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Comments 112051 to 112100:

112051. Peter Hogarth at 02:24 AM on 22 August 2010
        The Past and Future of the Greenland Ice Sheet
        Berényi Péter at 01:05 AM on 21 August, 2010 You state: “However, people here are denying both air and sea surface temperatures were considerably warmer in the Arctic during the Holocene Climatic Optimum than they are today just to make the present feeble warming unprecedented and alarming” I do not think this is generally being denied, though we should quantify “considerably warmer”. The high resolution ice core data from Greenland and nearby (eg GISP2, NGRIP, Agassiz) is proxy evidence that Northern Greenland temperatures were up to 3 degrees warmer around 8000 years ago than the average for the 20th century, (your suggestion of regional variations is also validated by the evidence, eg Agassiz shows a more pronounced “Holocene Climactic Optimum”). The Bednarski 1989 paper you cited, and many other more recent ones also provide convincing circumstantial evidence (such as driftwood deposits) that at least some of these coastal Arctic areas which are now ice bound were bounded by areas of open water for at least some periods since the last glacial. This is generally accepted and is consistent with the proxy temperature data. The current global decadal temperature trend is upwards, and appears “amplified” in the high latitude NH. If the current or centennial trend is sustained as modeling suggests, Greenland temperatures will exceed post glacial Holocene temperatures in a relatively short timescale. The word “feeble” is perhaps inappropriate given the likely persistent nature of GHG forcing. The recent Arctic temperature rise is not unprecedented over geological timescales, but is highly significant compared to the past 2000 year proxy records (see Kaufman 2010 update and the zoomed in ice core record from Agassiz (Vinther 2009) and GISP2 (from Alley 2004 update). It should be emphasized, that the orbital parameter forcing which is thought to have driven the gradual fall in NH temperatures since the post glacial temperature maximum is not global in effect, it is not clearly apparent in the deep sea sediment alkenone temperature proxy records for much of the rest of the globe (as is clear in Rimbu 2003) and is not apparent in the Antarctic ice core records. The Greenland Ice Sheet mass is currently diminishing at an accelerating rate due to localized warm waters and warm currents transported from lower latitudes Hannah 2009, Di Iorio 2009, Straneo 2010, Rignot 2010 as well as recent rapidly warming Arctic air temperatures. The recent rapid change in positive forcing from increasing anthropogenic GHGs is a new factor not present in previous glaciation/deglaciation cycles. It is effectively a global effect (rather than a high latitude effect such as NH insolation) – which combines with the effects of other forcings. The oversimplistic point you make about higher relative NH insolation forcing levels in the past does not strictly hold. Perhaps more importantly, the massive ice sheets that covered much of the NH in the last glacial period did melt (in most places completely) over the “deglaciation” time span, and we know rapid changes in temperature have been triggered by a combination of the slow change in solar forcing combined with positive feedbacks possibly from changes in the Atlantic Meridional Overturning Circulation and/or changes in GHG. This shows how sensitive our climate can be to proportionally small changes in forcing. I also do not expect the massive central Greenland ice sheet to vanish overnight, but the relatively rapid recent increased rate of loss is of legitimate concern and should not be belittled.
112052. John Russell at 02:08 AM on 22 August 2010
        What caused early 20th Century warming?
        miekol at 13:27 PM on 21 August, 2010 I think I can speak for everyone who contributes to this website when I say that we share your concerns about energy availability and poverty. For me, personally, I can say that my concerns also include biodiversity loss and food availability. Please understand that we don't take any satisfaction in the fact that humans are changing the climate, complicating other issues. I really wish a magic wand could make the AGW problem disappear. I think we 'warmists' -- or whatever you want to call us -- just recognise that everything will be that much worse if the majority refuses to recognise the problem and bury their heads in the sand. To overcome the world's problems, first we must all agree what they are and how they interact. I urge you to read the links others have provided and understand the science for yourself. The facts will speak for themselves -- provided you're willing to be open and objective. From the way you end your last comment I think you are.
112053. MichaelM at 02:05 AM on 22 August 2010
        Is the sun causing global warming?
        As it says at the top of the page "This post is the Basic version (written by John Russell) of the skeptic argument 'It's the sun'" The comments at that page number over 550 covering a period of 3 years. Is this page, and indeed the other Basic versions not in danger of rehashing old points? I mention this as the chances are that the points Kamilian brings up here and at other Basic pages may have been covered over the last few years at the relevant main page. Is the intention to have Basic, Intermediate, Advanced share the same set of comments or will each have their own? I've seen moderators note things as being Off-Topic so should they note things as being Off-Level?
112054. nealjking at 01:56 AM on 22 August 2010
        Communicating climate science in plain English
        - I think tabs make more sense than a slider: Discrete choices vs. a continuous range. - However, I think the choices should be: 1) The one-liner 2) The "basic" explanation 3) The "in-depth" explanation I think it's going to be hard to do a really good job on the previously discussed "advanced" explanation, because you're really talking about an expert's level of understanding re-packaged in layman's language. The most I would do for this site is to find pointers to appropriate existing discussions (if any). So this should be a 4th tab, but mostly with pointers. - With respect to writing style: 1) One-liner: From what I've seen of the examples, they look about right. 2) "Basic" explanation: Should really aim for an 8th-grade level of language use. I think this is about what writers aim for in documentation that they really need people to understand. As I've remarked elsewhere, this doesn't mean the argument is "dumbed down", just that the style is trimmed and the vocabulary not too extensive. 3) "In-depth": I think the current level of writing is about right. 4) Pointers to advanced presentation: Same level as 3). - Just one more comment on the importance and dignity of explanation at the audience's level: The great experimental nuclear physicist Ernest Rutherford once remarked: "If you can't explain to a barmaid what you're doing, you don't understand it!"
112055. CBW at 01:44 AM on 22 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        I think papertiger is saying that because we can observe the geology in some detail, we can infer something about the ancient climate (e.g., the existence of certain kinds of sedimentary layers suggests the presence of standing water at some point in the planet's history). But, no, we don't know much about climatic trends in the last century. But even if we did, it wouldn't tell us much -- that's the point of the article. We can directly measure solar output and we can measure how much of it is reaching the Earth. Using Mars as a proxy would introduce huge amounts of uncertainty under the best of circumstances, and we have anything but the best of circumstances with respect to our understanding of Mars' climate. gpwayne, John -- I think each of these short explanations should end with a sentence like: "If you'd like to know more, see our intermediate explanation." Where "intermediate explanation" is a link to the more detailed entry.
112056. Ian Forrester at 01:28 AM on 22 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        theendisfar said:

        Calling someone a liar could be considered ad hominem

        Wrong. Calling someone a liar who has obviously just told a porkie is not an ad hominem attack just a reflection of the truth. As far as I am aware the only proven liars are all on the side of the deniers: Monckton, Singer, Michaels, Lindzen et al. If you have proof of climate scientists lying then please provide evidence otherwise you are the one guilty of an ad hominem attack. You are just arguing from a baseless "I don't like it therefore it is wrong" attitude. Also please explain to us how convection and evaporation add energy to the atmosphere. They only move the energy around, the enhanced green house effect is what adds the additional energy. Please read some simple physics texts.
112057. Peter Hogarth at 01:18 AM on 22 August 2010
        The Past and Future of the Greenland Ice Sheet
        Berényi Péter at 09:21 AM on 20 August, 2010 “SST was more than 2°C above its present value for several thousand years with no adverse effect on the Greenland ice sheet” The second part of this statement is doubtful. One of the points of this post is that there is plenty of evidence and peer reviewed research which shows that the Greenland Ice Sheet volume has varied in step with the NH high latitude temperature variations in the past, see Vinther 2009. Areas at the ice margins may have completely melted over periods as short as decades (Alley 2010 cited above).
112058. kamilian at 01:10 AM on 22 August 2010
        How climate skeptics misunderstand past climate change
        Perhaps you may like to illustrate how this blog, and climate science in general, doesn't seem to understand past climate change. This site suggests that warming starts in the SH, is amplified by greenhouse gases and other positive feedbacks, and greenhouse gases transport this to the NH. 1) Richard Alley (at ~38m) suggests the "physically realistic" models show reduced summer sun causes ice sheets to grow in Canada eventually leading to a globally average reduction of ~5-6 °C, yet this page contains Vostok ice core data suggesting temperature falls before CO2 does. If the change starts in the NH, how does CO2 still lag temperature (during these cooling periods) in the SH if CO2 has such a significant effect, particularly in transporting heat from one hemisphere to the other? 2) This page suggests charts provided by Ned (located here), which don't appear to bear any relevance to climate science, are a good example of how positive feedbacks don't lead to a runaway climate. Looking at the Vostok data here: a. How do you explain the almost linear temperature rise in the three warming periods at ~125,000, ~240,000, and ~325,000 years BP? If positive feedbacks don't lead to a runaway climate they need to illustrate asymptotic behaviour, which the empirical evidence doesn't support. b. In the most recent warming (~20,000 years BP), where in the EPICA Dome C data (which is what I look at, but it's seems to also be visible in the Vostok data) there's warming for a few thousand years, then cooling for about 1,500 years, then warming again for about 1,000 years. If positive feedbacks are so strong, how do you explain such (relatively) rapid changes in gradient (as they're significant, rather than being almost zero)? c. How do you explain the significant (~10-15 %) drop in CO2 around ~325,000 years BP with no corresponding change in temperature? In response to Dappledwater (Comment #28) and the Moderator Response, thank you for illustrating what seems to me as the biggest issue with this ice core data, the correlation between temperature and numerous variables that apparently cause the change. Hansen et al. 2008 Figures S18 and S19 illustrate the strong correlation between temperature and CO2, CH4, and surface albedo. Page 2 attributes the change in temperature between the LGM and pre-industrial Holocene to a radiative forcing of ~6.5 W/m^2 with ~54 % surface albedo, ~35 % CO2, ~6 % CH4, and ~5 % N2O. We also know that warmer climates lead to less snow and ice as well as cause vegetation changes, which are changes in surface albedo, and warmer climates also lead to greater concentrations of CO2 due to out-gassing. In other words, temperature has some influence over at least two of the supposed forcings. My reasoning is along these lines. If the data showed perfect correlation between these variables, then the only possible explanation is that changes in temperature caused all the other changes and they had no influence on temperature (as climate science suggests there are external forcings of temperature such as solar variability, orbital effects, etc.). In reality there's strong correlation (particularly between the LGM and pre-industrial Holocene) suggesting that change in one variable (independent) is the significant cause of change in the other variables (dependent), since external forcings only directly influence temperature it's unlikely to be a common cause for all variables. It also suggests that changes in any of the dependent variables would have little if any influence on the independent variable. There's a couple of things that suggest temperature would be the independent variable: 1) Temperature is directly influenced by external forcings. 2) The relationship describing the correlation doesn't correspond to the forcing (e.g. the trendline for CO2 appears to be a quadratic which is contrary to the logarithmic relationship provided by climate science). I'm not worried about the lag between temperature and CO2, how do you explain the strong correlation between all these variables if there are multiple drivers of climate which would tend to break the correlation?
112059. kamilian at 01:07 AM on 22 August 2010
        What caused early 20th Century warming?
        Please refer to this comment as it's relevant here as well. In response to Dappledwater (Comment #14), perhaps you may like to do your own investigations, the page you linked to here is misleading at best, and just plain wrong in some cases. First, Figure 2 combined with the paragraph preceding it suggests it shows the measured change in outgoing radiation, which it doesn't, it shows the simulated change. You can see this here which quite clearly labels that same graph as simulated. It also shows that in Figure 1b) the middle graph offset -5 K (simulated) shows a reduction in the CO2 band (~540-800 cm^-1) up to ~740-750 cm^-1 while the graph above it (observed) doesn't show any change. It also refers to the Griggs 2004 paper which appears to be available here as well. Figure 2 in that paper again clearly shows little if any change measured in the CO2 band with the simulated results suggesting there should be a drop between ~700-740 cm^-1. Also, there's a measured increase in the CH4 band between 1997 and 2003, which the authors do not provide an adequate explanation for, and conclude that the simulations (which are meant to be based in physics) require more work as they were unable to predict the change. Secondly, Figure 3 has this description before it: When greenhouse gases absorb infrared radiation, the energy heats the atmosphere which in turn re-radiates infrared radiation in all directions. Some makes its way back to the earth's surface. Hence we expect to find more infrared radiation heading downwards. Surface measurements from 1973 to 2008 find an increasing trend of infrared radiation returning to earth (Wang 2009). A regional study over the central Alps found that downward infrared radiation is increasing due to the enhanced greenhouse effect (Philipona 2004). Taking this a step further, an analysis of high resolution spectral data allowed scientists to quantitatively attribute the increase in downward radiation to each of several greenhouse gases (Evans 2006). Which misleadingly suggests that Figure 3 illustrates the change in downward radiation, even though Figure 3 is correctly labelled. I would have thought it was more important to explain how the Evans paper can conclude that a measured/calculated change of 3.52 W/m^2 "compares favourably" with a simulated change of 2.55 W/m^2. On what planet (with or without a greenhouse effect) is a ~27 % error considered to compare favourably? Another important issue that description raises is a qualitative idea floating around this site about how a tropospheric hotspot is not a signature of an enhanced greenhouse effect (it would be caused by any warming at the surface), apparently it's the warming troposphere and cooling stratosphere due to more energy being "trapped" in the troposphere. Climate science says that the stratospheric cooling is due to increased greenhouse gases in the stratosphere having a net cooling effect, suggesting there would also be additional greenhouse gases in the upper troposphere. As that description suggests, greenhouse gases absorb radiation, become warmer, and then emit more radiation. If the tropospheric hotspot is not a signature of an enhanced greenhouse effect, it suggests that the additional greenhouse gases in the upper troposphere are not absorbing any significant radiation (from any direction), otherwise it would be a signature in it's own right. This leads to: 1) If this region is not absorbing any additional radiation to any degree, then no radiation can be passing through this region (from any direction) that could be absorbed by greenhouse gases, otherwise the additional greenhouse gases would absorb the radiation and become warmer than if there was some other cause of surface warming. How is it be possible for less radiation at greenhouse gas wavelengths above the tropopause that originated from below the tropopause if the upper troposphere is not absorbing any radiation to any significant degree? 2) If everything below the tropopause is getting warmer and emitting more radiation at all relevant wavelengths, and the stratosphere is cooling as it can emit more radiation at greenhouse gas wavelengths, why would there be less radiation reaching space? This leads to another explanation often given, that adding greenhouse gases increases the "optical thickness", leading to radiation being emitted from a higher altitude which is cooler. The problem here is I'm yet to find one that provides a quantitative approach and include tropospheric warming. Explaining this more completely, at pre-industrial times the radiation was emitted at a height h1 at temperature t1, and there was another height h2 at temperature t2. Between then and now greenhouse gases were added and the temperatures increased, increasing temperature t1 to t1' and increasing temperature t2 to t2', also changing the emission height from h1 to h2. The question that doesn't seem to be properly addressed is if t2' is less than t1, as opposed to the explanation given that t2' is less than t1'.
112060. kamilian at 00:55 AM on 22 August 2010
        Is the sun causing global warming?
        So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming. No credible science? So you're suggesting that this site isn't about credible science? Seeing as this page quite clearly states: The other consequence of the warming ocean is it means there is additional "warming in the pipeline". Even if CO2 emissions were to start falling now, we already face further global warming of about another half degree by the end of the 21st century (Meehl 2005). So even if the forcing was reduced, there'd be warming for potentially 90 years. Considering this page suggests that the temperature in the graph on this page also corresponds closely to SSTs, then the cooling trend around 1940-1950 doesn't correspond to the increasing solar activity. Seeing as the temperature fell or remained stable while solar activity increased between 1940 and 1960, and a reduction in CO2 now would see continued warming, it suggests that temperature doesn't directly correlate (temporally) to the forcing. It seems far more likely that the increase in solar activity of ~0.8 W/m^2 up to 1960 in that graph is the cause of recent temperature changes rather than the CO2 change since 1960 of 5.35*ln(390/317) = ~1.1 W/m^2 (i.e. they're of similar magnitude) due to the thermal inertia of the system. Perhaps you would also like to put things in perspective. From 1880 there's been a minimum ~0.5 W/m^2 increase in solar activity (~0.8 W/m^2 until 1960, then a decrease). In the same time there's been a change in CO2 of 5.35*ln(390/290) = ~1.6 W/m^2. According to the IPCC there was a change in CO2 between 1750 and 2005 of ~1.7 W/m^2 and a net change in anthropogenic forcing of ~1.6 W/m^2. How can solar variability be completely discounted, since the graph here suggests it's at least ~30 % of the change due to anthropogenic sources? How do you explain why the IPCC graph suggests ~0.1 W/m^2 due to solar irradiance when this graph suggests otherwise? Perhaps the IPCC doesn't consider it cherry picking, but ~0.1 W/m^2 doesn't show the full story even if it is an accurate delta between 1750 and 2005. Furthermore, what known physical properties of greenhouse gases are you referring to? When I think of physical properties, I think of this as an example. We see that the Stefan-Boltzman constant is considered to be known to a standard uncertainty of 4e-13 W/m^2 and relative standard uncertainty of 7e-6 (68 % confidence interval). For two standard deviations (95 % confidence interval) it would be an uncertainty of 8e-13 W/m^2 and relative uncertainty of 1.4e-5. I would have thought that the effect of CO2 is pretty important in climate science, Section 6.3.1 of this document says: IPCC (1990) and the SAR used a radiative forcing of 4.37 Wm-2 for a doubling of CO2 calculated with a simplified expression. Since then several studies, including some using GCMs (Mitchell and Johns, 1997; Ramaswamy and Chen, 1997b; Hansen et al., 1998), have calculated a lower radiative forcing due to CO2 (Pinnock et al., 1995; Roehl et al., 1995; Myhre and Stordal, 1997; Myhre et al., 1998b; Jain et al., 2000). The newer estimates of radiative forcing due to a doubling of CO2 are between 3.5 and 4.1 Wm-2 with the relevant species and various overlaps between greenhouse gases included. So it used to be 4.37 W/m^2, which was revised to between 3.5 and 4.1 W/m^2, leading to the current 3.7 W/m^2, all of which are estimates as opposed to physical properties. These estimates have an uncertainty of 0.2 W/m^2 and relative uncertainty of 0.05 (with no mention of confidence interval). Interestingly, IPCC AR4 WG1 Section 2.3.1 suggests 3.7 W/m^2 +/- 10 % for a 90 % confidence interval, giving an uncertainty of 0.37 W/m^2 and relative uncertainty of 0.1, which could be considered worse than the TAR! I don't think they really compare as physical properties, and don't see how they can be considered to be known when they're estimated.
112061. theendisfar at 00:45 AM on 22 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        KR, First, regarding the 'CO2 is not the only driver' post, it seemed as though the replies were stuck at 250, my posts were not showing up, I thought the post had closed so I abandoned the effort. I see that it is not closed so I'll pick it back up, I have more to add. This is about our futures, our descendents futures. (Moderator, this is not an attempt to inject my beliefs, just motivation) Precisely, without knowing whether an afterlife is reality, I believe my best chance at immortality is to raise children who can take care of themselves to better raise children who can do the same. The better job I do, the better the chances that what my parents, mentors, and experiences have taught me will live on and be expanded. Not as fancy other's beliefs, but it's the best I can come with and it seems a worthwhile effort. It is truly in my best interest that a healthy environment exists for as long as possible. We want the same things in that regard. If you have actual issues with the data or the conclusions drawn from them, we can talk about it. I welcome the offer and hope to make it worthwhile for you and SS as well. Looking back over some posts I recognize that we and others have traded many jabs, it is obvious you and others are learned in this subject and I would not be interested in discussing this if you all were not. With that, I believe that the confirmation or falsification of AGW can be achieved within a year if subjective influences are put aside. I recognize that many here do not share my position that AGW has not been confirmed, or falsified for that matter, and this presents additional challenges, but I'll do my best to earn your patience.
112062. Philippe Chantreau at 00:43 AM on 22 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        So let me get this straight papertiger: you are arguing that the statement that we don't have historical data on Mars prior to the 70's is not true because an orbiter has been observing since 2006? Makes sense...
112063. Daniel Bailey at 23:34 PM on 21 August 2010
        The main culprit in mid-century cooling
        Tamino over at Open Mind has a nice post showing just when (1975) the warming "resumes" (pollution controls kick in, allowing the true warming signal to no longer be masked/inhibited by the aerosol cooling effect). The CO2 concentration/temperature climb continues unabated to this day. Good post, Anne-Marie The Yooper
112064. nealjking at 23:08 PM on 21 August 2010
        Plain English climate science - now live at Skeptical Science
        First: I applaud the effort to boil down the arguments to the basic gist: People can always find more detail in the intermediate-level discussion. However: My impression is that even the basic-level discussions are written at an advanced-undergraduate level of English. If you want to get through to the majority of American readers, I think something more like 8th-grade level is called for. It doesn't mean that the argument needs to be "dumbed down", but that the manner of expression should be a little plainer, and the range of vocabulary should be cut back. I hope this makes sense to you. Best regards!
112065. Eric (skeptic) at 22:28 PM on 21 August 2010
        How climate skeptics misunderstand past climate change
        CB, that's hardly a fair comment (no effort), I looked up C-C and found the reason you quoted it and KR assumes constant RH. I believe that Soden and Held are oversimplifying by using C-C globally. I don't disagree that a warmer world has more water vapor in the air, my question at beginning of the thread was when does the positive feedback stop. Your answer was two-fold: never (22) and use the math (37) which I answered in 38. It may interest you and others to know that there were number of days here in the DC area this summer where our humidity was higher than Miami including total precipitable water. Also his year we had many days that were warmer than Miami where it never got above 95 (we were above 100 several times). Here's our plot: http://www.erh.noaa.gov/er/lwx/climate/cliplot/KDCA2010plot-2.png and theirs: http://www.srh.noaa.gov/mfl/?n=cliplot
112066. Rob Painting at 21:19 PM on 21 August 2010
        The Past and Future of the Greenland Ice Sheet
        BP, the Stott graph shows SST cooling from 11 to 10 kyr BP onwards, whereas the Greenland ice core record has a thermal optimum between 8 to 6 kyr BP. There is also evidence of the Northern coast of Greenland being free of sea ice between 8.5 to 6 kyr BP. See here beach ridges, striated boulders & marine sediment
112067. CBDunkerson at 21:03 PM on 21 August 2010
        How climate skeptics misunderstand past climate change
        Eric, as I have explained before, and KR and johnd both just did again, the REASON there is more precipitation in a warmer world is that there is more water vapor in the air to precipitate out... because more heat causes more evaporation which puts that water vapor into the air. As you seem to insist on adhering to beliefs which are clearly false without making any effort to examine the proof to the contrary presented to you I don't see much point in continuing this. You should head to Miami and enjoy the ultra low humidity your logic indicates exists there.
112068. MichaelM at 21:02 PM on 21 August 2010
        Waste heat vs greenhouse warming
        The slope doesn't flatten out as the slope changes with the height of the sun in the sky i.e. the amount of energy a plate on the lunar surface receives is directly proportional to the angle of the sun. The graph in fig 2 is that dome shape, with the initial near-infinite slope, because it is at the equator. As you move north or south the shape changes away from a dome towards a flatter sine wave as the sun rises more gently above the horizon. This image shows the paths of the sun at a latitude of roughly 50deg north (actually from Bristol in the UK) over a period of months. The closer to the poles the flatter the slopes, the limit being the axis not being perpendicular to the sun.
112069. scaddenp at 20:56 PM on 21 August 2010
        Can't We At Least Agree That There Is No Consensus?
        Poptech - what impact indices measure is the no. of times papers are cited by other journals, not just the E&E echo chamber. While E&E is not about tobacco (hence the quote marks) it certainly appears to be used by those following tobacco industry tactics. I would say the impact of papers in E&E to science is approximately zero and nothing you claim can change that. On the whole, scientists dont share the denialist problems in discerning good from bad.
112070. Berényi Péter at 20:52 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        "How many cats' tails would it take to reach the sky?" "Just one if it's long enough!"
112071. scaddenp at 20:45 PM on 21 August 2010
        What caused early 20th Century warming?
        Michael, well please do work on the matter provided. Disbelieving something because it is inconvenient might be human nature but not rational, and in this case downright dangerous. Reality is not necessarily arranged for our benefit and the laws of physics do not bend to our wishes. That said, I think you are way too pessimistic and falling for disinformation spread by those who most certainly would be adversely affected. Try having a look at MacKay's Sustainable Energy without the hot air. He doesnt pull too many punches about the problems (often criticised as being pro-nuclear but MacKay counters that he is pro-arithmetic) but hardly condemns the world to energy-poverty either. Regards, Phil
112072. RSVP at 19:16 PM on 21 August 2010
        Waste heat vs greenhouse warming
        MichaelIM 234 You are correct, "Hours" in the caption refers to Moon hours which means 29.5 hours per notch. Things dont warm so fast apparently so it looks like I am wrong. In any event, Fig 2 is still very intersting as it shows heating has a nearly infinite slope coming out of the Lunar "night", without the presence of GHGs. :) Obviously on an expanded time scale, it would be seen to leaning, but it is intersting to see this is no sine wave and that it can only get so cold. (cold enough for me) Is there an explanation for why the high doesnt flatten out like the low on both Mercury and the Moon? As a hard core skeptic, its hard to believe the rotational cycle just happens to coincide to give perfect dome shaped profiles. Dont worry, if you arent sure, I will read the article in my spare time.
112073. John Russell at 18:05 PM on 21 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        The quote you use starts; "We have virtually no historical data about the climate of Mars prior to the 1970s..." (my emphasis). So it is true. And 4.5 years is not long enough to gather any meaningful data about climate on Mars (particularly as I assume you mean Earth years). But thanks for the interesting info about HiRISE.
112074. RSVP at 17:11 PM on 21 August 2010
        What were climate scientists predicting in the 1970s?
        Marcus 27 You got me very wrong including my insertion there about hubris. We could turn the whole thing around however and perhaps even veer towards the correct "topic". That would be a question like, "could man provoke an ice age?". Supposely all those sulfur based aerosols helped cooling, not to mention what all that nuclear testing did. All these questions seem very difficult and who knows, maybe we were going into an ice age until we "fixed" one problem to only get another. I have a hard time not seeing hubris as a big stumbing block, but I think you did not understand the remark. It is not to say we cant mess up the entire planet, we can, and we are doing this just fine. The hubris has to do with wanting to believe we have all the answers, when in reality the problem is much more complex than we think.
112075. Doug Bostrom at 16:35 PM on 21 August 2010
        NASA-GISS: July 2010-- What global warming looks like
        "AGW proponents." Comical. Some remarks about Pakistan by Dr. Ricky Rood here.
112076. RSVP at 15:55 PM on 21 August 2010
        What were climate scientists predicting in the 1970s?
        JMurphy 22 There is no such thing as "the science", however it is good to be aware that some people think that way. Thanks for the warning.
112077. johnd at 15:55 PM on 21 August 2010
        What caused early 20th Century warming?
        adelady at 14:24 PM, there is almost always a drought somewhere in Australia. With various indicators such as the IOD and IPO seemingly taking 6 or 7 decades to cycle through both phases, it is impossible to determine any trends before any cycle has completed fully. The Queensland National Resources and Mines put out a chart depicting the rainfall across all of Australia for each year beginning 1890. Such a chart makes it easy to see the "flow" as the dry and wet years are cycled through and as the distribution varies across the regions, something that is not always evident looking at graphs.
112078. The Skeptical Chymist at 15:53 PM on 21 August 2010
        1934: the 47th hottest year on record
        As far as I can tell 2007 is the hottest year in the NCDC global land record. Given that ocean covers most of the worlds' surface using the land-ocean record would be better, which would give 2005 as the hottest year (as noted by other posters).
112079. johnd at 15:42 PM on 21 August 2010
        What caused early 20th Century warming?
        Marcus at 13:58 PM, SST is a primary influence over the El-Nino, La-Nina cycles. Apart from the heat already in circulation within the oceans, the most obvious means by which SST may vary is solar radiation. However the solar radiation that reaches the surface is dependent on cloud cover and this varies considerably, not only seasonal, but over longer cycles as this diagram indicates, as well as geographic distribution.
112080. KR at 15:32 PM on 21 August 2010
        How climate skeptics misunderstand past climate change
        johnd - what goes out (storms) must come in (latent heat via evaporation). First law of thermodynamics...
112081. johnd at 15:14 PM on 21 August 2010
        How climate skeptics misunderstand past climate change
        KR at 14:15 PM, whilst extreme precipitation indicates that a large amount of rain is concentrated on a small area, it doesn't necessarily mean that a large amount of moisture was evaporated from a similarly small area. Certainly in tropical storms that is what drives the storm with the moisture being picked up and then dumped rather quickly over a relatively small area. However at other times it all depends on the circulation patterns with small amounts of moisture being picked up traveling over a vast distance until the system happens to collide with another system that creates the conditions that triggers the rain event. This is what often happens when moisture that is picked up in the Indian Ocean under the normal course of events is transported across Australia to the SE corner where it is released. However there are also times when the remnants of tropical storms that also originated in the Indian Ocean to the NW of Australia also cross to the SE corner where it is released. Whether the rain is released over a wide area or dumped over a smaller area is really dependent on what conditions the rain bearing system collides with.
112082. papertiger at 14:39 PM on 21 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        We have virtually no historical data about the climate of Mars prior to the 1970s, except for drawings (and latterly, photographs) that reveal changes in gross surface features (i.e. features that can be seen from Earth through telescopes). Not true. We have detailed geographic evidence of changes in the climate on Mars. How? I couldn't tell it nearly as well as J Kelly Beatty of SkyandTelescope, so in his words; "NASA's Mars Reconnaissance Orbiter has been circling the Red Planet since March 2006, for some 4 1/2 years.Yet it's the Mars mission that hardly anybody knows about. As of June 18th, MRO'sprimary camera -- the High-Resolution Imaging Science Experiment, or HiRISE -- had made 16,077 observations and returned 13.4 trillion pixels of digital imagery. Picture yourself viewing the Red Planet through an exquisite 20-inch (0.5 -meter) f/24 telescope without Earth's atmosphere to contend with. Naturally, you'd expect a great view. Now imagine goosing your magnification up another 20,000x by moving that scope to a vantage just 190 miles (300 km) above the Red Planet, and then throw in a camera able to capture long ribbons of terrain more than 20,000 pixels wide and as long as will fit on a 16-gigabyte memory card. This is the reality of HiRISE, which boasts the largest scope ever floan to another planet. With it Geologists once content to decipher Martian geology fron a patch-work of vague features a mile or so across are now able to follow the tracks of boulders that have rolled down from a crater's rim, or to count thin sedimentary layers in an ancient lakebed." Ain't it a beautiful thing? I'd love to continue, but Jack Horkheimer, my ambassador to the stars has died today at the age of 72, so I'll be in mourning the rest of the evening. Probably in front of an eyepiece. Keep looking up. See the Sep 2010 issue of Sky and Telescope, the one off
112083. Daniel Bailey at 14:28 PM on 21 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        Soundoff, that's perhaps due to the fact that people have a better view of Mars' polar caps than they do of ours. :) The Yooper
112084. dhogaza at 14:28 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        

        Thanks for the challenge, many of the arguments are redundant or can be falsified in chunks, but I agree it will take some time, but I'm confident we have plenty of time before climate disaster strikes :)

        Oh, this should be fun, black-is-white and up-is-down stuff, and of course all scientists studying such things are wrong because theendisfar is an über genius ... Climate disaster *is* striking, firmly enough that Russia's government, long semi-entrenched in the denialist mode, has talked (at least) about an about-face, and it has nothing to do with international politics (internal political pressure, instead).
112085. dhogaza at 14:24 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        

        Yes, I think many climate scientists are purposely misrepresenting conjecture as empirical and repeatable evidence quite frequently using subjective terms to provide wiggle room and plugging conjecture into GCM's, passing the predictions off as reliable.

        Doug Bostrom's rebuttal is fine, but it's worth noting that this is *exactly* the argument creationists, smoking-is-harmless types, etc use against science. Look, we should I care what the uneducated think, theendisfar? The more you make clear your ignorance, the less I care ...
112086. adelady at 14:24 PM on 21 August 2010
        What caused early 20th Century warming?
        johnd Late 1990s rainfall might have been better than the early 90s. But where did it fall? Scroll down this page to the Murray Darling basin and you'll see that rainfall has dived from 2000 onwards. The previous variability seems to have disappeared. One variable has changed significantly. Between 1960 and 1980 only one year has had over 200mm above average, but since 1980 there are 3 years 200 below average and 2 of those are in the last 10 years. It's not a good look. http://www.abs.gov.au/AUSSTATS/abs@.nsf/Lookup/4613.0Chapter55Jan+2010
112087. dhogaza at 14:22 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        

        1. The comments policy forbids it, and the terms I've used are already fairly close to crossing that line. Say what you like but AGW Believers get away with far more here than Skeptics.

        We also got better grades in science classes when in school, something I'm sure many denialists still resent ...

        I agree, skeptics have done just as much a terrible job in rebutting AGW as AGW Believers have done in preparing and proving it. Time for someone else to do the job.

        Physics actually works for me. CO2 lasers and all that. You're arguing from a position of personal incredulity ... "I don't believe science, therefore it must be wrong!". You're no different than those who believe the earth is 6,000 years old.
112088. Doug Bostrom at 14:17 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        The "skeptic" debate wildcard: Yes, I think many climate scientists are purposely misrepresenting conjecture as empirical and repeatable evidence quite frequently using subjective terms to provide wiggle room and plugging conjecture into GCM's, passing the predictions off as reliable. No point in discussing anything with this fellow, he'll just answer anything and everything with conjecture not related to science when pressed. Facts? Nope, just conjecture, speculation. Thanks for saving my time, "theendisfar." You're a skeptic of the new school, not the old school and thus beyond reason.
112089. KR at 14:15 PM on 21 August 2010
        How climate skeptics misunderstand past climate change
        Eric - extreme precipitation requires extreme evaporation to provide the WV needed. It ain't gonna rain without sufficient water in the air. So an increase in extreme storms indicates an increase in evaporative generation of water vapor, not a total decrease in relative humidity. That doesn't mean that there might not be changes in RH with temperature - just that you cannot assume drier conditions based on more extreme storms, quite the contrary.
112090. barry1487 at 14:12 PM on 21 August 2010
        1934: the 47th hottest year on record
        "Globally, the ten hottest years on record have all occurred since 1998, with 2007 as the hottest." It's 2005, not 2007, according to GISS and NCDC. HadCRU, and the two major satellite records have it at 1998. Making these distinctions is not fit for a 'Basic Version' post, I guess, but you should at least change 2007 to 2005.
        Response: Hottest year has been corrected from 2007 to 2005. Thanks for the feedback.
112091. SoundOff at 14:12 PM on 21 August 2010
        Dust-Up On Mars: Should Martians Be Sceptical of Global Warming?
        It is ironic people rush to claim that a polar cap melting on Mars is a sure sign of global warming there, while they are not persuaded by the same here on Earth.
112092. Doug Bostrom at 14:11 PM on 21 August 2010
        What caused early 20th Century warming?
        Here's another thing to consider, Miekol. Play with the numbers as you please but as a benchmark thought remember, we could for instance this moment increase the incomes of the poorest 40% of the people in the world by roughly an order of magnitude simply by a contribution from the top 20% of earners essentially unnoticeable for many of us, the price of a few deluxe pizzas per year. Let's not make the mistake of believing if we ignore global warming we're going to raise the world's poor into a new level of prosperity. We choose not to do so today, why would we tomorrow? Is something about human nature going to change? How?
112093. KR at 14:03 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        theendisfar - Nope,, this just isn't recreational. This is about our futures, our descendents futures. It's about how well we've taken care of the world we live in. This isn't a joke, this isn't a rhetorical exercise. This is about living well, doing well, or suffering the painful consequences of bad decisions. Not about scoring 'points' with debate tricks. You want to play semantic games? Fine. You tried that a couple months ago on the CO2 is not the only driver of climate thread, and I simply won't play that game. If you have actual issues with the data or the conclusions drawn from them, we can talk about it. But rhetorical games are not worth playing, not with the current stakes.
112094. Marcus at 13:58 PM on 21 August 2010
        What caused early 20th Century warming?
        So John D, what do you think drives the El Ninos & La Ninas? We know that Solar Activity increased quite rapidly throughout the first half of the 20th century, yet solar activity has largely been in decline for the better part of 30 years. So if the sun was the primary driver of the events of the first half of the century, what was driving the events of the 2nd half?
112095. dsleaton at 13:53 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        Theendisfar: yet consensus is what an unskilled public demands in order to perform informed democracy. Because the public is, in general, unable to do the math (due to restraints of time and/or mental faculty), we turn to scientists. We can't trust one scientist. Getting a second opinion is a natural thing to do in such circumstances. We have the opportunity here to get hundreds of second opinions (from the most informed scientists) and see if a consensus exists. Within the scientific community, "consensus" is simply another name for the peer review and publication process: "Here, I tried my best with the math and the lit review, but maybe you'll see something that I missed," which gets answered by a "No, it looks like--to the best of our knowledge--you've done your homework, and the math looks good." Scientists know they're working with an object (the universe) that hasn't yet been fully defined, and no human mind can encompass all the details, so the natural uncertainty that >everyone< must deal with leads to requests (informal or formal) for consensus. Short version: the demand for consensus is for non-experts, and scientists don't do science only for themselves: they do it for us (non-experts and scientists), so it's no surprise when scientists respond to the demand. (oh, except for the Objectivist types, who do all the science from the ground up without relying on any existing research and don't publish because that would be altruistic. They also don't engage in public forums like this either, because that might lead to their pristine individual selves becoming contaminated by the ideas of others, and all of that ungoverned by social contracts.).
112096. Marcus at 13:50 PM on 21 August 2010
        What caused early 20th Century warming?
        #17. At the risk of straying off topic, not even the most ardent Green is calling for an outlawing of coal or oil as an energy source in the short term-simply that we use what we have much, much more efficiently-especially here in The West. That said, though, most alternatives for coal & oil already exceed them for quantity (the amount of energy that the Earth has in terms of Geothermal, Solar, Tides etc are many times more than what humanity currently use, & will never run out within the span of human civilization). They are also rapidly approaching the point of matching coal & oil for availability, continuity & cost (solar panels, for example, have fallen from $25 per Watt to under $4 per Watt in the space of only 25 years, whilst efficiency has improved from barely 5% to more than 20% in the same time). Some sources of energy (such as bio-gas & co-generation) are already there. Meanwhile, the cost, quantity & availability of coal & oil are actually getting worse-which makes the goal of ridding the world of poverty much less achievable if we continue to rely on them into the future. Of course, much of the world's poverty has less to do with access to resources, & more to do with the continued uneven distribution of said resources!
112097. theendisfar at 13:28 PM on 21 August 2010
        The Oregon Petition: How Many Scientists Does It Take To Change A Consensus?
        KR, No, I will not flat out state it for two reasons. 1. The comments policy forbids it, and the terms I've used are already fairly close to crossing that line. Say what you like but AGW Believers get away with far more here than Skeptics. 2. To state that someone is lying automatically brings motivation into the debate, and I don't give a damn what their motivations are, about consensus, or someone's credibility. It detracts from the debate. Whether it's incompetence or lying, how about you decide? Folks (in general) try to do the best job they can. Let us do the same. You defend AGW, and I, being the skeptic, will attempt to falsify it. No hard/personal feelings, strictly recreational. I cannot imagine a world where the majority are incompetent and the few dissenting voices are on the ball. History is full of examples. Look, I'm not argue this with you. You stated there are lots of repeatable tests, you provided links, and I'm looking them over now. and those with axes to grind against the consensus have entirely failed to come up with consistent alternative hypotheses other than anthropogenic global warming. I agree, skeptics have done just as much a terrible job in rebutting AGW as AGW Believers have done in preparing and proving it. Time for someone else to do the job. I'll make a prediction. By dismissing consensus, motivations, credibility, and any other subjective influence and by strictly following the Scientific Method, we bloggers will either falsify or confirm the AGW Theory on or before August 21, 2011. Anyone else want to help figure out how to put this debate behind us? I've got several ideas and would welcome additional help. Any objections to starting in the Empirical Evidence post noted in #40?
112098. miekol at 13:27 PM on 21 August 2010
        What caused early 20th Century warming?
        :-) many thanks Dappledwater, doug_bostrom and scaddenp. You've provided me with heaps of stuff to ponder on. Thank you. I admit I resist the idea that its man's production of CO2 that is causing the current increasing heat retention. My reason is because just when the the human race is on the threshold of ridding the world of finacial poverty, we are going to condemn the world to greater and even more widespead poverty if we 'outlaw' coal and oil as an energy source. Google "Globalism world of plenty." The alternative sources simply cannot match coal and oil for availability, quantity, continuity, and cost. Thanks again guys for your help. Michael
112099. Berényi Péter at 13:19 PM on 21 August 2010
        The Past and Future of the Greenland Ice Sheet
        Sorry, looks like I've mixed up links. This is Stott 2004. The link above is to Conroy 2008, which is about holocene precipitation history of the Eastern Pacific, based on a Galapagos lake sediments.
112100. Marcus at 13:04 PM on 21 August 2010
        What were climate scientists predicting in the 1970s?
        RSVP, my decision to reduce my CO2 footprint was not ideological. I actually just wanted to save money & reduce my consumption of non-renewable resources. The reduced CO2 footprint is just an added bargain. That I have succeeded in all 3 endeavors actually proves that, once you strip away the ideological arguments of the Fossil Fuel industry & its Cheer-Squad, you see that mitigating our CO2 emissions can be surprisingly easy & painless. However, like a drug addict, our society is addicted to its inefficient, high-consumption life-style even as it steals the hard-earned money from their pocket. Like good drug pushers, the fossil fuel industry is all too happy to keep encouraging this ongoing addiction-no matter what damage it will cause-so long as it puts money in their pockets. You see, unlike you, I have been more than willing to countenance a *NATURAL* cause for recent global warming, but the fact remains that the evidence for a *NATURAL* cause has been sadly lacking from your side of the debate. Instead, your side continues to engage in cheap political stunts & the demonization of the entire scientific community! Its not *hubris* to be concerned about how our alteration of the planet's atmosphere-in a short space of time-will impact on our climate, but it is the height of naivety to keep claiming its natural when you have absolutely *NO EVIDENCE* on which to base such an assertion!

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