. I just found this website. I’m in the midst of looking at both sides of the global warming yay/nay debate. Recent talks in my area of carbon taxes and other financial incentives to curb greenhouse gases has peaked my curiosity. Since me and the other citizens of my country will soon have another hand in our pockets, I want to see if I’m getting what I’m about to be paying for. I like this site so far, but I’d like to know, is this issue cut and dry for the most of you, the science is settled and it’s CO2 that is solely driving our climate? Thanks for your time.

    Comment by Pat — 18 Nov 2009 @ 8:57 AM

  33. I notice the CA post on this topic has way more graphs. You will never “win” these encounters if you just have one graph.

    Comment by bigcitylib — 18 Nov 2009 @ 9:00 AM

  34. Where is the nearest surface station temperature data,for the last century ?
    Thanks

    Comment by Bill J — 18 Nov 2009 @ 9:07 AM

  35. > way more graphs

    Yep, this is something I keep finding — I’ll search Google, then Scholar, then Google Images on anything about climate. The septic sites are _very_ far ahead in posting pictures that show up in the Image search results.

    It doesn’t mean they’re using them right — it means they’re using them far more.

    Advertising, basically. They’re way, way ahead in attention-grabbing.

    Comment by Hank Roberts — 18 Nov 2009 @ 9:55 AM

  36. Pat, you’ve gotten the basics wrong in the question you posted above.

    There’s no hand in your pocket except your own — assuming you support things like schools, public health, highways, air traffic control, public utilities.

    It takes work to understand all of the things you as a citizen do by taxation.

    School isn’t just arithmetic; public health isn’t just whooping cough prevention; highways aren’t just asphalt. Warming isn’t just CO2. All are areas where people found problems worth solving by cooperating in paying for things business can’t do.

    If you want to argue about that, this isn’t the place; try this one: http://www.ginandtacos.com/2008/08/31/atheistsfoxholes-libertariansairplanes/

    The “Start Here” link at the top of the page is a good place to begin for the very basics. Give it at least a few minutes of your time.

    Comment by Hank Roberts — 18 Nov 2009 @ 10:02 AM

  37. He who hath the most graphs wins!!!

    So McIntyre’s jumped into this one now has he? My surprise is exceeded only by my urgent desire to follow his labyrinthine path of amalgamated “insight” and innuendo. By the way, is he up to triple digits yet on the number of Yamal articles?

    Comment by Jim Bouldin — 18 Nov 2009 @ 10:06 AM

  38. The graph is for binned and averaged ring widths based on 50 year intervals. 1950 would be the last starting date of a 50 year bin, so 1950 is the last data point. Date is for the first year of the bin.

    Comment by Rattus Norvegicus — 18 Nov 2009 @ 10:16 AM

  39. Sorry, Geoff, I tried but I can’t support your claim by trying to look it up for you. Can you? Best summary I can find is:
    http://scholar.lib.vt.edu/theses/available/etd-112399-131003/unrestricted/03ch2.pdf

    Even if submerged whole trees did somehow shrink, such wouldn’t change the relative thickness of the annual rings–it’s those patterns that are used to correlate one tree with another to establish a timeline.

    Comment by Hank Roberts — 18 Nov 2009 @ 10:17 AM

  40. I wasn’t arguing, I was asking a question, there is no need for insult. I did read quite a bit so far on this site and I’m still continuing to do so. Thanks Hank.

    Comment by Pat — 18 Nov 2009 @ 10:28 AM

  41. The last point on the graph is indeed around 1950, but the caption explicitly states that these are 50 year means (averages) plotted on the first year of the interval. In other words, the last point at 1950 is the 1950-2000 average.

    If you’re going to plot an average you have to pick a point in your range. In this case they picked the beginning of the range instead of, say, the middle or the end.

    Comment by Steve — 18 Nov 2009 @ 10:28 AM

  42. off topic:
    can anyone tell me where the world’s meteorological data are stored and processed to climate change information? is it in the climate centre (such as hadley) itself or how does it work. many thanks, any answer to this is much appreciated.

    Comment by Mathis — 18 Nov 2009 @ 10:37 AM

  43. One thing was not clear to me on the original post:

    On that graph, is the growth function removed? In other words: did that region experience a similar temperature today and some 4,000 years ago? Or are the rings growing so much now that they are matching the early tree´s intense ring growth?

    Comment by Alexandre — 18 Nov 2009 @ 12:28 PM

  44. I wasn’t arguing, I was asking a question, there is no need for insult.

    Well, when you post an obviously denialism-strawman statement like:

    I want to see if I’m getting what I’m about to be paying for. I like this site so far, but I’d like to know, is this issue cut and dry for the most of you, the science is settled and it’s CO2 that is solely driving our climate?

    Science has never, does not, and will never say that CO2 is solely driving our climate. Despite what you may’ve been told by others, climate scientists do occasionally raise their head from their computer workstations and look outside on sunny days, for instance. Scientists are aware that we’ve had ice ages in the past, warm periods in the past, etc.

    You’ll get a more understanding response here if you take the time to learn what science says *first* – and …

    Big hint coming up:

    You will not find what science actually says about climate if you read denialist sites which lie to you.

    Comment by dhogaza — 18 Nov 2009 @ 12:38 PM

  45. Pat @32,

    It is deceptive to ask whether “the science” is settled, because science is a process that continually advances our understanding of its subject matter. The issue of whether increased CO2 will lead to warming, however, is very well settled. It is an inevitable consequence of our current theory of Earth’s climate–a theory with mountains of evidence in support of it. The naysayers (I prefer “denialists”) have neither science nor evidence on their side–only misinformation and the unfortunate human tendency to believe what we want to believe.

    Comment by Ray Ladbury — 18 Nov 2009 @ 12:40 PM

  46. #43:

    The graph is of raw ring widths, no detrending was done. The paper states that the earliest portions of their data come from remnant wood and that it is impossible to get an estimate of pith offset values, so they just don’t know.

    Comment by Rattus Norvegicus — 18 Nov 2009 @ 12:44 PM

  47. re 22 and 43:
    The age-related trend is not removed in that graph, nor in any graph from the study. The implications of this for the wide ring widths over 3000 years ago are discussed in the first subsection of the Discussion section.

    Comment by Jim Bouldin — 18 Nov 2009 @ 12:53 PM

  48. Mathis, it’s not all in any one place. See
    http://tamino.wordpress.com/climate-data-links/

    Comment by Jim Bouldin — 18 Nov 2009 @ 1:02 PM

  49. Pat, no insult intended, we do try to be helpful (and most of us here are ordinary readers, not climate scientists; the Contributors (sponsors of the site) are listed in the sidebar. You’ll get to know the other climate scientists.

    Don’t blame them for our mistakes — or occasional impatience (grin).

    We’re trying. (“Sometimes _very_ trying” as someone quite close to me is wont to say.)

    Many of us tend to reply too fast when a new userid posts FAQ about “settled” and “only CO2″ — patience furthers.

    Comment by Hank Roberts — 18 Nov 2009 @ 1:12 PM

  50. 32 Pat

    The way I read it is this:

    the data says that the climate is warming. The data also say that by far the most likely cause is CO2 produced by humans burning things (Coal, oil, gas).

    So to that extent the science is settled. I suppose it is possible that tommorow somebody might come up with evidence that something other theory explains things better. However, people have been trying for many years and have produced nothing that contradicts the CO2 theory.

    Comment by Jaydee — 18 Nov 2009 @ 1:45 PM

  51. Gosh, if you want to understand the relationship between global forest cover, human activity and global warming than the best place to look is indeed the Bristlecone Pine forest in the White Mountains…

    Or maybe – just maybe – a more complete survey of the Amazon, the Canadian pine forests, the Siberian forests would be appropriate?

    The only reason this particular story gained traction in the press is that is provides fodder for the “global warming is good for the planet” PR line. If trees are growing under global warming, than the fossil fuel lobby wants that publicized, so they lean on their PR people, who call the newspapers and cable networks, and there you go – propanganda 101. Amazon rainforest or Canadian pine forests just could not substitute in this headline:

    “Ancient bristlecone pines enjoying global warming”
    By Associated Press
    Monday, November 16, 2009 at 12:29 p.m.

    http://www.signonsandiego.com/news/2009/nov/16/ancient-bristlecone-pines-enjoying-global-warming/

    Similarly, we’ve headed off a new ice age and also recharged the planet with CO2 for photosynthesis – geoengineering in action. It’s actually a big success story…

    However, if you go with that line, you also have to admit that the phenomenon and the physics are real… and if you admit that, you have to consider the associated processes of water vapor feedback and shifts in ocean-atmosphere circulation and terrestrial soil moisture and the vulnerability of modern human civilization to water scarcity…

    What are the largest North and South American forests? Canadian pines and Amazon rainforest. What is global warming doing to those forests? Pine beetle invasions in the north due to warming conditions, and dieoff in the Amazon:

    http://www.guardian.co.uk/environment/2009/mar/11/amazon-global-warming-trees

    Do we see extensive media coverage of these two gigantic regions – no – but we see the bristlecone pine story developing traction. Do we see any mention of long-term forecasts of the conditions in the White Mountains, however? No – instead, we see a cherrypicked trend that has been spun to meet the needs of the fossil fuel lobby – that’s what our press system has become. The Associated Press is particularly bad, as is the company MediaNewsGroup, run by one Dean Singleton, the chair of AP and a noted global warming / fossil fuel spin artist for the billionaire class. MediaNewsGroup owns the SanDiegoTribune, and about 1500 papers across the western U.S., such as the SanJoseMercury – and they all run the same climate & energy disinformation stories.

    If there was ever a good reason to pursue anti-trust legislation targeting the corporate media holding companies, this is it. The media distortion and spin is breaking all records on this, all over the world, as media ownership becomes consolidated in fewer and fewer hands, most of them with a few fingers in fossil fuels as well.

    As another example, take the worst drought in a century in Mexico, such a common phrase these days:

    Farmers reeling from Mexico drought – 17 Nov 09

    Wait – not to worry – the Middle East-based Al Jazeera network is covering the story, and they say it’s just El Nino drying out Mexico. That makes perfect sense. In an El Nino, warm water from the equator piles up along the western coast of North and South America, usually resulting in giant storms due to the increased evaporation, a function of the surface temperature of the oceans (and other factors)… and that dries out the local region, right, yup. Warm wet conditions lead to drought. What could be wrong with that claim?

    Here is the typical view on El Nino effects in Mexico, a wiki blurb:

    In North America, El Niño creates warmer-than-average winters in the upper Midwest states and the Northeast. Meanwhile, central and southern California, northwest Mexico and the southwestern U.S. become significantly wetter while the northern Gulf of Mexico states and northeast Mexico are wetter and cooler than average during the El Niño phase of the oscillation.

    What is the current situation in Mexico?
    http://www.latimes.com/news/nationworld/world/la-fg-mexico-drought7-2009sep07,0,6988447.story

    A months-long drought has affected broad swaths of the country, from the U.S. border to the Yucatan Peninsula, leaving crop fields parched and many reservoirs low. The need for rain is so dire that water officials have been rooting openly for a hurricane or two to provide a good drenching.

    And yes, they then repeat the El Nino claim – strange, because they were previously claiming the drought was due to La Nina:

    2009: LA Times

    This is supposed to be Mexico’s wet season, when daily rains bathe farmland and top off rivers and reservoirs. But rainfall has been sporadic and unusually light — the result, officials say, of an El Niño effect this summer that has warmed Pacific Ocean waters and influenced distant weather patterns.

    2007: San Diego Tribune

    But if La Niña reprises its 2008 performance in the Sierra, California’s water resources will become even scarcer. Deliveries to Southern California farmers were slashed in the past year because of court-ordered pumping restrictions to protect the endangered Sacramento delta smelt.

    Wow – both La Nina AND El Nino cause drought! This new scientific learning amazes me, Sir Belvedere..

    Back in the real world, if atmospheric circulation patterns are shifting along projected lines – Hadley cell expansion northwards – this would explain the ever-more-persistent drought conditions, wouldn’t it? If so, much of Southern California across to Texas might end up looking like Baja and the Sonoran Desert in 100 years.

    No cause for alarm! Global warming is good for you – think about the, um, new desert tortoise habitat?

    There will be winners and losers, but I don’t see too many human winners here – pine beetles & toxic jellyfish are thrilled, however.

    Comment by Ike Solem — 18 Nov 2009 @ 2:03 PM

  52. I would like to second dhogaza’s response to Pat’s question, and his plan to study the science by reading RealClimate and some skeptical websites. The denialist sites make a habit of repeating a fabricated piece of evidence or repeating a particular lie that they believe they can sell over and over. It helped me a lot to know about the most common lies in advance, so that I could assess the credibility of the site. For the unvarnished current information on climate science, RealClimate is the best site, but it takes quite a bit of background information to understand the discussion here. In the meantime, the denier sites package a bunch of misleading information or outright lies, and sell the information to people who are gullible enough to believe the fabricated ‘science’.

    I found that the site Skeptical Science really helpful in debunking the most common denier lies. If you go to the site, on the home page you will find a list of the “Hottest Skeptic Arguments, and what the science really says”. Before reading any skeptical information, you should peruse this list, so that you will be able to spot the lies.
    http://www.skepticalscience.com/

    On a lighter vein, and in a more humorous way, the Peter Sinclair videos on YouTube hit the most common ‘Climate Denial Crocks’ which I recommend as a quick briefing that you will need before venturing into the den of deniers. Here is the Denial Crock video covering the original ‘hockey stick’ controversy:
    http://www.youtube.com/user/greenman3610#p/u/15/vrKfz8NjEzU

    A word of warning; be especially careful of Anthony Watts. His site is the most heavily censored of the denial sites, and Watts will go after you personally, using information from your sign-in profile, if he doesn’t like what you are saying. You may prefer to simply identify yourself as ‘Pat’, but Watts will happily publish your full name and attack you personally. He did that to me. He snipped my comment, then mis-quoted it, then used my full name from my profile in the inline response to the comment.

    Good luck, and come back and report in.

    Comment by Paul Klemencic — 18 Nov 2009 @ 2:43 PM

  53. RE #32, Pat, “Recent talks in my area of carbon taxes and other financial incentives to curb greenhouse gases has peaked my curiosity. Since me and the other citizens of my country will soon have another hand in our pockets, I want to see if I’m getting what I’m about to be paying for.”

    The whole idea of any tax — which would NOT have been necessary had people started doing the right thing 20 years ago — is to inspire them to reduce their fossil fuel consumption through energy/resource efficiency/conservation.

    And once they take their first baby steps in doing so and suddenly realize they can do so without lowering living standards (down to a 1/2 to 3/4 reduction), then they can reap in the great savings (like the $2000 I saved from my $6 low-flow showerhead), help the economy, help their pocketbook (despite any measly taxes the gov might impose), and live happier and healthier lives. My husband and I chose to do so 20 years ago and we’ve been laughing all the way to the bank ever since.

    The climate denialists, on the other hand, are so hell-bent on causing global warming until they rearch 101% confidence that it is happening, that they will insist on paying the higher prices for things and will refuse to implement even one common sense, cost-effective measure to reduce their emissions. I think they’ve booked their Hummers for the next 20 years.

    So, anyway those darned taxes won’t really do much good to inpsire people to reduce, and maybe the government will have to raise them more, and the denialists will just become more obstinate about not reducing, even in the plethora of cost-effective ways that exist, and will insist on emitting all the more (because they just won’t believe in AGW until they die and go that much hotter place). And they’ll get their children to emit even more.

    And that’s history. Er, rather history will be ending sooner than we think….

    Now the scientists are saying 6 degrees C by 2100 — which as Mark Lynas points out in his SIX DEGREES is pretty much doom for the vast majority of us. See http://www.climateark.org/shared/reader/welcome.aspx?linkid=142726

    Comment by Lynn Vincentnathan — 18 Nov 2009 @ 3:09 PM

  54. I had a question about that past warming era about 1900-1300 BC. Were there any great floods in the Mediterranean area at that time. I teach mythology, and one author suggests that the Mediterranean flood myths might be based on some great flooding way back then (but he suggests sometime between 3000 & 2000 BC).

    Comment by Lynn Vincentnathan — 18 Nov 2009 @ 3:15 PM

  55. Just as a matter of interest.

    I am from the UK, but I have been up among the high altitude bristlecone pines of the US.

    I would hate to see them chopped down. Are they investigated in a non-destructive way?

    Comment by Theo Hopkins — 18 Nov 2009 @ 3:43 PM

  56. #54 – Lynn. I wouldn’t read too much into the 1900 BC period of high growth. This is time period that is difficult to interpret in this study as no detrending was done on the trees and it is possible that that era is represented by young, fast growing trees. Also this is a regional study and by itself it is of very limited utility in inferring paleoclimate of the Mediterranean.

    #51 – Ike. This paper has nothing to do with global forest cover. Rather it investigates growth trends and their possible causes in one species of tremendous importance to paleoclimatology.

    Comment by DrCarbon — 18 Nov 2009 @ 4:10 PM

  57. @Lynn Vincentnathan, 53.

    Lynn, that’s a pretty big brush you’re tarring ‘denialists’ with. I’m sure there are some that fall into that category, but also there are many that are well educated and have an environmental conscience. Many also take practical steps to be more environmentally friendly. Personally, I’m not as optimistic as some that we understand enough about the various multitude of interactions between the biosphere, atmosphere and beyond to be able to build deterministic computer models of global climate; that’s the main source of my skepticism. I emphatically agree that humans need to do a lot better and treat the environment with much more respect, but don’t agree that global capping and trading of carbon credits is going to give us our best bang for our bucks when there’s a whole host of other options out there that we should seriously be implementing regardless of whether CO2 is the nasty boogieman or not.

    Human’s have a pretty good track record of being proven wrong every time it’s declared the science is settled (earth’s flat, earth is center of the solar system, continents are stationary, etc).

    Comment by D MacKenzie — 18 Nov 2009 @ 4:31 PM

  58. @ #52 Paul: Speaking of hockey sticks, doesn’t this graph remind you of something. If you look at the last 3,000 years or so.

    (What were those Greeks up to in 1900 BC anyhow?)

    Comment by John D. Wilson — 18 Nov 2009 @ 5:25 PM

  59. I would hate to see them chopped down. Are they investigated in a non-destructive way?

    Yes, with one pretty unfortunate exception

    Comment by Jim Bouldin — 18 Nov 2009 @ 5:31 PM


  60. Human’s have a pretty good track record of being proven wrong every time it’s declared the science is settled (earth’s flat, earth is center of the solar system, continents are stationary, etc).

    Boilerplate talking-point alert!!

    Comment by anony mouse — 18 Nov 2009 @ 5:38 PM

  61. #55 Theo:

    Are the [bristlecones] investigated in a non-destructive way?

    Yes. Researchers drill a long, skinny “core” sample to get their numbers, and you need to get a permit to be allowed to do even this. (Ideally you’d want to core from several angles and average the results, but a lot of these studies involve single-core samples. None of the studies in question involve chopping down a live tree to see rings in detail, helpful though that might be.)

    Whether you do one core or a few, the tree should heal quickly. You can see what a core and a coring tool look like here:

    http://www.fri.sfasu.edu/pages/resources/landownbriefs/html/treecore.html

    Comment by Glen Raphael — 18 Nov 2009 @ 6:14 PM

  62. D MacKenzie: counterexamples

    cholera; smallpox; lead; asbestos; tobacco; chlorofluorocarbons; DDT; phthalates …..

    All cases where people were doing something provably stupid, learned that it was stupid, and (after years, or decades, or in the case of lead, a couple thousand years) mostly got organized to see that fools were stopped from continuing to do what everyone knew was doing damage.

    Comment by Hank Roberts — 18 Nov 2009 @ 7:21 PM

  63. 55 Theo, they bore into the trees and pull out a tiny core. The wound is sealed and the tree isn’t harmed.

    Comment by RichardC — 18 Nov 2009 @ 7:39 PM

  64. @joseph (comment #8): there was an episode of The Nature of Things* a year or two ago which spoke of periodic drought periods evident from tree rings etc. in the prairies, beginning at the eastern edge of the Rockies, which made the Great Depression of the 1930’s look like nothing, lasting from decades to a century.

    Not to say that what you’re seeing is not evidence of global warming, I don’t know, just a possible path for future research.

    * http://www.cbc.ca/documentaries/natureofthings/
    unfortunately this particular episode is not one of the ones available online

    Comment by matt wilkie — 18 Nov 2009 @ 7:52 PM

  65. D. MacKenzie, Given that science dates from about 1600, perhaps you would care to provide some evidence that the scientific consensus that Earth is flat or a geocentric Universe. Or perhaps you would care to give a concrete example of an uncertainty about the biosphere or “the beyond” that is sufficiently large to negate anthropogenic warming.

    Failing that, perhaps you would care to provide us with some reason why we should not consider you just another denialist reveling in his ignorance.

    No? I thought not.

    Comment by Ray Ladbury — 18 Nov 2009 @ 7:57 PM

  66. Hmm, my memory may be faulty. It could have been “Big Thirst: The Coming Drought” http://www.cbc.ca/mrl3/8752/wmv/iso/eds/bigthirst.wmv (teaser), http://www.cbclearning.ca/CBCEDS/shopping/product.aspx?CatalogName=CBCEDSBase&CategoryName=business_and_economics_economics&Product_ID=Y8Q-06-05&Variant_ID=Y8Q-06-05-010101

    Comment by matt wilkie — 18 Nov 2009 @ 8:00 PM

  67. “Personally, I’m not as optimistic as some that we understand enough about the various multitude of interactions between the biosphere, atmosphere and beyond to be able to build deterministic computer models of global climate;”

    I’d like to hear what you think the uses of GCMs are.

    Comment by Jeffrey Davis — 18 Nov 2009 @ 9:28 PM

  68. Great Post, Ike, #51.

    Forests are going to broadcast warming sooner and much more consistently than Western droughts or Atlantic hurricanes. Effects on hydrological cycles and regional microclimates are likely to be catastrophic: while logged or dead forests have more albedo, this is more than compensated locally by 10 degree hotter local air temperatures due to less transpiration, according to numerous studies.

    Dead pines in Canada and withering trees in the Amazon are a mild preview. When we see another 2 degrees, it will be hickory barbeque time- with another undervalued feedback.

    You’re also right about the sorry state of media coverage of climate change. It would really make me crazy were it not for the fact that most educated younger people have wised up and gone to blogs for information- such as this one. The New York Times, AP, Newsweek, and the rest of them have cut their own throats by permantly destroying their credibility.

    Comment by mike roddy — 18 Nov 2009 @ 9:47 PM

  69. Lynn @53: I have the misfortune to have a number of hardcore denialists around me at work. I think their motivation is the pure free-market stuff, the fear of any sort of government regulation is orders of magnitude greater than any concern about the planet. But I do find they are open to saving energy, both for the impact on their families expenses, and because they know energy insecurity is an issue for the country. It is possible to work with them on some conservation issues (just not on why it is important to do so). I probably have an anomalous sample, as they are high end engineers, and can appreciate system issues -so long as they aren’t too ideologically threatening.

    Comment by Thomas — 18 Nov 2009 @ 10:05 PM

  70. It might be worthwhile to point to tree limit changes in Scandinavia :over the last century the tree limit (limited by cold) has increased 150-190 m, as measured over several sites, and with different tree species …
    Holocene pine tree-line evolution in the Swedish “Scandes: Recent tree-line rise and climate change in a long-term perspective”, by Leif Kullman et al
    http://www3.interscience.wiley.com/journal/119820109/abstract?CRETRY=1&SRETRY=0
    http://sbf.c.se/www/pdf/97%285%29/Kullman.pdf
    And a very old tree:
    http://news.nationalgeographic.com/news/bigphotos/33944715.html
    http://www.lansstyrelsen.se/NR/rdonlyres/D47CDAEC-437F-4C4A-9AEC-70F11A5B0700/0/tradgransprojekt_2008.pdf

    Comment by Dr Dahlstrom — 18 Nov 2009 @ 10:13 PM

  71. Whoa! Touchy bunch over here aren’t we.
    @ Ray Ladbury: How about Galileo being placed under house arrest in 1632? His views were contrary to the science (in the general sense of knowledge) of the day. If you must know I work in ecology and have seen plenty of people using models completely inappropriately. Often they fall into the fallacy of believing the model represents truth and not thinking hard about the underlying assumptions and what the consequences are if those assumptions are not meet 100%. Sometimes those assumption violations are relatively minor, sometimes not. It’s particularly important when people try to extrapolate beyond observed data. The fact that there’s no single model that everyone can agree upon immediately indicates that not everything is known. I have no problem working with multiple models either, provided they represent the spectrum of the uncertainties and those uncertainties are suitable acknowledged and incorporated into final conclusions. From what I’ve read, that doesn’t always seem to be the case.

    Some pretty important things are still being discovered in ecology (eg Ca pooping fish), some of which could have big impacts on our understanding of things like the carbon cycle (especially if you consider that a lot of fish have been taken out of the worlds oceans over the same timeframe C02 has been rising, and no I’m not implying a causative link there), it would be great news for ecologists everywhere if the climate scientists have got it all figured out already, though they’d have to start looking for new jobs.

    @ Hank Roberts: most your examples also started as situations where majority of folks said 1 thing, a few tried to buck the trend and got shouted down for it, but it turned out those that went against the grain were right afterall.

    Look, if you disagree with my views, fine, I don’t really care. I was just trying to note that just because you’re a ‘denalist’ that doesn’t mean you want to keep on ransacking the earth until it’s nothing but a burnt ember then move on to the next planet and start again. I lot of us are pro-environment but just disagree with the direction things are going especially with proposed cap and trade schemes. 10 years I whole-heartedly agreed with AGW, now with the more I read, the less I’m convinced.

    Comment by D MacKenzie — 18 Nov 2009 @ 10:50 PM

  72. Actually Hank, the tobacco smoking rates have increased globally, so if that’s a strange form of success… All the tobacco companies had to do was accept a higher cost per cigarette, with the taxes going to anti-smoking campaigns. Some 21% of adults today have smoked cigarettes within the past week, according to the polls. On a global scale, the numbers are slightly higher, according to the WHO:

    “Worldwide, between 80,000 and 100,000 kids start smoking every day. Approximately one quarter of children alive in the Western Pacific Region* will die from smoking.”

    The latest effort by tobacco involves sugary candy-laced tobacco products, aimed at kids – almost all lifetime smokers begin smoking as children or teens. The actual tax increases are passed on to the addicted consumers, and the tobacco companies make the same profit as before. A few cities have tried to ban the sale of tobacco products except in licensed ‘smoke shops,’ but the grocery stores, corner markets and gas stations don’t like that any more than the cigarette makers do.

    Limiting smoking is “an imposition on basic rights” – but what about secondhand smoke and the right of redress for harm caused to bystanders?

    Arguing that one did not intend to cause harm does not usually work, especially if people have been pointing to the harm caused for decades.

    Fossil fuel emissions? Clearly, there’s been harm associated with this over a prolonged period of time. While there are still a few denialists running around making ever-more ridiculous claims about global cooling, solar cycles, and so on, much of the fossil fuel lobby has settled on a new tactic: rather than denial, they’re going with deception.

    The central deception is a lot like that involved in tobacco: a big public show followed by moves to create “low-tar cigarettes”, which is suspiciously similar to the “low-carbon coal” line. Healthy cigarettes, made with modern technology that removes all the problems – Futuregen cigarettes.

    Or try the patch – made from nicotine extracted from tobacco, and equally addictive, just not as carcinogenic. What is the patch for coal? Coal-to-gasoline programs, which are all based on coal gasification, and syncrude production using natural gas and tar sands.

    The deception is based on creating the appearance of doing something to fix the problem, such as cap-and-trade or carbon sequestration. By appearing to be doing something, one can avoid binding legislation that funnels investment away from fossil fuels and towards renewable energy.

    In that case, a tobacco farmer might suddenly find themselves unable to get credit – and the bank wouldn’t put up money for a new tobacco processing center, because they wouldn’t recoup the investment. All that would have to happen is for the government to remove the subsidies granted tobacco farmers, and banks would walk away.

    The same goes for fossil fuels and renewables. That’s the real problem with failure on Copenhagen – what will investors make of the apparent opposition on the part of world leaders to binding legislation that would step up the replacement of fossil fuels by renewables?

    http://www.guardian.co.uk/business/2009/nov/18/climate-change-renewableenergy

    Comment by Ike Solem — 18 Nov 2009 @ 10:56 PM

  73. Yep, the marketing to youngsters, the ones who get addicted, proceeds apace; most of the world hasn’t gotten the message yet.

    And there’s still lead turning up freshly painted on kids’ toys too.

    And going to chloramine instead of chlorine in water supplies flushed an awful lot of lead into some cities’ drinking water.

    It’s not that science _makes_ people change. But science, and statistics, gives people information they couldn’t get before the methods were invented.

    Science isn’t enough. Y’all who try to get policy people to pay attention have all my respect — ‘try everything, something’s got to work or else …”

    Comment by Hank Roberts — 18 Nov 2009 @ 11:19 PM

  74. D. MacKenzie, you say you’re an ecologist; you also say
    > regardless of whether CO2 is the nasty boogieman …

    Do you mean you’ve studied ecology, as opposed to being an ‘environmentalist’?
    The CO2 work is physics, but ought to be clear enough to be understood.
    Have you read the history (first link under Science in the right hand sidebar)?

    Touchy? If you’re wondering “whether CO2 is the nasty boogieman” there may be some difficulty here but not entirely on the part of those of us who’ve been reading here for a while and read the science.

    Where are you starting from? How much ecology, for example?

    Comment by Hank Roberts — 18 Nov 2009 @ 11:30 PM

  75. On carbon trading (yes, a lot of us think it’s business as usual)
    http://www.cartoonkate.co.uk/pdf/CarbonSupermarket.pdf

    Hat tip to the inimitable:
    http://throbgoblins.blogspot.com/

    Comment by Hank Roberts — 19 Nov 2009 @ 12:56 AM

  76. I know this is off topic. But with talk of denialists trying to disrupt Copenhagen, maybe not so far off …

    Friends of Science radio ads are playing across Canada. And, as in the case of the Monckton tour and the 2006 election ads, the usual suspects appear to be involved: The Calgary Foundation and oil and gas lobbyist Morten Paulsen (who also happens to be well connected with Stephen Harper’s Conservative Party).

    http://deepclimate.org/2009/11/19/friends-of-science-hits-the-airwaves/

    Meanwhile, Harper and Environment Minister Jim Prentice keep trash talking chances of meaningful agreement and seem to be relieved at the prospect of a weak, political agreement. But some are starting to push back …

    The leader of the federal Green Party and about 1,000 supporters had strong words for Prime Minister Stephen Harper Tuesday night.

    They gathered at the Victoria Conference Centre to call on the government to shape up and get serious about the upcoming UN Conference on the Climate in Copenhagen, Denmark.

    http://www.bclocalnews.com/news/70409747.html

    Comment by Deep Climate — 19 Nov 2009 @ 1:08 AM

  77. #71 D.MacKenzie,

    “10 years I whole-heartedly agreed with AGW, now with the more I read, the less I’m convinced.”

    I am interested in that, your last comment. What exactly have you read over the last few years that has made you less convinced. I would be interested in following some of it up since I too have read lots in that time and I can’t seem to find anything, anything at all, that would make me less convinced.

    Cheers
    Andrew

    Comment by Andrew Hobbs — 19 Nov 2009 @ 1:15 AM

  78. I now believe climate science has got to be the most absorbing and fascinating fields to be invloved in. I used to have a healthy scepticism when it comes to climate modelling but now finally it seems to be getting more predictable and a more reliable tool for forcasting future outcome scenarios. As more variables are being understood and the sheer increase in raw data from almost every source it’s beginning to become quite useful. One new example I read in Science daily… http://www.sciencedaily.com/releases/2009/11/091118143211.htm Re: the oceans abiltity to absorb CO2 may be waning but paradoxically the land seems to be taking more of it up than before even with continuing logging and land clearing. Gavin, your colleague Tim Hall has said that the increasing atmospheric CO2 has probabaly caused a faster growth rate in vegetation thus a larger ability to uptake the gas. However, like the oceans this increased uptake cannot last forever since the amount of nitrogen in the soils also determines uptake. So I would suggest this is uccuring more in the equatorial regions is this correct?
    Since the oceans make up over 2/3rds of the earth’s surface and their CO2 uptake is trailing off..for chemical reasons now and probably later down the track (or perhaps even now) because the oceans’s are warming at surface levels and so thermally less able to sequester carbon this will or is compounding the level of atmospheric CO2 (the slight increase in land carbon sequestration is more than offset by the relative area of the oceans) producing a viscious +ve feedback loop exponential in nature. To me this would indicate we need to adopt a reverse log approach to CO2 reduction if we are going to win this battle. Anotherwords immediately adopt a 95%+ global emmissions reduction and then only when CO2 reaches 350ppmv or lower can we afford to take the breaks off a little. Sounds impossible? I think so too! I hope you can see that only having a global concensus of a pathetic 20% reduction by 2020-2030 is like pissng into a raging forest fire..utterly useless!

    Comment by Lawrence Coleman — 19 Nov 2009 @ 2:00 AM

  79. Your figure caption says “Median ring-widths (non-overlapping 50-year means)” but the graph in the paper is captioned ” Ring-width medians for non-overlapping 50-year intervals plotted on first year of interval.” Are you sure they took used means in this graph? The supplementary material includes data for means of the bins but as far as I can tell that is not used in the main paper. Or am I missing something?

    In any case, if you take the mean rather than median, it is more influenced by rapid increases (if the last few data points are much higher than the rest, they pull the mean up but the median is not influenced by anything other than whatever was the midpoint in size). As you can see from the earlier peaks, those were not particularly long-lived. But the last 3 data points look like a pretty steep rise. Any bets on what the 2000-2049 data point will look like?

    Hockey, anyone?

    Comment by Philip Machanick — 19 Nov 2009 @ 5:36 AM

  80. Lynn,

    There is good geological evidence for massive flooding around the Mediterranean Basin area in 4000, 2400, and 1600 BC. Probably one of those events influenced the Utnapishtim/Noah/Deucalion story.

    Comment by Barton Paul Levenson — 19 Nov 2009 @ 5:45 AM

  81. D. MacKenzie,

    Please read this:

    http://BartonPaulLevenson.com/ModelsReliable.html

    Comment by Barton Paul Levenson — 19 Nov 2009 @ 5:49 AM

  82. RE #57, D MacKenzie, yes I heartily agree that “cap and trade” is not the way to go. We need a carbon tax that slowly (or quickly) increases each year, and we need all of that money it generates to go back to the people as some sort of divident (equally divided in the U.S., say, among all SS card holders) — they can pay for their higher energy bills, OR better yet become energe/resource efficient/conservative and pocket that money, get a better education or those braces for Suzie.

    That’s what James Hansen proposes, and it makes a lot of sense – see http://www.columbia.edu/~jeh1/mailings/2009/20090226_WaysAndMeans.pdf

    I also think a portion of that tax money should go to the poor peoples around the world, esp in Africa and Asia, that are suffering from GW impacts — you know, the people who don’t even have electricity or cars, whose crops are failing due to global warming — those crops they sow and reap by hand bec they don’t have tractors…..

    We break it, we buy it

    Comment by Lynn Vincentnathan — 19 Nov 2009 @ 6:00 AM

  83. #71 & “How about Galileo being placed under house arrest in 1632?”

    Are you suggesting that because most people believe the earth goes around the sun that they might be wrong, and that some flat-earther might be the one who is actually right? And we should accept (or even consider) what he says because he’s a loner?

    And BTW, the Catholic Church is sorry now for that incident, and they’ve decided to support science, and are speaking out about our need to mitigate global warming, such as the pope’s recent address at the World Food Summit.

    Comment by Lynn Vincentnathan — 19 Nov 2009 @ 6:14 AM

  84. I really can’t understand the conclusion from your final paragraph. Salzer’s Fig. S4 in his SI clearly shows that strip-bark ring widths have increased massively over the last 300 years (from about 0.2mm to about 1mm) whilst whole-bark trees have varied much less (from about 0.5mm to about 0.6mm with peaks in 1720-ish at about the same level as 1980).

    How is it possible to conclude that “there is no significant difference in their results when the data are divided into two classes—strip bark and non-strip-bark cases –when the raw unstandardized data are compared”?

    [Response: Hmmm. You seem to be somewhat confused about what that figure is showing. Fig. S4 of the paper uses data from the previously published work of Graybill and Idso. Figure S4A shows that the growth rates of their strip bark and whole bark trees have been similar over the last 100 yrs. or so. Before that, the whole bark trees have wider rings because the whole bark trees are younger. S4B shows that only when Graybill and Idso standardized the data was a divergence was introduced! -mike]

    Comment by Tony Rogers — 19 Nov 2009 @ 6:24 AM

  85. I hope the denialists at least are happy. Mission accomplished. They can all now go and take a breather. I understand the U.S. is not going to have anything to take to Copenhagen (see http://www.climateark.org/shared/reader/welcome.aspx?linkid=142960 ). Our beloved legislators are bowing out of the issue for now.

    Anyone for a tea party? Organic, sun-cooked tea?

    Comment by Lynn Vincentnathan — 19 Nov 2009 @ 6:29 AM

  86. “10 years I whole-heartedly agreed with AGW, now with the more I read, the less I’m convinced.” – D MacKenzie.

    Very clearly a typo. Seeing as this is a site run by climate scientists, surely he/she meant “10 years I whole-heartedly disagreed with AGW, now with the less I read, the more I’m convinced”

    Comment by Dappled Water — 19 Nov 2009 @ 7:01 AM

  87. Pat,

    #40

    I think you are the first commenter on this site to feel insulted by Hank Roberts.

    Questions are rarely just a request for information, they usually convey a lot of information too.

    You wrote “will soon have another hand in our pockets”

    I thought: “here’s another right-wing, tax-hating free market fundamentalist thinking global warming is merely an excuse for raising taxes”

    You wrote: “and it’s CO2 that is solely driving our climate?”

    I thought: “here’s another person that has been tricked into believing the fabrication that climate scientists disregard all other factors because their orders are to prove that CO2 is the culprit”

    My thoughts are a caricature, don’t conclude too much from them. They are not meant to insult you. I know I am almost certainly all wrong about my analysis of your beliefs, I am not a professional profiler, but I can’t help me from reading between the lines.

    You are not the first one to pose a question in this manner. RC regularly gets visitors claiming true skepticism and an open mind. But that skepticism usually breaks down pretty fast as the exchange of comments progresses, and you find out they merely come here for confirmation of their beliefs. Or you never hear from them again after 2 or 3 comments. Forgive us from being skeptic about ‘skeptics’ and ‘open minds’.

    Comment by Anne van der Bom — 19 Nov 2009 @ 7:15 AM

  88. RE D. MacKenzie: “How about Galileo being placed under house arrest in 1632?”

    Maybe my history is a bit fuzzy, but wasn’t that the Church’s doing?

    Comment by Deech56 — 19 Nov 2009 @ 8:30 AM

  89. Number 60#, I don’t think that has anything to do with “Settled science.” That’s a misrepresentation. You seem to be confusing science with religion. It’s settled science that’s disproved the religious claims that you used.

    Comment by Dale — 19 Nov 2009 @ 8:46 AM

  90. #71 D.MacKenzie,

    “10 years I whole-heartedly agreed with AGW, now with the more I read, the less I’m convinced.”

    Well, it depends upon what you have been reading, and how hard you have been willing to work at the details. For example, if you have been reading from Plimer’s tome, then you have a problem. You see, that book isn’t science, as Ian Plimer himself explains on Lateline earlier this year:

    By contrast to what Barry Brooks says, this book is not a book of science. It’s a book for the public who have felt quite disenfranchised and quite helpless that they have scientists talking down to them and they know there’s a smell, they can’t quite work out where the smell’s from, but they know there’s a smell, and this book is to give the public some information such that they can say, I think we’re being led astray.

    The difficulty here is that Plimer has written a book that has taken a detour past the usual scientific process, which he justifies by saying it isn’t a book of science. Fair enough at this stage. But then, he goes on to make the book a centre-piece in his all out assault upon climate scientists and the like. As far as I’m concerned that is reprehensible behaviour because Plimer, of all people, knows why the scientific process matters. Once a scientist starts misbehaving as badly as this, they are off my Xmas list.

    These sorts of landmines make it more difficult than ever for a newbie to get a starting point on Climate Science that is scientifically honest; this site here isn’t bad (in fact it is very good, excellent even) at doing just that. Have a perusal through the archives and you will find some great articles which help you to find a way into the literature, should you wish to venture that way.

    Good luck.

    Comment by Donald Oats — 19 Nov 2009 @ 10:18 AM

  91. I would like to gauge some opinion on using Geo-engineering as a solution to global warming. The telegraph made this report last week:

    http://www.telegraph.co.uk/earth/copenhagen-climate-change-confe/6498732/Geo-engineering-might-help-tackle-climate-change-but-do-we-really-want-every-cloud-to-have-a-silver-iodide-lining.html

    Would this type of activity on a wider scale be a solution to the warming that is occuring? Or possibly this:

    http://current.com/1g2mm4c

    Now that’s two questions there, don’t kill me!! haha j/k, hope you got a sense of humor :)

    Thanks guys

    Comment by Pat — 19 Nov 2009 @ 10:50 AM

  92. Carbon taxes are a bad idea, unless connected to renewable energy feed-in tariffs. Just look at the record around the world – all the countries with the biggest renewable energy programs have instituted significant feed-in tariff programs.

    What this would do is obligate all of the nation’s utilities, public and private, to buy power from renewable energy producers at above market rates. These guaranteed above-market rates give investors the confidence to put money into solar projects that will pay off over 10-20 years if they are guaranteed market access.

    Unlike a carbon tax, feed-in tariffs for renewable energy technology are designed to be phased out once the technology reaches about 20% market penetration. At that point, the technology should be able to compete with old fossil fuels with no assistance, as long as the government subsidies for fossil fuels are removed.

    Using this strategy, it should not be too hard to get 20% wind and 20% solar electricity generation across the U.S. – and with another 20% coming from nuclear, you could, within a decade, end up with a 60% non-carbon energy power system.

    This would mean the end of coal, it is true. But isn’t that the goal?

    Not according to the U.S. government, specifically Assistant Secretary for Land and Minerals Management Wilma Lewis:

    “America’s vast coal resources are a vital component of our energy future and our economy, but we have a responsibility to ensure that development is done in a way that protects public health and safety and the environment.

    How are you going to meet Obama’s campaign promise to “roll back global warming” without getting rid of coal combustion? With cap-and-trade and carbon capture and sequestration? That’s not going to work – both strategies are failures, economically and technicallly. Neither one results in lowered fossil CO2 emissions or renewable replacements for fossil fuels.

    An entirely new strategy is needed, one that doesn’t cater to coal and tar sand operations.

    Comment by Ike Solem — 19 Nov 2009 @ 11:24 AM

  93. P.S. for a good discussion of the issue of whether carbon sinks filling up to the point of exhaustion, see:

    http://arstechnica.com/science/news/2009/11/have-we-started-to-fill-our-carbon-sinks.ars

    John Timmer did a very good job of discussing two different papers on the subject, as well as pointing out how various other media outlets were distorting the results:

    So, are carbon sinks beginning to reach their limits? Given the two papers, I have to admit I lack the expertise to judge.

    What is clear, however, is that two extremely cautious and technical papers have been handled awkwardly from a media perspective. The GRL paper was heralded with a press release that touted it as “Controversial new climate change data,” even though it didn’t directly address climate change, and actually applies new methods to existing data sets. Two articles removed from the press release, and you end up with an article that claims “new research shows that atmospheric levels of CO2 have effectively remained unchanged since the advent of the industrial revolution.” It’s hard to imagine anyone getting it so badly wrong.

    Press release, GRL paper: “Controversial new climate change data”

    New data show that the balance between the airborne and the absorbed fraction of CO2 has stayed approximately constant since 1850, despite emissions of CO2 having risen from about 2 billion tons a year in 1850 to 35 billion tons a year now

    http://www.eurekalert.org/pub_releases/2009-11/uob-cnc111009.php

    Press release, Nature Geosciences paper: “Fossil fuel CO2 emissions up by 29 percent since 2000.”

    The strongest evidence yet that the rise in atmospheric CO2 emissions continues to outstrip the ability of the world’s natural ‘sinks’ to absorb carbon is published this week in the journal Nature Geoscience…

    http://www.eurekalert.org/pub_releases/2009-11/uoea-ffc111609.php

    Interestingly, both see an increase in the airborne fraction, but the GRL author claims this is due to land use variables, not to sink limitations – the Nature Geoscience folks disagree.

    There is a third line of research as well that relates here:
    CO2 emissions caused by humans rise 2% despite global financial crisis</a

    …despite the economic effects of the global financial crisis (GFC), carbon dioxide emissions from human activities rose 2% in 2008 to an all-time high of 1.3 tonnes of carbon per capita per year. The research, by scientists from the internationally respected climate research group, the Global Carbon Project (GCP), said that rising emissions from fossil fuels last year were caused mainly by increased use of coal, but there were minor decreases in emissions from oil and deforestation.

    There are clear physical reasons why CO2 uptake by plants and the oceans is set to decrease, and this seems to be going on. Coal remains the #1 problem, as well as the #1 opportunity for reduced emissions. Despite the full-scale propaganda effort, there’s no way to burn it for energy generation without increasing fossil CO2 and hydrocarbon residues in the air and mercury, arsenic, and sulfur pollution in water and soils. Cap-and-trade won’t solve it, sequestration doesn’t work, and that leaves replacement with renewables as the only option, assuming you want to keep the lights on while avoiding terminal climate destabilization and ecological collapse.

    Comment by Ike Solem — 19 Nov 2009 @ 12:02 PM

  94. #69, Thomas, you are fortunate to have climate skeptics around you who are into “saving energy, both for the impact on their families expenses, and because they know energy insecurity is an issue for the country.”

    Most denialists I’ve known just don’t care about the plethora of measures they can take to reduce GHGs and save money. Probably because most measures in themselves don’t save a whole lot — it’s mainly when you add them all up that you realize bigger savings; and then many are a “wash” which neither cost nor save.

    So I’ve come to realize that it takes heart (not just an economic mind) to mitigate GW; heart to seek out and find solutions and more heart to implement them. Because most solutions are very very small, and people don’t care about pennies & don’t think that pennies add up to $$ and eventually to big $$. They just can’t be bothered.

    And we are too rich to bother.

    And (skip the carbon taxes) there’s the subsidies to coal and oil (not even counting the military costs & lives involved), so we’re paying the rest of our energy & product* bills April 15th, even if we have electric cars running on 100% wind power and conscientiously reduce, reuse, recycle, & buy recycled, and thus don’t use nearly as much (direct/indirect) oil/coal as our neighbors, but have just as high a living standard and accomplish just as much as they.

    So we’re paying for our neighbors’ oil/coal addiction on April 15th. But more than that, what really hurts me, is we’re paying for their killing of people in Africa thru GW harms.

    Where’s Stupak when you really need him?
    ______________________
    *Note that most products have an energy (most likely fossil fuel) component, and/or involve other GHGs.

    Comment by Lynn Vincentnathan — 19 Nov 2009 @ 12:30 PM

  95. 77. Comment by Andrew Hobbs — 19 November 2009 @ 1:15 AM
    “I too have read lots in that time and I can’t seem to find anything, anything at all, that would make me less convinced.”

    That really is an astounding comment Andrew.

    You had to have been shletered by some means from the plethera of material produced by the dozen or so major skpetics and their troops.
    Even Gavin has acknowledged their existence and work.

    Respone: I doubt the issue is that Andrew doesn’t think they exist. Rather that they are not convincing. And indeed they are not. – gavin]

    Many of us who have long followed the issue by devouring both sides of the “campaign” grow more conviced there is insufficient science to sustain the IPCC/AGW theory.

    Respone: It’s a well known trick to strengthen your convictions by convincing yourself that more and more people are agreeing with you. That may or may not be true, but it makes no difference to the truth or falsity of your actual belief. – gavin]

    For one to state that they can’t find anything at all is a little too convenient.

    Perhaps the debate here is insufficient. Offering or allowing too little of what you appear to be missing.

    It may be a result of challenging posts recieving a less than welcome response.

    Round we go.

    Respone: Round we go? Who are the people keep stating that Gerlich has proved the greenhouse effect doesn’t exist? Who brings up Miskolciz who says it exists but can’t change? Who brings up Essex saying that there is no such thing as a surface temperature in any case? Not us. If there is round-and-round arguments happening, it’s because the ‘anything-but-carbon’ crowd can’t let anything go and refuse to spend even one iota of critical thinking on dumping the nonsense. Why you find it surprising that this isn’t convincing to people who know something about the subject is the real surprise. – gavin]

    Comment by John H. — 19 Nov 2009 @ 1:25 PM

  96. Pat, you link to the Freakonomics/Geoengineering notion and an earlier notion about covering deserts with something shiny — you must have missed the extended discussion of both of those ideas; the Search box (top of the page) will find it. Try ‘geoengineering’ and ‘albedo’ as search terms.

    Comment by Hank Roberts — 19 Nov 2009 @ 2:12 PM

  97. Some people have asked about the causes of the wide ring widths in the graph about 3500 years ago. In addition to what’s already been said on that, I did some quick analyses on the data from the 3 treeline sites in the study, using a simple robust biweight mean of the ring widths, all trees included.

    Couple of points. First, the pattern of that spike differs between the two sites where there is any decent sample size (SHP and MWA), and even at those it is very marginal (n = 20) (which generally takes one back about 1100 to 1500 years b.p.) the recent increase is very coherent among the sites, and unprecedented at each, as per the authors’ Fig 4b, but taken further back in time.

    Comment by Jim Bouldin — 19 Nov 2009 @ 4:15 PM

  98. That post was apparently mangled by inequality signs. Second try here.

    Some people have asked about the causes of the wide ring widths in the graph about 3500 years ago. In addition to what’s already been said on that, I did some quick analyses on the data from the 3 treeline sites in the study, using a simple robust biweight mean of the ring widths, all trees included.

    Couple of points. First, the pattern of that spike differs between the two sites where there is any decent sample size (SHP and MWA), and even at those it is very marginal (n under 10). At SHP the spike is very pronouned about 3800 years ago, whereas at MWA it is lower but broader, covering several hundred years to about 3300 years ago. The third site (PRL) had only a couple samples that old, and is thus very unreliable. Conversely, for each period, across the sites, having a respectable sample size (n over 20) (which generally takes one back about 1100 to 1500 years b.p.) the recent increase is very coherent among the sites, and unprecedented at each, as per the authors’ Fig 4b, but taken further back in time.

    Comment by Jim Bouldin — 19 Nov 2009 @ 4:20 PM

  99. Since it does little good (and Gavin dislikes it) I won’t go into any detail but just say, in my perfunctory response to refute Ike (72), use my tobacco rebuttals #3 and #4.

    In a more helpful topical vein and in keeping with Guy’s concern (if not his recommendation) I do not think hyperbole and conspiracy theories peppered with hubris and arrogance is a good way to win hearts and minds.

    Comment by Rod B — 19 Nov 2009 @ 4:21 PM

  100. Ok, my post from last night on GCMs doesn’t seem to have appeared for some reason, but..

    @ Donald Oats: Haven’t read Pilmer, but web-sites, blogs and source articles where I can and time allows. Tried to cover the full spectrum of views in order to establish my own.

    @ Lynn Vincentnathan: Thanks for the link to the Hansen article; hadn’t come across that before. His ideas are interesting, and personally more palatable than the creation of a carbon market. As for Galeleo, that’s just an example. The point I was trying to make is that just because the current wisdom supports a certain hypothesis about how a system works, then someone else comes along with an alternative hypothesis, that person isn’t necessarily dumb, stupid, ignorant, uncaring, etc. They’re not necessarily right either. Knowledge advances when information is collected to determine the degree of support for the different hypotheses. If you want to get all Popperian about it you’d be trying to falsify hypotheses although there no reason you can’t do science under a multiple hypothesis framework either. I’m not trying to suggest I’m right and you’re wrong, I’m just saying I don’t view things the same as you at this point in time and that as I read and learn more, my view may change and so may yours ( ;-) ), that’s the way of life.

    @ Hank Roberts: I’m actually an ecological statistician with a PhD and 10 years experience behind me. I’m well versed with models and computer simulations as such are aware of the pros and cons of such approaches. GCM’s are a couple of orders of magnitude more complex that anything I’ve ever dealt with, but the basics are still the same. I also think hard about appropriately accounting for and expressing uncertainty in estimated quantities. Things like error bars on quantities that are clearly estimates seem to be in short supply in much of the literature I’ve read to date. Data quality and sample sizes are also something I think hard about. When you’re working with data that wasn’t expressly collected for the current topic of interest and/or very small samples sizes then it is possible for the statistics to mislead you.

    I know about the physics side of thing with CO2, but my understanding is that that only contributes a certain percentage of the projected warming (can’t recall the figure off the top of my head), the rest comes from hypothesized positive feedbacks.

    Constructive comments and links appreciated.

    Comment by D MacKenzie — 19 Nov 2009 @ 4:22 PM

  101. #60 anony mouse
    It’s a staple at RC to proclaim that “people thought the earth is flat”.
    NO ONE EVER THOUGHT THE EARTH IS FLAT. It’s a joke invented by Washington Irving in a fanciful account of a conference in 1491 at the University of Salamanca to investigate Columbus” claim that he could reach China by sailing west. The faculty told him he had rigged the numbers to make the earth smaller and China larger (which he had) and he and his crew would die of thirst if he tried. But if anyone suggested that they would fall off the end of the earth, they would have laughed themselves to death.

    Comment by monty — 19 Nov 2009 @ 4:29 PM

  102. Hank, 19 November 2009 at 2:12 PM

    Albedo… reminds me of this odd study by I think the university of bristol or something that claimed that the change of land use has been cause of a substantial part of the warming and the inclusion of the ‘we should slow down the deforestation’ comment in there… duh. I thought that agricultural land increased Albedo. Aside deforestation, interrupting the water vapor cycle at that, I’m more worried about the millions of square km of additional snow cover missing during summer period and the effects it has on the underlying permafrost. Coal plant sooth part of the cause?

    Comment by Sekerob — 19 Nov 2009 @ 4:35 PM

  103. #101 Hmm. “No one “, “ever”. China perhaps before 1000CE. Ancient Egypt, Babylon and other Mesopotamian cultures. Hunter/gatherer culturers in many parts of the world? On other hand I agree that it was not the world view of Europe at time of Columbus.

    Comment by Phil Scadden — 19 Nov 2009 @ 5:02 PM

  104. Andrew Hobbs wrote: “I too have read lots in that time and I can’t seem to find anything, anything at all, that would make me less convinced.”

    John H wrote: “You had to have been shletered by some means from the plethera of material produced by the dozen or so major skpetics and their troops.”

    The plethora of material produced by the dozen or so major “skeptics” and their troops is powerfully convincing, alright — it has powerfully convinced me that the dozen or so major so-called “skeptics” are brazenly, deliberately dishonest frauds and/or ill-informed, arrogant cranks, who neither understand nor care to understand the basic science, and their “troops” are gullible dupes who think a “skeptic” is someone who unquestioningly believes whatever Rush Limbaugh says.

    Comment by SecularAnimist — 19 Nov 2009 @ 5:06 PM

  105. Dave McKenzie. Alternative hypotheses are welcome – wouldnt we be relieved if it was suddenly discovered that AGW was wrong? However, alternative hypotheses are few on ground and they are only welcome if they make physical sense and match empirical observation better than current theory. AGW wins big time here. There is vast amounts of MISinformation, fraud and downright lies on various blogs – try sticking to the published science for fact. At very least, read IPCC WG1, SPM (Summary for policy makers). This outlines the science in easy to understand way. You delve then into the WG1 chapters for more detail, and from there to the science papers themselves.

    If you still think that blog science has points to make over the published papers, then RC would be very happy to discuss these with you I am sure.

    Comment by Phil Scadden — 19 Nov 2009 @ 5:11 PM

  106. Is it possible to determine how much of the increased tree ring width in recent times is attributable to a more readily available supply of carbon dioxide? Is there any evidence that the width of the tree rings is increasing (perhaps in proportion to the increase of atmospheric CO2). Interested in whether this is significant and if so, how the observations are altered, if necessary, to accommodate for the increase in CO2.

    Comment by JE — 19 Nov 2009 @ 5:30 PM

  107. @ Donald Oats: Haven’t read Pilmer, but web-sites, blogs and source articles where I can and time allows. Tried to cover the full spectrum of views in order to establish my own.

    Do you do this with all areas of science, or do you just study anti-science sites on the subject of climate science?

    For instance, if you want to understand physics, do you seek “balance” by reading perpetual motion crank sites?

    Do you seek “balance” on biology by reading Answers In Genesis? Or do you “balance” geology by studying the writings of those who claim the earth is 6,000 years old?

    If not, why not? What is it about climate science that requires “balancing” knowledge with outright lies? That’s what these people are doing. They’re lying to you. Why pay them attention?

    As for Galeleo, that’s just an example. The point I was trying to make is that just because the current wisdom supports a certain hypothesis about how a system works, then someone else comes along with an alternative hypothesis, that person isn’t necessarily dumb, stupid, ignorant, uncaring, etc.

    Galileo is a horrible example, as it really had nothing to do with science at all. If anything, climate scientists are in the position of Galileo vs. the Church. The Church claimed we should ignore observation when it contradicts the Bible, and if you get special permission from the Pope to very carefully put forward data in opposition to the Bible, don’t put the Pope’s words and beliefs in the mouth of a character whose name can be translated as “simpleton”. Doing so led to Galileo being hauled up in front of the Inquisition.

    Today, we have an anti-science backlash which in essence says we should ignore observation/science when it contradicts certain political beliefs. Ignoring this dogmatic insistence risks your being hauled in front of Inhofe’s Inquisitional Senate Committee where you’ll be accused of scientific fraud on national TV.

    I’m well versed with models and computer simulations as such are aware of the pros and cons of such approaches. GCM’s are a couple of orders of magnitude more complex that anything I’ve ever dealt with, but the basics are still the same.

    There are different kinds of models and simulations so how do we know for certain that your experience is with models that are essentially the same as GCMs? Describe models you’re well-versed with, please.

    I know about the physics side of thing with CO2, but my understanding is that that only contributes a certain percentage of the projected warming (can’t recall the figure off the top of my head), the rest comes from hypothesized positive feedbacks.

    Why do you say they’re “hypothesized”? Why, for instance, is the statement that water vapor is a GHG a “hypothesis” rather than an observed fact? Why, for instance, is the statement that absolute water vapor will rise with temperature if there’s sufficient liquid water around to evaporate a “hypothesis” rather than part of established physics?

    I also think hard about appropriately accounting for and expressing uncertainty in estimated quantities. Things like error bars on quantities that are clearly estimates seem to be in short supply in much of the literature I’ve read to date.

    Yeah, right. This explains why climate sensitivity is nailed down to being roughly 2 to 4 C per doubling of CO2. It’s precise to so many digits because climate science is unaware of notions like “error bars” and “uncertainty”…

    Comment by dhogaza — 19 Nov 2009 @ 5:44 PM

  108. @ Phil Scadden: read big chunks of IPCC AR4, and that’s what got me really going down my current track. Bit ironic really. ;-)

    Comment by D MacKenzie — 19 Nov 2009 @ 5:46 PM

  109. Re 101: “NO ONE EVER THOUGHT THE EARTH IS FLAT.”

    The fact that the earth was a sphere had to be discovered. Educated people knew of the discovery. JB Russell’s paper goes over the details “Inventing the flat earth: Columbus and modern historians”

    However most people were not so educated. Even some educated people, up to the 1800’s, found this to be in conflict with their religious views and worked mightily to disprove the theory. The most famous was Parallax, see http://www.sacred-texts.com/earth/za/.

    Similarly just because most educated people believe the Earth is 4.6 billion years old does not mean that is what everyone believes.

    Comment by mike coombes — 19 Nov 2009 @ 5:53 PM

  110. D MacKenzie – okay what did you read in IPCC AR4 that made you more skeptical?

    Comment by Phil Scadden — 19 Nov 2009 @ 6:20 PM

  111. Read big chunks of IPCC AR4, and that’s what got me really going down my current track. Bit ironic really. ;-)

    Great, D MacKenzie. So now you’ll have no problem telling us precisely where you think climate science has it wrong. If you’re right, you’ll find us easy enough to convince.

    Comment by dhogaza — 19 Nov 2009 @ 6:22 PM

  112. > JE says: 19 November 2009 at 5:0 PM
    > Is it possible to determine how much of the increased
    > tree ring width in recent times is attributable to a more
    > readily available supply of carbon dioxide?

    That’s where the timberline comes in handy. CO2 is a well mixed gas and the CO2 will change in the same proportion everywhere on the mountain. So they look for the place where a slight increase in temperature will allow trees to grow noticeably better, right at the timberline.

    Comment by Hank Roberts — 19 Nov 2009 @ 6:29 PM

  113. D. Mackenzie writes:

    “Things like error bars on quantities that are clearly estimates seem to be in short supply in much of the literature I’ve read to date.”

    …which leads me to believe you haven’t read much of the scientific literature including “big chunks of IPCC AR4″. You might be interested in this concise review article on the lines of evidence leading to estimates of climate sensitivity. You can follow the various studies it summarizes. It’s pretty hard to miss the error bars.

    http://www.iac.ethz.ch/people/knuttir/papers/knutti08natgeo.pdf

    Feedbacks aren’t merely “hypothesized”. Some are observed as well.

    http://www.agu.org/pubs/crossref/2008/2008GL035333.shtml

    Comment by MarkB — 19 Nov 2009 @ 7:13 PM

  114. re #’s 103-&-109 Flat Earth
    It may be true that only educated people knew that the earth is a sphere but the poor couldn’t have cared less, living very hardscrabble lives. As far as dates go, Erastostenes in 300BC calculated the circumference of the earth within 2%.

    Comment by Monty — 19 Nov 2009 @ 7:56 PM

  115. Jon at 29

    re Hastings – I recall reading that Britain is rising at the north end and sinking at the south. Bit like a see-saw with a large weight (a mile or so of ice) taken off one end. So the sea level would be higher (actually land lower) 1000 years ago.

    Another possible explanation is that the salt marshes which fringed the coast have gone due to human activity – leaving a wider margin of firm ground.

    Comment by Peter T — 19 Nov 2009 @ 8:44 PM

  116. Could someone point me to a study analyzing the early 80s downturn in GHG emissions and corresponding registered CO2 etc. levels – which, to my not so keen eye, look not to have noticed the concurrent change at all. This is puzzling, and alarming. I wouldn’t be surprised if someone has attempted to put it forth as evidence that anthropic sources have nothing to do with CO2 levels, too.

    A recommendation for a book covering the subject would be welcome as well. I’ve snooped around a bit for info but to no avail.

    Comment by KLR — 19 Nov 2009 @ 8:49 PM

  117. D MacKenzie: Dhogaza makes an important point that I think needs to be reinforced when he writes, “This explains why climate sensitivity is nailed down to being roughly 2 to 4 C per doubling of CO2.” If climate sensitivity with feedbacks is much less than 2°C/doubling, then we can breathe a sigh of relief, but if it is in the 2°-4.5° range we have real problems.

    I hope in your perusal of the literature, you’ve found John Cook’s excellent post describing Knutti & Hegerl’s review of the various climate sensitivity calculations. Yes, there is a range, but there are constraints. James Annan used another observation-based analysis to bolster the consensus 3°C value.

    If anyone tells you differently, they need to show pretty strong evidence.

    Comment by Deech56 — 19 Nov 2009 @ 9:08 PM

  118. I hope that humans have enough foresight to plant bristlecone pines in a number of habitats in hope that some might survive long enough to provide a long history, for whatever intelligent creatures might want to know why the climate tanked in the previous five or ten thousand years.

    Comment by Dan M — 19 Nov 2009 @ 9:10 PM

  119. JE @106 – you should read the paper that this post points to – they explicitly test whether an effect such as increased CO2 could have caused the wider rings, but have to discard that hypothesis because the data very clearly doesn’t support it.

    There is a good reason why these tree ring chronologies all seem to come from very cold places and not just any old trees…

    Comment by William T — 19 Nov 2009 @ 9:32 PM

  120. #71 D.MacKenzie,

    “10 years I whole-heartedly agreed with AGW, now with the more I read, the less I’m convinced.”

    Maybe you should stop reading so much and get out a bit more. Visit the countryside or the mountains, ask the old locals a few questions…

    Comment by William T — 19 Nov 2009 @ 9:44 PM

  121. A bit off topic, but it is highly likely Parallax knew the earth was round. He was just an artful scammer who knew where the fame and money lay. However, some of the people who took up his torch were almost certainly genuine believers in a flat earth. [/OT]

    Comment by Ken — 19 Nov 2009 @ 10:53 PM

  122. #95 John H
    Thanks Gavin, I couldn’t have put it more succinctly myself.

    It is a bit hard for immediate comment with the rest of you being so out of phase with the real world here, in Australia. :-}

    As for the original comment. I have probably read as many articles arguing against global warming as I have for it, and, indeed, I am sure that I have seen at least some of “the plethera (sic) of material produced by the dozen or so major skpetics (sic) and their troops.”

    However if I forget the myriad of articles with little substance, and only consider those published articles which have ‘original’ research results or ‘original’ re-analyses of published results, many have flaws which even I, as a non-statistician and non-climatologist, can see through. By the time one includes the papers where the flaws have been pointed out by professional statisticians and climatologists, and one can follow the arguments etc, there really isn’t much left. Certainly none come even close to suggesting I should rethink my position on AGW.

    Besides which the stage at which one or two contrary results can completely ‘disprove’ AGW is long past. Such a position may have been acceptable in the middle of last century. Now the hypothesis of AGW and its ramifications have been so well studied, it explains so many phenomena that are happening today, and it fits so well with well established, fundamental physical principles it would take much more to overturn it than a few contrary results that may have been misreported, misinterpreted etc.

    Comment by Andrew Hobbs — 20 Nov 2009 @ 9:24 AM

  123. Mike,

    Re #84. Thanks for your answer. I did understand that the data was from Graybill and Idso’s study and I did get the point about the standardisation. I was just struck by the difference in trends between the strip-bark and whole-bark over the period shown in the graph (S4).

    When you say “Before that, the whole bark trees have wider rings because the whole bark trees are younger” is that because really old trees eventually all become strip-bark? Are there any/many old whole-bark trees or young strip-bark trees? (Reminds me of “there are no old, bold pilots…”) Thanks.

    Comment by Tony Rogers — 20 Nov 2009 @ 1:26 PM

  124. William T (120), the old Ted Turner proof of AGW, eh?

    Comment by Rod B — 20 Nov 2009 @ 3:38 PM

  125. #123 – Tony. It is harder (but not impossible) to find whole bark trees at the highest elevation. The mean segment length given in the S4 figure caption (1,052 years for strip-bark and 279 years for whole-bark) indicates that the whole bark trees are younger and therefore faster growers. The lack of trend in the young whole bark trees from figure S4 is interesting. There is no guarantee that Graybill and Idso sampled their strip-barks and whole barks at the same elevation. And the Salzer paper makes it clear how important very short elevation differences are that to modern trends! Compare the trends in the whole barks from figure S4 to figure 3 and see what you think.

    Comment by DrCarbon — 20 Nov 2009 @ 4:17 PM

  126. Re #125 – DrCarbon. I would say that the whole-barks in figure S4 and figure 3 are fairly similar over the period shown for the Graybill data; about .4mm to .8mm +/- quite a lot using my Mk 1 eyeball. The strip-bark differences between the two are greater, Graybill’s showing a much larger trend.

    Maybe it depends which strip-barks you choose or how much bark they lost? Salzer has shown that trees below the upper forest border don’t show the thickening trend so I wonder what the location/situation of Graybill’s strip-barks were and why they show such a marked trend?

    Assuming Graybill’s strip-bark data was correct and show a very high ring witdth trend whilst Salzer’s strip-barks (on average) were no different to whole-barks, doesn’t that mean you have to very careful about which strip-barks you use and test to check that they are not anomolous in comparison with whole-barks? I would probably conclude that it may not be wise to use Graybill’s strip-barks in a reconstruction rather than conclude that all strip-barks are as good as whole-barks.

    Comment by Tony Rogers — 21 Nov 2009 @ 7:11 AM

  127. D MacKenzie (#100): the feedbacks are more than “hypothesized”. The starting point for understanding the contribution of CO2 to climate was paleoclimate studies that attempted to explain movement in and out of ice ages, when it turned out that energy variation arising from adjustments in the earth’s orbit and axial tilt were insufficient to explain the magnitude of the resulting temperature shifts. We know that any initial trigger for warming will increase humidity, because relative humidity tends not to vary, and water vapour is a greenhouse gas. We know that if there is less ice on the planet, its albedo decreases, increasing absorption of incoming radiation. We also know that if the oceans warm, their capacity for holding CO2 decreases. All of these things are well studied in paleoclimate research, going back to the 19th century. You also can’t explain venus without an interplay between factors like runaway water-vapour driven initial greenhouse warming, followed by subsequent absence of chemical processes requiring liquid water to scrub CO2 out of the atmosphere. You can find all this on this site, or at Spencer Weart’s Discovery of Global Warming pages (or find his book with the same title). You can also find Raypierre’s The Climate Book if you’re quick: it will disappear from the web once published.

    This stuff is extremely well studied through both paleoclimate research and planetary climate research. The myth that this is some new, flaky area of science made up by pot smoking hippies to de-industrialise the world is an image created by the denial camp because they have no plausible competing hypothesis let alone theory. They don’t particularly care even if they contradict themselves, as long as they keep the uninformed public confused. If you read the denial sites uncritically, you will certainly get confused, because that’s the goal. Read them critically and you will quickly realise that there is no plausible alternative theory out there (if there were, we’d all be happy, because disaster is not something one likes to predict, particularly when the political will to avert it doesn’t exist).

    Here’s a little experiment for you to try: search for “DNA not double helix molecule”. You’ll find at least one person pushing that particular barrow. Why does he not get regular column space in The Australian? The Watson-Crick discovery of the double helix structure of DNA has roughly the same amount of history behind it as the discovery of the greenhouse effect. Why, you have to ask yourself, does a conservative newspaper give massive publicity to one bunch of dissenters against mainstream science, and completely ignore another? I have some ideas, but I’ll leave this as an exercise for the reader.

    Comment by Philip Machanick — 21 Nov 2009 @ 7:26 PM

  128. A few comments on the tree questions:

    Regarding damage to the trees caused by sampling – as others said above only small cores are removed from living trees and the holes heal within a year or two. Trees are well adapted to survive damage that naturally occurs and pines are particularly adept producing resins that seal off the wounded area prior to covering it with new tissue. Tree stems function as mechanical support and consist largely of dead tissue. Additionally, this study made use of a large number of samples that came from dead wood.

    Regarding the strip bark form of growth – full-barked trees of any species must grow larger every year. This is the nature of the growth form, as older tissue becomes non-functional new cells must be produced and added to the core every year. One can see that for an organism capable of living thousands of years this mandate to become larger becomes a liability – the larger you become the more gravity is your enemy. The larger you become the more living tissue must be supported by providing an ever increasing volume of food and water.

    Among other long-lived species like giant sequoia that don’t have strip-bark growth form death by falling over is extremely common. These trees commonly deal with the height-growth problem by dying back at the top once they reach about 250′, but they still increase in circumference every year.

    The strip bark growth form allows trees like the bristlecone to maintain a relatively fixed amount of live tissue that needs to be supported. The trees don’t become taller every year and suffer increasing risk of toppling over. The oldest trees typically grow only along one or two linear axises and maintain relatively fixed live crown, bark, and root ratios.

    Because of this growth adaptation the usual geometric growth problem that afflicts a full-barked tree that is adding circumference every year (and necessitating mathematical treatment by standardization to remove this geometric growth trend from ringwidth series) is minimized or eliminated.

    Val LaMarche used the raw bristlecone pine ringwidths to make climatic inferences in a 1974 paper: LaMarche, Jr., V.C. 1974. Paleoclimatic inferences from long tree-ring records. Science 183: 1043-1048.

    Regarding the contribution of increasing CO2 to growth: The authors make the point that trees growing at lower elevations (with similar CO2 concentrations) do not show increased growth over the past century – despite the fact that trees growing at lower altitudes respond strongly (positively) to moisture availability and thus might be expected to benefit from increases in CO2 concentrations by increasing their water use efficiency, and thus their growth rates. For this reason the authors assign the most likely cause of the increasing growth at upper treeline to warming and rule out CO2 as an important factor.

    Comment by CB — 22 Nov 2009 @ 1:51 PM

  129. When I said “hypothesized” I was meaning it in a general sense about how people believe a system was working, didn’t mean to imply that there might be no data supporting such a view.

    Comment by D MacKenzie — 22 Nov 2009 @ 3:06 PM

  130. One additional note:

    Although I haven’t seen it mentioned in comments here the break in the time series graph at about ~2,000BC is related to frost damage to trees at these sites around 2,030BC. The damaged ring presents a site of physical weakness that is attacked by the weathering process and over thousands of years wood from this time period fractures and decays leading to a discontinuity in a majority of samples – and thus low sample depth and inability to properly estimate the curve value.

    Comment by CB — 22 Nov 2009 @ 5:39 PM

  131. Re: #17, Pinus longaeva is generally found at elevations of over 3000 m., including sites in California such as the ones mentioned outside of Bishop. The highest mountains in the geographic range of this species get up to about 4300 m. (the White Mountains near Bishop) but most mountain ranges where these trees grow top out at more like 3500 m.,leaving little range for upward expansion. Natural expansion northward (via planting of seeds by birds) would be possible with a much slower warming process, but at the likely speed of warming this migration will need to be artificially assisted.

    Re: #130, cross-dating of discontinuous tree ring records to continuous ones is routinely done to enable accurate dating of such records. This is basic dendrochronology.

    Comment by Bill DeJager — 22 Nov 2009 @ 9:30 PM

  132. Dear Bill,

    I was just pointing out the reason for the gap in the figure – low sample depth because of a physical problem with the majority of samples. Of course the earlier portion is cross-dated using the few continuous specimens and material from lower elevation sites that don’t experience severe frost damage.

    Comment by CB — 22 Nov 2009 @ 9:43 PM

  133. I have only just had time to read the paper in full and have not read all of the comments here, so someone might have answered this. If the trees at the lower sites are responding negatively to increased temperatures and are located as little as 150m below to trees at the upper sites which are responding positively to temperature, this suggests to me that only a small increase in temperature (less than 1.5 C) above the present will result in the upper trees first becoming unresponsive to temperature and then flipping and responding negatively to increased temperature, like the lower trees. Given this , these trees seem unlikely to show evidence of higher temperatures that may have existed in the past, indeed higher temperatures in the past will look like lower temperatures, so how useful really are these trees as temperature proxies?

    Comment by Paul Gosling — 23 Nov 2009 @ 10:30 AM

  134. A good question Paul. I didn’t see that the authors addressed this in the main paper and I haven’t read through the supplemental material, but here is a quick answer.

    Treeline has fluctuated over time at these and all similar sites. There is an abundance of remnant material above current treeline and many of the samples used came from this pool. All samples were mapped with a GPS and it is possible to map the target zone as it fluctuated through time. The presence of latewood frost rings in a sample is also a pretty clear indication that the tree was growing within this zone.

    While it is true that individual trees can live over 5,000 years and thus would have experienced changes in their surrounding environment over such a span, typical samples are from trees that were a few thousand years of age and lived out their span within one or other of the response zones.

    I believe the authors are working on modeling the tree-line fluctuations and their relationships to temperature and would expect to see more from them on this subject.

    Comment by CB — 23 Nov 2009 @ 11:05 AM

  135. Paul, I think you’re mixed up there.
    Think about the time series of events.

    Look at the long slow cooling since the last ice age
    (from many different proxies)

    http://www.globalwarmingart.com/wiki/File:Holocene_Temperature_Variations_Rev_png

    Look at the change of the Bristlecone treeline over time — it’s been moving downhill until the very recent past:
    http://www.jstor.org/pss/1550214
    Those remnant trees above current treeline go back many thousands of years.

    Look at the sudden temperature jump (the line rises to “2004” at the right edge of that picture)

    Comment by Hank Roberts — 23 Nov 2009 @ 2:18 PM

  136. Hank

    It looks to me as if the presence of so many large trees above the current tree line is confirmation that this location was much warmer in the past and therefore the trees at the current tree line are highly likely to have had a negative response to temperature in the past. It’s a hell of a job to try and disentangle when the current tree line trees flipped from negative to positive temperature response, I guess using ‘fossil’ wood from above the current tree line, but still, rather them than me.

    Comment by Paul Gosling — 24 Nov 2009 @ 8:19 AM

  137. Following the money trail:

    Can anybody name 2 scientists who aren’t paid directly or indirectly by government (that includes Friends of the Earth) or charities/foundations specificly committed to alarmism who have said catastrophic warming is real. That excludes statements along the lines of “most of the 20thC warming (0.6C) may be anthropogenic” but genuine catastrophism.

    Comment by Neil Craig — 24 Nov 2009 @ 11:16 AM

  138. Paul, the short answer is they are still highly useful, notwithstanding the fact that you have hit directly on a very important point. You’re touching on one of the possible causes of divergence (there are other, non-environmental, possible causes as well; see Esper and Frank, 2009). This is one of the difficulties of using any biological proxy–it’s always constrained to function best only within a certain range of environmental forcings (temp in this case), and if you go beyond that range, its responsiveness WILL decrease, as you note. In this case, it even flips from + to – response.

    One of the key points of this, and many, TR reconstructions, is the spatial aspect. The comparison of their Sheep Mtn chronology, with the two treeline chrons in eastern Nevada, as shown in their Fig 4b, shows a broadly concordant spatio-temporal pattern–that’s important. One could argue that this would not be the case if any of the 3 sites had become unresponsive to temperature over the past 600 years. However, the 3 sites are not perfectly correlated over that time (e.g. the 1700s aren’t as “tight” as the other centuries are), so maybe climate-change induced divergence is the cause of that. But that could also be explained by say, differences in the spatial patterns of weather systems/air masses at different points in time, not changing tree sensitivity. Such different possibilities could be tested by intensifying the spatial sampling and looking at the spatio-temporal concordance between sites.

    Also, I’d add that I’ve extended their figure 4b back about 500 to 1000 years further, depending on site sample size, with some quick analyses, and the concordance still holds over the last 1000 to 1500 years.

    The other thing to keep in mind is that their elevational transect in the Whites was not all from one place–the lower elev chrons were 1 to several km away from the treeline chron at Sheep Mtn. There could thus have been topographic factors, esp slope aspect, at work in addition to the elevational gradient. Maybe they accounted for that though–I’ll have to check again.

    But I like your thinking. It’s legitimate–and productive–skeptical scientific thought, unlike the garbage that is offered up as such by various elements.

    Esper and Frank, 2009. Divergence pitfalls in tree ring research. Climatic Change 94:261-66.

    Comment by Jim Bouldin — 24 Nov 2009 @ 12:20 PM

  139. p.s.

    I would hasten to add, amidst the roar of those screaming about “data secrecy” problems, that I was able to extend their treeline chronologies back in time–and do a host of other possible analyses–because….

    …they freely offered up ALL of their relevant data files, from all 3 sites, so that anyone could use them.

    I bet you won’t hear about that from Steve McIntyre.

    Comment by Jim Bouldin — 24 Nov 2009 @ 12:29 PM

  140. Can anybody name 2 scientists who aren’t paid directly or indirectly by government (that includes Friends of the Earth) or charities/foundations specificly committed to alarmism who have said catastrophic warming is real. That excludes statements along the lines of “most of the 20thC warming (0.6C) may be anthropogenic” but genuine catastrophism.

    Define catastrophic. Scientists don’t generally talk in such terms. Look to the press and politicians for that.

    If you’re denying that catastrophic warming is possible if we don’t change course, that’s plainly foolish. As for the government funding, it’s ubiquitous and does NOT come with strings attached as to what the result needs to be.

    Comment by Jim Bouldin — 24 Nov 2009 @ 6:36 PM

  141. “Can anybody name 2 scientists who aren’t paid directly or indirectly by government (that includes Friends of the Earth) or charities/foundations specificly committed to alarmism who have said catastrophic warming is real. That excludes statements along the lines of “most of the 20thC warming (0.6C) may be anthropogenic” but genuine catastrophism.”

    Define catastrophic. Scientists don’t generally talk in such terms. Look to the press and politicians for that.

    If you’re denying that catastrophic warming is possible if we don’t change course, that’s plainly foolish. As for the government funding, it’s ubiquitous and does NOT come with strings attached as to what the result needs to be.

    Comment by Jim Bouldin — 24 Nov 2009 @ 7:16 PM

  142. Catastrophic warming would be warming whose effects were likely to be catastrophic. Certainly above the 2 degree increase of the MWP or even the probably 4 of the Climate optimum, neither of which melted Greenland. Obviously only such warming would justify cutting the use of fire by 50%, 80% etc.

    Comment by Neil Craig — 25 Nov 2009 @ 8:54 AM

  143. Comment No. 142,
    Your Statement is incorrect as the MWP was not 2 degrees warmer than the current climate. It was in fact on par with the early parts of the 20th century at its warmest (Viau et al. 2006).

    Comment by Robert Way — 4 Dec 2009 @ 8:04 PM

  144. I notice that paragraph 2 of the intro above contains the infamous word trick, and in the context of analyzing dendro data. Viz:

    Because the growth of trees is radial, as trees get older and the diameter of a tree increases, annual ring widths decline in thickness. This is the normal “growth function” that is commonly removed from measurements before further analysis is carried out. The trick is to do this carefully so that as much climate information is retained while the growth function is discarded, and dendroclimatologists know how to do this quite well.

    The date is 17 Nov. This looks like the key to what Phil Jones was talking about in the unfortunate e-mail.

    Comment by Dan Lufkin — 11 Dec 2009 @ 11:07 AM

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