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Comments 45701 to 45750:

45701. Tom Curtis at 07:46 AM on 14 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Oriolus Trailli and Rob Painting, following up from a hint by 64jcl at Potholer's channel, I have found a reference to fossil coral on Devon Island, Nunavat (in the Canadian Arctic).  The fossil formation spans an interval from 600 million years ago (ie, in the Pre-Cambrian and approximately the time of the last snow ball Earth episode) to 39 million years ago.  The fossil corals, however, appear in the late Ordovician, or approximately 450 million years ago.  If this is indeed the reference Potholer had in mind, he has confused the timing of the corals with the begining of the formation.

       To place the timing of the coral fossils in context, here is the broad temperature history of the Earth:

       

       The fossil corals appeared in the late Ordivician just prior to the partial glaciation indicated by the thin blue line.  The chart has a resolution of 10 million years, so fluctuation of CO2 concentration by up to 2000 ppmv (with corresponding fluctuations in temperature) may have occured at finer resoltuions and not show up on the chart, so global temperatures at the time of the corals may have been several degrees above those shown in the chart.  However, it also cannot be excluded that the fossils are of cold water corals.  

45702. Tom Curtis at 07:04 AM on 14 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       KK Tung @12, I would be fascinated to hear what portion of variance in the annual temperature series you ascribe to seasonal temperature differences.  Failing that explanation, I have to regard your introduction of seasonal temperature variation when annually resolved temperature differences are the finest resolution under discussion as a pure red herring.  Ineed, I also consider the introduction of annual and ENSO variations a case of misdirection when the issue is that your AMO does not show up in the CET series using a 21 point binomial smooth, (described as equivalent to a 10 year moving average by the met office).  A 10 year moving average would filter out merely annual variation, along with nearly all variation related to ENSO and the solar cycle.  Indeed, if a 50-80 year oscillation does not show up with a 10 year moving average, the most parsimonious explanation is because it does not exist.  And it does not show up in the 21 point binomial smooth (equivalent to a 10 year moving average) applied by the MET office to the CET.

       Beyond noting your evasions, I note that you have not responded to the first, and key point, that the fifth RPC of MBH98, which you take to represent the AMO, represents around 3% of variance of the NH temperature reconstruction.  It is not true for hemispheric temperture records that either the twentieth century warming (or the purported AMO) are much smaller than ENSO or annual variations in temperature.  On the contrary, the "hockey stick" in MBH98 comes from RPC1, which explains 38.2% of the variance.

       Finally, you are unclear regarding which "AMO" the CET shows statistically significant correlation to.  Is it the "AMO" as seen in the 1850- present instrumental temperature set?  In that case the lack of an AMO signal in the CET prior to 1850 is strong evidence that there was no such AMO signal prior to 1850.  Or was it a correlation with the spurious RPC5?  But that RPC is not statistically significant and therefore not a reasonable basis for asserting the existence of an AMO signal prior to 1850.

45703. Rob Painting at 07:03 AM on 14 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       JoeT - Figure 1 is from model simulations with a global energy imbalance of 1 W/m2. The point being that the model demonstrates 'hiatus decades' even under strong global warming. That would likely be due to the changes in wind, as discussed above.

       Balmaseda (2013) suggest the current top-of-the-atmosphere (TOA) radiative imbalance is larger than that found in the Loeb and Stephens papers. 

45704. JosHagelaars at 05:52 AM on 14 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       Dana, thanks for the informative post.
       A copy of the Stephens paper can be found here:
       http://www.aos.wisc.edu/~tristan/publications/2012_EBupdate_stephens_ngeo1580.pdf

45705. jdixon1980 at 03:57 AM on 14 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years?
       

       It will be interesting to see Dr. Tung's response to KR@49, assuming that Dr. Tung's conclusion rests on the premise that CO2 is increasing "almost exponentially" as opposed to "more than exponentially."    

45706. dana1981 at 03:41 AM on 14 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       JoeT - Figure 1 comes from Meehl 2011, so you'd have to check that paper (I don't have access to it).  Measurements tend to vary between about 0.5 and 1 W/m2 though, depending on the data set and the paper you choose.

45707. JoeT at 03:32 AM on 14 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       Dana, just to make sure I understand -- Fig.1shows the TOA imbalance at 1.0+/- 0.1 W/m2 at most. Is this a model estimate or a measurement? The Graeme Stephens paper has 0.6 +/- 0.4 W/m2 which is a satellite measurement. Is the Stephens' result still the best estimate of the imbalance?

45708. Composer99 at 01:52 AM on 14 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       I tried to make the point we need to examine the evidence with out the hysterics in the light of the actual measurements now coming available.

       ... on a post featuring a video consisting almost entirely of Peter Hadfield's dry, measured delivery.

45709. KR at 01:22 AM on 14 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       Dr. Tung - You are continuing to advocate using a linearly detrended AMO in your calculations, attributing some 40% of warming over the last 50 years to AMO variations. 

       A linear detrending would be appropriate if and only if warming from other influences over that period were linear. That, however, is not the case. The radiative forcings over that period are distinctly non-linear:

       

       [Source - GISS]

       Hence a linear detrending will, as argued by Trenberth and Shea 2006, still contain non-linear portions of that signal, and will inappropriately reduce the global warming signal if subtracted - in effect subtracting a significant portion of overall global warming before attributing temperature changes. As they note:

       About 0.45
       C of the SST anomaly is common to global SST and is thus linked to global warming...

       Linear detrending does not isolate a SST anomaly from overall global warming; a 0.45C misattribution represents roughly 45% of observed warming over the last 50 years - and which matches to the 40% of warming you attribute to the AMO. A linear detrending is therefore inappropriate when attempting to attribute warming against variability. 

       It may well be (as I believe you have argued) that this becomes an argument of definitions, a chicken/egg question, with different answers based upon the AMO definition. To that extent, it is worth checking assumptions against additional data - for example the Anderson et al 2012 paper I referred to before, and which you have not commented upon. There an analysis of global warming against ocean heat content (OHC) indicates that more than a 10% warming contribution by natural variability is ruled out as inconsistent with observed OHC - if more was contributed by natural variability the oceans would have to be cooler. 

       The AMO cannot have contributed more than 10% of the warming signal over the last half-century based on conservation of energy, and the 40% attribution you make to the AMO is within 5% of what T&S estimate as misattributed to the AMO by linear detrending. Based on these issues alone, I would have to strongly disagree with your papers conclusions. 

45710. Warren Hindmarsh at 00:14 AM on 14 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Kevin come back tomorrow and I will explain it

        

45711. Kevin C at 00:02 AM on 14 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren: Did you try the model I gave you?

45712. Kevin C at 22:44 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren @9: This might interest you:
       http://diyclimate.x10.mx/responsemodel/nbox.html
       
       It's a toy 'empirical' climate model, which works by determining the climate sensitivity which best explains the observed temperature record from the forcings. It's got a lot of limitations, but it can provide a good cross-check on your intuition.
       
       Go to the page, scroll down and set 'Years to fit' to 1880 - 1997. Now click Calculate. Underneath you'll see a figure for TCR (a measure of climate sensitivity over a human lifetime). You should get a number like 1.58C.
       
       Now change 1997 to 2011, to include the most recent data available to the model and hit calculate. Note that including the last decade and a bit increases the estimate of climate sensitivity.
       
       Your intuition may rebel against this, but think about it for a bit. If you can't work out why, come back tomorrow and I'll explain it.
       [Note: I'm not claiming validity for the model, only that intuition is unreliable concerning the interpretation of recent temperature trends.]

45713. XPLAlN at 21:47 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       @mcooke #2

        

       at 3:45 - 3:53 we are told that "a doubling of Co2 from pre-industrial levels will lead to a rise in average global temperatures of about 1 degree Centrigrade". And that at 5:30 - 5:39 - "for a doubling of CO2 concentrations we should see a rise in global temperatures of between 2 and 4.5 degrees" This might cause some confusion

       
       ...except the video content between the two points is actually an explanation of how one gets from one figure to the other - namely positive feedback due to water vapour.

45714. Tom Curtis at 21:12 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren Hindmarsh @9, the global climate warmed at a rate of 0.071 C per decade durring the twentieth century (1901-2000).  In contrast, it warmed at 0.108 C per decade from Oct 1994 to the present, the longest period of statistically insignificant warming (for Gistemp).  That is, in this supposed warming pause, the Earth has been warming more than 50% faster than the record breaking Twentieth century rate of warming.  Only in the wierd world of climate change denial can the rate of warming be significantly above average but it be called a warming pause solely because the chosen time interval is too short to contain enough measurements for statistical significance.

       Now, can you explain to me without the deceptions why a warming rate greater than the twentieth century average, and very close to the predicted rate once known confounding factors (ENSO etc) are accounted for requires us to fundamentally reconsider the theory?

45715. Rob Painting at 20:25 PM on 13 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       R Gates - Increased heat transport into the deep ocean is broadly consistent with what is known about the wind-driven ocean circulation. Stronger tropical easterly trade winds during La Nina-dominant periods (negative Pacific Decadal Oscillation [PDO]) will lead to stronger Ekman pumping in the ocean gyres. Indeed, one can see the piling up of water in the Western tropical Pacific in the sea level trend over the period of satellite altimetry (1993-to present) - a clear sign of the intensified winds there. Additionally, the intensified winds of the mid-latitude westerlies, and a poleward shift of the strongest winds toward the Antarctic Circumpolar Current will also lead to stronger convergence of surface currents, and stronger downward heat transport.

       This will throttle back when we enter a period of El Nino-dominance (positive Pacific Decadal Oscillation) because the easterly trade winds will weaken. Less heat will be mixed into the deep ocean and more will remain at the surface - to be exchanged with the atmosphere. So, even though global warming will slow during that time, surface warming will speed up.

       John Brookes - light-blocking sulfate pollution from global industrial activity has been declining since about 2007. This is primarily from the installation of scrubbing technology in Chinese smokestacks.

       It is interesting, however, that the slowdown in ocean heat content accumulation during 2004-2007/2008 coincides with a strong global dimming during that interval. There is a tendency to ascribe changes to only one variable, but in reality a combination of variables may explain recent events.

       There is the worrying possibility that 3 variables may have acted to slow surface warming during that time; the negative phase of the PDO, industrial sulfate pollution, and increased sulfates from increased volcanism of tropical volcanoes. Let's hope that that wasn't the case - it would imply significant surface warming when these 3 are no longer holding back greenhouse gas warming. 

45716. Dikran Marsupial at 20:04 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren "no statistical warming" does not mean "no warming", it just means that the observations do not effectively rule out the possibility that there has been no warming over the period in question. 

       If you want a statistical test to show there has been no warming, you need to show that the observations are inconsistent with the extistence of a warming trend of the magnitude suggestsed by the IPCC.  If you do this you will find that the evidence for no warming isn't statistically significant either.  Curously the "skeptics" never actually do this ;o)

45717. Rob Painting at 19:41 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren -  Global warming has accelerated. Only by excluding all the evidence for warming and focusing on the (roughly) 2% of global warming that goes into heating the atmosphere, and only over a short period of time, does it appear otherwise.

       I'm sure that you'll agree that looking only a one small piece of the evidence is not a valid scientific approach. 

45718. shoyemore at 17:07 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Warren #9

       No one should really take seriously statements likes no statistical warming for nearly 20 years despite increase of CO2 (or 17 years, or 15 years). That has been oft-refuted here and on other blogs.

       www.skepticalscience.com/short-term-variability-vs-long-term-trends-mclean.html

       www.skepticalscience.com/watanabe-et-al-2013-another-piece-of-the-puzzle.html

45719. Warren Hindmarsh at 16:07 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       We all know CO2 is a green house gas, we all know atmospheric CO2 increases alone won't force significant warming by it self, we all know forcing by H2O in the atmosphere will multiply the CO2 effect.  What isn't certain yet is the value of the forcing by H2O. because the actual measured results - (-snip-)?  Maybe we need to go back to the basics with a fresh look at this, (-snip-).

       Moderator Response:

       [DB] Sloganeering and inflammatory tone snipped.

45720. R. Gates at 15:35 PM on 13 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       I am still unconvinced of the overall thermodynamics behind the notion of "ocean heat uptake efficiency". I have no doubt mind you, that the bulk of the TOAenergy imbalance from increases in GH gases can be be found in the ocean at various depths, but what I seriously question is the direction of energy flow in accounting for the accumulation of about 0.5 x 10^22 joules per year of energy down to 2000 meters, and more when looking at even greater depths. 

       Given that the vast majority of energy in the oceans comes from solar SW, and that the net flow of energy planet wide is from ocean to the atmosphere, and that at any given time somewhere around 1/3 of the energy in the atmosphere came via the oceans, it seems far more accurate thermodynamically to speak about a slowdown in the transfer of energy from ocean to atmosphere. This is precisely what we see on a net basis during periods of La Niña activity or the cool phase of the PDO. Moreover, increased GH gases in the atmosphere would be expected to have the precise effect of slowing the rate of energy flow from ocean to atmosphere to space via several mechanisms. Finally, given the measured a increase in advection of energy to the Arctic via ocean currents, the increase in energy of the oceans should be expected to have the exact effect we are seeing with a rapidly declining Arctic Sea ice volume, with a great deal of this happening from ice being melted from underneath. 

45721. John Brookes at 15:30 PM on 13 May 2013
       Another Piece of the Global Warming Puzzle - More Efficient Ocean Heat Uptake
       

       Which makes you wonder if something similar was happening in the hiatus in temperatures in the middle of last century.  But I imagine we didn't have accurate ocean heat content measurements then.

       If our current models accurately modelled the absence of surface warming from 1940 to 1980, and did not include heat transport to the deep ocean, then maybe other assumptions of these models are questionable.  For example, the amount of aerosols in the atmosphere may have been overstated to explain the cooling, when it was actually heat moving to the deep oceans.

       This certainly is a good chance to improve the models!

45722. Bob Loblaw at 14:22 PM on 13 May 2013
       2013 SkS Weekly Digest #19
       

       Chris:

       It's not the result of a wave carrying the ice that far up the beach. It's an "ice push". Get a long lake, a strong wind, and a lot of loose, moving ice, and there is a lot of momentum behind it. Ice gets pushed up on shore, and pushed further by more ice getting pushed ashore, and so on. It's like trying to stop an oil tanker.

       Although such ice pushes are uncommon, I have been on many lakes in the Northwest Territories where the rocky beaches (typically made of rocks 10-20cm in diameter) have many ridges in the beach itself caused by such ice pushes. The ridges are easily several metres above normal water level, and there will be several of them at different heights, from different ice push events of varying strength.

45723. Daniel Bailey at 14:15 PM on 13 May 2013
       2013 SkS Weekly Digest #19
       

       Chris, this type of thing happens occasionally on large lakes in northern climes.  I can recall several instances over the past few decades on Lake Erie, Lake St. Claire and Lake Huron here in North America.  A wind-driven occurence.  Extreme, yes.  Rare, also.

       The term "tsunami" is inapplicable, however.

45724. chriskoz at 14:02 PM on 13 May 2013
       2013 SkS Weekly Digest #19
       

       What's the the SkS team take on this news:

       Tsunami of ice plows into dozens of Canadian homes; no one injured in freak disaster

       I don't know much about iceshet dynamics or how the insignifficant wind without any earthquake can cause such tsunami waves on the inland lake.

       Further, is it just a "freak event" or can warming in the arctic together with jetstream pattern change, result in more frequent such events in sub-arctic lakes ?

45725. bill4344 at 12:15 PM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Potholer has released a sources video for this one - it's currently his most recent. I'm sure he'd be happy to have any errors pointed out.

45726. Rob Painting at 11:04 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       If that's the case Tom, it would place the timing hundreds of millions of years before the evolution of Scleractinian (reef-building) coral.

45727. Tom Curtis at 10:10 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Oriolus Traillii @3, I think Potholer may have made a mistake in this case.  He cites a solar luminosity of about 0.94 of the current value at the time of the purported near polar coral reefs.  That places the event at around 700 million years before the present, or over 100 million years before the evolution of the first corals in the Cambrian.  In the precambrian, the most probable reefs to be formed would have been stromatolite reefs, although there were other forms of precambrian reefs.

       You should really contact Potholer for the source of that claim, and the basis for claiming the reef as evidence of warm water.  I am sure he will be able to provide you with a suitable scientific referrence that will get the facts straight (and possibly prove me wrong).

45728. Steve J at 07:29 AM on 13 May 2013
       Dueling Scientists in The Oregonian, Settled by Nuccitelli et al. (2012)
       

       Talking of Fulks, just sat through this:
       
       http://blip.tv/jim-karlock/climate-orthodoxy-perpetuates-a-hoax-5924187
       
       Painful viewing; my knowledge of climate change is mostly limited to Potholer's videos and browsing New Scientist, but even with that I was thinking "that doesnt seem right".  You can see how convincing it would seem with no prior knowledge though.
       
       Can anyone bring themselves to review this talk?
       
       PS Sorry if this is off topic, new to this site and didn't know whre else to put it - this thread is all that came up when I searched for Fulks.

45729. goonobear at 07:21 AM on 13 May 2013
       Muller Misinformation #3: Al Gore and polar bears
       

       Am I incorrect, or is your quote from the film inaccurate?  You say in the film Gore says:

       
       "That’s not good for creatures like polar bears, who depend on the ice. They’re now, actually, looking for other ecological niches. It is sad what’s going on in the Arctic ecosystem."

       
       In actuality, at approx 45:30, he states:

       "That’s not good for creatures like polar bears who depend on the ice.  A new scientific study shows that for the first time they’re finding polar bears that have actually drowned, swimming long distances up to 60 miles to find the ice. They didn't find that before. What does it mean to us to look at vast expanse of open water at the top of our world that used to be covered by ice? We ought to care a lot because it has planetary effects."

       
       While the overall truth of your point about Gore and Cicerone may hold, this inaccurate quotation should be corrected.   Where did you find that particular line?

       Thanks.

45730. Rob Painting at 07:12 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Also note that the equatorial oceans would have been extremely warm during the "Greenhouse Periods" on ancient Earth. Too hot for reef-building coral similar to modern-day to have survived. 

45731. Rob Painting at 05:49 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       The oceans only become corrosive when CO2 is added to the atmosphere in a geologically-rapid manner such as today.  This is because the chemical weathering of rock is able to supply alkalinity back to the oceans over tens to hundreds of thousands of years.

       There is an upcoming rebuttal on this - it's one oversight that needs to be fixed.

45732. Oriolus Traillii at 03:04 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       Dear Dana,

       Great summary! One thing got me frowning, though. Do you know why there were coral reefs at the poles (at 8:05) although CO2 was 25 times higher than it is today? Did the ocean have a higher pH or were they a different type of coral or what was different when compared to todays coral reefs dissolving in highly diluted carbonic acid?

       Regards

45733. mcooke at 02:49 AM on 13 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       On observation of this video, at 3:45 - 3:53 we are told that "a doubling of Co2 from pre-industrial levels will lead to a rise in average global temperatures of about 1 degree Centrigrade". And that at 5:30 - 5:39 - "for a doubling of CO2 concentrations we should see a rise in global temperatures of between 2 and 4.5 degrees"  This might cause some confusion.

45734. Nick Palmer at 01:12 AM on 13 May 2013
       What you need to know about climate sensitivity
       

       Rob. I'm pretty sure I was initiating a comment thread...

45735. CBDunkerson at 01:07 AM on 13 May 2013
       Dueling Scientists in The Oregonian, Settled by Nuccitelli et al. (2012)
       

       Dana commented on the D&K response here. Basically, the claims D&K made (e.g. massive unexplained 'step change' shifts in global energy levels) are so ridiculous that they refute themselves.

45736. Rob Painting at 19:42 PM on 12 May 2013
       What you need to know about climate sensitivity
       

       Nick - perhaps you are responding to a particular comment that has been deleted? Any replies on that chain are likely to be deleted too. 

45737. Rob Painting at 19:23 PM on 12 May 2013
       Dueling Scientists in The Oregonian, Settled by Nuccitelli et al. (2012)
       

       What is there to respond to? What do you think they have refuted?

45738. KK Tung at 17:59 PM on 12 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       In reply to post 3 by Kevin C. El Chichon erupted in 1983, and Pinatubo in 1991, during the most recent period of accelerated warming 1980-2005.  This is also the warm phase of the AMO. Volcanic aerosol cools.  Tambora, arguably the largest volcano eruption in 300 years, was followed by a warm phase in N. Atlantic. "The year without summer" was only temporary until the ashes were washed out.

45739. Doug Hutcheson at 17:57 PM on 12 May 2013
       What you need to know about climate sensitivity
       

       dana1981 @ 9:

       Earth System Sensitivity (in the ballpark of 6–8°C for doubled CO2)

       Yikes! That's the first I've heard of ESS and its 6–8°C. I have been stuck in my own little world, thinking the 3°C bandied about would be the end of the matter (barring methane amplification, which I didn't think was quantified as yet). Big wake-up call to whoever is asleep at the wheel. Thanks for cheering me up. Not.
       

45740. KK Tung at 17:51 PM on 12 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       In reply to post 11 by Tom Curtis: Most variance of climate data is usually in the high frequencies, and the AMO is in the low frequency.  If we judge the significance of a signal by its variance, then one would have arrived at the conclusion that the 100 year long term trend of global warming, which is only 0.8 degrees C, much less than the seasonal, annual, and ENSO variations, must not be significant. Then we would all be wasting our time debating its cause.

       The statistical significance of the AMO in the CET data was shown to be at the 95% confidence level, as compared to a red noise model at those frequencies.

45741. Doug Hutcheson at 17:34 PM on 12 May 2013
       Climate change will raise the sea level in the Gulf of Finland
       

       <pedantry>'Missippi'should be 'Mississippi'.</pedantry>

       Sigh: old age has many pitfalls ... "8-/

45742. FrankShann at 16:27 PM on 12 May 2013
       Dueling Scientists in The Oregonian, Settled by Nuccitelli et al. (2012)
       

       I repeat my question of 14th April. Nuccitelli et al 2012 (Physics Letters A 376 (2012) 3466-3468) is often cited on Sceptical Science, but this paper has been "refuted" by Douglass and Knox in Physics Letters A 376 (2012) 3673–3675. Has there been a response to Douglass and Knox? If not, are there any plans to respond? Without a response, it is inappropriate to keep citing Nuccitelli 2012.

45743. bill4344 at 14:11 PM on 12 May 2013
       The evidence for climate change WITHOUT computer models or the IPCC
       

       More great work from Potholer.

       No 'skeptic' appears to be doing well in taking up his challenge in the comments below the video. Perhaps one of the locals will do better? Unlikely...

45744. Tom Curtis at 10:09 AM on 12 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       KK Tung @9, I do not think you can say so blithely that the AMO has been "observed".  What has been observed is temperature variation in the North Atlantic, and it has been conjectured that that variation is the continuation of a persistent oscillation.

       You purport that a persistent AMO has been observed by showing us "Fig 4:, ie, the seventh (and second last) figure in the article above.  That compares the fifth Reconstructed Principle Component from MBH98 to the AMO index, and various 50-80 year band signals of various instrumental records.  However, the fifth RPC of MBH98 explains only  (approx) 3% of the variance of what is, afterall, a NH temperature reconstruction.  That low percentate of variance explained almost certainly indicates that the RPC is not significant; and if you are seriously taking it as the AMO signal then you are commiting yourself to the idea that the AMO explains less than 5% of the variance in NH temperatures, an idea I am sure you would reject.

       What we have observed in MBH98 RPC 5, then is not the AMO but just some random noise.

       What is worse, the actual temperature signal of the CET, which presumably follows that of the North Atlantic very closely, is misrepresented by the "50-80 year band signal" of the CET that you show.  This is easily seen in the figure below, which overlays your "figure 4" with the CET temperature series.  The blue bars are annual values, while the thin red line is a 21 point binomial smooth of the annual data.  It is evident that the "50-80 year band signal" must represent only a small component of the total CET signal; and hence that your "observed" AMO signal is just a small component of North Atlantic temperature variation prior to 1880.  If that is the case, either the AMO is not a persistent feature of the NA, or it is a very minor factor in global and NH temperature variation.  In either case you have a major problem explaining why it suddenly should appear so dominant in the twentieth century.

        

       

45745. Nick Palmer at 09:49 AM on 12 May 2013
       What you need to know about climate sensitivity
       

       Dana. The comments policy on your Guardian articles is so draconian - or one of the moderators is so over the top - that it seems impossible to have a robust intelligent discussion at all. You may recognise my user name and, if so you may recall that I am not one for wild offensive tirades against climate "sceptics" yet my comments are being consistently deleted, as are those of many others. What gives?

45746. KK Tung at 08:29 AM on 12 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       Reply to post 4 by K.a.r.S.t.e.N.: Thank you for pointing out the proper credit of the Figure 5, which I attributed to you.

       Currently the debate in peer reviewed literature is about whether the AMO is forced by anthropogenic (tropospheric) aerosol or by the AMOC as a natural oscillation.  What you are referring to is a third possibility, that the AMO is forced by the stratospheric aerosol from volcano eruptions.  It is possible, though I think it is unlikely ( Please see my comment in post8). But I can be persuaded.

45747. KK Tung at 08:21 AM on 12 May 2013
       The anthropogenic global warming rate: Is it steady for the last 100 years? Part 2.
       

       Reply to post 6 by KR: By "the upward trend of the AMO" I assume you are referring to the North Atlantic mean SST, because AMO is supposed to be detrended. I agree that anthropogenic forcing can force an upward trend in the N. Atlantic mean SST. In fact I am quite certain of it.  In addition I think it is entirely possible that anthropogenic forcing can also force an oscillatory N. Atlantic mean SST. It is just that no credible model has been able to simulate it without contradicting some other aspect of the observation. Furthermore it is difficult to have this theory explain more than two cycles of the observed AMO.

45748. grindupBaker at 06:08 AM on 12 May 2013
       What you need to know about climate sensitivity
       

       eschwarzbach @ 6 Another way to view situation when "CS target remain stable". If, say, +2.8 degrees required to balance TOA in/out, I see no logical reason why 80% lowest ocean, now at ~6 degrees  avge, will not need to be ~9 degrees avge before all is stable in centuries/millenia.

45749. grindupBaker at 05:43 AM on 12 May 2013
       What you need to know about climate sensitivity
       

       Should add @10 "thin veneer" for surface temp includes top ocean veneer. Need to study to decide a reasonable few metres depth in which thermal conductivity & local mixing significant. It's most significant because each ~6.5m ocean depth = all land+air heat. Land is significant for radiation balance only, not heat content, because it's mostly quite dark albedo.

45750. grindupBaker at 04:47 AM on 12 May 2013
       What you need to know about climate sensitivity
       

       eschwarzbach @ 6 "Global Warming" is an increase in the ocean heat content. I suggest a lay person will have endless difficulty contemplating land-air & ocean surface temperature unless they start by understanding it's just heat moving through into ocean, has 97.5%, freshwater=2.3%, land+air=0.2% of ecosystem heat content. Land solid has no currents so thin veneer only involved (I read ~6.5m deep somewhere), ocean liquid so heat mixes ~6km deep (ex. trenches) ~4km avge, but over centuries-to-millenia. Equator to poles top veneer takes heat, warms poles, saltier, drops, returns at depth. Tiny bits of ocean heat like ENSO sucking in & burping out seem really big to us on/in the negligible 0.2% land+air bit. Surface temperature is (1) a proxy (2) a symptom (3) what determines heat in/out balance at TOA. Example: if ocean mixing slowed to stop for few years (just fantasy for example) land+air reaches TOA balance quickly at "final" temp & AGW pauses. Ocean mixing resumes in (unrealistic) example, surface temp drops & AGW resumes. Humans now see "global cooling" when it's the exact opposite - AGW now resumed. Exaggerated example shows why must understand ocean mass, depth, heat capacity (572 yrs for +1C @ +0.9 wm**-2 is what I computed), currents before can hope to understand surface temperature changes.

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