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Forum » SpaceEngine » Off-topic Discussions » General Global Warming / Climate Change Discussion (because a thread for this was long overdue)
General Global Warming / Climate Change Discussion
WatsisnameDate: Tuesday, 29.10.2013, 13:12 | Message # 76
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Thanks midtskogen, these are good posts.

Quote midtskogen ()

No, but you would expect to see both, pre-Holocene and Holocene optimum, in many places.


Mmm, well I don't, and neither do the people who actually study this kind of thing for a living. They were extremely surprised to see such old vegetation at all. smile

The pre-Holocene moss doesn't stick around for very long after it has been re-exposed. If the moss was covered up by the glacial ice and then thawed out during the optimum, then you're not going to see it now; you’ll only see the younger vegetation. You only see the old stuff where the moss existed, got frozen over, remained that way through the whole period, and then got uncovered extremely recently. That's a hard set of circumstances to reproduce in many areas.

As you saw, only a few of the many sites examined show the pre-Holocene moss, and these sites are in close proximity to those that don't, as well as being at typically higher elevation. These data are extremely interesting. They show that much of the ice in this region melted out sometime during the HTM, but not all of it, such as the ice at higher altitude where it survives more easily. Yet the conditions now are such that even that ice is melting. Otherwise we would not see this evidence at all.

It is a pretty fortuitous congruence of geological circumstances there on Baffin Island that make this study possible. I was quite impressed by it and its conclusions.

Quote midtskogen ()
Even if you carefully choose the temporal resolution that best fits your message, I think you'll find it very hard to find a higher modern dT/dt, given that you use the same resolution then and now. If you use a higher temporal resolution both the modern warming and its warming rate become less severe.


Yes, perfectly correct. smile You can find very large dT/dt's with high temporal resolution data (just a heads-up though that high resolution means short interval between points) or data from a single location in space, and that's a big part of why I said no to your earlier question. Now of course I could point out a logic exercise in that I had said:

If A or B, then C, where A is high temporal resolution, B is a single point in space, and C is faster temperature change.
and now you've presented "Okay, now A is false and B is true and look we still get C!"

Although that is a little bit humorous, dissecting it further would probably be unprofitable and I also don't make any veiling of the fact that the Gisp2 ice core record is actually a reasonably good representation of the whole Arctic. Though the values of dT/dt would almost certainly be more benign if we could examine an Arctic-wide temperature data set, but could still be comparable or even greater than present rates. The interval examined matters a great deal too; such as I'm sure you noticed looking at the pre-Holocene. The intervals coming out of glacials tend to be incredibly fast paced with a slow decline to the next one.

We're starting to approach a good synthesis of the reasons why I and many others call this period of warming unprecedented, but it may take a few steps as we proceed through them each at a time.

Quote
I need to move up to 300 years and above, and if you do that to modern temperatures, the AGW signal gets pretty lost. Sorry.

and
Quote
Nono. Well, yes, more, but my 2x was a comparison between the amplitude of the multi-decadal cycle against the long term local trend over a century (The exact factor will of course depend on the smoothing used. 30y gives about 2x, but using a 30y average for a 60y cycle mutes the amplitude, so it seems best to say at least 2x).


Indeed! Nothing I find controversial here; just acknowledging you.

Quote

If you compare the 1910 to 1940 30y trend against the 30y global trend of the same period (e.g. 30y HadCRUT4), it's more like 7x (and 8x if I chose 1905-1945 instead). That's precisely why I warn against interpreting the Arctic warming of the past decades without an understanding of a possible multi-decadal cycle. If you look at the rate of the 30y mean in the 20's and 30's, it's approaching 7C/century.


I agree, and I think the probability of this cycle being a real phenomenon is probably quite good. I don't know a whole lot about it though, but I'll read up on some of these papers when I have the opportunity.





 
midtskogenDate: Wednesday, 30.10.2013, 10:19 | Message # 77
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Quote Watsisname ()
Mmm, well I don't, and neither do the people who actually study this kind of thing for a living. They were extremely surprised to see such old vegetation at all.

Yes, it's exciting. And surprising, since the early Holocene was warm and had little ice. The question is, is this an isolated instance?

Quote Watsisname ()
The pre-Holocene moss doesn't stick around for very long after it has been re-exposed.

I agree. Just a few years, hardly centuries. This was just a minor point on the burden of proof on "unprecedented", since the current warming has only exposed old vegetation for a few years so far and unless "unprecedented" is assuming things of the future, that exposed vegetation could be covered up again shortly to become "unprecedented" a second time when the ice melts again.

Quote Watsisname ()
just a heads-up though that high resolution means short interval between points

Yes. Just a communication problem between my brain and fingers. I meant of course a wider temporal window.

Quote Watsisname ()
We're starting to approach a good synthesis of the reasons why I and many others call this period of warming unprecedented, but it may take a few steps as we proceed through them each at a time.

The starting point of the pre-Holocene warming (or warming events) was totally different. If you couple the warming with the temperature level it starts at, then, yes, the modern warming may be unprecedented depending on some minor but important points.

If you use a narrow window, 30y or less, which makes the current warming evident and dramatic, then it looks similar to the one in the early 20th century and I think it's fruitless to say which of the two was most severe (so far, since we can't declare that the current one has rounded its peak, or will for that matter). They just seem pretty similar to me. And we don't have data at such fine scale going 44,000 years back anyway, and for that reason alone we then can't really claim "unprecedented" at this scale (and we can't prove otherwise either, so we can hedge and say "may be unprecedented" if we really need to use and hollow the word). If we move up to the century scale, it becomes too soon to say what the rate of the current warming really is without some projection.

If the projections pan out and we have a pretty much open late summer Arctic Ocean as a lasting feature within 100 years, then I would say that the warming (dT/dt) is clearly unprecedented for the Holocene (perhaps not for the glacial period, though), and the warmth or state of the Arctic would be pretty similar to the Holocene optimum.

I encourage you to go all the way to the bare instrument data.

Oh, Vardø (69N 31E) has not only a very long homogenised record, but also one fitting the AWG story much better. This is what I found:

If you want unprecedented warming in the Arctic, make sure to rely heavily on those data. wink You need to go to eklima.met.no to see the data like that. The record in GISS is much shorter.

Added (30.10.2013, 13:19)
---------------------------------------------
Miller replies to some of the criticism:
Quote
We never claim that our data demonstrates Arctic-wide unprecedented warming, despite what Wyatt writes. Read the ms carefully, please. Our current research is expanding this study to other Arctic regions to evaluate the spatial domain of the Baffin Island pattern

Attachments: 9380143.png(12Kb)





NIL DIFFICILE VOLENTI


Edited by midtskogen - Wednesday, 30.10.2013, 10:20
 
expandoDate: Friday, 01.11.2013, 01:46 | Message # 78
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GREENHOUSE THEORY COMPUTER FAIL: REAL EVIDENCE SLAYS CARBON 'SCIENCE'

Written by Alberto Miatello & John O'Sullivan

So what gives with the climate theory that says more emissions of carbon dioxide means more warming? Despite atmospheric levels of carbon dioxide (CO2) up more than 40 percent in recent decades global temperatures have stubbornly remained flat for more than 15 years. Indeed, in the mainstream UK press global cooling is fast becoming the big news story with Arctic ice growing 60% in 2013 and Antarctic sea ice extent breaking an all-time maximum (September 14, 2013)Arctic Ice Growth in 2013

Alarmists have long insisted increased human industrialisation was a dangerous 'experiment' and we should stop adding more 'greenhouse gases' to the atmosphere. But the planet's stubborn refusal to get hotter has confounded expectations. At last, even the UN's Intergovernmental Panel on Climate Change (IPCC), in its upcoming Fifth Report admits the models may have exagerrated the impact of CO2.

Read rest of the article here http://principia-scientific.org/latest-....ce.html





"Religion is regarded by the common people as true - by the wise as false - and by the rulers as useful."
Lucius Annaeus Seneca
 
HarbingerDawnDate: Friday, 01.11.2013, 02:19 | Message # 79
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Welp, it was 10 degrees warmer today than it was yesterday, therefore it must have been 300 degrees warmer 30 days ago. Oh wait...

You're either a complete troll, or you haven't the slightest clue how math or science work, or what this thing called a "trend" is. I have a hard time believing that you're so dumb as to be the latter, so I'm going to go ahead and conclude the former. Either way, you need to stop this. This is the last time you're going to be asked.





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midtskogenDate: Friday, 01.11.2013, 12:51 | Message # 80
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You can't look at a few years of ice extent and say, "look, it's recovering". You can't say "look, it's collapsing" either, which is just as silly. The Arctic is a very volatile place in terms of weather and sub-centennial climate trends.

So, there was much more ice this summer than last year, and the Arctic is freezing up pretty quickly this autumn as well. October was cold in Svalbard (close to the cold 1961-90 normal), colder than in several years. Early freeze-in should keep that warm open ocean air away and bring promise of a cold winter and more ice, right? Not a chance. This October was pretty similar at 78N to October 2005 which was -5.3C, close to the normal, but then November followed with -3.9 (6.4 above normal), and -3.8 in December (9.4 above normal) and a ridiculous -2.7 in January (12.6 above) when it's pitch dark around the clock, the maximum reaching +5.1C in December and +7.7C in January way above the normal summer temperatures when the sun shines high and white even at midnight. The rest of the winter was way above normal, and April offering a grand finale of +0.1C (12.3 above normal). The Arctic is unpredictable and crazy stuff happen from time to time. Or rather frequently. Any trends are totally dwarfed by the short term variations.

Looking decades into the future, yes, I think the window for ice free summers is soon closing with the next one opening in the latter part of the 21st century (see previous discussion). But it hasn't closed yet. "Perfect storm" conditions could wipe the ocean clear up to the North Pole next year or even much later. You never know.

A warming in the Arctic is detectable during the 20th century, though it's in my opinion dwarfed by a greater multi-decadal oscillation. Some think the 20th century warming is just a LIA recovery. I don't think the LIA was much colder, if at all, in the Arctic than the 20th century. There's been human activity on Svalbard since the early 17th century, even overwinterings, and if it were colder, the summer snowline would have more or less reached the ocean and I think then few would go and even fewer return. I wouldn't be surprised if it was slightly warmer, even though much of the NH was freezing.

Added (01.11.2013, 15:51)
---------------------------------------------
Paper finding the early Holocene oceans quite much warmer than the last century:

Quote
Observed increases in ocean heat content (OHC) and temperature are robust indicators of global warming during the past several decades. We used high-resolution proxy records from sediment cores to extend these observations in the Pacific 10,000 years beyond the instrumental record. We show that water masses linked to North Pacific and Antarctic intermediate waters were warmer by 2.1 ± 0.4°C and 1.5 ± 0.4°C, respectively, during the middle Holocene Thermal Maximum than over the past century. Both water masses were ~0.9°C warmer during the Medieval Warm period than during the Little Ice Age and ~0.65° warmer than in recent decades. Although documented changes in global surface temperatures during the Holocene and Common era are relatively small, the concomitant changes in OHC are large.





NIL DIFFICILE VOLENTI


Edited by midtskogen - Friday, 01.11.2013, 10:40
 
WatsisnameDate: Sunday, 03.11.2013, 06:09 | Message # 81
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Quote HarbingerDawn
Welp, it was 10 degrees warmer today than it was yesterday, therefore it must have been 300 degrees warmer 30 days ago. Oh wait...

You're either a complete troll, or you haven't the slightest clue how math or science work, or what this thing called a "trend" is.


I like to portray his argument in visual format. smile



"Gee, I keep taking all these steps upward, why do I keep going farther down?"
--Expando, on trying and failing to walk up the down escalator.

Midtskogen also hit the nail on the head regarding short term variability vs long term trends.

But on to more serious discussion:

Quote midtskogen
Looking decades into the future, yes, I think the window for ice free summers is soon closing with the next one opening in the latter part of the 21st century (see previous discussion). But it hasn't closed yet. "Perfect storm" conditions could wipe the ocean clear up to the North Pole next year or even much later. You never know.


I agree with this assessment. There have been a handful of scientists who argue that ice-free Arctic summers could occur very soon, but I think it would require as you say a perfect storm, or a severe failure of our understanding/modeling of sea ice evolution. To be fair, the latter is certainly not impossible; it's a pretty tough problem with a lot of nonlinear relationships.

In the longer term ice-free conditions become all but certain; the question instead becomes how soon is it realized. It depends very significantly on emissions scenario, climate sensitivity, and the physics of ice loss itself, so there's a pretty big spread in projections, though from the modelling side these projections have improved a fair deal. One of the nice things we can do with models is look at the occurrence of ice-free conditions as a function of globally averaged temperature, with the CMIP5 models indicating this occurs at about 2°C warmer than the 1986-2005 period. (See AR5 Fig. 12.30).

In tying this to a date, we can anticipate mostly-ice-free conditions (extent less than 1 million square km) around the 2050s under high emissions scenarios.

Quote

Paper finding the early Holocene oceans quite much warmer than the last century:


Thanks! I haven't read the full paper yet (I've been very busy with my own papers lately, so sorry for the delays!) but judging by the abstract this is great information, and supports the consensus that the HTM was a couple degrees warmer than the 20th century average. smile

Notice also they are looking at intermediate ocean water, which doesn't respond to changes in surface/atmosphere temperature quite as rapidly as surface water. So that demonstrates that the HTM's warmth stuck around long enough to really get the ocean heat content up. Compared with the ocean heat content today, there should be a greater discrepancy than a comparison of surface/atmosphere temperature because the oceans have significant thermal inertia (the thermohaline circulation itself takes over a thousand years to cycle), and the present period of human-driven warming is both ongoing and hasn't lasted very long (only ~ a century). So the oceans now are very far from thermal equilibrium.

Another consequence of this inertia is that the oceans (the whole planet really, but especially the oceans) would still warm, though to much lesser degree, for quite some time even if we suddenly halted emissions and then maintained constant GHG concentrations.





 
midtskogenDate: Sunday, 03.11.2013, 06:58 | Message # 82
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Quote Watsisname ()
Thanks! I haven't read the full paper yet (I've been very busy with my own papers lately, so sorry for the delays!) but judging by the abstract this is great information, and supports the consensus that the HTM was a couple degrees warmer than the 20th century average.

I haven't either, but it seems to suggest that much heat can "hide" in the oceans, which we keep hearing about now during the "pause". If so, it could explain an open Arctic Ocean and still open up possibilities that there was more land ice during the Holocene optimum than we assume. While surface air temperature is what we mostly experience and happens to be the metric for climate change, it also suggests that the path from emissions to land surface air temperature change is potentially less straightforward than some might have it. Precisely what I keep saying. smile Of course, OHC changes then and now have different causes, but it leaves the possibilities open.

Quote Watsisname ()
I like to portray his argument in visual format.

Indeed!

Anyone can pick their doomsday scenario of choice. And they do. smile

It is possible that the 2013 rebound was the turn until the next cycle. But as long as some people claim that we hit bottom every time the cat bounces, someone will eventually be right. So if they turn out to be right, I'll give them no credit for their predictive skills.

Attachments: 2715504.png(32Kb)





NIL DIFFICILE VOLENTI


Edited by midtskogen - Sunday, 03.11.2013, 09:04
 
WatsisnameDate: Sunday, 03.11.2013, 14:21 | Message # 83
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Quote midtskogen ()
I haven't either, but it seems to suggest that much heat can "hide" in the oceans, which we keep hearing about now during the "pause".


You say that as if it is/was a mere hypothesis. biggrin The importance of the ocean has been known for a while, and if you think about it it is just a basic result of thermodynamics. The mass of the oceans is greater than the mass of the atmosphere, water has a higher specific heat than the air, and the two are in thermal contact with one another.

Quote
If so, it could explain an open Arctic Ocean and still open up possibilities that there was more land ice during the Holocene optimum than we assume.


Uh, no. I think you should probably not try to formulate these kinds of conclusions without being more knowledgeable of the field and how researchers do their work.

The fact that heat is transferred to the oceans does not affect our conclusions about prehistorical land or sea ice which are arrived at through observation. There is modeling, too, but most models these days do ocean-atmosphere interactions.

We don't know if the Arctic Ocean was totally open during the HTM, and I am personally not convinced that it was. The best data we have right now indicate that large portions were ice free at certain times, but not all of it at once, and some regions appear to have maintained significant ice concentrations throughout the whole period. This view is consistent with many of the studies you've been providing on this subject as well.

Recall the results of Vernal et. al, which are based on dinocysts, which are ocean sedimentary fossils.

Same idea holds with land ice. We don't assume how much there was, we go out and measure it. An understanding of ocean heat content does not change the data.

You may also recall the results of Renssen et. al which is based on a combined atmosphere-sea ice-ocean-vegetation model.

If you are also tying this back to the conclusions of Miller et. al, the paper I started page 5 with, then more land ice surviving the HTM would mean less sites showing Holocene flora, more sites showing pre-Holocene flora, and it would be even more remarkable that the same ice that survived the HTM is melting out presently.

Quote
Indeed! [image]
Anyone can pick their doomsday scenario of choice. And they do.


Yes, and anyone who does is being very dumb if they do so without any understanding of timescale or the physics involved.

With regard to Arctic sea ice extent we're looking at projections of ice-free or mostly-ice free Arctic conditions within our lifetimes. And these aren't merely projections made by looking at trends, but by sophisticated computer models and understanding of the relevant processes. Expando tried to argue against this by confusing short period variability with a long term response to a climate forcing, the latter being the trend that is physically meaningful to this purpose.

The red trend line in your image is also physically meaningful -- it's the long term trend towards what would be the next ice age if not for human activity. It's also a nice confirmation of what was stated in Miller et. al, that the region had been cooling by ~3°C over the last several thousand years. This long term cooling trend is pretty well understood, too, as a result of Earth's orbital/obliquity cycles. We can even predict these changes to astounding accuracy, recall the discussion about it at the end of the Snowball Earth thread.



I also don't know if the series of earlier blue trend lines are physically meaningful or not, or if they are representative of the whole arctic or planet (I highly inclined to doubt it).

Quote
It is possible that the 2013 rebound was the turn until the next cycle. But as long as some people claim that we hit bottom every time the cat bounces, someone will eventually be right. So if they turn out to be right, I'll give them no credit for their predictive skills.


Yep, I'd say predictions based only on data/trends and no understanding of the underlying processes have pretty poor predictive potential and should probably just be ignored. By no coincidence do I find unappealing the predictions of imminent ice-free Arctic summers which are usually based on analysis of trends and not physics. Even the IPCC report gives a few criticisms of such predictions.

The best knowledge we have yields the projections of Arctic sea ice extent that I described in my previous post. smile





 
midtskogenDate: Sunday, 03.11.2013, 21:12 | Message # 84
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Quote Watsisname ()
You say that as if it is/was a mere hypothesis.

"Hypothesis vocanda est".

It draws attention to a couple of problems. First that temperature measured a couple of metres above ground globally has been chosen as the metric for global warming (e.g. the two degree target). Second that the models didn't in general predict that the heat would go into "hiding" from the late 90's. That doesn't reduce the likelihood that this is exactly is happening, the problem is more on the philosophical level. If this can happen unpredicted, it also means that if surface temperatures perfectly obey warming models, we must likewise with great precision independently know what the heat exchange was between air and ocean to exclude the possibility that this didn't mask an incorrect model (like oceans today mask temperatures from a presumed correct model).

If this sounds like outrageous scepticism, let's return to Newton's full quote above (written in 1713), which in my opinion touches some important principles of natural science:

Quote
[H]ypotheses non fingo. Quicquid enim ex phaenomenis non deducitur, hypothesis vocanda est; et hypotheses seu metaphysicae, seu physicae, seu qualitatum occultarum, seu mechanicae, in philosophia experimentali locum non habent. In hac philosophia propositiones deducuntur ex phaenomenis, et redduntur generales per inductionem. Sic impenetrabilitas, mobilitas, et impetus corporum et leges motuum et gravitatis innotuerunt. Et satis est quod gravitas revera existat, et agat secundum leges a nobis expositas, et ad corporum caelestium et maris nostri motus omnes sufficiat.

The context of this was why Newton didn't propose a cause for gravity and why it's not necessary to propose one. But at the same time he defines a couple important requirements for theories in natural science: They must be deduced from observations, and the observations must be rendered general, i.e. must be shown to act according to laws. The IPCC uses phrases like "very likely" meaning 90% probability or more. For natural science I think such a figure is extremely weak. If there for every action was an opposite reaction only 90% of the time, or if you dropped a stone and 1 in 10 times it would fly into the air, I don't think Newton would have made his theory.

90% might be sufficient for some practical purposes, but that's not the point here.

Quote Watsisname ()
The fact that heat is transferred to the oceans does not affect our conclusions about prehistorical land or sea ice which are arrived at through observation. There is modeling, too, but most models these days do ocean-atmosphere interactions.

I didn't speak of modelling, but rather extrapolation. It could mean that the direct evidence that we have is less representative if we interpret them according to today's situation. Such as the N Greenland evidence for an ice free Arctic Ocean. IIRC the Baffin island samples were not taken on the ice caps that we already know survived all of Holocene, and it is an interesting find that there were more areas that the early Holocene didn't melt.

Quote Watsisname ()
The red trend line in your image is also physically meaningful -- it's the long term trend towards what would be the next ice age if not for human activity.

Are you saying that human induced warming will cancel the next ice age?





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WatsisnameDate: Monday, 04.11.2013, 10:59 | Message # 85
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I don’t see any problems other than that you continue to feel capable of forming opinions and arguments on a subject for which you are neither academically nor professionally involved in. Even a historical understanding of climate science may help you here.

We understood that heat goes into the oceans for a long time, but the devil of course lies in the details. It is very difficult to model how the heat is transferred through these systems and the ability to do so was and still is very much in its infancy.

As to the fact that it happens, it really is just that – an observationally confirmed fact as well as a necessary result of basic thermodynamics. To not accept it is as silly as not accepting that you’ll burn your finger if you touch a hot stove.

Quote
The IPCC uses phrases like "very likely" meaning 90% probability or more. For natural science I think such a figure is extremely weak. If there for every action was an opposite reaction only 90% of the time, or if you dropped a stone and 1 in 10 times it would fly into the air, I don't think Newton would have made his theory.


You probably think that because you lack a proper understanding of what these phrases mean or how they are arrived at. A reading of the very first section of any of the IPCC reports may help you here.

N% confidence level does not simply mean a finding was reproducible N% of the time (so you can ditch the stuff about Newton and philosophy, but thank you for your effort.) It means rather that as experts in the field, they have examined, either by qualitative or quantitative means, the type, amount, quality, and consistency of evidence, and conclude “based on this evidence, we are N% confident that this result is correct.”

In climate science, we are effectively 100% confident that CO2 is a greenhouse gas (radiative physics, laboratory measurements, paleoclimate evidence, direct observation by satellites of flux from Earth's atmosphere vs. surface, etc). And we are 95-100% confident that the current warming is due to human activity. (Models, paleoclimate perspective, contribution of various forcings, etc). Other aspects of climate change, such as regional changes in precipitation, storm tracks, North Atlantic hurricane frequency, etc. obviously come with lower confidence levels. They are hard to figure out and less supported by empirical data.

Quote midtskogen ()
Are you saying that human induced warming will cancel the next ice age?


Almost certainly no; CO2 doesn’t remain in the atmosphere nearly long enough. (Then again, if global temperature goes up several degrees C over a span of centuries, then there is not much precedent by which we can figure out what the very long term effects are.) But so far we can tell that we’ve canceled some of the period of cooling into it, several thousand years worth.

The purpose of the comment though was to show you that your red trend line actually is physically meaningful. If not for human activities, we'd be in a long term period of cooling toward the next ice age. I am not even remotely worried about this, let alone consider it a ‘doomsday scenario’. A gradual decline into an ice age over thousands and tens of thousands of years is something humanity does need to think about but the raising of global temperature by several degrees Celsius over a time frame of centuries is a very poor solution.





 
midtskogenDate: Monday, 04.11.2013, 13:15 | Message # 86
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Quote Watsisname ()
I don’t see any problems other than that you continue to feel capable of forming opinions and arguments on a subject for which you are neither academically nor professionally involved in. Even a historical understanding of climate science may help you here.

As opposed to the basis for your, at times pretty polarised nothing-between, opinions? I keep trying to move the discussions up to a slightly more epistemological level, allowing the existence of grey shades. I spent 10 years at university, mostly natural science which also includes the basics of the philosophy of science, finishing one MSc degree laudabilis prae ceteris which doesn't necessarily mean much except securing some scientific ballast for post-university life.

I wrote:
Quote midtskogen ()
It draws attention to a couple of problems. First that temperature measured a couple of metres above ground globally has been chosen as the metric for global warming (e.g. the two degree target). Second that the models didn't in general predict that the heat would go into "hiding" from the late 90's. That doesn't reduce the likelihood that this is exactly is happening, the problem is more on the philosophical level. If this can happen unpredicted, it also means that if surface temperatures perfectly obey warming models, we must likewise with great precision independently know what the heat exchange was between air and ocean to exclude the possibility that this didn't mask an incorrect model (like oceans today mask temperatures from a presumed correct model).

If you want to disqualify me from reasoning about science, try at least to link what you write a bit more explicitly to what I wrote.

Quote Watsisname ()
N% confidence level does not simply mean a finding was reproducible N% of the time (so you can ditch the stuff about Newton and philosophy, but thank you for your effort.) It means rather that as experts in the field, they have examined, either by qualitative or quantitative means, the type, amount, quality, and consistency of evidence, and conclude “based on this evidence, we are N% confident that this result is correct.”

So if Newton was N% confident about his laws, how many % of the time should we expect to reproduce the predictions of the laws? This is getting weird. Well, the answer is 100%, as any other number mean would that Newton was wrong. The point was, if he was 95% confident, he would likely call it a hypothesis having no place in science (hypotheses have later become quite accepted as part of the scientific method, though).

The director of Cicero speaks of humans as the cause for the observed warming like this: "It's not possible to be more sure than this. It's like whether the sun will rise tomorrow. We don't know for sure, but it's very likely". Actually, I'm prepared argue that it is possible to become more sure. Such statements represent an unscientific attitude in my opinion.

Another paper seeming relevant for Arctic temperatures. I wonder if it complements the recent Curry paper. The final figure looks similar to Curry's argument.





NIL DIFFICILE VOLENTI


Edited by midtskogen - Monday, 04.11.2013, 16:26
 
WatsisnameDate: Tuesday, 05.11.2013, 03:55 | Message # 87
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I welcome a philosophical examination of science, but if you like to do so then the premise of your analyses should not be based off of misconceptions about the field that you're trying to apply them to, would you agree?

I'm not attacking your wisdom or your educational background. I know you are a very intelligent individual and I have great respect for you. But you're falling for the same trap that many other people do when they argue about topics that they haven't studied well enough. I have seen the same thing in discussions of evolution, Big Bang theory, cosmology, etc, wherein people who are otherwise very intelligent feel that they understand the topic better than those who actually study or do it for a living.

Quote
If you want to disqualify me from reasoning about science, try at least to link what you write a bit more explicitly to what I wrote.


I did. Your conclusions are based off of a lack of understanding of how climate models work and the history of modeling in general, and I explained this to you explicitly. You question the correctness of the models because they did not predict the slowdown of atmospheric temperature due to this mechanism of transfer of heat between atmosphere and ocean. Of course they didn't. The ability to model it did not even exist at the time and we are still very much unable to completely model such variability even today.

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So if Newton was N% confident about his laws, how many % of the time should we expect to reproduce the predictions of the laws? This is getting weird. Well, the answer is 100%, as any other number mean would that Newton was wrong. The point was, if he was 95% confident, he would likely call it a hypothesis having no place in science (hypotheses have later become quite accepted as part of the scientific method, though).


It is not weird at all. If the laws of physics come with anything other than a 100% reproducibility rate, then either they are not laws of physics or else something is seriously wrong with the universe. But this is apples and oranges to what confidence levels mean in climate science, or nearly any other field of science. The majority of scientific study is not laws of physics, but rather based on laws of physics. It is not a law of physics that a cloud of molecular gas and dust should collapse to form a star, it is instead a consequence of various laws of physics that it sometimes does.

Confidence in the correctness of a finding is not simply how frequently an experimental result was confirmed, it is a more abstract concept involving how powerful the evidence and level of understanding is.





 
midtskogenDate: Tuesday, 05.11.2013, 12:49 | Message # 88
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Quote Watsisname ()
You question the correctness of the models because they did not predict the slowdown of atmospheric temperature due to this mechanism of transfer of heat between atmosphere and ocean. Of course they didn't. The ability to model it did not even exist at the time and we are still very much unable to completely model such variability even today.

Ok, so it was my observation that the models didn't predict the pause (or still only slowdown if you go for 30y trends) that made you jump from your chair and land on some hasty conclusions. I said they didn't, like you just did, except that I didn't equally strongly suggest they completely lack the ability to factor in heat transfers between air and ocean (whether they do to some degree do or don't at all is irrelevant for the argument).

What I questioned was the metric. And I pointed out that it fails to test the correctness of the models (whether predicting near surface air temperatures or OCH). A poor metric doesn't make the models less or more correct. It could make them appear incorrect (or correct when they aren't), for people who haven't studied things properly etc, if you like.





NIL DIFFICILE VOLENTI


Edited by midtskogen - Tuesday, 05.11.2013, 13:17
 
WatsisnameDate: Thursday, 07.11.2013, 22:13 | Message # 89
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This is where an understanding of climate models and their evaluation would be helpful. It is practically a field of itself and there is an entire chapter of the IPCC reports devoted to it, including discussion of the last 15 years of surface temperatures.

The skill or lack thereof of the models ability to reproduce observed behavior in the climate system absolutely is testable.





 
midtskogenDate: Sunday, 22.12.2013, 10:06 | Message # 90
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A study recently fixed the surface temperature hiatus by using satellite data to fill in missing areas, particularly the Arctic, usually missing in global temperature records. It was discussed at Realclimate and I was pointing out that care must be taken as 1979, the beginning of the satellite measurements which was picked ny the study, coincides with a temperature trend shift in the Arctic that might be cyclical (~70y), as we've previously discussed here. Apparently, one can not speak of any Arctic cycle at Realclimate, it doesn't exist, pan-Arctic temperature was totally flat until GW set it, but it's ok to talk about cyclical behaviour of the AMO. So let me post the 30y AMO trend here as well:



The link between the Arctic and the Atlantic should be obvious, but this cycle, whether it's called AMO or Arctic, still seems relevant to the study. It should have dealt with the coincidence that last AMO turn and satellite era begins at the same time.





NIL DIFFICILE VOLENTI
 
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