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Comments 49701 to 49750:

49701. edhawkins at 19:27 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       I used HadCRUT4 because I was a little parochial. Also, I don't necessarily agree with interpolating over regions where there isn't any data, like GISS do, especially the Arctic. But, I agree that any proper comparison should mask the data appropriately. This animation was purely a visualisation. @JasonB - People do the tests on model data as you suggest. I notice that the Berkeley Earth Temperature project have just released a memo on exactly this - interestingly they only discuss uncertainty, and not bias: Link
       Moderator Response: [PW] Hot-linked reference
49702. JasonB at 17:51 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper:

       Using the 0.074C/decade of GISTEMP over the last 15 years, the number of months between 2000 and 2050 below this threshold in all 5 model runs is 5.8%.

       Thanks.

       As for why I don't use GISS, why don't you ask Ed Hawkins the same question?

       My guess is he wanted to avoid claims he was deliberately understating the degree of "slowdown" in order to make it easier for the climate models to exhibit that behaviour by using a temperature record that shows less of a slowdown — but I could be wrong, it might be entirely parochial, since he's in the UK. :-) But as soon as you start making statistical assessments of the differences I think it becomes important to ascertain whether the real-world measure you are using accurately reflects the real world or not, because as you can see, some might claim statistical significance if one measure is used (3.4%) and not if the other is used (5.8%) — ignoring all the other issues, of course. (The "correct" way, IMHO, is still to run the models with the actual forcings of the past 15 years if you're going to compare them with the climate of the past 15 years.) I really would like to see someone (not me :) actually evaluate the various global temperature reconstruction algorithms against model simulations to give an idea of how well their algorithms determine global temperature in cases where we know what the global temperature "should" be, at least with respect to each GCM. (Technically you don't need a GCM for this, but since certain characteristics of the real world are relied upon — such as the temperature anomaly correlation between sites up to ~1,000 km apart, in the case of GISTEMP — I would hope GCMs would exhibit those same characteristics.) There is another issue, of course — the ability of a model to capture internal variability is not necessarily correlated to its ability to predict long-term warming trends. So a model with very low noise levels — and therefore very few 15-year runs of trends "below the mean" — might still give a very accurate idea of the average climate 80 years from now, while one that has enough noise in it to show plenty of negative trends over 15-year periods might utterly fail to capture the long-term warming trend due to e.g. an unusually low sensitivity. Using short-term comparisons to "validate" models is therefore somewhat questionable.
49703. sotolith7 at 17:49 PM on 21 January 2013
       Was 2012 the Hottest La Niña Year on Record?
       Can't believe this post has got me thinking in post-structuralist terms. Does the expression "warmest La Niña year" actually have any substantive content?
49704. Klapper at 16:15 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Tom #21: 1) I didn't say the models didn't allow ENSO behaviour, I guessed based on variability they didn't but that's not the same thing. 2) From Foster & Rahmstorf 2011, Figure 7, the effect of Pinatubo is all done by 1997 at the latest. The 15 year trend doesn't start until a year later. Looking at the AODepth graph from F&R 2011 it's apparent the current trend is not being affected in any significant way by volcanic activity.
49705. Klapper at 15:59 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Skywatcher #20 In Hansen's Figure 6(b)diagram the net forcing doesn't rise above zero until 1915 or so. Negative forcings drive cooling. I'm not sure how quickly global SAT can equilibriate to forcings but it seems to me there should be an inflection point in temperature where the forcings change from negative to positive. And there is. I think a legitimate calculation, given the inflection point in temperature more or less matches the negative to positive switch in net forcing is evaluate the warming after the inflection point based on the delta F after that. As for why I don't use GISS, why don't you ask Ed Hawkins the same question?
49706. Klapper at 15:36 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Jason #18 Using the 0.074C/decade of GISTEMP over the last 15 years, the number of months between 2000 and 2050 below this threshold in all 5 model runs is 5.8%.
49707. Doug Hutcheson at 14:45 PM on 21 January 2013
       CO2 is plant food
       Soilfertility @ 14

       "This paper was read before the 11th Annual Meeting of the American Institute of Dental Medicine, Palm Springs, California, 1954."

       A reading in front of a Dental Medicine meeting does not constitute peer review. As Tom pointed out, Albrecht wrote his work without referring the the then-extant body of work on global warming, so there is no reason to believe that he came to any valid conclusions about the phenomena he reported. To claim, as you do, that current science is mistaken because a person who did not know about global warming wrote a paper without mentioning it, is wrong-headed. To cut to the chase, can you post one single factoid Albrecht wrote about, which current science is mistaken about? Hint: don't expect others to do your research for you, as you are currently doing by making vague claims about it all being explained in Albrecht's paper and your article. Instead, reply with quotes from and references to the information you are relying on and remember to include quotes from and references to the scientific publications that show current science is mistaken. The onus is on you to provide evidence. Remember, extraordinary claims require extraordinary proofs.
49708. Tom Curtis at 14:35 PM on 21 January 2013
       Was 2012 the Hottest La Niña Year on Record?
       From Peru @1, even if you classified 2010 as an EL Nino year, it would not significantly affect the result of the graph. It would certainly not be as cool relative to trend as 1978 is for an El Nino year.
49709. Tom Curtis at 14:31 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper @16: 1) I appreciate that you attempted to include ENSO variability in your model selection; but by your own account the models available did not allow you to adequately incorporate that variability. That caveat should be allowed fro when interpreting your 3.7% figure. Once allowed for, it shows that figure to be an underestimate. 2) Actually there has been a net negative over the most recent fifteen years, with no volcanic erruptions in the early part of that period, but several small ones since 2001. The effect is small, but relevant. More importantly, deniers have been quite happy to quote the period terminating around 1996 as a "pause" in global warming, or (nowadays) as a "step change". That "pause" was most definitely due to a volcanic eruption, so volcanic eruptions are relevant to your analysis. 3) The change in volcanic forcing over solar cycle 23 was 0.185 W/m^2 (see figure 5). That is equivalent to the change in forcing from changes in GHG concentrations over approx 5 years at current emission rates. The difference in solar forcing from minimum to minimum over cycle 23 was 0.04 W/m^2, an order of magnitude less than the increase in GHG forcing over the period in question. Larger changes have occurred in the past, and may do so again. Ergo, my claim that solar forcing is near constant in forward projections is justified.
49710. dana1981 at 14:26 PM on 21 January 2013
       Was 2012 the Hottest La Niña Year on Record?
       From Peru @1 - not by my methodology. 2010 comes in at the 17th-strongest El Niño influence, putting it in the Neutral category. The La Niña conditions in roughly May-August were enough to bump it out of the top 15. Note that 2010 makes the top 15 El Niño years in ONI (#7), but just misses in MEI (#16), and was quite moderate according to SOI (#23), so it depends which measure of ENSO you want to use.
49711. Soilfertility at 14:18 PM on 21 January 2013
       CO2 is plant food
       Hi Tom: Where did I say that Albrechtson (sic) analysed which of two potential causes has had the greatest impact on changes in climatology? When I said he was dead before global warming became an issue, I assumed the reader would realize that, of course, it would have been therefore impossible for him to make such an analysis. Have you read the article I wrote or "The Drought Myth--An Absence of Water is Not the Problem"? I can understand if you have not yet read "Droughts-- The Soil As Reasons For Them" as you might not find the book in your local library and you might need to purchase it and have it sent to you. I cannot understand, however, if you have not yet read either my article or "The Drought Myth--An Absence of Water is Not the Problem" or both as they are both available on the internet. If you wish to challenge my position on causes and cures for increasing severity of droughts and floods, read the evidence that has caused me to come to my conclusions and refute that evidence.
49712. From Peru at 14:10 PM on 21 January 2013
       Was 2012 the Hottest La Niña Year on Record?
       I am a bit confused about 2010. Wasn`t it a moderate El Niño year? (Yes, I know there was a strong La Niña later in the year, but given the 4-month time lag between ENSO and global temperatures its effects were felt mostly during the next year, i.e. 2011)
49713. skywatcher at 12:55 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper, That figure does not change my opinion in the slightest - PDO does not force climate in some mythical 60-year oscillation. When looking at Hansen's figure, note the change in forcings between the 1880s and 1930s, then the change in forcing between the 1950s and 2000s. Is the difference so much that the temperature changes over the respective periods (the more recent GISS temperature warming is 50% larger in GISS than the pre-WWII warming) cannot be accounted for given the forcings? I don't think it is. In your original comment, why did you use the Hadley temperature trend rather than GISS, when Hadley does not include the Arctic?
49714. JasonB at 12:33 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper,

       As for the comment on extending the trend, note that from 2080 on emissions decrease in RCP6.0, so it was legitimate to check if at the end of the period we might see some "standstill" trends.

       The emissions might have decreased, but their rate is still a lot higher than the past 15 years and the total forcing for the period after 2080 is still more than double and still climbing, which may affect the relative ratio of forcing:internal variability (i.e. make it harder for internal variability to temporarily swamp the effect of anthropogenic forcing).
49715. JasonB at 12:25 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper,

       Does that effect the capturing of natural variability and warming standstills? I don't know. The numbers are what they are.

       It does affect the trend that you are trying to benchmark against. You found that "3.4% of months had a 15 year linear trend of less than 0.043C/decade, the current number" (emphasis mine). What percentage of months had a 15 year linear trend of less than 0.074 °C/decade, which is also "the current number"? To ascertain which "current number", if any, is the true number that should be used for comparison, you could sample each simulation at the same locations and in the same way as each of the stations used by the various reconstructions, then feed those simulated measurements into that reconstruction's algorithm, and then see what each one says the temperature anomaly is for the simulation that you have "perfect" knowledge for. (Sounds like a good blog post, and possibly even a paper.) Personally I'd expect GISTEMP to be the closest due to known limitations in the other products regarding the Arctic coverage coupled with stronger-than-average warming in the Arctic in recent decades, which GISTEMP mitigates using the empirical results from Hansen's work on climate teleconnection that he published in the 80s. To do the test rigorously, however, you should run a large number of simulations of the last 15 years using the same forcings to see what percentage lie below the current trend, rather than look at a small number of simulations of a large number of years with evolving forcings that are different to the last 15 years.
49716. Klapper at 12:01 PM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Skywatcher #14: You are right that the 60 year cycle has a limited data series to prove it out, at least from surface stations. However, if you think there is no 60 year cycle and that the PDO has no forcing ability, go look at Hansen's Figure 6(b) from his Jan.15 2013 report on the 2012 climate update. Look at the net forcing in the period 1910 to 1945. Pretty low isn't it? However, the warming rate from this period was pretty high. Where did this warming come from? The net forcing in Hansen's graph doesn't appear enough to drive warming rates of 0.12 to 0.16C/decade which is the range of the datasets.
49717. Klapper at 11:43 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Tom #13: Point 1) I tried to include the models which I had read were the best emulators of ENSO according to the Dessler comments. However, the model versions used then have been upgraded so I moved on guessing these same models might still be good at emulating ENSO. However, without resorting to watching for ENSO patterns, frame by frame in the monthly global map I can't make that call. However, neither can you. My guess is they do a poor job since ENSO is the primary source of short term variability and these models appear to have not so much as real data. Point 2) There are no volcanos including the the threshold trend of 0.043C/decade so this comment is irrelevant. Point 3) The forcing is definitely not constant, the change over cycle 23 was proably 0.1% to 0.14%. However the 15 year trend should smooth that out. Point 4) The recent papers by Foster & Rahmstorf et al don't include the suppressing effect of anthropogenic aerosols. You're throwing it on the table but can you quantify it? For the record all RCP scenarios have significantly decreasing sulphur over the 21st century (check the link at the bottom) so it is certainly less of a factor going forward. As for the comment on extending the trend, note that from 2080 on emissions decrease in RCP6.0, so it was legitimate to check if at the end of the period we might see some "standstill" trends. However, I did not find any, at least with the models I picked. Here's a link to the various emissions scenarios graphically displayed in CMIP5. https://tntcat.iiasa.ac.at:8743/RcpDb/dsd?Action=htmlpage&page=compare Just click the "+" buttons in column 3 and then one of the sub-options from the expanded menu, like "Total" to generate a graph. Very handy to compare scenarios.
49718. Klapper at 11:14 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @Jason #10: I expect the models calculate global temperature "perfectly", that is the weighted surface air temperature by grid cell, by hour, day, month etc. Obviously no observation system in place, either satellite or surface station comes close to that temporal/spatial resolution. We have holes particularly in the Arctic and less so the Antarctic. Does that effect the capturing of natural variability and warming standstills? I don't know. The numbers are what they are.
49719. skywatcher at 10:40 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       #9 Klapper: My only additional comment (beyond Tom's excellent points; I hadn't thought of the difference in model forcing between early and later 21st Century) would be that it is dangerous to think of the PDO as a '60-year cycle'. In direct observations, we've had less than two periods of this "cycle", which appears significantly acyclical in that time, and longer palaeo studies such as MacDonald and Case (2005) don't show great evidence at all for a pervasive 60-year cycle in PDO. I'm in favour of hypotheses that the PDO is substantially an integrated product of ENSO variations. Certainly the PDO on its own is not apparently a strong global climate driver. To follow up on JasonB's point, using Hadley series as a comparison to models is risky as HADCRUT3/4 are not global teperature data - notably they miss out much of the Arctic, hence their trends will be underestimated with comparison to a model which is outputting global temperature estimates. In that case, GISS (which is global) may be closer to the mark for the past 15 years.
49720. John Hartz at 10:37 AM on 21 January 2013
       2013 SkS Weekly Digest #3
       vroomie: You're welcome and thank you for the positive feedback. PS - Dana actually composes the "SkS in the News" section each week.
49721. Tom Curtis at 10:26 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       edhawkins @11, Klapper has underestimated the probable frequency of such events because: 1) His sample of models do not all include ENSO mechanisms; 2) The forward model runs do not include volcanic events; 3) The forward model runs include a near constant, albeit low solar forcing; 4) The anthropogenic forcings (particularly aerosols) do not include significant fluctuations over periods of around 15 years; and 5) As he says, "My guess is these models for the most part don't really emulate ENSO very well", suggesting that even the models that incorporate ENSO dynamics understate potential variability in ENSO states. All five of these factors mean the individual model runs will tend to understate variability in 15 year trends, and hence his estimate from the models of a very low frequency of low 15 year trends. What is more, by extending his survey to 2100 on the model runs, he included a period with a significantly greater increase of forcing over time than is currently the case; and hence with a greater underlying trend. That again means his estimate is an underestimate of the probability of such a low 15 year trend at the start of the 21st century. Further, and more importantly, he does not estimate the probability of a low 15 year trend given a near maximum EL Nino state at the start of the 15 years and a near extended La Nina conditions at the end of it. Those two conditions make the probability of a low trend significantly greater than his estimate (or a more accurate, higher estimate if we could find one). All in all, Klapper's estimate is interesting only because it sets a ball park lower bound to the estimate of the probability of such a low trend. It certainly does nothing to suggest that the current low trend given known ENSO fluctuations was in anyway improbable. As noted before, in other analyses it has clearly been shown that the lack of such a low 15 year trend given the background anthropogenic trend plus known ENSO, solar and volcanic variations would be extraordinary.
49722. Tom Curtis at 10:06 AM on 21 January 2013
       CO2 is plant food
       Soilfertility @14, your response has simply confirmed my point. First, you respond by quoting Albrecht from 1954, having previously made the point that "Albrecht did not address global warming as he was dead before global warming became an issue". If he did not address global warming, then he cannot have analysed which of two potential causes (global warming or loss of soil fertility) has had the greatest impact on changes in climatology. Ergo, if you are basing your claims on Albrechtson (as clearly you are), you have not shown of any particular droughts, floods, temperature rises, etc that loss of soil fertility rather than global warming is responsible. You specifically mention an article by Albrechtson titled "The Drought Myth--An Absence of Water is Not the Problem". Well, in Southwestern Australia an absence of water is clearly the problem: What is missing in Southwestern Australia is water falling from the sky as frequently, something that is not under the control of soil fertility. Southwestern Australia is a good test case, because the connection between winter rainfall and climate change is straightforward; there has been no appreciable loss of soil fertility (probably the opposite as agriculture in the region is based on irrigation turning desert into wheat fields); and Albrechtson almost certainly never studied the region. Yet because of his studies of the dustbowl you expect his explanation to trump straightforward science in Southwestern Australia. I look forward to your evidence based proof that the decline in rainfall in Southwestern Australia is caused by declining soil fertility, or your acknowledgement that your assumption that any consequence predicted by both global warming and decreased soil fertility is explained by decreased soil fertility alone.
49723. vrooomie at 09:28 AM on 21 January 2013
       2013 SkS Weekly Digest #3
       Thanks, John....well-done.
49724. dagold at 08:38 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       As an interested lay person climate activist, there is something I am not 'getting' when following these conversations about 'hiatus periods': There is very little mention of the aerosal factor. ENSO is constantly discussed and solar variability is often mentioned. But...I have heard Kevin Anderson (in his now famous climate lecture) cite the (mostly) Asian aerosals as a HUGE temporary damping factor. And I believe (correct me if I am wrong), there is at least partial attribution to aerosals for the damping of the 1940-1970 period. So...what's up the scant mention of this element of the puzzle. Is it because there is a great deal of uncertainty and so better to leave it out?
49725. edhawkins at 05:19 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       @JasonB This is a good point, and not taken into account in this particular animation. I have discussed on my blog previously that it makes a small difference exactly how you do this type of comparison. ----------------- @Klapper Agreed that this type of slower trend is not especially common in these simulations (a few % as you suggest), but as there are many 15 year (overlapping) trends it is almost inevitable that we get one or more.
       Moderator Response: [PW]Hot-linked URL.
49726. JasonB at 01:57 AM on 21 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       The last 15 years of actual climate are reported as 0.043 °C/decade for HadCRUT4, 0.074 °C/decade for GISTEMP, and 0.036 °C/decade for NOAA, because each uses a different method to calculate the global temperature anomaly. I'm curious to know how the CMIP5 model run temperature anomaly is calculated? I had a quick search but couldn't find an answer. If you're comparing the last 15 years with model runs, you need to make sure that they're being calculated the same way (i.e. that the figure is what e.g. HadCRUT4 would have reported if that simulation exactly matched the real world) to have an apples-to-apples comparison.
49727. Soilfertility at 01:00 AM on 21 January 2013
       CO2 is plant food
       Hi Tom: Your assumption that my argument "fails at that point" is unjustified. Why? You have failed to review Albrecht's evidence. If you would only have read the article I mentioned on "The Bovine", it would have directed you to Albrecht's article, the basis for the article on "The Bovine". Albrecht's article, titled "Droughts-- The Soil As Reasons For Them", is chapter 23 in Volume I of "The Albrecht Papers". This is the first paragraph from his article: "When one follows the meteorological reports rather regularly since most of us talk about the weather, at least when the radio reports it for us daily, one might well be asking with serious concern, 'How come that we keep on breaking flood records, heat records, past records for droughts or for extent of long-time rain free periods and other weather records?' Are the meteorological conditions changing for the worse, or are the biological manifestations of weather, labeled as drought, merely intensified and on the increase as reciprocal to some other factor under serious decline through which the same meteorological disturbances are magnified in their detrimental aspects? We have larger floods and we have more severe droughts as the records truly report. But should we not examine these in relation to the soil for possibly more comprehensive explanations of them and our reduction or prevention of the disasters?" From the introduction to the chapter: "This paper was read before the 11th Annual Meeting of the American Institute of Dental Medicine, Palm Springs, California, 1954." "The Albrecht Papers" Volume I has been reprinted and is now titled, "Albrecht's Foundation Concepts" and is available from Acres, U.S.A. Also at Acres, U.S.A. there is an article available for download by Albrecht titled, "The Drought Myth--An Absence of Water is Not the Problem. It is available in this list of articles- http://www.acresusa.com/toolbox/articles.htm
49728. Klapper at 18:27 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Skywatcher @#8 The solar irradiance input to the CMIP5 model runs is based on repeating cycle 23 (1996 to 2008) going forward. Or at least that is the recommended input. Cycle 23 is a pretty long cycle, longer than the typical 11 years. If you've looked at Hansens Figure 6(a) from his 2012 update, published Jan. 15, you can see he gives very low input to solar irradiance changes. In his text he states that recent declines in the irradiance trend may have decreased the irradiance forcing by 0.1W/m2. However, he doesn't specify the time period this has occurred over. As for the ENSO trend you are right, depending on how you define "recent". It looked the same about 1975. This could be used to support the argument that ENSO trends, rather than being just random noise supperimposed on a warming signal, follow patterns that are not random and are tied to the 60 year PDO cycle.
49729. skywatcher at 17:19 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       This is a very nice graphic - another excellent illustration to support the Escalator and Kevin C's recent animation. Klapper, without going into your point in too much detail... how do the model runs you selected handle solar activity? One of the noticeable features of the past decade and a bit has been the fairly remarkable transition from a pretty active to a pretty quiet Sun. In conjunction with a 15-year trend in ENSO that is unmatched in the recent record (linear trend in bimonthly MEI data leans unusually far from horizontal), the potential for an unusual illusory slowdown in warming has been exceptional. With just ENSO, the conditions of the past decade and a half have been unusual. Adding the unusual pattern of solar activity has made the short-term trend even more weird, yet GHG forcing has continued unabated. Unfortunately for us, neither the solar activity nor the ENSO can go a huge amount lower (notwithstanding very strange low solar activity), and so the GHG-driven warming trend will inevitably dominate once more, aided by the equally inevitable neutralisation of the negative trends in solar and ENSO activity.
49730. Klapper at 16:35 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Tom @#4: Your questions on El Nino can't be answered from the data I used, which was a simple global monthly surface ari temperature anomaly series. However I can comment on the nature of the deviations in the AOCGCM models. Two models had no 15 year trends below .07C/decade (GISS and GFDL). Of the 3 remaining, MRI only had 4 months where the rolling 15 year linear regression trend dropped below the threshold, and not consecutively, mostly at the end of the period (near 2050). The two models which made up the bulk of the "standstill" trends, CSIRO and Hadley, had these sub-threshold trends come all in one continuous period, both around 2030. My guess is these models for the most part don't really emulate ENSO very well. I also checked the period from 2050 to 2100. None of the models show any months with a 15 year trend below the threshold of 0.043C/decade. Note that the CMIP5 RCP6.0 scenario is the least aggressive for CO2 emissions growth in the early part of the forecast. In fact under this scenario there is no emissions output growth between 2010 and 2030, which is probably not realistic. However, after 2040 RCP6.0 surpasses emissions growth compared to the scenarios RCP4.5 and RCP2.6, peaking in 2080 or so.
49731. noelfuller at 16:20 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Actually Tom, getting a handle on short term variability might enable closure of the gap between the long term trend prediction and the short term weather stuff. If we can put the natural variability into the climate context we are in a better position to explain what is going on and make predictions of value to growers and planners so it is not entirely uninteresting - if the greater context is always there.
49732. noelfuller at 15:40 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       I fancy you might enjoy my lurching Bedford analogy based on Hansens use of the term standstill. Of course it can't be taken too far: When learning to drive I was one afternoon given the wheel of a 2 ton Bedford truck with an unbaffled tank of water on the back and instructed to drive it from Napier to Taradale. As I pulled out the water surged backwards, then forwards and so forth resulting in an uneven motion of the truck which I struggled to get control of. Ahead was a major intersection. A vehicle was approaching from the right. I clapped on the brakes but nosed onto the inersection with the water slopping forward over the cab. The car having dodged the truck, I tried to keep going but the wave was heading aft. The truck remained almost at a standstill with more traffic coming in all directions – then the wave started forward again with my foot still on the accelerator and the impulse of the wave, the truck rocketed across the remainder of the intersection to the surprise and consternation no doubt of the oncoming drivers. Eventually I got the hang of it. So if we label the wave in the tank ‘ENSO’, the road toward Taradale ‘Climate Change’ and paint ‘Rising Global Surface Temperature’ on the truck we have it. The wave in the forward direction is El Niño, the wave going aft La Niña. Perhaps the engine could be labeled ‘Fossil fuel Combustion’ and the exhaust ‘GHGs’. Hmm, what about the driver? – new video animation for skeptical Science?
49733. Doug Hutcheson at 13:55 PM on 20 January 2013
       CO2 is plant food
       Soilfertility @ 11, I am still puzzled by your comments. Where in points 1,3,4,5 and 6 in the list, is there a scientific error? You are the one asserting there has been a scientific mistake. No-one is disputing the rôle of soil impoverishment on plant growth. Exactly what error(s) are you claiming?
49734. Tom Curtis at 13:37 PM on 20 January 2013
       CO2 is plant food
       Soilfertility @11, you introduced your original comment by saying, "... consequences of declining soil fertility are incorrectly said to be caused by global warming." Your evidence of this is that certain predicted consequences of global warming are also predicted consequences of reduced soil fertility. You proceed to make the unjustified assumption that any observed feature that is predicted as a consequence of both global warming and of decreased soil fertility is in fact only a consequence of reduced soil fertility. Your argument fails at that point. Your assumption is unjustified. It appears to be worse, however. You point out that decreased soil fertility can result in increased floods and drought due to, respectively increased water runoff, and decreased water retention. You then simply assume the increased floods and droughts actually experienced are due to reduced soil fertility without providing evidence of that reduces soil fertility at the locations of said floods and droughts, or even checking rainfall figures to see if they have changed over time (they have). So not only do you assume that decreased soil fertility is the proper explanation without examining the evidence, you do so even when it is against the evidence.
49735. Tom Curtis at 12:58 PM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Klapper @3, what percentage of 15 year trends cherry picked to have a record breaking EL Nino event in the start year had low trends? And what percentage cherry picked to stradle a record breaking El Nino at the start, and two very strong La Nina events at the end of the record? And why do we care about cherry picked short term trends when it has been repeatedly shown by different methods that once allowance is made for ENSO influences on temperature, the underlying trend continues unabated? The simple fact is that 15 year trends in temperature are scientifically uninteresting - but they sure make good politics.
49736. Soilfertility at 12:17 PM on 20 January 2013
       CO2 is plant food
       Hi Doug: I was commenting on numbers 1,3,4,5 and 6 in the list of "...the effects of an increase of CO2 on agriculture and plant growth in general". I was not commenting on any topic on this thread. I thought comments were invited to made on the article itself. In the article I wrote for "The Bovine" titled, "Albrecht on Droughts and Soil Fertility" I have included references to where in Albrecht's papers I came across the evidence. I am not going to retype that article here. If you have any interest whatsoever in challenging the evidence provided by Albrecht you might just go and read the article and then tell me where I am wrong. Ignoring evidence does not refute it. I don't know the name of the person who wrote this article but the person's lack of knowledge of the consequences of declining soil fertility has resulted in the mistake of blaming more carbon dioxide in the air for consequences that are actually caused by declining soil fertility. In conditions of higher soil fertility there would be no need to plant trees and trees would grow better free from insect and disease problems and they would thereby do a better job of removing carbon dioxide from the air and they would make better firewood. If you knew that agriculture produces food for yield at the expense of its nutritional value, would you be concerned? If you would be concerned about this, that would give you another reason to wade through Albrecht's papers which would serve you better than wading through any post of mine.
49737. Klapper at 11:39 AM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       In the model world, how rare are months where the previous 15 year trend is less than 0.043C/decade, the current 15 year linear regression? To find out I downloaded a number of runs from CMIP5 for the same scenario used above(RCP6.0)for the parameter SAT. To start I chose the 3 "best" models for simulating ENSO according to Dessler 2011 (MPI, MRI and GFDL). However MPI didn't have a RCP6.0 run (yet) and I needed a better representation than just 3 models. So I added the model used in this post (CSIRO) plus 2 more from prominent institutions (GISS and Hadley). That gave me 5 model runs, not a lot but a start. Where there were multiple runs under RCP6.0, I used a random individual run. Source of the data was the KNMI Climate Explorer website. I ran a 15 year rolling linear regression by month for all 5 runs and found that 3.4% of months had a 15 year linear trend of less than 0.043C/decade, the current number. I used 15 years since that's what the graph above used (1998 to now). So while temperature growth "stand-stills" do happen in the model world they are certainly not common.
49738. Doug Hutcheson at 10:49 AM on 20 January 2013
       CO2 is plant food
       Soilfertility @ 9, you said

       I have come to the conclusion that blaming consequences of declining soil fertility on global warming is a scientific mistake

       I asked you for evidence that scientists have made such a mistake, but you have not produced any. Who, exactly, is making this "scientific mistake"? Where is your evidence? Without support for your allegation, it appears you have constructed a strawman argument. I am sure Albrecht makes some interesting points about soil fertility, but what precisely is the connection with the topic of this thread?
49739. Bob Loblaw at 10:18 AM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Yes. I wonder if some of the people that think that the recent (non-significant) observational "trends" are meaningful also think that there are "unknown factors" causing "pauses" in the simulations, too.
49740. Albatross at 09:02 AM on 20 January 2013
       Ed Hawkins: Hiatus Decades are Compatible with Global Warming
       Now that is a great animated gif by Ed Hawkins, and it really illustrates the problem of cherry picking short windows of time and then making misleading claims about what they suggest for the future. Hey look, there are multiple "slowdowns"/plateaus in the future too, that must be good news for those in denial ;) They can be playing this game of seeking out stalls and claiming AGW has ended many decades from now. PS: My guess estimate was that the blue trace would, in the short term, exceed the red trace but that was wrong.
49741. DSL at 08:10 AM on 20 January 2013
       16  ^  more years of global warming
       Isn't there a paper on the "shift" in the AMO-GST relationship post 1960? You can see the emergence of the GW signal in the development of the lag between GST and AMO post 1960. Or am I hallucinating publications?
49742. DSL at 08:05 AM on 20 January 2013
       2012 Shatters the US Temperature Record. Fox, Watts, and Spencer Respond by Denying Reality
       Oh, come on DB! The entertainment value . . . sigh. Maybe we should have a deleted comments thread--one that doesn't get aggregated into the "all comments" stream.
       Moderator Response: [DB] Patience. Such a thing is in development.
49743. Dikran Marsupial at 04:28 AM on 20 January 2013
       16  ^  more years of global warming
       @curiousd/ianC Tamino discussed AMO here, and makes the point that AMO may be the effect rather than the cause.
49744. IanC at 04:07 AM on 20 January 2013
       16  ^  more years of global warming
       curiousd, An issue with their analysis, IMO, is that the AMO index used is based on the North Atlantic sea surface temperature, which is not surprisingly highly correlated with global temperature change: Even though the AMO index is constructed by detrending the north atlantic SST, it is very likely that the nonlinear component of global warming signal is still embedded in the index. The issue is that when you use the AMO index as a regressor, you are potentially trying to use part of global temperature to explain global temperature, which exaggerates the role of the AMO.
49745. Klaus Flemløse at 03:43 AM on 20 January 2013
       Accumulated Cyclone Energy Questions and Answers
       It has been positive to read R. N. Maue's blog with easy access to data. However, I am somewhat surprised to read one of his conclusions of his paper, namely that R. N. Maue:“Additionally, the global frequency of tropical cyclones has reached a historical low”. Considering the fact that the tropical storms have only a small impact on ACE – approx. 12 %? - and it is common knowledge among climate scientists that the proportion of Major Hurricanes is growing, it is difficult to understand why R. N. Maue reaches his conclusion. He ought to have concluded: “The number of Tropical Storms has according to my analysis and in line with IPCC been decreasing and Major Hurricanes increasing. It is a paradox that we have not seen an increasing ACE.” Remember that scientists love paradoxes. Therefore R.N. Maue ought to be happy that I have appointed a paradox to him.
49746. citizenschallenge at 03:29 AM on 20 January 2013
       Accumulated Cyclone Energy Questions and Answers
       And how does the Power Dissipation Index (PDI) fit into this? Atlantic tropical cyclone (hurricane) activity, as measured by both frequency and the Power Dissipation Index (which combines storm intensity, duration, and frequency) has increased. ~ ~ ~ ~ ~ ~ ~ And for discussion sake there's this: https://ams.confex.com/ams/90annual/techprogram/paper_165391.htm 18th Conference on Applied Climatology (5B.5) The misuse and misinterpretation of the ACE and PDI indices for hurricane energetics Angela M. Fritz, Georgia Institute of Technology, Atlanta, GA; and J. I. Belanger, J. A. Curry, and G. J. Holland "The Accumulated Cyclone Energy (ACE) index and the Power Dissipation (PDI) Index are widely used as metrics to quantify seasonal hurricane activity both in the Atlantic basin and worldwide. It can be shown that both of these indices are based on inaccurate assumptions that lead to a misuse and misinterpretation of the resulting index. Towards advancing the indices of hurricane energetics that are associated with potential damage, we develop a new methodology for calculating an integrated kinetic energy (IKE) climatology. A simple, observation and dynamical – based radial wind speed model is used with the Extended Best Track dataset to calculate IKE for North Atlantic Hurricanes from 1988 to 2008. The method is evaluated against previous methods of tropical cyclone intensity analysis, and the results are compared to traditionally misinterpreted indices in terms of characterizing storm energetics and relating it to storm surge. It is shown that the traditional indices are inaccurate measurements of hurricane energetics, and the assumptions that they are based on are not valid." Session 5B, Topics in Applied Climatology II Tuesday, 19 January 2010, 1:30 PM-3:00 PM, B212
49747. JoeT at 03:17 AM on 20 January 2013
       2013 SkS Weekly News Roundup #3
       Thank you for putting together this round-up. I always find something interesting to learn. One thing I would point out --- in the article titled "Megadrought took long-lasting toll on Amazon rainforest" there is this quote from Sassan Saatchi, of NASA's Jet Propulsion Laboratory, the lead author of the paper: "Our results suggest that if droughts continue at five- to 10-year intervals or increase in frequency due to climate change, large areas of the Amazon forest are likely to be exposed to persistent effects of droughts and corresponding slow forest recovery," Saatchi said. "This may alter the structure and function of Amazonian rainforest ecosystems." I would point out that Ranga Myneni is a co-author on the paper. Myneni is the guy who Matt Ridley quotes in his Wall Street Journal article as saying that the increasing greening of the planet is half due to increased warming or rainfall and half due to carbon fertilization. All the more reason for someone to check with Myneni and see if his views were represented accurately.
49748. Philippe Chantreau at 02:15 AM on 20 January 2013
       2012 Shatters the US Temperature Record. Fox, Watts, and Spencer Respond by Denying Reality
       I perused through Backslider's posts and I did not see a single real scientific reference. Plenty of rethoric with words such as "very", "unscientific", "qualified" and what not. No analysis, no peer-reviewed paper, nothing. How am I to take it seriously? I'll add that arguing Urban Heat Island when the temp records are across the entire country is a rather amusing stand. Ironic that this happens on a thread about denying reality.
49749. citizenschallenge at 02:08 AM on 20 January 2013
       Accumulated Cyclone Energy Questions and Answers
       It would be interesting if a future update of this post included a comparison of the strengths and weaknesses of these two metrics and what they tell us. ~ ~ ~ ~ ~ ~ ~ Alternative Metrics of Tropical Cyclone Impact http://www.aoml.noaa.gov/hrd/ike/ Tropical cyclone damage potential, as currently defined by the Saffir-Simpson scale and the maximum sustained surface wind speed in the storm, fails to consider the area impact of winds likely to force surge and waves or cause particular levels of damage. Integrated kinetic energy represents a framework that captures the physical process of ocean surface stress forcing waves and surge while also taking into account structural wind loading and the spatial coverage of the wind. Integrated kinetic energy is computed from gridded, objectively analyzed surface wind fields of hurricanes now available in near real-time from the H*Wind web page http://www.aoml.noaa.gov/hrd/data_sub/wind.html ~ ~ ~ 11/02/2012 Superstorm Sandy packed more total energy than Hurricane Katrina at landfall By Brian McNoldy ~ ~ ~
49750. curiousd at 01:49 AM on 20 January 2013
       16  ^  more years of global warming
       Technical Question on Zhou and Tung, J. Atm, Sci. vol 70, Jan 2013 pp. 3-8. Quite on topic, just out to academic libraries.. They do a regression analysis including the AMO and find this addition strongly reduces the rate at which the temp increases due to GHG. But they have data all the way back to 1850 and try only fits that are linear with time. Why should one even expect the GHG contribution is linear with time, especially over this long a time period? See their Fig. 4 to see problems that arise. If driven by CO2 temp increase is linear with respect to log to base two of COs concentration ratio, not linear with time and the difference will be pronounced if you go back to 1850. In my figure in comment 47 above, I get a good fit with a c.s. of 2.035 plus or minus .074. We should have, perhaps, a discussion about the Zhou and Tung paper.

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