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Comments 126251 to 126300:

126251. NewYorkJ at 04:06 AM on 30 November 2009
        Was there a Medieval Warm Period?
        "How comes Wikipedia doesn't even mention the word divergence in their Hockey Stick controversy article? Is this divergence something that was somewhat hidden before ClimateGate, or is this something that has been discussed as part of the ClimateAudit work?" The divergence problem (along with various other uncertainties) was discussed well before Steve McIntyre began his crusade against climate science. See John's post "What do the hacked CRU emails tell us?" and note the following article. Not sure about the Wikipedia article, but my take is that it covers mostly the political controversy instigated by M&M. It would be nice to update the Wikipedia article to include the fact that relevant issues such as the divergence problem were already documented in the peer-reviewed literature (some people seem to think McIntyre discovered this). Consider also that the original "hockey stick" graph contained a large uncertainty range, something consistent with a more pronounced MWP and LIA. See also the latest Mann et al. reconstruction. http://www.ncdc.noaa.gov/paleo/pubs/mann2008/mann2008.html thingadonta, "All that the final map, relative to the above discussion, shows, is show that the older proxies in the MWP are not picking up warmer temperatures the way modern instrumental methods do. " Well if one has already concluded that the MWP was warmer than today (based on?), that conclusion might make sense (keep in mind that reconstructions without tree rings reveals a similar pattern). I think there are many who badly want to believe that. Although it has no impact on greenhouse gas physics (although some might argue a more variable climate is a more sensitive one), if skeptics can show the MWP is equal or warmer than today, they think it will help convince folks that modern warming is entirely natural.
126252. nofreewind at 02:26 AM on 30 November 2009
        Was there a Medieval Warm Period?
        >Nofreewind, you don't really understand much about tree rings, do you? you are right! but i have a good head for finding out the truth and 8 yrs of science degrees. >In fact the divergence problem is only associated with a very small number of trees from one particular place. These are the rings reported by Briffa. You mean there was no divergence in the MBH reconstruction? It is incorrect that much of the Mann 2001 IPCC graph was primarily from a few bristlecone's in Colorado? What is "nonsesne" in this paper? http://www.climateaudit.org/pdf/ohio.pdf Seriously, have all climate scientists taken the time to look at the archeological history. (FAGAN, FAGAN, FAGAN - and he is one of yours!)I think if you did you would agree that the warming from 1976 to 1998 was completely unremarkable, at least the rate of change, even the CET series will tell you that. I agree that that 1998 might have been the warmest year for at least 500 years. And the past decade might be the warmest for 500 years or so. If there is even such a things as "global temperature". How comes Wikipedia doesn't even mention the word divergence in their Hockey Stick controversy article? Is this divergence something that was somewhat hidden before ClimateGate, or is this something that has been discussed as part of the ClimateAudit work? If they can't calibrate their instruments with good recent hopefully 100% accurate temperature data, (???), how do they know there weren't period of hundreds of years in length 200 or so years ago where there was "divergence".
        Response: The divergence problem was discussed in the peer review literature as early as 1995, suggesting a change in the sensitivity of tree growth to temperature in recent decades  (Jacoby 1995). There have been a number of papers since then examining the problem. For more info, see the page on the tree-ring divergence problem.
        
        And for the record, if you're talking about global temperature, 1998 is not the hottest year on record. 2005 is.
126253. dhogaza at 02:19 AM on 30 November 2009
        Was there a Medieval Warm Period?
        

        The variation in spatial data and distribution (ie maps above) would not 'average out' in a large dataset, as they are not 'random uncertainties'; they are in-built weaknesses inherant whenever one uses proxies

        You only need a sample size with sufficient spatial distribution to build a map of a particular resolution. So what you have to do here is to prove that the 1,000 proxies Mann has studied don't support the resolution he's claiming in his analysis. Yes, the spatial resolution is not as good as you go further back and have less spatial data. I note that the proxy reconstruction map uses big boxes- relatively poor resolution - while modern temperature maps such as the decadal map John's posted has much higher resolution.

        This quite predictably, and expectedly, actually enhances and highlights, rather than 'averages out', the outliers etc of an older dataset, when compared to a modern standard.

        I see no basis for this claim whatsoever.

        The MWP data is therefore misinterpreted, and which is also the skeptical contention of the hockeystick of Mann et al 1998-that the proxies are not picking up the full range of warmth of the MWP.

        Nor this - not that it matters. A warmer MWP than science actually supports doesn't impact the reality that a warmer tomorrow's going to require extremely expensive mitigation efforts.
126254. batsvensson at 23:11 PM on 29 November 2009
        Skeptical Science housekeeping: Comments Policy
        My intention was not to define skepticism. I wanted to define what a dogmatic view was in contrast to skepticism, and did so by pointed out a method that skeptics uses. This method is more or less equal with the quotation you give above in the first part. Then in the second part when you write, "The antithesis of genuine skepticism is to decide your beliefs, then use cognitive dissonance to do away with any evidence that contradicts your beliefs.” Makes me even more puzzled, as this is only a reformulation of my definition of a dogmatic viewpoint. Basically your long replay can be condensed into “I agree”. However after all these words you still avoided to address the point I made, namely that this site fails it mission. So, it is utterly unclear to me what you actually are trying to tell me in you replay as you seams to only repeat what I already have said.
126255. PortugueseDave at 22:13 PM on 29 November 2009
        Skeptical Science housekeeping: Comments Policy
        While I often disagree with you I applaud your even handed approach to comments and consider such housekeeping fair. There has been far too much mud slinging in this debate across all the sites I read - I wish they would all adopt such policies.
126256. thingadonta at 21:26 PM on 29 November 2009
        Was there a Medieval Warm Period?
        re13: "Actually, you'd expect random uncertainty in the data set to average out, given a sufficient sample, and a 1000 proxies is a large sample ..." The variation in spatial data and distribution (ie maps above) would not 'average out' in a large dataset, as they are not 'random uncertainties'; they are in-built weaknesses inherant whenever one uses proxies, which will tend to increase with age in comparison with a standard dataset (eg 1961-1990). (Much the same reason human history becomes more unreliable the further back in time you go-these 'unreliables' dont 'average out', they just get worse). This quite predictably, and expectedly, actually enhances and highlights, rather than 'averages out', the outliers etc of an older dataset, when compared to a modern standard. This is what 'standards' are supposed to do, highlight discrepancies in a non-standard dataset, which ironically, is just what the paper of Mann et al 2009 does. The MWP data is therefore misinterpreted, and which is also the skeptical contention of the hockeystick of Mann et al 1998-that the proxies are not picking up the full range of warmth of the MWP. This new Mann et al paper largely shows this again to be the case. The final graph is also a bit misleading, relative to the above discussion. If the proxies do not pick up past warmer periods well, and moreover will always show a greater number of (spatial) outliers and in-built variations and uncertainties, it will be a rather misleading and false comparison if they are then placed against any other warm instrumentally-based data. All that the final map, relative to the above discussion, shows, is show that the older proxies in the MWP are not picking up warmer temperatures the way modern instrumental methods do.
126257. RSVP at 20:24 PM on 29 November 2009
        The physical realities of global warming
        pdt Its not about CO2. Its about global warming. And the solution is to control population growth. We are in a bind like an animal trapped in quicksand. The more you try to move the deeper you sink. There is no technological solution, because no matter what you do, you will always be generating more heat. The only solution is to control population into the future with the realization that the Earth can house only so many people. End of story.
126258. RSVP at 20:10 PM on 29 November 2009
        Was there a Medieval Warm Period?
        Referring to the last graph. It seems odd that temperature anomalies are seen to affect the northern polar regions more accutely, whereas this region is plunged in darkness almost half the year. This does not seem to play into the idea that CO2 is the main cause of global warming. If this were the case, you would expect a distribution with the largest anomalies in the equatorial regions happening first. What the map seems to indicate is direct convective warming of the polar regions from a warmer atmosphere, and if man made, likely due to latent exothermal pollution sources. I am aware that this is not a popular idea, as I've been told that this energy doesnt amount to a hill of beans, but on the other hand, I am also suppose to believe in a environment that is precariuosly sensitive. It is sensitive, but not that sensitive, etc. At any rate, I understand, once you have sipped the Kool-Aid, its too late. There is no going back.
126259. RSVP at 18:42 PM on 29 November 2009
        Was there a Medieval Warm Period?
        nofreewind You said "So the tree ring data fits the MWP when we didn't even have thermometers, but it doesn't fit the era when we had literally thousands of surface based temperature stations throughout the world." I totally agree! --------------------------------- John, In previous articles, in looking for proof for global warming, local Antartic cooling is played down as not counting, whereas in this article, local conditions are interpreted as just a shifting of the Earths energy distribution.
        Response: The way to approach Antarctic cooling is the same as the approach to the Medieval Warming Period. Rather than focus on a specific region while neglecting the broader picture, look at the global pattern. Figure 3 above demonstrates that while there has been cooling in some Antarctic regions, the full global picture is that of warming. The planet has a net energy imbalance and is accumulating heat. This is in contrast to the global temperature pattern during the Medieval Warming Period which only suffered a mild energy imbalance and consequently showed a mild net warming.
126260. dhogaza at 17:37 PM on 29 November 2009
        Was there a Medieval Warm Period?
        

        Surely that list of caveats also applies to the data that 'fits' the model.

        Why? Liebig's Law of the Minimum is well-established, has nothing to do with climate science or paleo reconstructions of tree-ring temperature proxies, and is based on sound understanding of plant physiology important to science-based agriculture. Essentially you're saying "I don't like what I'm hearing, so I don't accept it".
126261. HumanityRules at 17:35 PM on 29 November 2009
        Was there a Medieval Warm Period?
        How does 300years of La Nina conditions work?
126262. dhogaza at 17:34 PM on 29 November 2009
        Was there a Medieval Warm Period?
        

        Because you are comparing high quality recent observations with past reconstructions, you would expect the past reconstructions to show more regional variation simply as a result of much lower quality data

        Actually, you'd expect random uncertainty in the data set to average out, given a sufficient sample, and a 1000 proxies is a large sample ...
126263. HumanityRules at 17:33 PM on 29 November 2009
        Was there a Medieval Warm Period?
        #7 Shawnhet you can get the map of the proxy positions from the supplementary data. See link in #12
126264. HumanityRules at 17:16 PM on 29 November 2009
        Was there a Medieval Warm Period?
        With regard the the Mann paper. John it would be useful for you to show the map of proxy locations (i.e. the rest of fig2 from Mann) for those that can't access the paper. Although I think everybody can access the supporting data freely here. To describe the spatial data for the MWP as sparse I think is generous. There are 6 proxy data sets for the whole area east of the horn of Africa. I would be interested how you get the large blue (cold) area in central eurasia when there are no proxy records for that area. Although its difficult to overlap the temp and proxy maps it appears that the only proxy points around central eurasia conicide with the couple of hotspots in that region. Also there are no proxy data over any ocean regions, most of africa, anywhere in S.America away from the west coast, the whole of malaysia/indonesia/philipines/australia(except tasmania)/pacific Islands, the middle east,Western Europe..... Do you get the point!! I really struggle to see he can allocate a colour to most of the globe during the MWP. I'd love to see the reviewers comments.
126265. Marvin at 16:10 PM on 29 November 2009
        East Antarctica is now losing ice
        Seems like this article is very alarming that Antarctica is losing ice at an accelerating rate. And during summer!
126266. HumanityRules at 16:01 PM on 29 November 2009
        Was there a Medieval Warm Period?
        #3 dhogaza Surely that list of caveats also applies to the data that 'fits' the model. I've noticed a trend were data that fits the theory is often simply presented and described while data that goes against the theory is often followed by a list of possible explanations to invalidate it. That's assuming the researchers have the grace to present it in the first place.
126267. javs at 15:19 PM on 29 November 2009
        CO2 is not the only driver of climate
        Gord, I must say I admire the patience with which you, Gord, have explained some physical basics that for some reasons are called laws. The reasons should by now be clear to even the most stubborn ones. I thank you for the lessons.
126268. Riccardo at 12:24 PM on 29 November 2009
        The physical realities of global warming
        RSVP, "Population is the ONLY point when no realistic energy alternatives are on the table" then yes, you're right. Before the fossils era (carbon included) energy came mostly from burning trees; in the then developed world forests were cut down. If "no realistic energy alternatives [came to] the table" we could not be where we are now. Definitely. For sure. Absolutely. In other words, if you do not allow for energy alternatives there's no solution. But not just for global warming, it would be impossible any development of the human race.
126269. pdt at 10:08 AM on 29 November 2009
        The physical realities of global warming
        RSVP, Fine, then how much CO2 is generated for things absolutely necessary to sustain human life? For example, in the United States, ~60% of the primary energy sources we consume are ejected as heat. The only reason this is true is because of the incredibly low price we pay for these primary energy sources.
126270. shawnhet at 10:07 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Can anyone who has read the paper please let me know how they can possibly get sufficient proxy data to cover the entire globe? I am particularily curious how they would work out the anomalies for the oceans. Is there some sort of algorithm at work here? Cheers, :)
126271. SNRatio at 08:29 AM on 29 November 2009
        Was there a Medieval Warm Period?
        The consensus in Norway seems to be that in the period 500-1500, the temperature in Scandinavia was 0.5-1 oC higher than the 1961-90 mean, which by no means seems to be reflected in fig 1. You may download a pdf (in Norwegian) from http://nou-klimatilpassing.no This is a official report, documenting climate changes and discussing possible changes towards 2100.
126272. NewYorkJ at 06:29 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Good post. For comparison, here's the anomaly map for the last couple of decades, same base period. Different color scale, but we can get the idea. It seems a bit unusual for both MWP and LIA to show a warm anomaly in the North Atlantic, until it's noted that the map is an offset from the 1961-1990 average, which showed generally cooler temperatures in that region during that period. Here is the 1961-1990 period in comparison to the 1900-2008 average. It would be interesting to see the MWP and LIA in context of the last century average (a more apples to apples comparison in terms of timeframes being compared), and also in comparison with the last 20 years. What's notable is that the anomaly map from the study isn't a comparison with the recent decade or two but with the 1961-1990 average.
        Response: You know, when I was writing this post, I did think it would be useful to compare current temperature patterns to the MWP pattern. But in my defence, it was approaching midnight when I wrote this post and I had just spent 5 hours that afternoon playing cricket in incredibly hot and humid Queensland conditions. But enough excuses! I've added the temperature pattern of the last decade. Thanks for the comment.
126273. batsvensson at 06:02 AM on 29 November 2009
        What does past climate change tell us?
        Riccardo, "luckly the CO2 we release with respiration does not come from fossile carbon ;) " You with drawing attention from the real point I made. The point was to show that the claim that it demands "hard work" to release 29 giggatonnes of CO2 in the atmosphere is at best a misleading, and at worst a false, claim.
126274. dhogaza at 05:52 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Having said all of the above, let me make clear that I'm just a layman with too much time on my hands, interpreting stuff I've read that's written by the experts. I may have, in fact likely have, gotten some of it wrong, so YMMV.
126275. dhogaza at 05:51 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Actually, Ian, the divergence problem refers to tree ring chronologies, mostly at high latitudes, that show *less* growth than expected in relation to increased temps in the 1960s. I think the paper you cite (Salzer et al) shoot down those who claim that recent *accelerated* growth in bristlecone pines at high elevations (but not latitudes) might be due to CO2 fertilization or something else other than a response to temps. It solidifies the bristlecone pine proxy so scathingly dismissed by skeptics (they also saw no significant difference between stripbark trees and those that don't show that growth pattern). However ... to nofreewind ... Ian's point still holds partially in that not all high latitude tree ring chronologies suffer from the divergence problem (in particular Briffa's Yamal reconstructions, which is probably why McIntyre is so focused on trying to demolish that particular reconstruction with such vehemence). There are three possible likely sources of the divergence problem: 1. anthropogenic changes (air pollution, for instance) 2. precip or snowmelt timing changes (causing drought/water stress rather than temp to be the limiting growth factor after temps warm to a certain point) 3. global dimming (which from my reading is thought to be a stretch, i.e. not likely) If #1 is true, then the current divergence has no relevance for reconstructions in the deep past. If #2 is true, it's only a problem where temps were warm enough in the past to trigger enough change in precip and/or snow melt timing changes to cause that to become the limiting growth factor. This could lead to an underestimation of the MWP from what I can see, but wouldn't be a factor at other times during the reconstructions. But there are other proxies, including (but not only) tree ring proxies not showing the divergence problem, that show a cooler-than-today MWP for many regions (and at least one northern siberian tree ring chronology showing a warmer regional MWP) that well, you end up with what Mann '09 here says ... some regional warming greater than today, some regional cooling, over all no global warming comparable to today. Oh, there are actually two more potential gotchas in the divergence problem: 4. Use of RCS rather than certain other smoothing techniques causes it to go away to some extent in many of the chronologies, i.e. there are end point problems with some smoothing techniques that contribute to an artificial "tailing off". 5. The thermometers are typically at lower elevations and some distance away from the various tree sites used by researchers, so there are microclimate differences that would lead one to expect that the temp and proxy results would differ. AFAIK, pretty much all of the above are being actively looked into by researchers, judging from a relatively recent review paper I've read (2007).
126276. batsvensson at 05:43 AM on 29 November 2009
        Skeptical Science housekeeping: Comments Policy
        @OP I all friendly manner I like to give some criticism to this post and the site in general. To be skeptical is not to prove everyone else wrong with "conclusions" from "data", it is to ask oneself the question "What if *I* am wrong?" and try to interpret data in a new set of ideas – which is knows as formulating a theory about data. Refuting everyone else is not to be skeptic, but is the definition on believing in a dogma. In this respect I think this site fails a mission of being skeptical. Its focus seams to be to prove any skeptic argument wrong as the "science is settled" and thus no alternative theories can be correct.
        Response: Thanks for your comments. Personally, I like the Oxford Dictionary definition of skeptic:

        ‘A seeker after truth; an inquirer who has not yet arrived at definite conclusions’

        Eg - a true skeptic doesn't let their preconceived notions influence how they interpret data and science. My observation is that by this definition, global warming skepticism is anything but skeptical. The antithesis of genuine skepticism is to decide your beliefs, then use cognitive dissonance to do away with any evidence that contradicts your beliefs.
        
        The common pattern with global warming skeptic arguments is that they focus on a narrow piece of the puzzle while ignoring the broader picture. This is textbook cognitive dissonance. The antidote to this approach is simple - present the broader picture. The goal of this website is simple - attempt to present the broader picture by explaining what the peer reviewed science says.
126277. Sam Spade at 05:33 AM on 29 November 2009
        Hockey stick is broken
        PROXY-BASED RECONSTRUCTIONS...OVER THE PAST TWO MILLENIA ...Using a greatly expanded set of proxy data... Recent warmth appears anomalous for at least the past 1300 years whether or not tree-ring data are used... ...with somewhat greater Medieval warmth in the Northern Hemisphere, albeit still not reaching recent levels. (above from abstract) ...a multiple proxy...database consisting of a diverse (1209) set of annually (1158) and decadly (51) resolved proxy series. including tree-ring, marine sediment, speleotherm, lacustrine, ice core, coral, and historical documentary series... ...59 (extend) back to AD1000... ......the conclusion that recent Northern Hemisphere warmth likely exceeds that of at least the past 1300 years thus appears reasonably robust... Mann et al, Sep2008 (PNAS, so no pay wall) GLOBAL SIGNATURES AND DYNAMICAL ORIGINS OF THE LITTLE ICE AGE AND MEDIEVAL CLIMATE ANOMALY ...The Medieval period is found to display warmth that matches or exceeds that of the past decade in some regions, but which falls well below recent levels globally. Science abstract Mann et al, 27Nov2009 Intervals of regional warmth and cold in the past are linked to the El Nino phenomenon and the so-called "North Atlantic Oscillation" in the Northern hemisphere's jet stream... Comparisons between the reconstructed temperature patterns and the results of theoretical climate model simulations suggest an important role for natural drivers of climate such as volcanoes and changes in solar output in explaining the past changes. The warmer conditions of the medieval era were tied to higher solar output and few volcanoeic eruptions, while the cooler conditions of the Little Ice Age resulted from lower solar output and frequent explosive volcanic eruptions. Penn State press release, Mann et al, 27Nov2009
126278. RSVP at 05:06 AM on 29 November 2009
        The physical realities of global warming
        Riccardo Population is not the key point. Population is the ONLY point when no realistic energy alternatives are on the table. I suspect no one is proposing these as each has it own forms of thermal pollution. pdt I wish I could believe you, but have to disagree. There is a very long chain of requirements for sustaining human life other than food production, such as building dikes.
126279. Ian Forrester at 04:32 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Nofreewind, you don't really understand much about tree rings, do you? In fact the divergence problem is only associated with a very small number of trees from one particular place. These are the rings reported by Briffa. Since his original papers there has been a recent paper published which explains why these particular trees were abnormal in their temperature response. As originally thought, there were other factors involved at that particular location. "Recent unprecedented tree-ring growth in bristlecone pine at the highest elevations and possible causes". Matthew W. Salzer, Malcolm K. Hughes, Andrew G. Bunn, and Kurt F. Kipfmueller http://www.pnas.org/content/early/2009/11/13/0903029106.full.pdf+html
126280. nofreewind at 03:45 AM on 29 November 2009
        Was there a Medieval Warm Period?
        Before you consider the MWP read The Great Warming by Brian Fagan, renowned archeologist. <$10 on Amazon. What is fascinating about Fagan is that he has fell for the same elixir as so many others drink. In his introduction he talks about how the tree ring data shows the warming, but at the time of his writing he didn't know about the "tricks" used. If the data don't fit, just splice something in that does! No matter what, don't give any cannon fodder to the those who might have inquiring minds. How can we trust the tree ring data, when it doesn't fit since 1960??? So the tree ring data fits the MWP when we didn't even have thermometers, but it doesn't fit the era when we had literally thousands of surface based temperature stations throughout the world. Corals, sediments, ice cores, proxies...I think in the last week we have only scratched the surface.
        Response: "How can we trust the tree ring data, when it doesn't fit since 1960?"
        
        You're talking about the divergence problem. The short answer is that the tree ring proxy record shows good agreement with other proxies in past periods. It is only in recent decades that tree ring proxies diverge from other proxies and the instrumental record. For more details, see the page on the tree-ring divergence problem.
126281. pdt at 01:25 AM on 29 November 2009
        The physical realities of global warming
        RSVP, "PS I still havent seen a proposal of how the world is to feed itself while reducing CO2 emissions as world population increases." Part of the answer lies in the answer to this question, "How much of the world's CO2 emissions are related to food production?"
126282. Riccardo at 22:17 PM on 28 November 2009
        The physical realities of global warming
        RSVP, if we kill half of the world population we will surely need less energy and emit less CO2, even more so if we actually chose people from the developed world. Does this mean that that population is the key point? Should be this our goal? In the last decades global per capita emissions has been almost flat globally. Developed world has reduced and developing world increase, but stil the former is 4-5 times higher (much more if you compare to the poorest countries). This and the historical responsability are the very reson why most of the burden of the reductions is on the shoulder of the developed world. The devolping world should take the responsability of not following our disastrous path.
126283. Riccardo at 22:01 PM on 28 November 2009
        Satellites show no warming in the troposphere
        hank, point those guy to this post. It stars exactly with the issue of flawed UAH data analisys; the webpage they link is old, well before the flaw was corrected.
126284. RSVP at 21:55 PM on 28 November 2009
        The physical realities of global warming
        Comparing CO2 Emissions values of (5.3 & 8.0 GtC/y) above for the years 1980 and 2005 gives a relative increase ratio of 1.51. Then going to: http://www.google.com/publicdata?ds=wb-wdi&met=sp_pop_totl&tdim=true&q=population+of+the+world ...and consider world population for the same years, we get 4.4 & 6.4 billion, which gives a ratio of 1.45, which is "coincidentally" very close to 1.51. Apparently, the per capita consumption of oil has remained relatively constant in this period, while the most significant growth in population has occurred in China and India (as per Google site). Somehow I have a hard time not seeing a direct correlation between population growth and CO2 emissions. PS I still havent seen a proposal of how the world is to feed itself while reducing CO2 emissions as world population increases.
126285. Riccardo at 21:35 PM on 28 November 2009
        East Antarctica is now losing ice
        HumanityRules, i wrote in my previous comment i downloded the data and found the same trend as before. No possible confusion on the stations, there just three in Antarctica. How comes you repeted the same thing and found diferent trends this time? Are you using monthly data or annual averages as in the graphe? Or are you mixing the two as both are in the same table? I'm using the annual averages, as is the case when you look at yearly trends. It's impossible to get different trends using the same data, definitely we used a different set.
126286. Barry Brook at 15:40 PM on 28 November 2009
        It's cooling
        Great work, just a slight niggle: "Considering a typical nuclear power plant has an output of 1 GigaWatt, imagine 190,000 nuclear power plants pouring their energy output directly into our oceans." A decent sized nuclear power plant is 1 GWe, which at a 33% thermal efficiency, is close to 3 GWt. 190 TWt of energy going into the ocean each year is closer to the heat output of 65,000 1 GWe nuclear power plants.
126287. hank at 15:31 PM on 28 November 2009
        Satellites show no warming in the troposphere
        This just got used by someone in a Deltoid thread, claiming it's the state of contemporary science: http://spacescience.spaceref.com/newhome/headlines/essd06oct97_1.htm The page begins: Accurate "Thermometers" in Space The State of Climate Measurement Science October 2, 1997 Just how accurate are space-based measurements of the temperature of the Earth's atmosphere? In a recent edition of Nature, scientists Dr. John Christy of the University of Alabama in Huntsville, and Dr. Roy Spencer of NASA/Marshall describe in detail just how reliable these measurements are....
126288. HumanityRules at 11:38 AM on 28 November 2009
        East Antarctica is now losing ice
        Sorry I truely don't know how to digitise graphs. Raw data Go to http://www.bom.gov.au/climate/data/weather-data.shtml You should be on historical data (right side menu) You can choose temperature from the drop down menu. Then Mean max temp Finally put the station numbers (see below) in the box then get data. This gives monthly and annual data. These tables can be imported into excel. 300000 300001 300017 The figures in the Turner paper (#14) suggests for a shorter time period. Mawson -0.11/decade Casey +0.01/decade Davis +0.03/decade Out of more general interest there are about 20-30 data sets in Australia that stretch back to 1800's and many more that go back to 1930s-1950s. They are worth a look if youhave an hour or two to search for them. I thought I recognised interesting trends but they are not relevant in this thread.
126289. SNRatio at 05:48 AM on 28 November 2009
        What do the hacked CRU emails tell us?
        Disclaimed, I think you have misunderstood a bit about the precisions of predictions. You may easily get the impression that the models already are very 'truthful', but when you look closer at the actual uncertainties, you will see they are rather large as estimated now. And that may well prove to be under-estimations in some cases, without disproving the basic usefulness of the models: They are continously adjusted. Just to say that the models are not at all that good is, however, not true at all. And short-term, they are really good in lot and lots of situations now. You can get an impression of the present situation if you look at Tim Palmer's presentation in the session on "Advancinc climate prediction science" on the recent climate congress, http://www.wcc3.org/sessions.php?session_list=PS-3#doc I will also suggest Mojib Latif's presentation in the same session. He has been misrepresented as predicting 30 years without warming - that's not what he said. But when you look at his NH 21-yr moving average curve (this will filter out most solar cyclicity), there is a 60-year cycle with an amplitude of 0.1-0.2 deg that could gives us something like that.
126290. SNRatio at 05:26 AM on 28 November 2009
        The physical realities of global warming
        @TruthSeeker If you look at the first graph I linked to, you will see that the two 'extremes' in temperature, GISS & UAH, follow each other quite closely - and they don't measure exactly the same (if I have understood it right) after all. And if you you use reasonably long periods for looking at the trends, the differences in most cases become very small. Short term, the differences may be bigger, but talking about 'trends' in such cases is mostly nonsense to me, whoever talks about it. You are in your full right as a layman to make up an opinion built on the impressions you get from media, but I would advice against drawing any sort of strong conclusions without looking closely into the matters. As dhogaza points out, the majority of HadCRU temp data are alreasy in the public domain. What I think could be a good idea, based on your opinion, is to organize 2-3 independent data sets, with somewhat different methodologies and philosophies behind etc. But we must be prepared for the argument that it would cost more than it would benefit. Using independent methodologies on the same (or overlapping) data is already carried out in many cases, but to counter all the (unfounded in most cases, as far as I can see) accusations of bias, it could be done systematically.
126291. dhogaza at 04:54 AM on 28 November 2009
        The physical realities of global warming
        

        That is the whole point. According to the IPCC TAR 12.2.3 etl. the arrived at reason for AGW and CO2 is because they can't find another explanation for the warming through 1998.

        Roughly 98% of the raw data used for HadCRU temp reconstructions is in the public domain, and that data forms the basis of the GISSTemp reconstruction. The algorithms are different, the results almost identical. The extra 2% of data that's proprietary apparently make little difference in the end product.
126292. Riccardo at 04:13 AM on 28 November 2009
        East Antarctica is now losing ice
        HumanityRules, i thought that "digitize a graph" was self explaining and i'm sure you understand it. Less clear to me, instead, is which data you used. I didn't notice the link to the raw data in the same page; i downloaded them and the result is the same. Which data did you use? Anyway, even with your results, Casey is warming roughly at the same rate as the global mean, the other two are warming too, even though less. No obvious trends there?
126293. HumanityRules at 01:48 AM on 28 November 2009
        East Antarctica is now losing ice
        #13 Pedantic is fine. I'm about to get pedantic on you! Not sure what you meant by "digitised the 3 graphs". The BOM website provides the actual numbers for each data point. Go http://www.bom.gov.au/climate/data/weather-data.shtml then fill in the appropriate fields you can get the station numbers from my linked graphs. I put those numbers in excel and added a trend line and got Mawson 0.0077/yr Davis 0.007/yr Casey 0.015/yr I agree with your last sentance. The Mawson Davis and casey data is all in the PDF below. #12 I showed 3 points because that is all the raw data the Australian website carries, I didn't choose them thats all there is. There are plenty of records for Oz as well, I thought given the site owners nationality there might be some interest for this site. I love the fact that you ask me for linear regressions and null hypothesis and then show me for comparison a map with different shades of pink!! Check the references for your article they make interesting reading. Here's one PDF http://www.scar.org/researchgroups/physicalscience/reader_turneretal.pdf . This shows a mixed picture over the continent. It appears something significant is occuring on the penninsula. But then what does that mean for the rest of the continent. They report 11 data sets rising and 7 falling. There are 3 data sets on the penninsula which means that for the rest of the continent there are 8 rising and 7 falling.
126294. neilperth at 00:12 AM on 28 November 2009
        What do the hacked CRU emails tell us?
        In a strange way the hacked HadCrut emails have finally convinced me that global warming is man-made :)
126295. Riccardo at 11:00 AM on 27 November 2009
        What do the hacked CRU emails tell us?
        TruthSeeker, you should be frustrated for not having looked at the science behind dendroclimatology and at the simple fact that one set of tree rings alone tells us just a little, many different cross-checked reconstructions are solid evidence. It would be really poor science if they throw away thousands of data sets just because a few got weird. Indeed, they are studying the divergence problem, which is related more to tree physiology than to climate.
126296. TruthSeeker at 09:57 AM on 27 November 2009
        The physical realities of global warming
        Also, what is wrong with asking for another source to support the data that the HADCRU provides. The whole accusation is that they are biased and fix the data to fit their hypothesis, they fight the freedom of information act and deny access to their data, and that independents don't support their conclusions. I could be convinced that their evidence is accurate if an independent part could replicate the data. Now, I would still like someone to explain to me that, if it is currently increasing, this trend isn't driven by the sun, as the thread on that subject is woefully lacking.
        Response: There are various independent studies that confirm the HADCRU data - coincidentally I'm working on a post on that very subject (hopefully later today).
        
        How do we know the sun isn't driving the warming trend? Because over the past 30 years, the sun has shown a slight cooling trend. Because of this, there is a long list of peer reviewed studies concluding the sun has played a very minor role in global warming.
126297. TruthSeeker at 09:52 AM on 27 November 2009
        The physical realities of global warming
        Here is the quote I was referring to but since has been deleted. " the people responsible for the graph may be accused of cherry-picking. I don't, but in the present situation, i would never have shown something like that. Other selections give entirely different results. " See, SNRatio suggested that they could be accused of cherry picking and that other selections give entirely different results.
126298. TruthSeeker at 09:40 AM on 27 November 2009
        It's the sun
        Did anyone answer the question as to why correlation has to be between increase and sun activity and temperature. As I heard it stated, I can put a pot of cold water on my stove, heat up my stove from fold to a constant temperature quickly, and then have the water take much longer to heat and continue to heat up even after my stove is at a constant temp. Why is it any difference from the sun? Especially now as the sun activity seams to be declining and the temperatures of the last decade are stagnate.
        Response: This issue is examined in Climate time lag.
126299. TruthSeeker at 09:33 AM on 27 November 2009
        What do the hacked CRU emails tell us?
        Riccardo at 20:23 PM on 25 November, 2009 TruthSeeker, "So why don't we exclude all the tree ring data, since its be proven to be faulty?" Never this proof appeared," Really, the proof appeared when they "diverged" from the temperature record, and as a result those individual entries are no longer considered good. If they arn't what evidence does anyone have that these were ever any good? Until someone can explain to me why, when their is no temperature record, they are good, but when a temperature record exist they are "to low" they will just be proof positive that these scientist are cherry picking. I am getting frustrated with the number of people telling me they were once good(supplying no supporting evidence) and then saying but now that we have temperature records they are to low.
126300. Riccardo at 08:31 AM on 27 November 2009
        East Antarctica is now losing ice
        HumanityRules, I know you're not in bad faith and i hope you'll not find me too pedantic for what i'm going to say. You should not take graphs for what they just appear; look at the tempeature scale, it's huge for the kind of difference you're looking for. I digitized the three graphs to check for trend. Casey and Davis are both increasing (0.014 and 0.019 °C/yr respectively) but the former is not statistically significant due to the few data available. Mawson is almost flat, 0.002 °C/yr not statistically significant. Doing science is a hard task and no one should draw conclusions without thinking twice and checking thrice. Or more.

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