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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 125201 to 125250:

  1. On the reliability of the U.S. Surface Temperature Record
    lord_sidcup at 01:03 AM on 25 January, 2010 I noticed the same thing. jpark sailed in under false colors, look like. I seem to remember something to the effect of "fence sitter", but unfortunately that seems to have been another performance of an old, tired gambit. Waste of time. So many people on the network, so few basic narratives to choose from, boredom is the upshot.
  2. Berényi Péter at 06:36 AM on 25 January 2010
    Peer reviewed impacts of global warming
    John, anonymous peer review is not a sacred cow. In it's present form it was introduced only after WWII, when the US as the sole indisputable victor of the armed conflict took over leadership in science. Government spendings soared and the state felt the need of some handle on this crowd of weirdos called scientists. The procedure has it roots in eighteenth century state censorship by absolute monarchies. The political charge of the institution as it is practiced now is related to its introduction and dissemination by US government policy guidelines. By the time of its post WWII reinvention, early forms a peer review were mostly abolished and replaced by a more informal and free system. As a quality control measure, it neither performs particularly well nor does it promote efficiency. After WWII scientific progress definitely slowed down compared to the pace of previous (from mid XIX. to mid XX.) century. Especially if the prodigious increase in both the number of "scientists" and expenditures are taken into account. The sorest spot is anonymity with its lack of accountability. Open peer review can be a remedy, perhaps. Nature (2006) | doi:10.1038/nature05005 Can 'open peer review' work for biologists? Biology Direct is hopeful. Eugene Koonin, David Lipman, Ros Dignon &. Laura Landweber http://www.nature.com/nature/peerreview/debate/nature05005.html So, peer review in itself would solve neither the problems of climate science in general nor those of IPCC in particular. The reason IPCC should have sticked to peer reviewed literature is entirely different. They have it in their own guidelines as a requirement. Yet in their AR4 report they frequently rely on non peer reviewed NGO material from WWF, Greenpeace and the like. It was the same with this Himalayan glacier issue, but the example is far from unique. More Dodgy Citations in the Nobel-Winning IPCC Report blogpost by Donna Laframboise http://nofrakkingconsensus.blogspot.com/2010/01/more-dodgy-citations-in-nobel-winning.html The whole scandal is more like a public political and legal issue than an internal affair of science.
  3. Peer reviewed impacts of global warming
    RE #8 Ned, "six degrees",that's great, but to quote an old adage, "if a tree falls in the forest, and there's nobody there to hear it, does it make a sound??? The short answer would be no.
  4. Peer reviewed impacts of global warming
    I'd like to second birdbrainscan's recommendation of "Six Degrees" (though note that it's by Mark Lynas, not Fred Pearce). It does a fantastic job of summarizing the peer-reviewed literature on impacts of warming, grouped by magnitude of warming (1, 2, 3 ... 6 degrees). Very eye-opening.
  5. Peer reviewed impacts of global warming
    Just this morning there was a letter to the editor about this. It's amazing how fast the denier camp to jump on these things. And naturally they're using this as an argument against global warming.
  6. Peer reviewed impacts of global warming
    How about the negative geopolitical factors such as: 1) China and India pass the US as economic superpowers 2) Increased immigration 3) Higher food costs 4) Greater government subsidies (higher taxes) 5) Higher insurance rates 6) Increased authoritarian governments 7) Increased terrorism 8) Nuclear proliferation 9) Regional and global wars between countries with nuclear weapons which I outline here and also on my blog at: http://profmandia.wordpress.com/
  7. Peer reviewed impacts of global warming
    Excellent stuff, John. I do agree with Ned, though, on the wording of that one sentence.
  8. Skeptical Science now an iPhone app
    I get your point but we are trying to cut back to individual components. Its not me that is suggesting 1Wm-1 change in radiative forcing will lead to 0.6oC change in temeparture at the surface its climate scientists. It is this I have a problem with, maybe you are agreeing things have been over simplified.
  9. Peer reviewed impacts of global warming
    we, as fleas on the butt of gaia can, do nothing to affect a changing climate. therefore the solution is to adapt not try to impede.
  10. Peer reviewed impacts of global warming
    Didn't the original report state that the Himalayan glaciers would be substantially reduced by 2035? Quite a bit different than disappearing by 2035. If the IPCC is this succeptible to media hype, then the deniers have already won, and all the good work here is for naught. Might as well grab some popcorn, sit back, and watch the world burn. Unless you all find your balls, and fight back. I won't hold my breath.
  11. Peer reviewed impacts of global warming
    Good work on this page. Have you read Fred Pearce's book _Six Degrees_? He references hundreds of peer-reviewed citations in constructing his account of expected impacts of each added degree (I read up through 3 degrees before I wimped out on the rest!) Maybe you'll want another source or two on glacier loss impacts, knowing how this is the current hot button? Can you re-word this one for clarity? "Increased deaths to heatwaves - 5.74% increase to heatwaves compared to 1.59% to cold snaps" First the dash confused me as I read it as a minus sign; second, is the 1.59% to cold snaps a (smaller) reduction? (and is that apples to apples, or are these % changes in two distinct absolute numbers which might be unequal? The 2003 heat wave in Europe killed ov 37,000, while the first list I found (wikipedia on disasters by death toll) lists far fewer deaths from "blizzards" (in the hundreds annually), and recent news headlines mention, e.g. 22 dead in the UK from the past month's extreme winter weather.
  12. Peer reviewed impacts of global warming
    "If the IPCC's mistaken prediction of disappearing Himalayan glaciers taught us anything [...]" John, most of us understand what you mean by that, but it might be worth rephrasing slightly. Obviously, the majority of glaciers in the Himalayas are in fact disappearing; the "mistake" was suggesting that could happen by 2035. But someone who comes here from a site like WUWT might take your opening sentence as confirmation that glaciers are not in fact disappearing at all.
    Response: Agreed, I can see how the original wording could be miscontrued - have updated the text.
  13. michaelkourlas at 02:42 AM on 25 January 2010
    Tree-rings diverge from temperature after 1960
    Mr Cook: Regarding: "The divergence problem is unprecedented, unique to the last few decades, indicating its cause is anthropogenic." One thing I don't understand is this assumption that if we don't know what causes something in the climate system to happen, it must be us. I think the best way to explain this is the study on the links between telephone poles and cancer, where scientists found that in areas with high per-capita telephone poles, there were higher rates of cancer. Thus, telephone poles must be causing cancer! Now, this sounds silly, because there are other factors which may cause an increase in both factors (something to do with industrialization/urbanization, etc.), but it is quite comparable to current climate science. We assume that because we can't find any other natural factor that could cause the current warming (or tree ring divergence), it is automatically us. But we can't assume that. We have to assume it is natural until it is proven to be caused by us.
    Response: It's not definitely proven that the divergence problem is caused by us but the fact that over the last 1000+ years, it's only occured in the last 40 years is highly suggestive, particularly when likely causes like global dimming are anthropogenic. However, the key point is not that divergence is anthropogenic but that the evidence indicates divergence has not occured before recent decades so tree ring proxies are reliable before 1960.
  14. michaelkourlas at 02:31 AM on 25 January 2010
    Svensmark and Friis-Christensen rebut Lockwood's solar paper
    Mr Cook: Why did you not address the other graphs that were presented in the report (i.e. the sea surface temperature graph and the first tropospheric temperature graph)? Those seemed to have a fairly conclusive correlation as well. In addition, as a side note, the second set of tropospheric graphs was not necessarily created by Svensmark and Friis-Christensen. They are also present in the ISAC (http://www.spacecenter.dk/research/sun-climate/Projects/isac) final report (http://www.spacecenter.dk/research/sun-climate/Projects/resolveuid/6151e93eeb020789ed45ca109ab52346), and that paper does not cite Svensmark and Friis-Christensen's reply to Lockwood and Frohlich.
  15. michaelkourlas at 02:25 AM on 25 January 2010
    We're coming out of the Little Ice Age
    Mr. Cook: I think the whole flaw in the climate change argument can be expressed examining the words you have just used when saying "What the science really says": "The main driver of the warming from the Little Ice Age to 1940 was the warming sun with a small contribution from volcanic activity. However, solar activity leveled off after 1940 and the net influence from sun and volcano since 1940 has been slight cooling." OK, fine. While I don't necessarily agree with the sun portion (see Reply to Lockwood and Fröhlich - The persistent role of the Sun in climate forcing here - http://www.spacecenter.dk/publications/scientific-report-series/Scient_No._3.pdf/view), let's say everything you have said there is true. Even so, that does NOT automatically mean: "Greenhouse gases have been the main contributor of warming since 1970." Do we have any direct proof of that? Do we know exactly how much radiative forcing the greenhouse gases we emit produce? And do we know how much they produce when within the extremely complex climate system, as opposed to within laboratory conditions? Or is it just an assumption, considering we have exhausted all the possible natural causes that we can think of? I think that there may be other natural causes (maybe even ones we have not yet discovered) causing this kind of warming, at least to a certain extent. Syun-Ichi Akasofu here (http://people.iarc.uaf.edu/~sakasofu/little_ice_age.php) wrote about the possibility that much of the current warming could be simplified down to a natural 0.5 degrees C linear trend, with superimposed fluctuations and oscillations. Most importantly, he also notices that global warming has essentially stopped since 2000. This lack of warming does not agree with IPCC predictions. Instead it gives more credibility to this theory, as it could be explained as the most recent oscillation winding down and continuing on the 0.5 degrees C linear trend.
    Response: The direct proof of the radiative forcing from rising CO2 is explored in the empirical evidence for an enhanced greenhouse effect.

    Re Akasofu's assertion that "global warming has essentially stopped since 2000", presumably, this is based on the HadCRUT surface temperature record which omits areas of the globe of extreme warming in recent years. A more comprehensive analysis of the Earth's energy imbalance finds the planet continued to accumulate heat past 2000 right up to the end of 2008 (where the analysis ends). Global warming has not stopped.
  16. Berényi Péter at 02:14 AM on 25 January 2010
    Skeptical Science now an iPhone app
    Let's put it another way. Some excess heat in last December might have gone to the Arctic, leaving North America, Europe and Siberia in the cold. It could not come from anywhere else, for the Arctic, north of the 80th latitude is in permanent shade form about 22 October to February 20. Does it mean that "global warming" just shifted to the North and stayed there? No. Remember, the map at the top of this page is about temperature anomalies, not temperatures themselves. If parts of the Arctic are up to 8 centigrades warmer than average in December, they are still damn cold, below -20°C (-4°F). And now this excess heat has gone somewhere else again, circumpolar temperatures dropped by some 15 centigrades in just two weeks. The question is: Where did global warming go this time? One thing we do know for sure: heat does not go from a colder place to a warmer one, at least not as long as LTE (Local Thermodynamic Equilibrium) holds. As it always does in the atmosphere below perhaps 50 km (30 miles). So. The question is transformed to another one: Is there a place around the North Pole which is cold enough to suck away the excess heat from there during dark winter night? The answer is yes. There is one and only one such place. The temperature of the high skies is 2.7K (-270°C, -454°F). Except the solar disk of course (with an effective temperature of 5780K), but it occupies less than one hundred thousandth of the entire sky and is not visible from the Arctic this time of the year anyway. The only other conceivable heat sink around is seawater. But open seas north of Scandinavia, even if close to freezing, are much warmer than deep space and also considerably warmer than less cold than usual arctic air. They could do some heating job, cooling not, for sure. So, on this particular occasion global warming ended up in space, since it had nowhere else to go. Carbon dioxide was not able to prevent it, somehow. Some lax scaremongering about heating up the Universe by the Arctic perhaps? AUW (Anthropogenic Universal Warming) sounds cool, doesn't it? Anyone?
  17. On the reliability of the U.S. Surface Temperature Record
    Interesting. jpark arrives, writes more or less the same thing 3 times, then goes wildly off-topic. He tells us he will carefully read the links people have provided for him, but somehow I doubt he will. I visit this site to learn, not to have my time wasted. Thanks for the interesting and informative comments that others have made.
  18. On the reliability of the U.S. Surface Temperature Record
    There is no UHI or microclimate influence over the oceans which cover 70% of the earth's surface. Trends in temps from these areas are comparable to those over land. Case closed.
  19. The chaos of confusing the concepts
    stevecarsonr, although i'm not Jacob Bock Axelsen (and not even expert on chaos), let me comment on a couple of points you made. First, it's not true that "Any system with positive feedbacks is likely to be unstable". It's just a possibility, they _might_ be unstable. It's definitely true if they have only positive feedbacks, but the climate system has at least on strong negative feedback, thermal radiation. Indeed, earth climate proved to be quite resilient to warming much stronger than projected for the near future. The example of slowing or shutting down THC is misleading in what you consider regional changes in temperature but using global heat fluxes. The correct heat balance for the northern hemisphere alone would include also ocean and atmospheric circulation, i.e. all the sources of heat fluxes. So, that an initial warming may lead to cooling should not come as a surprise, nor should the resuming of warming afterward. Indeed, the seesaw behaviour is hardly considered chaotic.
  20. The chaos of confusing the concepts
    Chris: Re your comments from 10:31 AM on 24 January You said: "I (and everyone here, I think) was using it as an example 'though. It's not really chaotic behaviour (it has its chaotic elements on a microscale), but it's really a stochastic phenomenon that is essentially predictable, if not in relation to the precise timing of events, at least as a phenomenon that is a definite and predictable consequent of particular conditions. "So, for example, it would likely be possible to model N. hemisphere ice sheet dynamics and ocean circulation during the last glacial period to reproduce the Daansgard-Oeschger (D-O) events, within an understanding of the conditions under which these events occurred (not sure if this is yet understood very well). " How do you know this is "essentially predictable"? The thermohaline currents are complex with difficult boundary conditions - the shape of the oceans along with the starting point of exactly the salinity, temperature and momentum vectors on your modeling day zero. Then you have the complexity of the interaction with the atmosphere, where dependant upon those conditions you might have more or less heat transferred, more or less momentum transferred, and depending on the cloudiness, more or less solar radiation received. And then you have the equations governing the melt rate of the Greenland ice. A nice analogy - the wall being knocked down - perhaps relevant, perhaps not. Analogies can be useful illustrations, but first of all, is it a correct analogy? I'm actually amazed that you are so confident that the THC shutdown can be modeled accurately. The dual pendulum is much simpler. But it's chaotic. THC might be non-chaotic and just very complex. But surely the starting point in determining chaotic or not is actually to know what equations we are dealing with?
  21. Miriam O'Brien (Sou) at 22:59 PM on 24 January 2010
    On the reliability of the U.S. Surface Temperature Record
    Marcus, there is a police investigation being conducted into the theft of the emails. http://news.bbc.co.uk/2/hi/uk_news/england/norfolk/8453117.stm
  22. The chaos of confusing the concepts
    Jacob Bock Axelsen: Re your follow up comment (06:01 AM on 24 January). I think I get the first point. In a well-understood system there are (or maybe) areas of non-chaotic behavior and also areas of chaotic behavior. And this is all non-controversial, chaos 101 perhaps. Then your comment which begins: "To exhibit chaos you need to be able to delay heat transport (advection) through fluid dynamics.." I might be reading into your comment what others say, so apologies if I am putting words into your mouth.. one way of looking at the earth's climate is almost like the billiard ball model - the basic thermodynamics govern the temperature, the rest is just like the bubbles in the boiling of water - it's extremely well-defined how long it takes to boil a kettle of water - and the fact that we don't know where the bubbles are, although interesting, is irrelevant. Ie in that example, chaos probably exists at a micro level, but the key parameters of importance are well-known and simple to calculate. So in climate, the heat in due to the sun and the absorption and re-emission of long wave radiation by water vapor and GHGs has to be balanced by the OLR. And nothing can really disturb that because the fluid dynamics of the situation is extremely "non-turbulent". If I've not captured the essence of your argument time to step in. And if I did get the gist, I would say.. However, unlike turbulent fluids, the earth's climate is full of coupled positive feedbacks as well as very non-linear and non-understood negative feedbacks. The positive feedbacks include water vapor (increasing with temperature), CO2 outgassed from the ocean (increasing with temp all other things being equal), ice albedo reducing with temp (therefore increasing solar radiation received). Negative feedbacks include the T^4 increase in outgoing radiation with temp. Large unknowns that are probably negative include clouds and aerosols. Any system with positive feedbacks is likely to be unstable. Start a movement in one direction and your positive feedback re-inforces it. Now that does not prove "chaos". But it certainly does create instability. That's why the THC is an interesting one because heating up the arctic can lead to cooling down the arctic, even though we don't have "turbulent fluid flow". Let's delve into the uncertainty here for a minute - heating up the arctic might instead lead to large releases of methane gases from permafrost thus a large further warming. (Not sure where the research is on that at the moment). Heating up the arctic might reverse the THC, thus a cooling. Which one happens first? We have a system with large positive and negative feedbacks. That is just one part of the climate. So I believe that to claim as your original post did that the system is "not chaotic" needs a lot more evidence.
  23. On the reliability of the U.S. Surface Temperature Record
    Oh, & before you say that this is simply limited to ground based stations Remote Sensing Systems (one of the groups which processes data from the microwave sensing satellites) shows the following anomalies. For the 1980's, the average anomaly (when compared to the 1979-2000 average) was -0.065 degrees C. For the 1990's, the average anomaly was +0.083 (a change of +0.148 degrees) & the average anomaly for the 2000's was +0.258 degrees (or a change of +0.175 degrees). Again, an acceleration in the warming trend.
  24. On the reliability of the U.S. Surface Temperature Record
    Consider this jpark. The average global temperature anomaly (compared to the 1961-1990 average temperature)-according to GISS-for whole of the 1960's was -0.012 degrees C. For the 1970's, it was +0.002 degrees C (a change of +0.0122 degrees). For the 1980's, it was +0.18 degrees C (a change of +0.178 degrees. For the 1990's it was +0.321 degrees (a change of +0.141 degrees-would have probably been a higher change except for at least one major volcanic eruption) & for the 2000's, it was +0.515 degrees C (a change of +0.194). So we essentially see an acceleration in the rate of change for each decade, in spite of the fact that there was a downward trend in solar irradiance (of around -0.3 watts/meter squared per decade) over that same period. So I really don't see where the case for skepticism is.
  25. On the reliability of the U.S. Surface Temperature Record
    More points jpark. Inquiry or not, the denialists who hacked & distributed the CRU e-mails have now had close to 3 months to find something truly damning about the way in which CRU has collected &/or manipulated the data. That they've not presented any case of fraud in this time strongly suggests that this is because no evidence exists to prove it. I'd personally like to know when there is going to be an inquiry into who hacked CRU-& who paid them-& when those responsible will be brought to justice (last time I checked, Hacking was a MAJOR CRIME in most constituencies). That such an inquiry hasn't taken place suggests that some very powerful vested interests were behind the hack. One wonders what you want, jpark? If graphs showing the warming trend don't suit you, then what about the images of the Earth covered in ever greater shades of orange & red showing the extent of warming over the last 30 years? Graphs remain the very best way of showing how the minimum & maximum temperature anomalies for each decade have changed. As to why certain stations are omitted, it might be for any number of reasons. Maybe local conditions meant the station was off-line for too many days out of a year, or maybe some localized event caused the station to become an obvious outlier. Maybe they simply had enough replicate data points, from a specific region, to get an average with a sufficiently small margin of error. The point is that the deletion of a handful of stations across the globe isn't suddenly evidence of a conspiracy. What is evidence of a conspiracy, though, is how many of the official denialist groups & individuals have strong ties to the mining & fossil fuel industries.
  26. On the reliability of the U.S. Surface Temperature Record
    jpark, can you be a little more specific about how the Met Office "got it wrong"? If you're talking about the recent cold snap, that was caused by an unforeseen change in the Arctic Oscillation, & has absolutely nothing to do with broader warming trends. What Menne's paper shows is that, in spite of the claims by people like Watts, so-called "poorly sited" weather stations are showing only a negligible difference in both their minimum & maximum temperature readings-over time. This therefore means that poor siting of US weather stations cannot be used to explain the global warming trend of the last 30+ years. This is hardly news, as satellites have shown an almost identical warming trend over the 30 years they've been taking readings. Your claim about "managed data" is meaningless, as *all science* is dependent on the manipulated-or management-of raw data. To try & equate "management" or "manipulation" with fraud is to essentially impugn the entire scientific establishment. Also, as someone who actually *knows* people in the IT industry, I can assure you that Y2K was not a hoax (though some news agencies deliberately overstated the threat). Had nothing been done about it, many industrialized nations would have been disrupted for days-if not weeks. Last of all, many of the people who helped create the sub-prime mortgage crisis walk in the same circles as those who're pushing the denialist cause in the media. Their motives are also identical-*profit*. That's why I'm so skeptical of the denialist case.
  27. The IPCC's 2035 prediction about Himalayan glaciers
    Charlie A, i did NOT say it's correct, i did say it's just simple math. Try yourself 2840/(1966-1845)=23.4 and 2840/(1966-1945)=135.2 and you'll see where the inconsistency in that table comes from. They guy who wrote the table probably mistyped the number and came out with the wrong rate. Or you mean it was intentional? In my life i've never seen a thousand pages book with no such errors and sometimes even happen in peer reviewed papers. Anyway, being the error really irrelevant for the whole picture I find the pertinacity you show by cross-posting the same "question" really pointless.
  28. On the reliability of the U.S. Surface Temperature Record
    Albatross - guys, thanks. The trend and climate models are great. I will study them some more, and of course I find them persuasive but my immediate reaction is 'oh, more graphs with dots on, is that it?' Others here have parried my question rather than answered it. Is the actual data duff or not? If the data going into all the trendy models is bad then we, the public, will simply dismiss the model. The Met Office in the UK got their predictions (and models) badly wrong this year while, to their utter horror, a chap called Piers Corbyn got it right. So much so that the BBC are considering using a different company. I know this has to do with 'weather' rather than 'climate', but let's face it if you cant predict one then the other looks fanciful. The UK Gov are setting up a parliamentary inquiry into the CRU leaked emails - this is good because it should be thorough and open. But it does mean, Doug, that you cannot say there is nothing to the emails and everything is fine. The IPCC report is, I am afraid, also important. If it includes rather wild speculation about Himalayan glaciers then the whole report looks rather suspect. Ian says that deleted stations are showing greater increases of warming - then why the heck are they not included in the data? Why do we have this adjusted/deleted/averaged/smoothed picture of what is happening - why not real/complete/comprehensive? So back to the topic here - if Menne's paper just tells us that the surface station data does nice trends then I, for one, am still left scratching my head. The case for catastrophic global warming seems too dependent on 'managed data' to me. After the Y2K bug, the sub prime mortgage/financial crisis there is good reason to be sceptical. This is very very poor PR - there has to be better than this.
  29. The IPCC's 2035 prediction about Himalayan glaciers
    Riccardo says at #28 "i just pointed out that plugging in the correct starting time the calculation of the rate is correct. " I ask again, what is your reference for saying that 1945 is the CORRECT starting date when all of the available literature points to 1845 (or 1847) as the correct starting date associated with the 2840 meters of retreat. To put it more simply, other references, such as 1958 reports make it clear that the 2840 meters of retreat is approximately correct, that 1845 is approximately correct, and that IPCC or whoever originated the chart incorrectly calculated the time span from 1845 to 1966 as 21 years rather than 121 years. These errors make it even more relevant that nominations for AR5 reviewers, which close on March 12th 2010, are not allowed to be submitted unless you are one of a certain list of privileged organizations chosen by the IPCC. I have been unable to obtain this list. The IPCC would be well served by including some reviewers without a strong confirmation bias in favor of AGW.
  30. On the reliability of the U.S. Surface Temperature Record
    Deniers are very good at confusing lay people in the use of absolute temperature and anomalies. For example Joseph D’Aleo and E. Michael Smith have accused "NOAA researchers of strategically deleting cherry-picked, cooler-reporting weather observation stations from the temperature data". They say that by ignoring these cooler stations the global temperature is artificially raised over what it would be if the stations were included. However, if you actually look at where the deleted or ignored stations are they are in areas of the world which are experiencing much faster rates of temperature increase than average (northern Canada, northern Russia). Thus their omission is actually lowering the global average, the exact opposite of what D'Aleo and Smith are saying.
  31. The IPCC's 2035 prediction about Himalayan glaciers
    nofreewind. It may not stop snowpack from forming, but it will effect the depth & total extent of the snowpack in the future-which *will* impact on future fresh water supplies. You see, even without global warming, we're already running into problems providing water to our populations. Imagine how much worse it will get if our sources of fresh water become depleted by global warming? That's not a "scare", it is something which we should be genuinely concerned about-in spite of efforts by the fossil fuel industry to try & cast doubt on the issue.
  32. On the reliability of the U.S. Surface Temperature Record
    jpark. Trends are very important because they tell us a lot about the *rate* of change. This is especially important if we can compare it to rates of change in the past. You see, though climate has changed in the past, all the available evidence suggests that it has *never* changed as rapidly as it has in the last 30-60 years, in spite of a relative lull in Total Solar Irradiance. That is why climatologists are so concerned, in spite of the efforts of people like Watts to confuse the issue.
  33. On the reliability of the U.S. Surface Temperature Record
    I've been following these threads and seeing how everything is going back and forth. Considering when somebody turns on the news and watch the weather report, we are presented with it in absolutes. So to an average laymen I could see how it seems to make more sense to want to see the data presented like that. And considering that the pdf on WUWT is very pretty and professional looking I could see how people will believe it. (He must have an army of dedicated followers, no wonder he doesn't want to report anything different, he will lose his crown) It wasn't until I started playing around with temperature data myself (DIY-Statistics) that I could understand it a whole lot better!! Is there any room for a post John or Mark on "anomalies verses absolute" or "this is what a raw reading looks like, this is what has to be done to extract sense from it..." (with lots of pictures of course, people like their pictures)?
  34. The chaos of confusing the concepts
    I think batsvensson's distinction between linear and nonlinear forcings is a red herring here, though I could be wrong (I'm not an expert in this). We can predict that (outside the tropics) it will be warmer in summer than in winter because we have a conceptual model of a forcing (the time evolution of the solar zenith angle at a given latitude as determined by the earth's axial tilt) that is large enough to override short-term variability in the weather. There are of course all kinds of feedbacks, positive and negative, that amplify or reduce that radiative forcing. Nonetheless, we can be confident that the magnitude of that forcing is large enough to make the winter-to-summer difference semi-predictable. Likewise, we have a good conceptual model of another radiative forcing (absorption of outgoing long-wave radiation by greenhouse gases) that is also becoming large enough to have a detectable influence on climate. We can't predict the weather in 2050 (just like we can't predict the weather next July), but in both cases we know there are predictable radiative forcings that will make it warmer (on average) in summer than in winter, and in a 500 ppmv CO2 atmosphere than in a 300 ppmv CO2 atmosphere.
  35. On the reliability of the U.S. Surface Temperature Record
    jpark: You're starting to get all mixed up here. "...last year we found out that CRU scientists made a hash of doing the data." Wrong. Be careful, there are a number of people with an unhealthy obsession with old email, to the point they've actually set up a web site all about it and apparently spend their days sifting through this stuff. There's really no "there" there. "Then Copenhagen fails." And that does not have anything to do with surface stations in the US. "Then this week Pachauri gets it in the neck ..." Again, nothing to do with this topic. "What does a trend mean..." A trend tells you useful things, such as whether you can expect your coffee to ever brew. "Because if those temps/trends are slightly higher than they should be and so, in reality, only slightly higher than older temp station data, or even older historic data then, yes, we have global warming but not very much..." There you go! That's the useful part! The trend provides confirmation of theory via observation, validation of models, etc. And that's why Watts et al are so determined to distract you from the importance of trends. Easy once you go through the steps, plus remember these folks are doing the same thing you used to see in word problems: throwing a lot of chaff in the air to confuse you so you can't come to a useful conclusion. Don't let yourself flunk the test.
  36. On the reliability of the U.S. Surface Temperature Record
    jpark at 07:05 AM on 24 January, 2010 Hi Doug! Many thanks, nice explanation. - But still not good enough, and I'm sorry. "I do understand the paper but still feel it does not, like a lot of posts here, answer the quite basic Watts question of how accurate the stations are." When you use the phrase "how accurate the stations are" I think it betrays that you don't understand the paper. It does not matter at all if the stations are accurate. Their utility for telling accurate absolute temperature from day to day is entirely separate from their utility for revealing a climatic trend. All that matters for extracting a trend is whether or not there's a unidentified longitudinal change of bias in measurements resembling a trend in temperature. More, that unidentified longitudinal change must be approximately the same for a multitude of stations. As it happens, there is no unidentified longitudinal bias change that meets that requirement, but there is a -know- reason for observing a trend, namely a change in climate.
  37. On the reliability of the U.S. Surface Temperature Record
    jpark, "if those temps/trends are slightly higher than they should be and so, in reality, only slightly higher than older temp station data, or even older historic data then, yes, we have global warming but not very much" Exactly, but it ain't so. In principle it might be a resonable concern, in practice it does not stand up an in depth analisys. Remember, people working on it check the readings for possible biases/errors; something may slip through the check but, well, just some. And unless you belive in the bad intentions of the researchers, errors and biases (plural) tend to average out. Don't be confused by absolute temperature and anomaly. The former is more intuitive given that it's what we feel. The latter has the advantage of being more stable and correlated over long distance and time, then more easily shows an underlying trend, which is what we are interested in.
  38. The chaos of confusing the concepts
    re #22 hmmm...this is why I suggested in post #12 that we have to be careful what we mean when we use the term "chaos" in any particular instance. We end up misarguing around the meaning of a word or concept rather than the phenomenon itself. Meltwater-induced suppression of the Thermohaline Circulation happened many time is the past. So one can hardly say it can't happen! Of course the boundary conditions are different now (interglacial rather than the many instances identified during glacial periods). I (and everyone here, I think) was using it as an example 'though. It's not really chaotic behaviour (it has its chaotic elements on a microscale), but it's really a stochastic phenomenon that is essentially predictable, if not in relation to the precise timing of events, at least as a phenomenon that is a definite and predictable consequent of particular conditions. So, for example, it would likely be possible to model N. hemisphere ice sheet dynamics and ocean circulation during the last glacial period to reproduce the Daansgard-Oeschger (D-O) events, within an understanding of the conditions under which these events occurred (not sure if this is yet understood very well). Where this differs from chaotic phenomena (as I understand it), is largely the independence with respect to initial conditions. We wouldn't know exactly when a D-O might occur, but we would be able to predict that, independent of inital conditions, once the important factors tended towards threshold values, that a D-O event would have a high probability of occurring.. Two examples: (i) Knocking down a wall with one of those splendid balls on chain swung by a crane. We don't know exactly when the wall will tumble, or exactly the pattern of its disintegration (one might consider the latter to be chaotic). However the event (the wall falling down) is predictable (if not precisely defined temporally speaking), given that we understand the forcings that act in this situation, and is independent of initial conditions. (ii) In a warming world we expect coastal flooding events that might have 100 year probability (say) to occur more frequently, as a result of rising sea levels combined with more extreme weather events as sea surface temperatures rise etc. Now, however chaotic the weather is (chaos), the likelihood of an increased frequency of coastal flooding events is predictable. We don't know when any of these events will occur (stochastic), but our prediction of an increase of events in a warming world is likely to be robust, and increasingly so as our knowledge of the climate system increases.
  39. On the reliability of the U.S. Surface Temperature Record
    Albatross - thanks for the links - I will read. Carefully.
  40. On the reliability of the U.S. Surface Temperature Record
    Albatross - I think an illustration on temp anomaly might be a good idea. Ok I will give this one more go because I think you guys might be able to give me an answer and you haven't yet (apart from Kforestkat) Here is the problem: the world is getting hotter - I think we all agree - but last year we found out that CRU scientists made a hash of doing the data. However kindly you read the leaked emails you realise this was not good science. Then Copenhagen fails. Then this week Pachauri gets it in the neck for getting the Himalayan glacier date wrong and putting pure speculation in the IPCC report (apparently it was not the only error) and an error that had significant financial consequences. So when Watts puts out a report showing images of severely compromised temp stations and Menne replies with 'trends' people like me say...'er so what? What does a trend mean, I want to know whether the temp stations work or they are being lovingly heated by a/c units". Because if those temps/trends are slightly higher than they should be and so, in reality, only slightly higher than older temp station data, or even older historic data then, yes, we have global warming but not very much - which is what the report at Science Daily says. But of course I may be missing something...
  41. On the reliability of the U.S. Surface Temperature Record
    Jpark "This means actual temps do matter and trends in this particular instance dont," The actual temperatures form part of a long-term trend. You can't have a trend in a time series without either increasing or decreasing time series of temperatures. Moreover, those tmepratures do not have to increase montonically to get a positive trend as illustrated by the surface air tmeprasture records. The long term temperature trend (globally) is about 1.7C warming per century, and yes, that is actually something to worry about. Regarding "why we have not warmed as much as we should have". You are probably referring to the work of Scwartz that is aboutt o be publishe din J. Climate. Perhaps John can again (Schwartz has done this before) refute the work of Schwartz et al. Jpark, be wary of site slike WUWT, their goal is to confuse. Really it is just that simple, and it is cleverly done under the guise of "science" and the pursuit of "truth". That is what makes the misinformation there seem so compelling. The long term observed warming trends is consisent with the projections made by the IPCC. Look here: http://tamino.wordpress.com/2010/01/13/models-2/ and here http://tamino.wordpress.com/2009/12/07/riddle-me-this/ and here http://tamino.wordpress.com/2008/01/31/you-bet/ I really encourage you to actually read the above articles carefully.
  42. Berényi Péter at 09:36 AM on 24 January 2010
    Skeptical Science now an iPhone app
    Back to the original claim. It is getting pretty cool in the Arctic (-35°C, -31°F) http://ocean.dmi.dk/arctic/meant80n.uk.php Still, it is not terribly hot elsewhere around it. I've just walked my dog in the park (lat=47.4717672, lon=19.0426755) and he was anxious to get back which is rather unusual. It is -10°C (14°F) here right now. US http://www.wunderground.com/US/Region/US/2xpxTemperature.html Alaska http://www.wunderground.com/US/Region/Alaska/2xpxTemperature.html Canada http://www.wunderground.com/global/Region/CN/2xpxTemperature.html Europe http://www.wunderground.com/global/Region/EU/2xpxTemperature.html
  43. On the reliability of the U.S. Surface Temperature Record
    Reading some of the posts here is incredibly frustrating because it clearly demonstrates the stunning success Watts et al. have had in confusing and brainwashing people (even well educated professionals it seems)to the point where it is impossible to explain a simple concept of a temperature anomaly to them. I was going to chime in and try to dispel some of the confusion, but others have repeatedly and clearly explained the facts only for those facts to repeatedly fall upon deaf ears. What I will add, is that the Menne et al. study needed to be done and their results are incredibly important. Their results also represent the final nail in the coffin for the complaints from Watts et al. as to the validity of the US SAT record. There is simply no dobting the validity of the SAT record anymore, but I doubt this study will discourage the contrarians and denialists from perpetuating and rehashing old myths. Prof Mandia re #35, I too once tried to explain the science with the folks at WUWT, and it was a waste of time. Watts knows his audience and plays to that; he is very good at telling them what they want to hear. He is also guilty of confirmation bias and ignoring the inconvenient facts regarding AGW. Anyhow, I do hope that some of the misguided posters here represent the views of people who are in the minority, b/c if they represent a much larger segment of the populous then we have a serious problem on our hands in terms of communicating the science. Why is it so much easier to disseminate misinformation than the basic facts? Maybe someone with some time can show some schematics illustrating how one obtains anomaly values from a temperature record, and why systematic bias does not affect the trend? A picture is oftentimes far more convincing and informative than even the most carefully chosen words. PS: Actually those in denial are having a bad decade-- 2009 second warmest year on record globally, first decade of naughts warmest on record globally, warmest year on record in S. Hemisphere (lots of heat stored in the vaste southern oceans), continuing acceleration of rate of loss of summer Arctic sea ice and glaciers, PIG glacier in WAIS found to have exceeded its tipping point, and for what it is worth, January 2010 warmest lower trop. temps in the satellite record despite extremely cold weather in Eurasia and portions of N. America. The list goes on.....
  44. Why does CO2 lag temperature?
    re #39: thingadonta, the evidence tends not to support the interpretation of inception of polar ice sheets in Antarctica, and Greenland (see my post #38) that may have been the dominant theory in your uni days! In the intervening 20 or so years, that theory has been tested both for the N. hemisphere polar ice cap (see post #38) and the Antarctic ice cap (see following). In each case the evidence indicates that glaciations only occurred when CO2 levels dropped below thresholds that forced sufficient global cooling (these are thought to be of the order of ~ 700 ppm for Antarcic glaciations and ~ 300 ppm for Greenland glaciations). It’s possible that ocean circulation changes made some contribution (as likely did earth orbital properties). But greenhouse gas concentration seems to be the major player: (i) CO2 changes and temperature changes during the Phanerozoic (last 500-ish million years). The problem with the idea that changes in atmospheric CO2 concentrations in deep time are the response to earth temperature change is that these CO2 variations are simply too large. We can determine, for example, that during ice age glacial-interglacial-glacial transitions, atmospheric CO2 levels cycle rather faithfully between ~270 (interglacial) and ~ 190 (glacial ppm). These are slow (~5000 year) transitions (so CO2 re-partitioning between ocean/land and atmosphere will have come close to equilibrium), involving global temperature changes of around 5-6 oC. Therefore temperature-induced CO2 rises/falls are of the order of 13-15 ppm per oC of warming/cooling. Since the entire Phanerozoic temperature variation was likely no more than 10 oC overall, we don’t expect to see temperature-induced variation in CO2 levels of more than 150 ppm. However the CO2 changes observed in the record are much larger than this. The slow fall of atmospheric CO2 from 1000-1500 ppm during the mid to late Eocene to around 700 ppm at the Eocene-Oligocene boundary around 33.5 MYA and further to ~300 ppm and below by around 24 MYA (and ever since until now) are simply incompatible with temperature-induced changes in atmospheric CO2. (ii) Timing The steady long term cooling from the Eocene maximum global temperature at around 50 MYA began far in advance of any ocean circulation change resulting from isolation of Antarctica and possible effects on ocean currents. And the opening up of the Tasmanian gateway preceded the Eocene-Oligocene transition that heralded major Antarctic polar ice sheet growth by ~ 2 million years [*]. The steady cooling right through the middle-late Eocene to the onset of Antarctic glaciations ~ 33.5 MYA is associated with a long slow drawdown of atmospheric CO2 from 1500 ppm or greater to ~700 ppm [**]. As indicated in (i) the extremely large drops in atmospheric CO2 concentrations are incompatible with the idea of temperature-induced repartitioning of CO2 between oceans and atmosphere. Most likely the slow drop in atmospheric CO2 was due to enhanced weathering (possibly a result of the drifting of the highly weatherable volcanic Deccan Traps into the equatorial humid belt as the Indian subcontinent shuddered remorselessly Northwards for its eventually intimate rendevouz with Asia [***]). (iii) <>Attribution There are a number of studies that indicate that the ocean circulation effects associated with the isolation of the Antarctic continent are minor contributions compared to the effects of reduced-greenhouse-induced global cooling. Some of these are: a. The temperature changes associated with the cooling during the Eocene-Oligocene transition ~ 33.5 MYA and the onset of build up of a permanent ice cap in Antarctica, were global, and poorly compatible with the regional effects associated with changes in ocean gateways [****] b. As well as the timing mismatch in (ii), a number of studies have reconstructed and/or modelled the effects of ocean circulation changes involving isolation of the Antarctic continent, and concluded that the ocean circulation changes are simply not able to produce the localized cooling required for onset of Antarctic glaciations. This can have only occurred when atmospheric greenhouse gas levels dropped below thresholds that maintained the earth in a state without a significant permanent Antarctic ice cap [*****]. [*] Stickley, C. E et al. (2004) Timing and nature of the deepening of the Tasmanian Gateway, Paleoceanography, 19, PA4027 http://web.ics.purdue.edu/~huberm/STICKLEY.HUBER.PDF [**] P.N. Pearson et al. (2009) Atmospheric carbon dioxide through the Eocene-Oligocene transition Nature 461, 1110-1113 http://www.ncdc.noaa.gov/paleo/pubs/pearson2009/pearson2009.html http://www.nature.com/nature/journal/v461/n7267/abs/nature08447.html M. Pagani et al. (2005) Marked decline in atmospheric CO2 concentrations during the Paleogene Science 309, 600-603 http://earth.geology.yale.edu/~mp364/data/Pagani.Science.2005.pdf [***] D. V. Kent and G. Muttoni (2008) Equatorial convergence of India and early Cenozoic climate trends Proc. Natl. Acad. Sci. USA 105, 16065-16070 http://www.pnas.org/content/105/42/16065.abstract [****] Z. Liu et al. (2009) Global cooling during the Eocene-Oligocene climate transition Science 323, 1187-1190 http://www.sciencemag.org/cgi/content/abstract/323/5918/1187 E. Thomas (2008) Descent into the Icehouse Geology 36, 191-192 [*****] R. M. DeConto et al. (2003) Rapid Cenozoic glaciations of Antarctica induced by declining atmospheric CO2 Nature 421, 245-249 http://www.geo.umass.edu/faculty/deconto/deconto_nature.pdf Huber M et al. (2004) Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters? Paleoceanography 19, PA4026 http://doos.misu.su.se/pap/paleo2004.pdf M. Huber and D. Nof (2006) The ocean circulation in the southern hemisphere and its climatic impacts in the Eocene Palaeogeog., Palaeoclim., Palaeoecol. 231, 9-28 http://web.ics.purdue.edu/~huberm/huber+nof.pdf
  45. On the reliability of the U.S. Surface Temperature Record
    Obsessively repeating the same concept is the standard tool people in the media use to make it true. Anthony Watts is pretty good at it and the fact that even if true it does not have any pratical impact has no importance for him and his fellows. They'll stubbornly keep repeating "Poor siting! Poor siting!" ad infinitum.
  46. On the reliability of the U.S. Surface Temperature Record
    Thanks Prof! Again very helpful but to me a trend is not at issue. I am a newbie here and like many this area of science has only become a really hot (pardon the pun) topic for me since climategate. Before then I accepted the general consensus. Most in the blogosphere seem to believe in global warming - it is the extent and the 'unprecedented' nature of the warming that I think (from what I have read on blogs so far) is the issue, which is of course linked to the anthropogenic part. This means actual temps do matter and trends in this particular instance dont, to me at any rate. If it is getting a bit hotter then, well that is not too bad, climate does tend to do that. But if it is getting amazingly hotter then, of course, we are all going to be in big trouble. So are the temps showing something dangerous or something not so dangerous I read this "Why Hasn't Earth Warmed as Much as Expected? New Report on Climate Change Explores the Reasons" from Science Daily. I think you can understand my layman's puzzlement. http://www.sciencedaily.com/releases/2010/01/100119112050.htm Apologies if that is off topic.
  47. On the reliability of the U.S. Surface Temperature Record
    As others have said the bias does not affect the trend. "A rising tide lifts all boats." Increased GHGs are the rising tide. Watts refuses to admit the obvious. In fact, even today he has the following post: http://wattsupwiththat.com/2010/01/23/sanity-check-2008-2009-were-the-coolest-years-since-1998-in-the-usa/ He is using US data to try to cast doubt on global data. He knows better but loves the attention from his misguided followers. I used to post there as the loyal opposition but it ended up being a huge waste of time.
  48. The chaos of confusing the concepts
    Jacob Bock Axelsen: First of all, a comment on the thermohaline circulation. You said: "However, the engine of THC is surface cooling in the Arctic which global warming might turn off." But there are 2 factors driving the ocean currents. One is temperature and the other is salinity. Both affect density in a non-linear way. The reason why it is potentially "a switch" is that as the oceans warm, as they are doing at the moment, there is increased melt from Arctic ice and the Greenland ice sheet. If this melt rate increases to a certain point - no one exactly sure what that point is - then the low salinity will outweigh the cold and this water will stop sinking and the "conveyor belt" direction will change. Therefore, a very complex situation, and one where increased temperatures will eventually (possibly) lead to a colder northern hemisphere and a refreeze of the Arctic with the consequent (positive feedback) of increasing albedo. More on your other points later..
  49. The chaos of confusing the concepts
    Chris, you wrote in #17, "the THC could slow down or stop if sufficient freshwater from Arctic ice melt were to flood the Arctic ocean." Mostly anything can happen if sufficient conditions are present, but the interesting question is, if this is likely to happen or not. Afaik, current understanding says this is not likely to happen at all - if ever. "At some point we might well understand this process well enough that it might cease even to be considered “stochastic”." I don't think so. "stochastic" is just another way to label non-linear or "random" system, system we previously not been able to model or control properly. Chaos theory is in principle a theory about non-linear system and how to treat them as non-linear. Before the time we had the mathematical tool to model and understand such system (which wasn’t all that long ago) engineers was busy making sure any non-linear system was modeled with in a certain local region that could be approximated as linear, outside this approximated region the behavior can not be guaranteed. The mathematical tools to do this exercises with is know as ‘differential equations’, and one requirement for these tools to be “trivial” to use is linearity – nonlinear differential equations are extremely hard to solve. Stochastic processes lacks the linear properties, thus they are always hard problem to solve with differential equations. Only a few non-linear processes of special interest are understood this way, like fluid dynamics, but even these are solved with numerical methods. However, new mathematical tools and theories theory have help use to better understand system outside the approximated linear boundaries, but such understanding wont make them less stochastic, rather it will help use to even more appreciate the very special behavior of these system.
  50. On the reliability of the U.S. Surface Temperature Record
    Gordon, many thanks. I think what you say is wise, But do look at the Watts report - lots of stations, lots of pictures ( worked for Al, it might just work for Ant) http://wattsupwiththat.files.wordpress.com/2009/05/surfacestationsreport_spring09.pdf

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