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scaddenp at 11:16 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
I think the information on you want (level of uncertainty in ocean indicators) can be found Schuckmann and La Traon
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Tom Curtis at 11:04 AM on 18 May 2015New study finds a hot spot in the atmosphere
chriskoz @11, in my comment @3, the first two images are the images used in the RealClimate post to show that both CO2 and solar forcing result in a tropospheric hotspot. The third image is, as you show the effect of halving CO2 (after 100 years). The fourth image, for comparison, is the effect of maintaining 1/3rd Pinatubo forcing for 100 years.
I would certainly be interested in, and gratefull for, Chris' rerunning of the GISS model for the equivalent experiment.
I cannot comment on Ben Santer's input as I have not seen it. Could you provide a link. Further, if he is commenting on the topic somewhere, and you can respond, could you ask his opinion of my point 4 immediately above. Specifically, what is the algorithm for "MSU Space"? Does converting to it have the effect I postulate? Also does he have any graphs of absolute temperature values with altitude in MSU space as the test of the effect of using MSU space?
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bozzza at 10:56 AM on 18 May 20152015 SkS Weekly News Roundup #20B
Precisely correct, Bjorn Lomborg is blind to intergenerational inequality. His political message is a global one: that carbon emissions be allowed to warm the earth by three degrees. (What was his choice of measurement btw as I cannot recall?)
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Tom Curtis at 10:55 AM on 18 May 2015New study finds a hot spot in the atmosphere
Tom Dayton @9 & 10, Michael Mann writes:
"Just compare the GHG signal in Santer et al '13 (which shows a hot spot) and the volcanic (which doesn't, and shows a change of sign at 500 mb, which is very close to the 595 mb PEAK of the TMT weighting function--if there were a mid-tropospheric hotspot, it should be seen in TMT)."
My emphasis.
Below is a figure showing the trend warming rates from 1979-2012 in the troposphere by altitude for all CMIP5 RCP8.5 models:
The source of the diagram is John Christy, which is dubious in some respects, but I presume he has not misrepresented the model outputs. That being the case, the CMIP5 models show a clear upper tropospheric hotspot with a multimodel mean peak warming at 250 mb. Despite this the trends from 1979-current are:
GISS 0.158 C/decade
RSS TLT 0.121 C/decade
RSS TMT 0.077 C/decade
RSS TTS 0.011 C/decade (from 1987)
RSS TLS -0.269 C/decade.
Clearly the trends decline as the mean altitude of measurement rises, with the TMT trend being less than either the TLT or surface trends, and greater than any trends above it. It follows that if Mann's claim highlighted above is true, then there is no tropospheric hotspot contrary to the model predictions. In other words, if Mann's highlighted claim is true, the models have been falsified on a fundamental issue that is vital to estimates of climate sensitivity and future warming. Michael Mann may want to claim in response that his claim is only applicable to volcanic warming, and not warming in general. If so that is just the rankest special pleading. If not he either has to accept my claim @8, point (3), above, or radically revise his reliance on models, and his view as to the dangers of AGW.
Further, the GISS Model E vIII 1880-2000 all forcing response by altitude is shown below:
As you can see, the peak warming is around 350 mb (337.5 mb). That is in fact lower than the CMIP5 multimodel mean, and also lower than the CMIP5 versions of the GISS Model E (six versions, shown with dotted lines of various shades in the first figure above). That discrepancy may be simply due to the different forcing periods, but if anything the evidence is that the altitude of peak warming has shifted upwards from CMIP3 to CMIP5, not downwards as would be required for the GISS model E images I have been using to be in need of significant correction.
As an aside, there is certainly no reason to prefer the data from cone CMIP3 era model, ie the Parallel Climate Model (PCM) as shown in the IPCC reports and used by Mann over another model of the same vintage (GISS Model E vIII). As a further aside, the peak cooling for the one third Pinatubo forcing shown @3 is also at 337.5 mb). This point should be irrelevant in that I originally rebutted Mann's claim that, "if global warming really *were* due to a (natural) decrease in volcanic activity over time ... then we would expect to see an increase in global surface temperatures WITHOUT any mid-tropospheric "hot spot"". Mann now appears to be trying to make the issue about the exact altitude of peak warming, which shifts the goal posts. He also misrepresents the altitude of the peak warming (or cooling) in the GISS model, claiming (@10) it is about 140 mb higher in the atmosphere than actually shown by the model.
3) Fairly abviously, the PCM models shown @10 do not use a period with significant volcanic forcing, with the consequent that any coldspot is too small to register for the volcanic forcing given scale. The same also applies with sign reversed for the solar forcing. That is telling in that solar forcing is definitely one of the forcings which does show a hotspot, but shows no hotspot in the PCM figure. As Mann accepts that solar forcing generates a hotspot, he must attribute the lack of a visible hotspot in the solar forcing panel to the small quantity of warming relative to the temperature scale used. He cannot therefore consistently argue that that is not also the case with respect to the volcanic forcing.
4) Finally, with respect to figure 2 from Santer et al (2013) (see your post @6 above), Santer et al write:
"Zonal-mean atmospheric temperature trends in CMIP-5 models (A and D–G) and observations (H and I). Trends were calculated after first regridding model and observational TLS, TMT, and TLT anomaly data to a Graphic latitude/longitude grid, and then computing zonal averages. Results are plotted in “MSU space,” at the approximate peaks of the TLS, TMT, and TLT global-mean MSU weighting functions (74, 595, and 740 hPa, respectively)."
My emphasis.
It is not explained what "MSU Space" is, although it is almost certainly not a linear function of temperature with altitude. More likely, at each altitude, the value shown is the weighted average of the TMT, TLS and TLT trends, with the weighting determined by the relative weight of each channel at that altitude as shown in my post @8, although different algorithms with similar effect could also be used. As such, it loses vertical structure. That is because it first reduces the vertical structure to just three values, and then tries to recompose it from those three values. It is, in effect, a complex smoothing of the data. As such it will not more show the tropospheric hotspot than will the TMT channel (for reasons given above). What it will show is what will be found by attempts to reconstruct the vertical temperature signal from the MSU or AMSU channel outputs. That, of course, is very useful for comparison with satellite data, but renders the graphs positively misleading about the detailed vertical temperature structure of the atmosphere.
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Daniel Bailey at 10:47 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
Here's a couple to give you a head start on your research:
Google Scholar wants to be your friend. Call him.
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bozzza at 10:46 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
Owenvsgenius, you can't measure everything: this is called 'the uncertainty principle'. Thus all measurements have to be verified by other means making repetition of results central to scientific method!!
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chriskoz at 10:09 AM on 18 May 2015New study finds a hot spot in the atmosphere
Tom Curtis @3,
Looks like Mike Mann did not even change the details of his hypothesis based on your input. And as it turns out MM hypothesis is backed by Ben Santer, your inquiry to the authority of Gavin Schmidt on the subject is unlikely to change anything. Meanwhile Chris Colose offered to run GISS model you claim about volcanic hot spot is based on, to run it and check the apparent discrepancy: we are all eager to see the results, thanks Chris!
Meanwhile, pardon my punt, I don't see the extraordinary evidence you need to provide in support of your extraordinary claim taking on the top scientists. If particular, your third image is just a hot spot cooling due to a loss of 50% of CO2, as seen in the NASA link you cite. Where is the "1/3 rd Pinatubo level volcanic forcing" picture where you claim "the patterns in the tropics are very similar"? Maybe you've seen but missed that picture. Please provide it for the benefit of us better understanding your point.
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Owenvsgenius at 10:02 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
Can anybody tell me the spacial resolution and coverage of ocean temperature surveys? This question impacts the subject matter directly, as models use survey data
Moderator Response:[JH] Perhaps you should do your own research on this matter.
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Tom Curtis at 09:43 AM on 18 May 2015Climate sensitivity is low
Bobl writes, "Now the IPCC says that 50% of warming is probably coming from humans and 50 % is natural variation ...".
What the IPCC actually wrote was that:
"More than half of the observed increase in global mean surface temperature (GMST) from 1951 to 2010 is very likely due to the observed anthropogenic increase in greenhouse gas (GHG) concentrations."
where "very likely" means "90-100%" likelihood. In other words, what the IPCC claimed was that there is a less than 10% chance that only 50% or less of 1951-2010 warming was due to anthropogenic forcings. That is sufficiently different, indeed contradictory of what Bobl claimed the IPCC wrote that prima facie, he is a bald faced liar.
Indeed, it is worse than that. The IPCC also provided a figure with the mean and uncertainties of attribution. This allows you to generate the Probability Density Function (PDF) of the AR5 attribution, as was done by Real Climate:
From this, in turn, it can be determined that the actual likelihood of less than 50% anthropogenic causes of warming since 1951 is 0.06%. It follows that at best Bobl is calculating the lower bound of the 99.9% probability range of the "climate sensitivity". To perform the calculation correctly (ignoring other errors), he should have used an attribution of 107.7% (the mean value of the PDF). Correcting for this factor alone would more than double his "climate sensitivity" estimate.
It should be noted, of course, that the IPCC attribution statement only covers the period 1951-2010. It cannot be arbitrarilly extended to cover periods back to 1900, 1880 or 1850. Natural forcings were negative from 1850 to about 1910, strongly positive from then to 1940, and remained positive to about 1950, as they more than recouped the losses to 1910, and have been effectively neutral or slightly negative since then. The result is that 70% is a better estimate than 108% for the anthropogenic contribution since 1900 (or 1880), but 100% is probably more accurate for the anthropogenic contribution since 1850. These figures, of course, are highly uncertain and not particularly precise. Sufficiently so that I consider estimating climate sensitivity from temperature differences between two dates with the first date prior to 1950 to be essentially a waste of time. If you are going to make those estimates, you should greatly increase the data used to counter the uncertainties. You do this by fitting a Transient Climate Response (TCR) function to annual data as Kevin Cowtan has done. The result is a TCR around 2 C per doubling of CO2, with an Equilibrium Climate Sensitivity necessarilly greater than that.
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Owenvsgenius at 09:09 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
KR, I would like to point out that we do not posses the coverage needed to properly survey the ocean and its depth to come up with anything concrete. Our surveys currently rely on a lot of speculation
Moderator Response:[TD] You need to back up your contentions with data.
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Owenvsgenius at 09:01 AM on 18 May 2015The climate 'hiatus' doesn’t take the heat off global warming
KR, so what you are saying to Ryland is...that %100 of all warming is due to human CO2 forcing which is offset by tiny amounts of natural cooling...in other words the main driver if climate, using your reasoning, is offset by blips in natural variability...that again, naturally occurring blips cancel out that warm feeling we're all looking for. So what is the primary driver then?
Moderator Response:[JH] Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
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Owenvsgenius at 08:26 AM on 18 May 2015Ice loss in west Antarctica is speeding up
Its an interesting survey. However the title is misleading, as the Antarctic ice, to the best our ability to survey, is growing. Yes a certain peninsula, which is subject to warmer temps, by warmer I mean less than 0 C average summer temp, has lost some ice...so what
Moderator Response:[JH] Unless you can back-up your assertions with proper documentation, they are just your personal opnions which very little weight on this website. Sarcasam is also frowned upon.
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Klapper at 06:19 AM on 18 May 2015Models are unreliable
@MA Rodger #922:
"Wouldn't such a 'hot model' not run with reduced TOA energy balance?"
If the TOA energy balance was zero (incoming = outgoing), we would for that instant be neither gaining nor losing energy, so although there may be temperature change by heat transfer from one global heat sink to another, total global heat stays the same. An AOCGC model with a positive TOA imbalance (incoming > outgoing) is gaining heat, either in the atmosphere or the ocean, or ice conversion to water (or all three), but it's unlikely you would not see a temperature rise in both the ocean and the atmosphere over longer periods. The higher the positive imbalance the faster the temperature rise, although SAT rise is obviously subject to the percentage of heat sinking into the ocean vs. the atmosphere.
In fact this is what we see in SAT. Over the last 35 years the ensemble modelled temperature rise is 0.25C/decade, while SAT only rose about 0.15 to 0.18C/decade depending on SAT dataset. So both the TOA spread from model to empirical and the SAT warming rate spread agree the models look to be running too hot.
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MA Rodger at 05:36 AM on 18 May 2015Models are unreliable
Klapper @920.
You write "I like to post numbers and let people decide for themselves" which is rather generous of you. But you do also present an opinion, writing "I still think the models run hot after this exercise." This implies that in light of your "exercise" you see nothing to contradict your contention that "models run hot." Indeed, you go on to argue that your "exercise" lends support to your 'hot model' thesis. "The average error on the over the last 35 years, model TOA forcing to OHC et al is +0.27 W/^2, so the models are definitely warmer in this analysis period." (My emphasis)But your 'hot model' thesis is surely to do with the modelled global temperatures being too hot due to their modelled temperature rising too fast. Wouldn't such a 'hot model' not run with reduced TOA energy balance?
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MA Rodger at 05:30 AM on 18 May 2015Climate sensitivity is low
Tristran @357.
I must say that JoannaNova comment thread is a classic. I think they could be sitting on a new direction for comedy. "Exactly Tristan, where are the published figures on jet stream friction, where are the published figures on kinetic energy of global rainfall…. though you can calculate that one, it’s about 0.05 Watts per square meter, comprising about 10% of the imbalance energy." Never one to shirk a challenge, if raindrops hit 20mph & average global rainfall 900mm, Bobl is only a triffling 5000% out!!
As for his question, if you use the forcings from AR5 AII Table 1.2 (which are a little higher than CO2 forcing alone), & the global numbers@359 (but assuming 0.86W/m2 imbalance) you get an ECS = 2.8ºC but most folk consider energy balance methods do underestimate ECS. The figure is also sensitive to negative forcing levels with their big error-bars.
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michael sweet at 02:19 AM on 18 May 2015Climate sensitivity is low
Tristan,
I used the Northern Hemishpere data instead of the global data (my link is to the correct data). 1880 was -.22 and 2014 was +.68. That gives .90 observed and 1.6 including warming in the pipeline. That is 2.3C per doubling or 4.1 incuding warming in the pipeline. Multiplying by 1.06 gives 2.4 observed warming and 4.3C at equilibrium.
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michael sweet at 02:09 AM on 18 May 2015Climate sensitivity is low
Tristan,
If Bobl claims that his estimate is "truth telling" it is easy tp see why he has trouble at SkS.
Checking the GiSS temperature records I find that in 1880 the anamoly was -.38 degrees while 2014 was +.86 degrees (it is more accurate to do a least squares fit but Bobl did not say how he got his numbers). I find that to be 1.24 degrees since 1880. The records previous to that are incomplete and inacurate. Bobl is probably using HADCRU which is well known to underestimate warming since it does not cover the entire globe. Since this year is currently running .15 degrees above last year and there is an El Nino that will increase temperatures later this year it will not be surprising to see 1.4C globally this year. At .15/decade it will only be 40 years to the 2C disaster threshold.
Bobl knows that the current temperature is not in equilibrium with the forcing. He has left this amount out of his calculation. Estimates range around .7C in the pipeline. That makes 1.94 degrees for an estimated final temperature with current CO2 concentrations. Using 1.24 degrees I get 3.18 degrees per doubling and using 1.94 I get 4.97 degrees per doubling (!!). The IPCC estimates there is greater than 95% chance of 50% of warming being due to humans with 106% the best estimate (Bobl knows that too). The 3.18 must be multiplied by 1.06, not by .50. That rounds the estimates to about 3.2 degrees per doubling for observed warming and 5 degrees including the warming in the pipeline.
The agreement is that above 2C is a disaster, not that below 2C could be good. Warming is accelerating so I expect 2C to happen in my children's lifetime.
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Tom Dayton at 01:48 AM on 18 May 2015New study finds a hot spot in the atmosphere
Mike Mann updated his post on the hot spot. This is the last time I'm going to copy over his posts and comments. Please go to his FaceBook page if you want to read and comment more.
UPDATE to "The Tropical 'Hot Spot' and Global Warming"
In response to some interesting comments in the comment thread of my previous post, I've decided to add some additional discussion (and two new figures). Figure 1 is a modified version (from Karl et al '09) of a figure that appeared in the CCSP SAP 1.1 report "Temperature Trends in the Lower Atmosphere" in 2006 that compares the PCM model-predicted patterns of response to the various forcings (based on Santer et al 2000). What I like about this particular figure is that the tropopause (border between troposphere and stratosphere) is explicitly shown, which helps to guide the interpretation of the results. The difference in the relative vertical patterns of response to the various forcings is clear here. Greenhouse gases and Anthropogenic Sulphate aerosols show a clear mid-tropospheric amplification. Volcanic forcing does not. Note that the peak warming in the response to greenhouse gases alone (i.e. the center of the "hot spot") is very close to the tropopause, but the response to all forcings combined shows a peak "hot spot" that is well below the tropopause. That is true because the other forcings do not follow the same vertical pattern of response as the GHG forcing alone.
Figure 2 is from the same report, and it is especially instructive as it shows the response of 4 different models (trend from 1979-1999) to the same imposed late 20th century forcing changes (greenhouse gas increases are the single largest forcing contribution). A "hot spot" of sorts is observed in each case, but note the dramatic variation in the vertical pattern and in the "shape" of the hot spot. GFDL for example has a very well defined hot spot peak at 300mb (and both PCM and CCM3.0 have peaks just above 300mb), while GISS-EH (the model used in the Skeptical Science post mentioned earlier) has a peak that is centered higher up, closer to 200mb. This speaks to the importance of varying convective and cloud parameterizations that govern the dynamical responses. There is no simple, universal response common to all models subject to all forcings. And I will leave it there...
Figure 1:
Figure 2:
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Tristan at 00:30 AM on 18 May 2015Climate sensitivity is low
Apologies for this one folks. Bobl over at joannenova is adamant that he has been banned from sks for his truth-telling, and I told him I'd ask a question for him. A couple commentators now have a bee in their bonnet given I tried to address it myself, so here you have it:
In 1850 the temperature was about 0.75 deg C lower than now, the CO2 was supposed to have been about 270PPM. Now it’s 400 PPM.We know from Arhennius that deltaT = k ln(CO2-2/CO2-1)
So, therefore 0.75 = k ln(400/270) and therefore k=0.75/ln(400/270)
k = 1.91
So lets then calculate the warming for a doubling
DeltaT = 1.91 × ln 2 = 1.34 degrees per doubling between 1850 and 2014
Now the IPCC says that 50% of warming is probably coming from humans and 50 % is natural variation so if we assume that 50% of all the warming from 1850 to now is CO2 induced (which it is not, the bit from 1850 to 1950 is unlikely to be CO2 related) at best we causing just 0.77 degrees of warming due to mans gasses, and the other 0.77 degrees must be something else which won’t necessarily accumulate.
0.77 degrees per doubling implies feedback was negative over the period from 1850 to 2014.
Given CO2 warming over the last 130 PPM was at best 0.37 to 0.75 degrees and the implied climate sensitivity from that is therefore 0.77 to 1.35 degrees per doubling, therefore the magic 2 degree figure (noting that the IPCC says up to 2 degrees of warming will be positive for the human race) is likely 500 – 1000 years away from happening, why are we even worried about it?
Moderator Response:[DB] "Bobl over at joannenova is adamant that he has been banned from sks for his truth-telling"
There is only one SkS user with "bob" prefacing their user name that is banned from this venue and that is user "Bob Smith", who had his commenting privileges revoked for being a sock puppet of yet another SkS user.
Bob Smith at 18:47 PM on 18 December 2012
IPCC Draft Report Leaked, Shows Global Warming is NOT Due to the Sun
I am a retired Professional engineer, not a scientist but let me make a few comments: You have scared the governments into giving you the enormous amounts of their taxpayers’ money that you use to maintain your lavished lifestyle. For instance, the lead authors of this report will have their meetings on Tasmania Island, a place that is as far from everywhere as you can possibly get, with air fares in thousands dollars each and with huge CO2 footprint to match them while we, ordinary people, suppose to walk or bike to work. Last month there were 14,000 of you, including 7,000 environmental activists, on all inclusive holiday at the taxpayers’ expenses in Doha. And just the accommodation, air fare and meals for these activist cost some $50 million. And last year it was Rio and before that Durban and Cancun. CO2 and the resulting warming suppose to run out of control but you must be an organization with the largest CO2 footprint in the world. And money you spent has also enormous CO2 footprint for before you can spent it on your salary, reports grants and perks ,like travel, the taxpayers must generate good and services to make them. This is not how the people claiming that CO2 and warming is out of control ought to behave. You are also in a huge conflict of interest for unless you can keep the public scared of the warming your paycheques, careers and perks would be gone. And that applies to the authors as well as peer reviewers. And there is more. -
Klapper at 20:01 PM on 17 May 2015Models are unreliable
@Rodger MA #919:
There is on point on my graph where the models do seem to make more sense than the empirical data, namely the early 90's when the model shows a sharp TOA forcing reduction due to a 2 W/m^2 spike in upwelling shortwave.
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Klapper at 19:55 PM on 17 May 2015Models are unreliable
@MA Rodger #919:
"...with my noting that you are ignoring mountain glaciers..."
As you pointed out the montane glacier effect was insignificant to the graph I was producing, being 0.005 W/m^2.
"...The moderator response @911 suggested it was inappropriate for you to be posting such this work-in-progress down this thread..."
The moderator can delete my posts if it's inappropriate. I'll consider this project done and won't however post my next project which is to compare TOA net forcing with ENSO, the AMO and the PDO.
"... I ask this becuse you could well be setting yourself to support the opposite..."
I like to post numbers and let people decide for themselves. I still think the models run hot after this exercise. The average error on the over the last 35 years, model TOA forcing to OHC et al is +0.27 W/^2, so the models are definitely warmer in this analysis period.
In your #912 post you state OHC to 2000 metres weighs in roughly at 1 W/m2, but I disagree. The actual number is 0.89 for a trend centred on Nov 2012 and 0.80 for a trend centered on August 2012. However, I think the issue with your choice of period is that it starts with a strong La Nina and ends with an El Nino (which I intend to investigate further). So is it representative of longer term forcing elements?
Moderator Response:[JH] Please do not use the SkS comment threads as a "blackboard" for your next project.
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MA Rodger at 18:48 PM on 17 May 2015Models are unreliable
Klapper,
I would caution you to slow down with your inputs into this comment thread and consider what you are responding to, rather than bash out the first rebuttal that come into your head.
As an example of this, your response @913 began @910 with my noting that you are ignoring mountain glaciers which you indicate @911 you are happy to do yet @912 I call it 'airburshing away part of the method.' Your response @913 sets out with this in mind but fails to deliver. Instead we get an account of what you see as failings in Hansen's analyses.
The moderator response @911 suggested it was inappropriate for you to be posting such this work-in-progress down this thread. Given these recent responses of yours are proving so inadequate, I am inclined to agree.
Perhaps then it would be better to ignore direct comment on your analysis and rather ask why you feel any result that were obtained has any bearing on what you call "my point was that the models run too hot."? I ask this becuse you could well be setting yourself to support the opposite.
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Tom Dayton at 14:42 PM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Curtis: Mike Mann read your most recent response, and replied:
After having read Tom's response to my response at SkS, I'm now not inclined to take the critique too seriously. First of all, his argument that there is little tropospheric IR signal in the Robock radiative forcing series is just wrong. The positive IR radiative forcing anomalies near 300mb (well into the troposphere) at the equator are similar in magnitude to the negative short-wave anomalies at the surface. This is not neglible. He has misinterpreted Figure 1 shown above--this is an adaptation of the key IPCC AR4 figure on fingerprint detection (based on simulations w/ PCM by Santer et al '03). I'm surprised he doesn't recognize it, since it is actually featured in main post at SkS on the hot spot. Over the shorter more recent interval shown in Santer et al '13, the volcanic surface forcing is indeed positive (that is a completely different interval and thus very different drend from the 20th century trend analyzed in Santer et al '03). But the sign of the net surface forcing, whether negative (for the 20th century trend) or positive (for the more recent trend), isn't the point. The point involves the vertical pattern of the response. And there is no way to reconcile that pattern of response w/ the GISS result Tom shows in his plot. Fully recognizing the complicating issue of the TMT/TLT vertical weighting functions (which Santer et al take some pains to deal with in their interpolation scheme) there are real discrepancies here. Just compare the GHG signal in Santer et al '13 (which shows a hot spot) and the volcanic (which doesn't, and shows a change of sign at 500 mb, which is very close to the 595 mb PEAK of the TMT weighting function--if there were a mid-tropospheric hotspot, it should be seen in TMT). That discrepancy cannot be explained away by the vertical weighting functions. So I think I'll go with the CMIP5 results shown in Santer et al '13 over the results of a single (GISS) model, which is certain to have its own peculiarities w.r.t. convective parameterizations, etc. Suffice it to say, I feel comfortable stating that my original post stands without need for any modification. And since Tom C chose to question my qualifications for talking about climate dynamics and climate models, I'll let the roughly 90 of my 170+ publications that deal with climate modeling and climate dynamics speak for themselves.
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Tom Curtis at 11:46 AM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Dayton @4-7:
1) The model used was the GISS Model E vIII, as can be found out by tracing back the links through the Real Climate link I provided. As such I suspect it is the same model that was used for the second figure in Mann's original article, with Mann's figure differing in being rapped around the hemicircle, and not being to scale relative to the real thickness of the atmosphere. Importantly, Mann's figure also differs in showing the effects of historic forcings (which are very different in magnitude between the various forcings) rather than the effects of forcings of approximately equivalent magnitude:
2) Santer et al (2013) shows historical forcings from Jan 1979 to Dec 2012. Santer's graph shows an overall positive volcanic forcing, with a negative forcing in southern polar latitudes, and no forcing in northern polar latitudes. That is, it shows a very different regional pattern (and a far smaller forcing) than does Pinatubo. Consequently I would hesitate to draw any inference from the differences in pattern between GISS model E and the CMIP5 mean. Such differences are as likely to be due to the different geographical pattern of the forcing as to any difference in model physics.
3) Each of the TMT (Channel T2), TTS (Channel T3), TLS (Channel T4) include a portion of the lower stratosphere in their weighting functions:
The result is that all are downgraded by opposite signed signals contaminating the data. This is particularly the case for the TMT (T3) channel which obtains approximately a third of its data from the stratosphere, and hence with opposite sign to the upper tropospheric signal. (This is also why certain deniers prefer to use the TMT channel as representative of tropospheric temperature trends.) As Santer et al graph by anomalies for these channels, I presume they have taken a weighted temperature function by altitude to match the weighting of the satellite channels, and will suffer the same problem. This by itself would lead us to expect a reduced TMT temperature response relative to the TLT response as shown by Santer et al, even with the GISS Model E temperature response.
4) Beyond that, it is possible that the CMIP5 models show a different response to volcanic forcing, and that consequently the Real Climate article and GISS model E data are out of date. If Mann could get Gavin Schmidt to comment on that point, I would be very interested. As it stands, however, I do not find his counter argument convincing, and nor is this topic close enough to Mann's core areas of expertise that I would take him as an authority on this aspect of AGW.
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Tom Dayton at 10:05 AM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Curtis: Mike Mann continued at FaceBook:
I suspect the model simulations shown by Tom may have a very different convective parameterization than the models employed in the CMIP5 average shown by Santer et al. The latter is consistent with maximum precipitation rate (and latent heating) in the lower-to-mid troposphere, with greater stability (and less latent heating) in the upper troposphere, while the results shown by Tom suggest a great degree of convective heating and instability all the way to the tropopause. The convective dynamics described by the two situations are greatly different.
I'm interested to hear Tom's response. I open to being disproved on this, but thusfar I'm troubled by the inconsistencies in what he has posted vs. what is shown in the peer-reviewed literature by Santer and others...
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Klapper at 10:04 AM on 17 May 2015Models are unreliable
@Tom Curtis #917:
"...and less than the error you made in correcting him @913.."
I didn't actually correct him at 913; I stated I thought he was double counting but did not quantify the amount he was double counting by. However, in my graph presented in #916, I use the 0.068W/m^2 as the total below 2000 metres, as per Purkey & Johnson Table 1, and elimate the 0.027 W/m^2 for the > 4000 m component of heat gain, so my assumption for heat gain since 1990 in my graph is that > 2000 m OHC gain = a constant 0.068W/^2.
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Tom Dayton at 10:03 AM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Curtis, I'm being go-between you and Mike Mann, because though he is popping over here to read your comments, he can't post here because he does not have an SkS account and doesn't want to get one because he already is too busy. (I don't buy that excuse, because I know the only way he can accomplish all the things he already accomplishes is by having an army of clones of himself. What's one more clone?) He wrote on FaceBook:
Tom: in fact, I've having a lot of trouble reconciling the trends shown in (the other Tom's) post at SkS and this plot from Santer et al '13. Tom's plots show maximum amplitudes in the way upper troposphere, while Santer's corresponding plots show greatest amplitudes in the lower-to-mid troposphere. In Santer's plot, the SIGN of the temperature anomaly associated with volcanic forcing actually reverses at the mid-troposphere (roughly 450 mb)! Perhaps there is something I'm missing or misunderstanding about the plots Tom has posted. They certainly don't seem consistent w/ Santer et al. The "hot spots" (or "cold spots" if you like, depending on sign of forcing) are located at greatly different altitudes.
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Tom Curtis at 09:09 AM on 17 May 2015Models are unreliable
Klapper @915, that is far from obvious. Specifically, Purkey and Johnson write:
"We make an estimate of the total heat gain from recent deep Southern Ocean and global abyssal warming by adding the integral of Qabyssal below 4000 m to the integral of QSouthernOcean from 1000 to 4000 m (Table 1). The 95% confidence interval for Qabyssal is calculated as the square root of the sum of the basin standard errors squared times 2, again using this factor because the DOF exceed 60. The warming below 4000 m is found to contribute 0.027 (±0.009) W m−2. The Southern Ocean between 1000 and 4000 m contributes an additional 0.068 (±0.062) W m−2, for a total of 0.095 (±0.062) W m−2 to the global heat budget (Table 1)."
That is exactly what Hansen did, and as he was following the recomendation of Purkey and Johnson, prima facie he was correct to do so. Further, Levitus et al (2009), from which Hansen obtains his 0-2000 meter data, write:
"We acknowledge that ocean temperature data are sparse in the polar and subpolar regions of the world ocean but we still refer to our OHC estimates as global. We do this because the OHC estimates are volume integrals so that only relatively small contributions are expected from the polar regions to our global estimates."
That appears to suggest that like Levitus et al (2005) (of which Levitus09 is an update), Levitus et al (2009) does not include OHC for the Southern Ocean.
If you want to make the case that the 1000-2000 meters of the Southern Ocean from Purkey and Johnson should not be included, you need to show either by obtaining a definitive statement from Levitus, or by comparing the gridded data, that Levitus et al (2009) included 0-2000 meter data for the Southern Ocean. Absent that, and given that excluding warming through too sparse sampling is as much of an error as including too much by double dipping, it appears that Hansen has proceeded correctly.
Finally, even if he has inadvertently "double dipped" the error involved is appreciably less than the error of the total calculation, and less than the error you made in correcting him @913.
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Klapper at 08:57 AM on 17 May 2015Models are unreliable
@All #91x:
Here is a graph of the total inputs. OHC 0-2000 is from NODC, pentadal in the early years and quarterly since 2005, land is from Beltrami et al 2002, > 2000 m OHC is from Purkey & Johnson, ice melt is from PIOMAS/my own model for Antarctica sea ice, Ice sheet melt is from GRACE and earlier some generic Wikipedia numbers, atmosphere is from RSS TLT. I started using 5 year trends, then switched to 6 since that is what Hansen used, but then switched back to 5.
Five years might still be a bit short. OHC seems susceptible to even quarterly steps in the rolling trend. For example the 5 year trend centered on August of 2012 is 0.89 W/m2, while May of 2012 is 0.80 W/m2. I think this is the effect of ENSO causing wobbles in heat gain.
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Klapper at 07:37 AM on 17 May 2015Models are unreliable
@Tom Curtis #914:
"...in table 1 they also mention 0.068 W/m^2 globally for below 2000 meters..."
If that's the case then Hansen has still made a mistake has he not? He used 0.068W/m^2 for 2000 to 4000, but that number is from 2000 to bottom is it not? In other words he double counted the 0.027W/m^2.
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Tom Dayton at 07:23 AM on 17 May 2015New study finds a hot spot in the atmosphere
Mike Mann on FaceBook followed up in his reply to Tom Curtis's above comment:
I did take a look at the piece. First of all, I am not ignoring convective transport of heat. What I am saying is that the convective transport of heat (which would normally lead to a "cold spot" in this case) is offset by the radiative forcing at least partly, eroding (if not erasing entirely) the cold spot. Now, I don't know the details of the calculation he's showing, because he hasn't stated where it comes from. I'd really like to see the details, i.e. how the forcing was implemented, etc. because it appears to be at odds, in terms of the pattern of response, with that shown in Santer's work.This figure is from Santer et al (2013) PNAS. Look at the amplitude of the response to the volcanic forcing events in the mid-to-upper troposphere vs the surface, e.g. Pinatubo, we see about -0.25C peak cooling for "TMT" (mid-to-upper tropos) and about -0.5C peak cooling in the lower troposphere. I don't see how that can be consistent w/ what Tom is showing in his figure.
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Tom Dayton at 07:18 AM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Curtis, I asked Mike Mann to reply to your comment. Here's what he wrote over on his FaceBook post:
I've explained (and shown) carefully in the post above that there is no hotspot associated with a global warming trend resulting from changes in volcanic forcing (this is also true for ozone forcing-related trends). The problem with the RealClimate post is that it doesn't acknowledge this exception to (Gavin's) argument. The argument works for GHG, it works for El Nino, it works for Solar. IT DOES NOT WORK for volcanic forcing (or ozone forcing, or any forcing which has a similarly complex vertical radiative forcing profile associated with it). I have confirmed my take on this with Ben Santer.
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Tom Curtis at 06:45 AM on 17 May 2015Monthly global carbon dioxide tops 400ppm for first time
PluviAL @12, I am rather less sanguine than you about extracting water from the atmosphere in deserts, which are deserts (after all) because of the low relative humidity of the atmosphere over those latitudes. The only technique I know of that could reliably extract the moisture woud be to be to massively cooling the air, a process that will require a lot more energy than could be extracted by the condensation of water. Indeed, I suspect that extracting energy from water condensation would run up against entropy problems very quickly, and hence also not be feasible. However, if you invent a device that can do it, more power to you. On this I would be happy to be proven wrong, if only for the opening up of agricultural land on the fringes of deserts, and to regreen regions recently suffering desertification such as the Sahel.
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Tom Curtis at 06:30 AM on 17 May 2015Models are unreliable
Klapper @913, you are mistaken about Purkey and Johnson. Specifically, while they mention 0.027 W/m^2 below 4000 meters globally, and 0.068 below 1000 meters "south of the Subantarctic Front of the Antarctic Circumpolar Current" in the abstract, in table 1 they also mention 0.068 W/m^2 globally for below 2000 meters. That the two values coincide does not make it a mistake to use the second figure (from table 1) in estimated OHC change below 2000 meters.
Indeed, Purkey and Johnson quantify the below 1000 meters Antarctic change in OHC because prior estimates of OHC failed to determine the change in polar waters. Ergo, arguably, the 0.032 W/m^2 between 1000 and 2000 meters in the Antarctic should also be added. Indeed, Purkey and Johnson do in fact argue that in the conclusion, estimating that the total contribution from Antarctic Bottom Water (ABBW) to be 0.1 W/m^2 globally averaged. Therefore Hansen may have underestimated additional contribution to OHC based on Purkey and Johnson's paper. Whether he has or not depends on exactly which 0-2000 meter estimate he used, and whether or not it included the 0-2000 meter warming in the Antarctic.
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Tom Curtis at 06:03 AM on 17 May 2015New study finds a hot spot in the atmosphere
Tom Dayton @1, in this case Michael Mann is wrong. As the RealClimate team have explained, the tropospheric hotspot is a result of the lapse rate feedback, ie, the change in decrease in temperature with altitude due to the increased heat capacity of the atmosphere resulting from a higher absolute humidity with increased warming. The RealClimate team illustrate this by comparing expected warming and cooling by latitude and altitude for a doubling of CO2, and an equivalent increase in solar forcing:
The patterns are broadly similar, although the CO2 forcing results in a stronger arctic warming (but note the difference in scales).
Unfortunately, it is not possible to similarly compare the result of CO2 forcing to a loss of background volcanic aerosols as the background level of aerosols is not that large. We can however compare the cooling due to a loss of 50% of CO2, and due to a 1/3 rd Pinatubo level volcanic forcing:
As you can see, for these negative forcings, the patterns in the tropics are very similar. At the poles, however, the increased volcanic aerosols result in stratospheric cooling, unlike the stratospheric warming resulting from reduced CO2. Further, the peak arctic cooling is further south with volcanic aerosols. Again the scales are different, but the forcings are not SFAIK of equivalent strength. The patterns, however, are the important feature.
The polar stratospheric cooling with increased volcanic forcing may be partly due to the location of the aerosol cloud, which is not global (and was tropical in Pinatubo's case) and ergo will have different regional effects. It is, however, at least partly due to a decreased warming of the stratosphere from upwelling IR radiation due to the cooler troposphere not being compensated by increases short wave radiation reflected of the stratospheric aerosols due to the low insolation at the poles. Ergo, it is at least in part a feature we would expect of any volcanic cooling, although the exact boundaries of warming and cooling zones will vary depending on the latitude of the volcano causing the cooling.
The important thing about this comparison for our discussion is that there is definitely a tropospheric cool spot for both reduced CO2 and the volcanic forcing. As can be seen by comparing the doubled CO2 and halved CO2, the patterns of change in temperature are the same for both. It is just that the signs of the change are different. The same would be true for a reduced volcanic forcing. That is, it would show a similar pattern to the increased volcanic forcing, only with warming where the volcanic forcing shows cooling, and vice versa. Ergo a reduction of background volcanic aerosols would definitely result in a tropospheric hotspot, contra Mann.
I believe Mann has been decieved on this because:
1) He fails to note that the observed heating for Pinatubo through radiative absorption and re-emission of the aerosols is primarilly above the 100 mb line, ie, the tropopause:
2) And because he focuses only on radiative heat transfer, ignoring the convective heat transfer effects that drive the change in lapse rate.
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Klapper at 05:46 AM on 17 May 2015Models are unreliable
@MA Rodger #912:
"...suggests some part of the method employed in Hansen et al (2011) Section 9 is being airbrushed away..."
Hansen made an error in Section 9 of Hansen et al 2011. Here's his quote: "The third term is heat gain in the global layer between 2000 and 4000 m for which we use the estimate 0.068 ± 0.061 W/m2 of Purkey and Johnson (2010)."
The 0.068W/m2 from Purkey & Johnson is not for the 2000 to 4000 zone, but the 1000 to 4000 zone, only in the southern ocean, which means he is double counting some heat (1000 to 2000 in the southern ocean). The Purkey & Johson paper is clear about this, as is the text in Hansen et al 2011 elsewhere in the paper. Keep in mind since the J&P 2010 paper is showing neglible abyssal warming in the northern ocean (see Figure 8 in that paper), its not clear the 1000 to 2000 overlap in the southern ocean is a wash with the "missing" 2000 to 4000 in the northern ocean.
As for your last comment: "which weighs in at roughly 1.0W/m2 (2010-2014)", I checked the numbers and the W/m^2 is 0.89. However, keep in mind the model CMIP5 is still increasing and so the model projected imbalance average 2010 to 2014 is 1.04, plus sea ice has been gaining 2010 to 2014 so you have at least one of your factors going negative, albeit one of those that have negible leverage.
You've stated there are "problems" with using TLT as a calculator for net energy change in the atmosphere but surely it's better than what Hansen did which was to use a metric representing maybe the lowest 5 metres of the atmosphere. TLT and TMT combined would likely be the best and certainly more representative of the atmosphere than any SAT data set which has much poorer spatial/volume coverage.
As for land heat, I would not use Hansens method. I think actual data from the boreholes is better, than a heat flux model. Using the 2002 paper by Beltrami et al, the heat flux from borehole temperature profiles was .039W/m^2, but that is land only. If you calculate this to a global TOA basis (and delete the ice covered continents Greenland and Antarctica) you end up with an average heat flux into land of only 0.010 W/m^2, making it another neglible component of the global energy balance. The recent decadal flattening of the surface temperature would indicate land heat flux is likely no higher now than the 1950 to 2000 average which is the basis of the Beltrami number.
In summary, my point was that the models run too hot. It is true that recently OHC gains come close to the model TOA imbalance, but then that happened back in 2002-2003 also and then the rate of ocean heat gain faltered somewhat. The bottom line is that even now, using very short periods to estimate the imbalance, the projected TOA imbalance of the models is higher than the actual TOA global energy imbalance as best we can calculate them.
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Mal Adapted at 04:48 AM on 17 May 2015Lukewarmers – the third stage of climate denial, gambling on snake eyes
OPOF, I'm pretty sure that the ostensible rationale offered by some lukewarmers is disingenuous. They know it's unacceptable to leave the cost of AGW to be paid by poor people in other countries. When they assert that the costs of AGW won't be high enough to justify mitigation, what they really mean is that they don't expect the costs to themselves or anyone they care about to be high. Their attitude (for which there is ample historical precedent, to be sure) is expressed by the Deacons' grace: "Lord bless me and my wife, son John and his wife, we four and no more."
Such people will only support mitigation if they can be persuaded that their personal costs will in fact be high. If they see their or their families' lives, homes or livelihoods threatened by heat waves, droughts, severe storms and rising sea levels, they'll call for action.
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One Planet Only Forever at 03:06 AM on 17 May 2015Lukewarmers – the third stage of climate denial, gambling on snake eyes
Mal Adapted,
It is worse than those people not caring about the cost someone else will pay.
Every economic evaluation that compares 'current day benefits that do not truly focus on assisting the least fortunate advance to a sustainable better future' with 'some calculation of future costs' is fundamentally unacceptable on two counts.
- Any unsustainable and damaging activity like the burning of fossil fuels really should only be for the temporary effort to transition the least fortunate to a sustainable more fortunate future. Global GDP has grown faster than the population, even African GDP has grown faster than the African population, and the wealthiest have gotten much wealthier yet many people remain stuck in desperate poverty.
- It is unjustifiable to compare the benefits obtained by some in a current generation with the resulting costs and damage that will be faced by future generations. And it is almost criminal to overstate the benefits that a current generation would have to give up and compare those with understated future costs and consequences, especially when ignoring the damage done to the environment that is not considered because it has no current legal or economic cost evaluation method (the robust diversity of life is priceless, and that is why it is ignored by the 'cost comparers')
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Tom Dayton at 02:03 AM on 17 May 2015New study finds a hot spot in the atmosphere
Interesting point in the comments at HotWhopper, that the term "tropospheric hot spot" seems not to be used scientifically. Implications of failure to use that term are more than merely semantic.
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Tom Dayton at 02:01 AM on 17 May 2015New study finds a hot spot in the atmosphere
Mike Mann has an excellent description of this new study's relevance to AGW. In brief,
What's the punchline? Well, if global warming really *were* due to a (natural) decrease in volcanic activity over time (rather than due to an anthropogenic increase in greenhouse gases), then we would expect to see an increase in global surface temperatures WITHOUT any mid-tropospheric "hot spot".
In the end, then, the confirmation of a "hot spot" in this latest study by Sherwood and Nishant isn't completely irrelevant to the issue of human-caused climate change. While it may not be a unique fingerprint of anthropogenic greenhouse gas increases, it does nonetheless potentially allow us to rule out at least one possible suspect (changes in volcanic activity). It turns out that anthropogenic changes in ozone (both tropospheric, as a surface pollutant, and stratospheric, as a result of stratospheric ozone depletion) are another potential "forcing" of climate change that does not have a clear "hot spot" signature as part of its fingerprint.
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michael sweet at 01:49 AM on 17 May 20152015 SkS Weekly Digest #19
Slcochran,
Perhaps you want to read about the Denial 101 course currently being run by John Cook, the originator of Skeptical Science. Come back and comment again after you read at least the course description.
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slcochran at 00:01 AM on 17 May 20152015 SkS Weekly Digest #19
You're going at this all wrong. The people who use critical thinking already acknowledge anthropogenic global warming, but you're not influencing those who are bound up by their belief systems. I'm surprised that everybody on SkS seems to be denying science! (jsut to tweak your nose).
Neuroscience tells us clearly that throwing facts at a belief system only enforces that belief system. They don't accept your facts and arguments because they don't want to accept them as it challenges their preconceived notions, and change to that belief system is threatening to them.
SkS would be even more useful if you began to tackle framing. Some references: The Righteous Mind- Jonathan Haidt, Moral Politics, How Liberals and Conservatives Think- George Lakoff, The Republican Brain- The Science of Why They Deny Science- and Reality- Chris Mooney, The Political Brain- Drew Weston. Yes, these are all politically oriented, but the science is the same. And, yes, they do point our the preponderance of irrational belief systems among Republicans, but I believe that the vast majority of climate change deniers belong to that particular party (I don't have a reference for that statement, but I don't have a reference that supports my claim that the sun comes up in the East either).
Moderator Response:[JH] Please enter the word "framing" into the SkS search box and read all of the articles that are identified. It's always best to "look before you leap."
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MA Rodger at 19:37 PM on 16 May 2015Models are unreliable
Moderator Response @911.
The exercise being embarked on is described by Klapper @908 thus - "I have been reviewing Hansen et al. 'Earth's energy imbalance & Implications' (2011) and think it would be a useful exercise to update this paper with the very latest data."I am assuming this exercise addresses specifically Section 9 of that paper although I fear the selective intent indicated @911 suggests some part of the method employed in Hansen et al (2011) Section 9 is being airbrushed away. There is also some issues with the use of TLT, the use of global land ΔSAT for the Land Heat Uptake, etc. However, while this analysis is not being addressed with the rigour it requires, all the palaver is a tiny a bit pointless. The update will, after all simply show that net energy imbalance is still overwhelming recorded in ΔOHC(0-2000) which weighs in at roughly 1.0W/m2 (2010-2014) compared with 0.65W/m2 (1993-2010) & 0.42W/m2 (2005-2010) in Hansen et al (2011).
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PluviAL at 12:05 PM on 16 May 2015Monthly global carbon dioxide tops 400ppm for first time
Tom Curtis @11, 100% in agreement with C-Tax to engage inventiveness of market.
@10, Thanks for excellent response, right as usual. My oops; top-of-hat calculation took the whole earth's surface instead of only land area. Forestation takes time, but plentiful water can reduce it by orders of magnitude. Living in the desert too, I have converted rocky lots into gardens in 2 years. Also, you are right 8kg/m2 is very conservative for sequestration.
Our reason for difference in appreciation of this line of attack is that I assume water can be pulled from the atmosphere at a negative cost. Process will produce electrical power as it is pulled out with nature's process. J. P. Espy's convection concepts is a starting ides. He was a founder of the science of meteorology. We know a lot more today than in the 1800. Burning forests is unnecessary, solar and latent heat energy are more than sufficient, and flow architecture can surpass natural precipitation production rates (conventional theory on this). As one byproduct, at 0.05% electrical production from free energy flux, a plant can produce more than a nuclear power plant, at <1/20th the cost, and mostly positive externalities. I'm working on a patent for that.
If it works, we can transport water in unlined canals specifically to percolate excess water from the oceans onto the earth, while absorbing CO2, and increasing forestation. I think the net radiation from earth increases with forestation, especially, if water for such growth is squeezed out of the subtropics as envisioned. The process concentrates heat in the upper atmosphere to radiate at k-temp difference to the 4th power.
Finally, I totally concur that desert habitat must be protected, but be we can afford to lose a lot more, hopefully redundant, desert than tropical forest at this time. Before proceeding with any of my ideas I expect many PHd's on each topic you point out to consider externalities.
A carbon tax, along with civic infrastructure improvement (laws which allow us to exclude, and move out troublesome people from communities, or with true rehabilitation which includes philosophical reprograming, nutritional re-regimentation, etc... etc... can allow for much more enjoyable walking cities and integrated communities. Such harmonious high density communities will be the biggest factor in reducing energy consumption as we confront the topic in full force at the end of the century. Markets can also be involved in this. Markets can also make this wild sounding idea practical and take the nasty sides out of it. ( I have a BA in sociology... but don't tell anyone from my U I am thinking these heretical thoughts.)
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Mal Adapted at 09:37 AM on 16 May 2015Lukewarmers – the third stage of climate denial, gambling on snake eyes
The loudest deniers, I am speculating, are doing it, even though they don't believe it, because inwardly they have been convinced that we don't need to do much, if anything. However, as political animals, they know that selling the public that is a weak flawed message. FUD works better to achieve their ends.
I don't think it strains credulity to suggest that Inhofe, Morano, Monckton inter alia understand perfectly well that the costs of AGW will be paid by someone, sometime, but they just don't care. They'll say whatever they think will maximize the profits of their patrons in the short term.
Knowingly making counter-factual assertions for personal aggrandizement is the second-oldest profession, after all.
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Klapper at 06:45 AM on 16 May 2015Models are unreliable
@MA Rodger #910:
No, I hadn't forgotten it. I just don't have a database to calculate it from (that I know of). Neither do I know of a database which estimates minus 2000 m heat content. I think I will do my own calculations of the land heat flux, and present all what I have calculated so far (0-2000, sea ice melt, continental ice melt, troposphere heat gain/loss and present that total W/m^2 forcing. The truth is that some components, like montane ice melt are less than the thickness of the line on the graph at these scales (as becomes readily apparent when looking at either my graphs or Hansen et al 2011 Figure 12.
Moderator Response:[JH] What exactly are you trying to accomplish with your calculations? What do they have to do with OP? Perhaps you should consider creating your own website to fully display what you are doing rather than expecting SkS readers to give you feedback on your "works-in-progress" on our comment threads.
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MA Rodger at 05:09 AM on 16 May 2015Models are unreliable
Klapper @909.
Do remember there is significant land ice melting that isn't sat on either Greenland or Antarctica. See AR5 Figure 4.25 which suggests such sources added some 4,500Gt to ice loss in 18 years = 250Gt/y. That would add about 0.005 W/sq m to your totals.
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Tom Curtis at 04:55 AM on 16 May 2015Monthly global carbon dioxide tops 400ppm for first time
An addendum to my @8, I should note that I am excited about new developments in battery technology. It is not that I think they are the way to a renewable future. It may turn out that Audi's e-diesel is the more economic option for transport, and systems similar to Isentropics pumped heat storage (both of which also excite me) are the better solution for standing power systems. What I want to see is multiple such developments competing in a world with a price on carbon. With such competition, the most economic overall system with the best side benefits will develop.
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Tom Curtis at 04:44 AM on 16 May 2015Monthly global carbon dioxide tops 400ppm for first time
PluviAL @8, according to wikipedia, the total land are of the Earh is 148.94 million km^2. The deserts of the Earth represent about a third of that, or 43.97 million km^2 if we sum the areas of the world's 10 largest deserts. That, however, includes 14.2 million km^2 from the Antarctic Desert, and 13.9 million km^2 from the Arctic desert. If nothing else, I think in any plan to tackle global warming we would want to keep both the Antarctic and Arctic deserts frozen (and have no choice in the short term for the Antarctic desert). That leaves approximately 20 million km^2 as the total available desert area for reforestation.
With a difference of C storage of 8 Kg per m^2, reforesting the 20 million km^2 would sequester at least 160 GtC, or the equivalent of 34 ppmv of atmospheric CO2 considering only the retained fraction in the atmosphere. That would indeed be a substantial contribution to combating global warming, but represents only 40% of the difference between current total cumulative emissions and the trillion tonnes of Carbon which is the upper limit to give us about a 2 in 3 chance of avoiding more than 2 C warming. Your C sequestration estimates are conservative, so it would not surprise me if you could double that, but not through reforesting more desert as there will not be more desert to reforest.
Having said that, reforesting deserts is a slow and complex process. You cannot plant trees in the Sahara and expect them to grow. You first need to build up a reasonable soil quality by planting arid friendly grasses. This would be a project over decades, and possibly centuries. We do not, however, have decades so the program, if pursued, would be a small supplement for mitigation by conversion to renewable technology, not a substitute for it.
Further, the energetics and engineering challenge of providing pipelines to water 20 million km^2 would be massive, not to mention the ongoing energy demands of desalinating and pumping the water. In addition, desert has a much higher clear sky albedo than does forest. Therefore your project could substantially increase the amount of solar energy absorbed. This is not entirely clear in that forests have much greater cloudiness than do deserts, but that in turn points to a substantial greenhouse effect from those clouds, and from the increased humidity in the formerly desert regions in general. It is beyond me to estimate the total forcing from such a project, but it may well be larger than that from the carbon sequestered. Finally, having grown up in a semi-desert, I have a fondness to arid landscapes. It is certainly not clear to me that we should condemn all the worlds desert species to exinction in our efforts to tackle global warming, as your plan would require.
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Xulonn at 04:00 AM on 16 May 20152015 SkS Weekly News Roundup #20A
After reading the David Roberts Vox interview with libertarian guru Jerry Taylor, I'm glad to find out that some libertarian thinkers are staarting to lea towards supporting a carbon tax. However, when Taylor says " the credible climate scientists — Dick Lindzen, [Pat] Michaels, Judith Curry, Bob Balling," I realized that he has a long ways to go to recognize scientific reality.
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