Arguments
Recent Comments
Prev 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 Next
Comments 41501 to 41550:
-
Elephant In The Room at 19:22 PM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
@dave 123 (#37)
Responsibility for details. I don't need to duplicate countless graphs on here to demonstrate our previous relationship with Co2. Now, if you want to tell me that the average global temperature isn't 22 degrees or that the current level of Co2 isn't the lowest it has been for 1 of 3 periods over the last 650 million years then I suppose I should go and find a graph for it. Do you really want me to do that?
This thread is asking 'contrarians' to provide scientific evidence that something doesn't exist when there isn't irrefutible evidence that it does. There is more credibility in referring to (if that's not sufficient) our previous temperature record.
We as humans are destroying this planet and everything else that lives on it. We cannot feed ourselves as it is. 10 percent of children in the UK for example live in poverty. We also cannot provide our current energy needs. Carbon dioxide emmissions follow from that because we currently need to and have to burn fossil fuels. There is no escaping it. I would rather Co2 wasn't coughed up into the atmosphere but that isn't going to happen. Furthermore I don't believe the net effect is as great as is being suggested. I am entitled to that opinion and that is what I say.
It is easy for everyone on here to talk about 'scientific evidence' when your view is the evidence of an army of climate scientists. Given that there is a distinct absence of investigation into the merits or not of climate science it will always be a one sided debate. If by association that makes you right and me wrong then it is very sad state of affairs indeed as let's be honest the view of the IPCC has just upped its belief to 95 percent from 90 percent. While there is still that uncertainty people shall continue to question the a science.
I am posting on a website that clearly supports the view that man made climate change is occurring. In the same way, if I had argued for man made climate change on a site that refutes man made climate change I would expect the same reaction. And here lies the problem. This is why there will never been any agreement.
Can the moderators just clarify the posting rules. Is it a rule that you must provide a graph every time you want to question a given subject? It seems that I am receiving quite a bit of back lash for sharing my opinion on a subject matter?
Also, would calling someone a tone troll also be an example of an ad hominen remark?
Not a very friendly welcome I have to say. I wasn't rude to anyone was I? Or does offering alternative views automatically make you a troll. (-snip-)
Moderator Response:[DB] "Is it a rule that you must provide a graph every time you want to question a given subject? It seems that I am receiving quite a bit of back lash for sharing my opinion on a subject matter?"
This venue is based in the scienctific method and discusses the science of climate change, from the standpoint of what the primary literature has to say about it. Every article here at SkS references the primary literature via hyperlinked text. Discussion in the comment threads is based on increasing the level of understanding of that science, hence the participation of subject matter experts and other talented individuals.
You will find that opinions are welcome here, but opinions that differ from the primary literature not themselves based on peer-reviewed articles themselves appearing in the primary literature are essentially caterwauling. And will then be treated as such. Repetitious behavior in this regard contravenes the "No Sloganeering" portion of the Comments Policy; which, based on your subsequent comment you have indeed read.
Future comments by you will be held to adherence to that policy with increasing rigor.
"would calling someone a tone troll also be an example of an ad hominen remark"
That would depend upon the context used. If used verbatim as delineated by you, likely so. Please provide a link to the specific instance you denote. Generally, ad hominem refers to "to the man" instead of to the argumentation used by the person. To call someone's behavior and comments an example of tone trolling might be unhelpful in improving the dialogue, but is not ad hominem.
Tone trolling snipped.
-
MA Rodger at 18:13 PM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Jubble @43.
I would strongly disagree with your statement that "there isn't as much genuine science to refer to" within the theorising on a contrarian site. I would suggest that on such sites there is actually no genuine science to refer to whatsoever.
It is of course possible to point to scientific papers that appear to fit the bill. As an example of these, Wyatt's "Stadium Wave" hypothesis was referred to @18. But will this "Stadium Wave" hypothesis stand up to proper scrutiny? As I am a little familiar with the profiles of PDO & AMO before they have been converted into pretty harmonic waves, and also the post-2000 data, my answer is a definite "No it will not!"
Because absolutely none of the hypotheses or analyses paraded on contrarian sites stand up to proper scrutiny, with such an asymmetry, how can this be a debate with two sides? It is not. It is better characterised as 'one side' refusing to accept the evidence presented by the other but unable to provide a reasonable argument for such a refusal.It would be good if there were a "third way" to address this impass but tackling AGW is not a straightforward task. (If it were, we would just tackle it, like we did CFCs.) Tackling AGW is going to require changes that many will not immediately consider desirable. So if you don't see AGW is a problem, you will resist such change rather than support it. And a large section of the public, of the media, of our politicians are still unable to see AGW as a problem. (An example of such change and resistance, local to me, planting 175 sq km of sea with wind turbines 20 km off shore has turned the county into a hot-bed of NIMBYs. To them cutting carbon emissions by 750KtC, equal to half the county's total carbon footprint, that counts for nothing.)
This post argues that contrarians owe the world a genuine scientific explanation. To date they have presented no "genuine science" but instead make fools of the world by continually presenting forgeries.
If you cannot make good a debt you owe, you can be declared bankrupt. I think the time is long overdue that contrarians are declared bankrupt. And that is why I brand them deniers. -
Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Stealth - "I’m just curious, what is your background?"
An Argument from Authority is a logical fallacy - it's the strength of the evidence and argument that matters, not the credentials of the person presenting a position. And regardless of your background, you have not supported your posts.
-
Levitus et al. Find Global Warming Continues to Heat the Oceans
Eric (skeptic) - There are, quite frankly, a number of misconceptions present in your last post.
"The latter paper also notes that the accuracy of temperature measurement was 0.002C so measuring a 0.002C change is problematic." - Incorrect. You seem not to understand how the margin of error changes with multiple measurements, the law of large numbers. Measurement error decreases with the number of samples, with the rough proportion of 1/sqrt(n). The uncertainty of a single measurement is a vast overstatement of the uncertainty of multple measurements.
WRT to sampling grid size, regardless of whether or not the sample spacing is fine enough to resolve individual 'salt fingers', the mass effect of heat transfer is quite measureable. And that holds whether or not the phenomena driving the mass transfer of energy is below the scale requiring parameterization in a model - if it has a significant effect, that will show up in the larger scale measurements.
The core of your post, however, appears to be a claim that there are inaccuracies not accounted for in Levitus et al and the literature in general, inaccuracies sufficient to invalidate the presented data. I would strongly suggest you actually read Levitus et al 2012, in particular the appendix labeled "Error Estimates of Objectively Analyzed Oceanographic Data", and if you have any serious objections to their methods point them out. Otherwise, you are simply making vague and unsupported insinuations of inaccuracies without evidence - and such statements without evidence can in turn be dismissed without evidence.
-
scaddenp at 12:34 PM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
"You cannot have accurate long term forecasts and inaccurate short term forecasts."
Um, I can forecast the average temperature for the month of May next year I suspect with greater accuracy than I can predict the average daily temperature for Sunday week times That is rather like the difference between weather and climate.
As to background - I program models for, among other things, thermal evolution of sedimentary basins and in particular the evolution of hydrocarbon geochemistry over time. This is to answer the questions like "does this basin produce hydrocarbons, and if so, when, how much and in what phases". More than most however, the problem is dominated by uncertainty and poor constraints.
-
Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Stealth does not appear to understand the difference between boundary and initial value problems.
Consider as an example Los Angeles freeway traffic. Predicting exact volume even a few hours from now (initial value problem) would require exact numbers of cars on the road, perhaps some estimates of how aggressively they are being driven, detailed road conditions, etc. From that you could make detailed and relatively exact projections of how traffic might behave a few hours later. But not for a week down the line - there's too much that can occur in the meantime.
If, however, you wish to make long term projections of what traffic might be (boundary value problem) - given information on population, predictions on neighborhood growth, planned on/off ramp construction, and perhaps the football schedule (for near-stadium effects), you can make an average traffic prediction years down the road. You won't be able to predict the exact number of cars passing a point on the road on a particular Tuesday five years ahead - but you can make excellent predictions of the averages. And in fact city planners do this all the time.
In terms of evaluating climate models, whose mean trends are a boundary value solution - the climate has many short term variations, and it is only to be expected that short term variations will indeed occur around energy bounded long term trends. Models are quite frankly doing very well right now:
In order for the models to be invalidated by observations, the long term trend would have to go beyond the boundaries - far enough that such a new trend +/- the range of variation departed from the model predictions +/- variations. That hasn't happened, not by a long shot - and (IMO) it won't, as we have a pretty good handle on the physics.
In the meantime, demanding impossible perfection from boundary condition models, in the presence of short term initial value variations, is just a logical fallacy.
-
jmorpuss at 12:24 PM on 13 October 2013SkS social experiment: using comment ratings to help moderation
I think it would be a good idea to have a third option, maybe a grey thumb pointing sideways and would mean skeptical. And providing a dropdow of the voters names when you move your mouse over a icon may stop gaming and trolling
-
Eric (skeptic) at 12:15 PM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Dave123, thanks for the critique. The core of my alternative explanation follows after I comment on the ocean-has-missing-heat theory. Obviously my critique of Levitus deserves a more thorough explanation which is here
-
Eric (skeptic) at 12:14 PM on 13 October 2013Levitus et al. Find Global Warming Continues to Heat the Oceans
In this thread I posted a link to Schmitt et al 2005 and stated that "The bottom line is we don't really know how much 'missing' atmospheric heat has wound up in the oceans." Dave123 replied that "the paper makes the case that mixing was faster than anticipated" and quoted form the paper here. He suggested checking cites so I did, although not all 71 of them. Searching within the cites for GCM was dry, but searching for ARGO brought up this paper: website: scientiamarina.revistas.csic.es path: /index.php/scientiamarina/article/viewFile/1384/1488 that suggests that the Schmitt results were localized that were not present in the rest of their Atlantic ocean cross section. I didn't pursue the cites further.
But more apropos is the Levitus papers themselves such as this one: World ocean heat content and thermosteric sea level change (0–2000 m), 1955–2010 In order to fill in missing data for the 700-2000m depth they have to model how much heat flows down from the 0-700 depth which has good coverage. The relatively small temperature changes that SASM asks about in post 28 is answered by Tom two posts later as being 0.1C over the period. However the annual energy change is roughly 1022 Joules so the temperature change for 6 x 1023 cubic cm of seawater with 4 J/g/C is 0.002C per year.
The answer to KR's reply a few posts later that the large number of sample points reduces the error: there are only 4 data points in each one degree grid square in the model in Levitus. The mixing shown in the Schmitt paper and the other paper linked above requires simulation at the 1 degree cell resolution to simulate the mixing processes.
The latter paper also notes that the accuracy of temperature measurement was 0.002C so measuring a 0.002C change is problematic. Also the ARGO network has about 3 degree spacing according to their website which makes it basically impossible to simulate the mixing, so it must be parameterized.
-
john3 at 10:56 AM on 13 October 2013Ocean In Critical State from Cumulative Impacts
There is an additional threat to our oceans and that is the slowly increasing levels of mercury and other heavy metals. Heavy metals have been locked up (and away) for eons in coal reserves and when coal is burned, they aerosolise. Large amounts eventually settle in our oceans, are absorbed by biota such as algae and eventually make it up the food chain on to your dinner plate. Hence the limits on eating palargic fish such as sword fish no more than once a week. A recent three year study measuring tissue levels of heavy metals in 500 whales found alarmingly high levels. The study surmised that this was directly linked to a fall in whale fertility. and this would likely doom most whale populations within 100 years.
Yet another reason to leave coal in the ground. Thankfully many countries have excellent plans showing a switch to 100% renewables is entirely possible within 10 years. (See Beyondzeroemmissions).
-
Bert from Eltham at 10:31 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Jubble this 'third way' you speak of used to be peer reviewed science. That is evidence based knowledge from experts in their field to influence the policy makers such as our political institutions and business leaders. This has been paralysed by very dark forces that continually throw doubt on the peer reviewed scientific evidence. This is in a time where the peanut gallery is a worldwide phenomena due to the web. This peanut gallery is louder than the worlds experts. They do not have to win arguments with any logic or evidence. Just put up a constant noise to drown out the message that they disagree with.
I am sure that that these dark forces are somehow also exploiting a form of Poe's Law where the pseudo scientific sites on Global Warming are indistinguishable from the real scientific sites to the average layman. Bert
-
Dave123 at 09:42 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Eric, your citation of Schmitt (2005) puzzles me. First, the paper makes the case that mixing was faster than anticipated.
The significant vertical dispersion of tracer observed in this thermohaline staircase supports the idea that salt fingers significantly enhance mixing in certain parts of the main thermocline. Our derived salt diffusivity of 0.8j0.9 10j4 m2/s is an order of magnitude larger than that predicted for typical internal wave breaking within the mid-latitude thermocline. Indeed, for this low-latitude region, parameterization of mixing supported by the background internal wave field (32, 33) indicates that a diffusivity of only È0.02 10j4 m2/s should be expected. The tracer derived
diffusivity is also larger than that implied by microstructure measurements previously
made in this staircase (16, 25, 34). However, it is in agreement with the salt finger
model applied to those dissipation data (35), as well as to our new observations. Notably, the diapycnal tracer mixing rate observed in the western tropical Atlantic is 5 times that observed in the eastern subtropical Atlantic during NATRE, because of the presence of the thermohaline staircase. The staircase appears to transform the T-S structure of the thermocline waters entering the Caribbean, increasing the salinity and density of Antarctic Intermediate Water (36) and preconditioning it for sinking at higher latitudes. The efficient vertical transport within this strong tropical thermocline must be taken into account in oceanic and climate models, where the parameterization of diapycnal mixing continues to be a major uncertainty in assessing the ocean's ability tosequester heat, pollutants, and carbon dioxide.In otherwords, I don't think the paper can be read the way you're claiming. Beyond that, this paper is 8 years old. Did you do any work to check citations. If this were a class paper, I'd certainly demand evidence that you'd followed the scholarly trail and were presenting an opinion grounded on more than one paper. What work has been done since.
Then there's this question. There's instrumental data from the Argo floats. You've made no mention of this, only models. Why not? If you don't like the data, wouldn't your exposition be sounder if you brought this up and disposed of it?
If you want to create a synthesis, you need to do the work. Especially here, where the aggregate of people do follow the literature, check citations, and routinely attempt sound scholarly syntheses. Unless of course, you think picking a few papers is "good enough for a 'C'", in which case you'll not convince anyone here.
-
Leto at 08:55 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Stealth, you wrote:
I have noticed that no one has answered the question of their background. This leads me to speculate that you are unqualified to discuss software modeling and accuracy.
This and similar comments, along with your login name, appear to be attempts to pull rank by virtue of your software 'expertise'.
In fact, programming software is fairly easy for anyone with a basic sense of syntax and logic. The difficulty with software modelling is not really in the writing of the code, but in understanding the domain you are trying to model. You clearly have very little knowledge of the climate domain, and you seem resistant to the patient attempts of others to educate you.
You also wrote:
You cannot have accurate long term forecasts and inaccurate short term forecasts.
This patently false comment reveals that you do not understand - even in the broadest terms - what the models are trying to achieve and how they relate to the real world, perhaps because you are drawing faulty analogies with the one domain you do understand (aviation modelling). There are countless situations where long-term projections are possible despite short-term unpredictability.
For instance:
- A hose is running into a half-empty backyard swimming pool at a constant rate. People are splashing about in the pool, so the water level near a monitor fluctuates wildly, but the rise is linear in the long term. (This example from some other SkS poster.)
- Snow depth on a mountain increases in fits and starts during winter, and melts off in spring. The general rise and fall in snow depth over months is predictable, despite the poor predictability over days.
- A professional poker player sits down with a novice. The hands and flow of money are totally unpredictable in the short term, but we know who is going to win by the end of the evening.
Some systems are highly divergent, and small-short term effects propagate to create vastly different outcomes, like the proverbial butterfly flap. But others are highly convergent, and small short-term effects are swallowed up. This is particularly the case for climate modelling, when many of the short-term effects are merely moving heat around within the system, without substantially changing the cumulative and predictable heat imbalance due to GHGs.
-
davidnewell at 08:27 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
ANYWAY, i meant
Moderator Response:[PW] Extraneous characters trimmed off.
Thanks for the kind words: As many have stated, moderation is a arduous and thankless job, and the commission of good, focused moderation is the hallmark of an excellent website. DB, JH, Ari, and JC himself, just to mention a few, do yeoman work in making the place consistently good.
-
davidnewell at 08:26 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
I'm going to slip in a plug for the moderation hereabout, though it may be "offtopic".
Whomever is doing it, it is outstanding. To keep up with all the arcane "facts", their sources, tone, effect, and intent: and the personas behind the sometimes sniping egos whose argumentation is occassionally specious..
and provide a net effect of lucid edification for those who seek education..
constitutes a great service.
Sometimes when I encounter a self righteous "denier", I send them here to hoist their petard, and get it trimmed.
==============
WTHell: what if it was "natural fluctuation" ( which it ain't):
if the biosphere is dying, we are all that CAN respond to support it.
=============
We WILL get around to "direct air capture" eventually.
============
Anywya, Good Work" moderator(s)!
-
Jubble at 08:05 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Why climate alarmists owe us a (scientific) explanation
For a while now, I’ve considered AGW to be akin to superstition, which the Oxford Dictionaries site defines as “a widely held but irrational belief in supernatural influences.” I mention this because when challenged, alarmists often claim that the climate changes we are witnessing are not due to natural variability, but products of humanity. In this context, I find that 'humanity' appears to be a synonym for ‘supernatural influence’.
Why? Because they can’t explain it. Not just that: many seem to believe they are not obliged to do so, which is suspiciously convenient, and all too reminiscent of those who would claim they don’t need to ‘explain’ God. In this, they share a view once expressed in a Daily Mail forum which, to this day, remains one of my favourite alarmist non-sequiturs. When challenged, a poster calling himself Romeo 4 insisted “I don’t need to prove climate change is caused by humanity. It just is.”
....
The above could easily be the start of a blog post on WUWT or some other denial blog. The point I am making here is that to someone who has not read extensively through the science with objectivity, it is very difficult to tell the difference and therefore it is very easy for confirmation bias to occur.
The only difference would be that in a denial site there are fewer papers from which to choose, and more of the references would have to be to non-peer reviewed literature, because there isn't as much genuine science to which to refer. That issue is easily dismissed by asserting that consensus science is not science at all - you can imagine a scientific consensus building up where in fact the truth lay in the minority view.
As long as both sides of the debate look the same it will be difficult for the changes in attitude needed to cope with climate change to happen.
What is needed is a "third way" - a way to avoid the constant to and fro wrangling; to find a different direction that takes everyone with it, rather than entrenching views.
Could that be business realising that it is better to mitigate than adapt? Could it be demonstrating the benefits of change rather than the reason for those changes? Could it be discussion and quantification of risk? Or could it be something else completely?
Unfortunately I don't know - and I'll stop there to avoid getting off-topic.
-
Tom Dayton at 07:37 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Stealth, for even more about initial values versus boundary conditions, see Steve Easterbrook's post. While you're at it, go to RealClimate's Index, scroll down to the section "Climate Modelling," and read all of the posts listed there. For example, in the post "Is Climate Modelling Science?", there appears:
"I use the term validating not in the sense of ‘proving true’ (an impossibility), but in the sense of ‘being good enough to be useful’). In essence, the validation must be done for the whole system if we are to have any confidence in the predictions about the whole system in the future. This validation is what most climate modellers spend almost all their time doing."
For the umpteenth time: You need to read the Skeptical Science post "How Reliable Are Climate Models?", including both the Basic and the Advanced tabs.
For a broader and deeper discussion of how climate models are verified and validated (V&Ved), read software professor and former NASA software quality assurance guy Steve Easterbrook's explanation.
A good, short, essay on the role of computer models in science is in the journal Communications of the ACM, the September 2010 issue, page 5: Science Has Only Two Legs.
-
Tom Dayton at 07:15 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Yes Stealth, your attempt to "not be a jerk" is failing. You are vastly overestimating the breadth of your knowledge by making such ridiculous assertions as "That is hogwash. You cannot have accurate long term forecasts and inaccurate short term forecasts," when that has been explained to you over and over and over for weeks (months?). Once more, for an explanation see "The Difference Between Weather and Climate." For even more, see "Chaos Theory and Global Warming: Can Climate Be Predicted?"
Moderator Response:"You are vastly overestimating the breadth of your knowledge by making such ridiculous assertions....when that has been explained to you over and over and over for weeks...."
[PW[ Indeed, and from now on, a newly-coined parameter will be taken into account, when posters do this. It's called 'anterograde amnesia,' and continuing utilization of the technique will be considered obfuscatory, and will be appropriately moderated. Tom Curtis has patiently explained such things to you, Stealth, and you've consistently acted as if the news was...well, new. No more.
-
StealthAircraftSoftwareModeler at 06:43 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
My bad. I asked for some background info and didn't see Tom's post that came in while I was typing. I'm really trying to have a good discussion and not be a jerk denier, because I'm not one. (-snip-).
Moderator Response:[DB] Sloganeering snipped. You have been pointed to resources which countermand your position. Unless you have new evidence, it is time to drop it.
-
grindupBaker at 06:26 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
@JRT256 #18 You can do a 1st-order approximation to gain some credibility re "temperature rebound". I'm hoping to find time off work for it myself this Christmas/Festivus. Simply estimate linear trends over a few thousand years of the temperature last 18,000 years, then integrate temperature anomalies using stated ocean heat increases and whatever you can find re ocean current rates & quantities to get this 1st-order approximation of changes in ocean heat content the last 18,000 years. Demonstrate that the last few decades of ocean heat content increase are simply a re-balancing from the few hundred prior years. Good luck.
-
StealthAircraftSoftwareModeler at 06:09 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
(-snip-). That is hogwash. You cannot have accurate long term forecasts and inaccurate short term forecasts.
Rob @137 and @138: I may not be understanding the “boundary conditions” -- please explain what it is. And for the record I am referencing Tom Curtis’ chart @126. It does not, I believe, have any of the “initial conditions” you mention. The boundary in Tom’s chart @126 seems to be well defined edges of accuracy and unlikely to be crossed. But if it can be crossed and the model still be correct, then what has to happen to determine that the model is inaccurate?
Moderator Response:[DB] Sloganeering snipped.
-
MA Rodger at 05:16 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
There are some wonderful examples of denial on this comment thread. Elephant In The Room @36 certainly provides such an example.
The main thrust of his argument is that natural variation is very large when considered over tens of millions of years. Thus an 8ºC increase in global temperature would do nothing but return the planet to the average temperature for such a time period. And over such timescales CO2 has been measured in parts per thousand rather than the present parts per million so the level of CO2 doubling or quadrupling through the burning of fossil fuels is nothing we should 'complain' about.
"Humans are a brief visitor to this planet," he boldly tells us (I think he means "inhabitor" rather than "visitor", but whatever.) which presents a very fatalistic view of humanities future but these are large sweeping timescales being discussed. Let's be fatalistic.
These ideas are presented by Elephant In The Room as "fact" which he tells us cannot be overturned by any "scientific explanation." I am sure many would agree with such argument within its proper place.
So where is it that Elephant In The Room places this argument?It is used to objection to mitigation measures to combat AGW. This is particularly odd as AGW is a phenomenon that will act over decades and centuries, a miniscule timescale compared with the prior items of discussion.
But that doesn't matter because AGW "is a global threat that isn't really a threat." It seems precipitating an 8ºC global temperature rise that could bring mankind's terestrial "visit" to an end is not "really a threat at all."
The end of all human existence is not really a threat to humanity? I think Elephant In The Room is suffering denial and sorely needs a reality check. -
william5331 at 05:09 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Please excuse the crudity but you are peeing agains the wind. Most contrarians wouldn't know a scientific thought if it bit them on the behind.
-
Eric (skeptic) at 05:05 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
...the change in energy levels – required to increase the global temperatures rapidly over three decades, to melt glaciers, to warm oceans...
Referring to this diagram:
Glacier melting did and does not use much of the assumed change in energy levels. The warming oceans are supposed to account for most of the recent lull in the atmospheric temperature rise, but is the heat transfer to the oceans adequately modeled? This paper http://www.sciencemag.org/content/308/5722/685.full.pdf suggests it is not. As they say in their conclusion, the mixing described in the paper is a major uncertainty in the parameterization of mixing (in climate models). The bottom line is we don't really know how much "missing" atmospheric heat has wound up in the oceans.
Here's a climate model that won't satisfy rader5:
The key point in the diagram (which is from Lindzen 2007 Energy&Environment) is that the angle of the arrows representing latitudinal heat transfer is a function of parameters, not physics, in all climate models. But AFAIK, Lindzen has not provided an alternative GCM with his own cherry-picked parameters to make that point.
Matt Fitzpatrick leaves out of his list (ending with "pirates") the "weather", specifically weather that increases or decreases latitudinal heat transfer. He probably leaves it out in the belief that it affects the short run and can't explain decades of change. But I don't think that is completely correct. I would suggest to Alexandre that a potential "magical negative feedback" is weather insofar as the increased in meridional flow and consequential increased in storminess (neither are true IMO) are supposed to be from Arctic Amplification. But wouldn't that increase latitudinal heat transfer and slow global warming?
But Alexandre is correct that we ought not believe "magical negative feedback" until we see some evidence for it. I believe that long term increases and decreases in meridional flow and latitudinal heat transfer come from long term natural factors, mostly solar.
Here's a quantification of meridional heat flux journals.ametsoc.org/doi/pdf/10.1175/JCLI3539.1 (Carl Wunsch: The Total Meridional Heat Flux and Its Oceanic and Atmospheric Partition, 2005) of about 5 PW atmospheric. Dana's diagram at the top of my post shows about 1022 Joules of increase per year. 5 PW equals about 1023 Joules per year. Obviously only a small part of the 5 PW is going to be lost to space as Lindzen's simple climate model implies. But the 5PW and fluctuations in that amount are clearly a factor in earth's energy balance.
Here's an old paper showing adsabs.harvard.edu/full/1981SoPh...74..399B showing how variations in solar UV could influence climate by changing planetary waves through photochemical changes in the stratosphere. The lower stratosphere has stopped cooling in the last 15-20 years:
(Note: the middle stratosphere is still cooling substantially). I believe these variations in the lower stratosphere are part of the explanation in the lull. If I am correct we should see substantial warming in that TLS graph in the coming solar minimum as the high frequency solar UV decreases causing an overall ozone increase causing TLS warming. The TLS warming is not a direct factor in the meridional heat flux, but it represents strong variations in stratospheric temperature which lead to greater meridional heat flux.
Here's a possible explanation of high sensitivity of early 2000's climate models: journals.ametsoc.org/doi/pdf/10.1175/1520-0442(2002)015%3C1659%3AIADVOP%3E2.0.CO%3B2 (Hu: Interannual and Decadal Variations of Planetary Wave Activity, Stratospheric Cooling, and Northern Hemisphere Annular Mode) which notes the stratospheric cooling to that point (paper is from 2001) potentially caused by GHG increases (plus ozone depletion) and asks whether the stratospheric cooling causes or is caused by an increase in NAM (Arctic Oscillation). (Note that AO has been trending negative since the mid 2000's after this paper was written).
Essentially high sensitivity in the models up to the early 2000's comes from a stronger polar jet which comes from a cooling stratosphere. This decreases meridional flow and meridional heat flux and thus enhances global warming. In more recent models the polar jet is weaker and consequently sensitivity is lower. Whether Arctic Amplification plays a role in the strength of the polar jet (e.g. as explained by Jennifer Francis and others) is still undetermined. My preferred theory is that external solar factors control it although the real answer is undoubtedly a mixture of external, internal natural and anthropogenic factors.
-
DSL at 05:02 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Lei: "And the truth is, you would feel far more comfortable sitting at the same dining table with the skeptics who are millionaires, than these poor folks who might steal your wallets."
Chuckle. So all poor people are thieves, and no millionaires are thieves. How medieval of you.
-
Tom Dayton at 05:00 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Stealth, your comment "First, aircraft model are not extrapolating models at all in the way that GCM operate" is irrelevant in the face of clear evidence that GCMs are successful.
Your statement "Second, the progression from aircraft design to deployment is very complex, and extensive usage of models is employed to get 'rough idea' of performance and features" is exactly true of every model, computerized or not, in every field of endeavor, throughout human history. The critical piece is the definition of "rough" in each particular use of a particular model: Is the model sufficiently accurate to serve the particular use to which you are putting it? As noted in the original post, climate models have indeed proven accurate enough to provide the information we need to choose actions to reduce greenhouse gas emissions, because the costs of not reducing are and will be far higher than the costs of reducing.
You continue to claim that climate models cannot project well enough for that use, despite the clear and robust evidence that they have, do, and will. You might as well be a newspaper editor in the early 1900s refusing to publish any reports of the Wright brothers' successful flights despite photos and your reporters' first-hand accounts, because you "know" that flight is impossible.
As for my background: PhD in cognitive science with focus on decision theory (normative and behavioral), scientific research methodology, human-computer interaction, and the combination of all those in how to use computers as decision making tools. Employment for 24 years after that, in designing software and managing software development projects. For the first 7 years of that, for the major telecommunications systems in the world. The second 7 years for critical, large scale computer server and network management. For the past 10 years, for spacecraft (both flight software that runs on the spacecraft, and ground software for mission operations).
-
Dave123 at 03:47 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Elephant- What you wrote only makes sense if you are given a free pass for leaving things out and having no responsibility for the details. It is an example of magical thinking, not scientific thinking. Every word you write is aimed at exactly one outcome: stop thinking, stop investigating, stop testing, stop learning.
You've said (in paraphrase) "the earth has warmed and cooled before, CO2 levels have gone up and down", and we can stop right there with that. That's all there is too it, and the entire scientific enterprise aimed at this (despite it being that same scientific enterprise that produced the paleoclimate data you make mistakes about), is a waste of time.
The question is, is this your philosophy of life or something you wish to deceive other people into adopting?
-
Elephant In The Room at 03:19 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
I am curious about the thread title - Why climate change contrarians owe us a (scientific) explanation.
When you say 'us' - to whom are you referring? Skeptical Science, the IPCC scientists, the politicians, the world as a whole?
As for scientific explanation - you seem to be laying down the gauntlet for people to refute with scientific evidence something that is currently theory. The threat of man-made climate change is a theory that currently the IPCC have a 95 percent certainty in (previously 90 percent). It's all semantics. 100 percent, 90, 50. It is immaterial. We could all quote our 'out of 10' view on any given subject. It does not add weight to the argument.
If you wish to talk about facts of course then I could refer you to this planets temperature and carbon dioxide relationship. With absolute certainty I can tell you that currently we are rather cool; in fact pretty chilly. Furthermore I should also add that we are currently carbon dioxide starved. I say we; I meant to say 'the planet.' Carbon dioxide is a warming gas; for me to say otherwise would make me a denialist. I am not. However, it is my belief, and it is a belief, that the effect of the Co2 that we as humans churn out is minimal compared to the amount produced through natural variation. This is supported by the fact that in our absence on this planet (the last hundred's of millions of years) not only the temperature, but also the levels of Co2 were both equally capable of being random. One common trend however is that the mean global temperature 'is' 22 degrees C and the ppm of Co2 has been in the thousands; all without our influence.
Alternative discussion about climate change is healthy. To ask a person or persons to refute 'evidence' with 'science' is ludicrous in the same way that it would have been to ask people to challenge that the world was once deemed to be flat.
Humans are a brief visitor to this planet. They will come and go. And I can assure you that our brief incursion here will have no effect on the long term future. The reason we have coal to burn is because at one time it was in the atmosphere feeding the plethora of plant life and vegetation. Are we complaining that we are returning it to the air after it had once been sequested? Are we complaining about sea levels when we know full well that this is a natural event that occurs post Ice Epoch? Is it the planets fault that we as humans choose to build houses in coastal areas that will as history tells us become inundated again with water?
Take a good look; there is enough history there to tell you what has been and what will be again. Do you really wish to throw all your eggs in one basket for the sake of a global threat that isn't really a threat at all?
Moderator Response:[PW] Elephant, in addition to your not-so sly tone-trolling, you've made numerous unsupported-by-credible-science assertions: either back them up and support them or risk any further comments of yours being moderated, *severely.* This is your first and last warning.
Addition: All caps is a violation of comment policy and have been changed to bold.
-
Rob Honeycutt at 03:00 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM... You seem to have a particular interest in this issue, and it's somewhat related to your own professional expertise. And yet you seem to be failing to grasp some basic elements of GCM work.
My suggestion would be that you try to contact a researcher who is actually doing work on GCM's. I've always found researchers to be very communicative with people interested in their work. I'm sure they could help you understand their work.
This is what I believe Admiral Tilly of the US Navy did when he was skeptical of AGW. Once he had the issue of climate modeling explained to him he began to take the threats of climate change seriously.
-
Rob Honeycutt at 02:53 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM again... "I read that as there was only a 2.5% chance that the global temperature would reach this level."
Again, you're reading these as an initial conditions problem and not a boundary conditions problem.
If you look at any of the individual model runs, those are more likely what we would expect to see GMST do. And yes, they all wander from the 97.5%ile to the 2.5%ile. So, your statement would be inaccurate.
-
Rob Honeycutt at 02:50 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM said... "Nevertheless, in both my chart and yours, it is clear that global temperatures are at the very low end of the model projections."
Once again, you don't seem to be grasping the boundary conditions aspect of this problem. Scientists do not expect the GMST to follow the model mean over shorter periods. The expect the GMST to remain roughly within the model bounds. Over longer timeframes (>30 years) we would expect to see a similar trend between GMST and model outputs.
-
PhilBMorris at 02:26 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
I recently made the mistake of responding to an article on a denialist website by trying to rebut some really poor arguments claiming that the debate wasn't over. I gave what I thought was a quite well reasoned response, but subsequently got back several replies that were equally trite in their arguments as the original article. I have decided that 'public discussions' on any of the multitude of denialist websites is entirely a waste of time. I'm better off finishing my rather lengthy presentation designed for the lay public and taking it to meetings etc. where I can actually lay out what we know, and why we know it, and see if I can help mobilise the small segment of the population where I live (Vancouver Island, Canada) that they cannot simply sit back and let business as usual happen. Of course, I'll continue to refer to this and a number of other 'quality' sites for information; in particular, I found the article on this thread to be very helpful.
-
Tom Curtis at 01:56 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
SAM @133, in fact HadCRUT4 only drops to the 8.38 percentile (%ile) in 2012, and to 7.87 %ile in 2011. In fact, over the entire period for which I have data for both CMIP 3 models and observations (1960-2012), it only once drops below the 2.5 %ile (to the 2.43 %ile) in 1976. It also drops to the 3.27 %ile in 1985 and to the 3.43 %ile in 1974.
That does not look like falsification to me. In fact, given that we have 53 years of record, we would expect the record to fall below the 2 %ile at least once in the period, but it does not. Partly that is because the two records are centered on their mean between 1961 and 1990, forcing HadCRUT4 to average close to the 50th percentile over that interval, but if the models were significantly in error, we would have expected a large number of instances where the observations were below the 2.5 %ile by now.
This is not to suggest that the models are not overpredicting the warming. They are, and the fact that they are is shown in the trend in percentile ranks seen above. However, that trend will not drop the observations consistenly below the 2.5% until 2035. Further, that trend is exagerated by the use of HadCRUT4 (which does not include regions of rapid warming which are included in the models). It is further exagerated by the final points observations being during a period of strong La Ninas.
Frankly, I am surprised that you and Klapper persist in trying to prove your point based on interpretations of the faulty 2nd order fig 1.4, and misinterpretation of significance intervals (which by definition, we expect to be crossed 5% of the time if the models are accurate). It would be far better to argue directly from the results of Foster and Rahmstorf, who show observed trends around 17 C/decade after adjustment for ENSO, solar variation and volcanism. That represents a 15% undershoot on the models; and a reasonable estimate of the discrepancy between models and observations.
-
Jim Pettit at 01:31 AM on 13 October 2013SkS social experiment: using comment ratings to help moderation
I don't know that it will be an issue here, but on other climate change forums of which I am a member, the comment rating moderation system has been gamed, almost exclusively by denialists. The primary method so far as I can tell has been for certain users to create mutliple handles, then log in under those handles to repeatedly vote down every comment supportive of climate change theory, and to repeatedly vote up every comment dismissive of it. (At one popular board, certain valuable forum members nonetheless found themselves accumulating literally tens of thousands of thumbs down votes over the span of just a few months by people using this method.). IOW, such comment rating systems have become a sort of corrupt and reverse popularity contest, and have seemed to do more harm than good.
I like what a few others have suggested: a simply "flag as abusive" button. The problem with that, however, is that a dedicated group of troublemakers can just as easily game the system by piling on those flags, as well...
I wish Popular Science wouldn't have chosen to kill comments for now, but I can certainly understand their reasons for doing so.
-
StealthAircraftSoftwareModeler at 01:28 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Tom Dayton @134: I’m just curious, what is your background?
First, aircraft model are not extrapolating models at all in the way that GCM operate. Second, the progression from aircraft design to deployment is very complex, and extensive usage of models is employed to get “rough idea” of performance and features. Computer models are used in coarse design, then things progress to scale model testing in wind tunnels, but even because of the non linearity of aerodynamics and fluid properties, not even scale models are final. In the end, any thousands of hours of actual flight test of full size aircraft are used to *measure* control parameters. Rarely are model derived parameters used because of the very systematic errors of which I speak. Rest assured that the errors between the various stages of aircraft design and development easily exceed 1%. This is, in fact, the primary reason that aircraft development is so freaking expensive: test, and adjust, test and adjust, and on and on. Testing and adjusting never ever stops -- at least not until the aircraft is retired.
-
Lei at 01:22 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
You are preaching to the choir, aren't you?
First of all, in the US the scientists are on the same side of the fence, politically, as very uneducated people who are using tax money for subsistance programs. These followers may not even have a high school education, may be hardened criminals and likely to be using up tax dollars for multiple abortions. I know it is true, because I worked for a large social welfare program.
You can preach all day about the uneducated who are following climate skeptics, but the truth is, it is the same for your side. You have massive amounts of uneducated people who really may say they care about climate but it is far from important to them. It isn't even on their radar.
And the truth is, you would feel far more comfortable sitting at the same dining table with the skeptics who are millionaires, than these poor folks who might steal your wallets.
-
perseus at 01:15 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
Interestingly Nassim Taleb believes there is an even greater burden of evidence on skeptics
Implication 1 (Burden of Evidence). The burden of evidence is not on nature but on humans disrupting anything top-down to prove their errors don’t spread and don’t carry consequences. Absence of evidence is vastly more nonlinear than evidence of absence. So if someone asks “do you have evidence that I am harming the planet?”, ignore him: he should be the one producing evidence, not you. It is shocking how people can put the burden of evidence the wrong way.
Implication 2 (Via Negativa). If we can’t predict the effects of a positive action (adding something new), we can predict the effect of removing a substance that has not been historically part of the system (removal of smoking, carbon pollution, carbs from diets).
-
Jonas at 01:14 AM on 13 October 2013Why climate change contrarians owe us a (scientific) explanation
>Hamlet 4 insisted “I don’t need to prove climate change is caused by natural variability. It just is.”
I don’t need to prove climate change is caused by natural variability humans. It just is.
-
Tom Dayton at 00:41 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
StealthAircraftSoftwareModeler, your claimed credentials seem more fictional the more you write. Would you really claim that "In order for aircraft models to be reliable for forecasting, there essentially cannot be any systematic errors within the model, and that is just not possible"?
-
StealthAircraftSoftwareModeler at 00:04 AM on 13 October 2013Why Curry, McIntyre, and Co. are Still Wrong about IPCC Climate Model Accuracy
Tom Curtis @126: I like your chart, and I usually like what you have to say or present. I understand the different between trend lines and comparing it to actual temperature data. At the origin (1990, +0.22 degC) of my chart @117 all lines are touching. As time advances forward, they are still very close and it is easy for the highly variable temperature data to go outside these lines (see the wide temperature swing in my chart @117 between 1998 and 2002). I think we all understand that this type of comparison isn’t meaningful in the initial stages of the forecast. But, as time advances forward the min/max trend lines become wider, and once they are as wide as the noisy temperature data, then the location of the origin really shouldn’t matter. For example, in your chart @126, you can see that the min/max trend lines are outside the 2.5%/97.5% model bands by 2013 or 2014.
Nevertheless, in both my chart and yours, it is clear that global temperatures are at the very low end of the model projections. You show the +/-2.5% bands and the current HADCRUT4 data is touching the lower 2.5% band. I read that as there was only a 2.5% chance that the global temperature would reach this level. This seems to indicate to me that the models are not very accurate. If you disagree, then how would any of you determine that the models are inaccurate? What is your method of testing and validation?
As a software modeler myself, testing is everything. In fact, in my world we have more test code than we have model code, and by a lot. Trying to gain confidence in a model is extremely difficult. Many of my models are very accurate, under specific and well defined circumstances, but outside of those conditions then my models are wildly wrong. Dana asserts in this post that “models have done much better than you think”, but for the life of me I cannot understand how he can make that claim. It doesn’t appear that Dana understands software modeling, and certainly not testing. And while I am not a GCM modeler, I have spent a bit of time reviewing the GISS Model E source code. I am not criticizing the developers of the code, but it is clear that engineers or physicists, not software engineers, have developed the code. Model E is not very large – about 100,000 lines of Fortran (a very old language) -- and some of the physics models I have examined (clouds, lapse rate, convection with respect to GCM cell size and iteration rates) are, IMO, simple and designed for limited computational resources. Yes, even with a zillion processors, what they are attempting to simulate is so complex and so large, that design and modeling simplifications have to be made. Otherwise the model will run too slow and not provide any output in our life time.
Those design and modeling simplifications are systematic errors, and essentially break the model. While I agree that true Gaussian errors will average out over time, systematic errors will not. Even very small systematic modeling errors – say 1%, which is impossible to achieve –will propagate over time and cascade into a large error. For example, let’s assume that GCMs are systematically accurate to within 1% on an annual basis. This means they *must* be able to model all aspects of the energy budget with accuracies greater than 1%. There is no way in hell they are doing that!!! Just look at the updated energy budget (http://www.nature.com/ngeo/journal/v5/n10/box/ngeo1580_BX1.html) and you can see that they have wide margins on every aspect of the budget. Climate scientists cannot measure the various components of the energy budget to within 1%, so there is no way they are modeling it to within 1%. A 1% systematic positively biased error will lead to an over estimation of +28% in 25 years (1.01 ^ 25 = 1.282), and in 100 years that same positive error will lead to an over estimation 170%.
In order for GCMs to be reliable for forecasting, there essentially cannot be any systematic errors within the model, and that is just not possible. To have no systematic error would require complete and total understanding of the climate (we don’t have that) and all physics models to include all first, second, third, and perhaps fourth order effects (and they don’t do that either). To make major economic and policy decisions based on the output of GCMs is pure and unadulterated foolishness. I form this opinion based on 30+ years of advance software modeling of physics based systems, and we are no where near 1% accuracy and what we’re working is way easier than modeling the climate. Just accept that the GCMs are wrong and not very accurate for forecasting, and that is okay; developing climate models should be useful in helping climate scientists understand the climate better. GCMs are just a tool, and like all tools they need to be used properly, otherwise someone is going to get hurt.
-
Philippe Chantreau at 23:27 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
"Recovery from the LIA" would then be a cause, which itself does not have a cause? Makes sense...
-
MA Rodger at 18:46 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
jmorpuss @29.
You present an interesting example of denial. Does the ionosphere actually dictate the climate? Are the elusive results of the ATLANT experiments elusive because they are being covered up? This, jmorpuss, is the stuff of the "reality" you speak of.
So to you, AGW is not a problem. All the climate scientists in the world are so dumb or corrupt that not one of them can see what you, a humble citizen of this planet, can see as plain as day in front of you.
Congratulations, jmorpuss. You are in denial. Any evidence of human science is irrelevant and rendered false if it supports AGW, because you know AGW is false. You are not alone. Prof. Richard Lindzen takes the same position as you do, and he is a proper climatologist, abet a rather elderly one. Lindzen ignores all the unhelpful evidence because he believes some vital ingredient is missing from the theories, some mechanism of climate that will make the problems of AGW disappear. (I'm not sure how it would make the unhelpful evidence disappear for him, but hey-ho, what do I know.)
Of course, because neither you nor Richard Lindzen are being scientific about AGW to a greater or lesser extent (you jmorpuss the greater, he Lindzen the lesser), you would neither agree with each other. Indeed Lindzen would consider you views ridiculous and insane. And he would not be alone in this opinion.
Such is the stuff of denial. Thank you for sharing it with us.
-
John Mason at 17:35 PM on 12 October 2013A rough guide to the components of Earth's Climate System
Link to NOAA's ONI page added and a screengrab of part of it dropped in above to overlay graphic :)
-
TonyW at 17:12 PM on 12 October 2013Ocean In Critical State from Cumulative Impacts
The state of the oceans is scary. But why, oh why, do apparently scientific reports keep emphasising the political limit of 2C/450ppm? Where is the current science that says anything up to 1.99C is not too bad, but 2C is terrible? Ditton 450ppm. I read something on realclimate recently which pointed at 1.9C being seen, in the past, as the lower limit of a small range of temperature rises that would consign Arctic sea ice to history. That temperature has surely been superseded by a much lower one. And the oceans are already acidifying faster than for millions of years; I can't see it being OK to limit CO2 to less than 450ppm. The urgency is even greater than this report tries to instill. -
jmorpuss at 16:55 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
I think if climate sience looked at reality and not debated theories and computer generated models we could all live in a better world. Do all climate change researchers get provided with the time frames when this is taking place ?LINK
And here in Australia I'd like to know if Atlant was running when Queensland got flooded? John Cook should be able to let us know http://www.australianrain.com.au/technology/howitworks.html
So as I said these links are not promoting a theory they are real and going on as we speak.
Moderator Response:[RH] Shortened links that were breaking page formatting
-
Tom Curtis at 15:58 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
JRT256 @20:
"Recovery from the Little Ice Age is probably one of the causes of Global Warming. To say that this is magical is possibly nonsense. Clearly if there was a cause of the LIA, then the cesation of this cause will result in recovery."
This sort of spurious reasoning is what gives "magical thinking" plausibility. Essential to JRT256's reasoning is an assumption that the "cause of the LIA" has in fact ceased to operate. But if he has not identified that cause, he cannot know that it has ceased, continued as before, or even redoubled in strength. For all he knows, climate sensitivity is far stronger than he imagines, but a redoubled strength of the "cause of the LIA" has slowed the anthropogenic global warming.
The only way around this quandary is to actually identify the cause of the LIA; and to then identify what it is currently doing,ie, to go beyond vague formulations in terms of "recovery from the LIA". Failure to do this, ie, simply assuming that the "cause of the LIA" is behaving in the way that best suites your intellectual prejudices amounts to magical thinking.
Curiously, when the actual causes of the LIA are looked into, it is found that the primary cause of the LIA was a period of greater than usual volcanism creating an aerosol veil sheltering us from the sun; which indeed did cease in the early twentieth century and the cessation of which did contribute to the early twentieth century rise in temperatures. Of course, volcanism has been renewed since then, and the rise in temperatures in the late twentieth century is opposite in trend to that which would be expected from natural (solar and volcanic) causes.
-
Bert from Eltham at 15:54 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
DSL it all reminds me of epicycles and the problems of turbulent fluid flow. Throw in enough epicycles or non sense variables and one can model anything we do not understand.
I find it absolutely amazing that people will rubbish computer models that are based on known physics and yet grasp at any 'magic' models that are based on short term curve fitting.
These same ignorant people will then accuse scientists of the very same fallacy they are committing all far outside the error bars that they cannot even begin to evaluate or contemplate. Bert
-
DSL at 14:47 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
JRT256, there's nothing in the article or in the comment stream that provides an overwhelmingly obvious antecedent for the target of your use of "explanation." I certainly would not have expected you to assume the reader would identify 'global warming over the last fifty years' as the target. Rob and Bert explain why. I also have a hard time accepting this quasi-periodic wave is independent of rapid and deep changes in the climate system. The physical mechanisms through which the wave is propagated are changing. To imagine that this wave persists through that change in such a way as to be used to reliably project a future hiatus in surface temp requires too great a suspension of disbelief. Ironically, Curry works on a project that seems ideal fodder for her uncertainty monster.
-
Rob Honeycutt at 14:29 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
JRT256... What would also be required here is an explanation as to why CO2 doesn't operate as we expect, and observe, to explain current warming.
In other words, you can't just dismiss the well understood radiative physics of greenhouse gases. You also have to take into account a whole host of things that are predicted results. Cooling stratosphere with a warming troposphere. Arctic amplification. Etc.
And again, for natural variation to be a rational explanation, you'd also have to show that global temperature has varied at least as much and as rapidly over the past 1000-2000 years. That, so far, has been shown not to be the case.
-
Bert from Eltham at 14:14 PM on 12 October 2013Why climate change contrarians owe us a (scientific) explanation
JRT256 the article you referred to in 18 is an attempt to describe 'natural variation'. It is for the Northern Hemisphere only and it does not propose any real physical mechanism for its affects. Just some vague hand waving of so called multi temporal and spatial interactions. It does not account for the linear increase in temperature due to anthropogenic CO2. It does not disprove AGW due to the increase in atmospheric CO2. For the analysis to work at all the linear AGW signal has to be subtracted from the data.
What is does do is show that AGW is not due to 'natural variation'! The opposite of what deniers are claiming. Bert
Prev 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 Next
