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billthefrog at 03:27 AM on 23 August 20142014 Arctic Sea Ice Extent Prediction
@ Gavin,
Absolutely no need for a mea culpa. I've been looking at the SEARCH (and now SIPN) stuff for about 5 years, and for the first 12-18 months I thought the same as you - and for exactly the same reason. It was only as I became more familiar with the data, that I realised it had to be the monthly mean which was being used. Largely as a consequence of this confusion, I've tried to drill myself to always explicitly state the time period of a min (or max).
I totally agree with your comments regarding the fact that, whatever the confidence interval selected, there is a gradual transition in the "confidence" of the result. A classic example of this being twisted to nefarious purpose was the loaded question that Phil Jones was presented with in 2010. The case was eloquently described by Dana on the SkS site, with the crux of the matter being the following question and answer...
Q: "Do you agree that from 1995 to the present there has been no statistically-significant global warming?"
A: "Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."
When I tried to work out the actual confidence level using the HadCRUT3 dataset, I think it came out at around 93% or 94%, but that's not how it was reported by the usual suspects.
For what it's worth, I tend to omit outliers such as 2007 (and latterly 2012) when trying to "outguess" the Arctic. This strategy wasn't bad in 2010 and 2011, but failed spectacularly in 2012, 2013 and 2014. (No prizes for guessing in which direction I was wrong about each of those years.)
Cheers Bill F
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One Planet Only Forever at 03:16 AM on 23 August 2014Global warming denial rears its ugly head around the world, in English
Lloyd Flack,
Please share some examples of the motivations of people who resist better understanding the climate science that are not greed related.
I agree that greed will not necessarily be the motivation for everyone who is reluctant to better understand what the constantly improving understanding of climate science is indicating about the acceptability of developed and developing human activity.
However, greed is definitely the motivation behind almost every effort to create and disemminate misleading marekting regarding the issue and attempts to discredit climate science. And greed is also likely the root motivation for almost all the members of the 'audience of information providers' who prefer to believe misleading criticisms of climate science.
What climate science, and so many other fields of scientific investigation, are developing is a better understanding that much of the developed and developing global economic and fiscal activity is fundamentally unsustainable and damaging. And the changes to the socioeconomic system that are needed to lead to have the system actually develop a sustainable better future for everyone are contrary to the interests of callous greedy people who have become powerful and wealthy by getting away with unsustainable and damgaing activity, and are contrary to the interests of people hoping to become wealthy and powerful through similar unacceptable pursuits.
Admittedly there are fearful people and desperate people also easily impressed by the attempts to misinform and discredit climate science. Many fearful people are afraid that they will not be able to live without burning dug-up hydrocarbons. That fear is related to their greed. They want the lifestyle they are accustomed to and fear not having it. That is a valid fear. But the lifes being enjoyed by high-consumption people not paying the full costs of ensuring there is no damage done by their lifestyle are living an illigitimate damaging life. Those who do not care to better understand the sustainability of how they live their life, do not care about future generations also being able to continue the same lifestyle, not caring that others who want to try today to live the same way cannot all be allowed to (only the winners of the dog-eat-dog competition to win to the detriment of others benefit, rather than having everyone compete to live sustainably better which would allow all people to live decently with competition finding even better ways for everyone to live decently) , would fear losing some of their benefits which are also illigitimate ways of living.
So, although there may be many other 'described motivations' most of them could be related to greed, even if the person does not internally recognise their motivation as greed.
And the media likes of Murdoch are not necessarily deliberately against climate science. It is just that greed can lead them to do what they are doing. Media sell advertising. And advertisers want to know what kind of people they are advertising to. The success of the likes of Murdoch can be seen as an ability to attract an audience that 'wants more new stuff', does not care about understanding negative implications of how they live or what they chose to consume, is easily impressed by a message that suits their image and is unlikely to check into the validity of a claim they thought they liked. That type of audience is golden for misleading advertisers who want to profit any way they can get away with.
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Leland Palmer at 03:03 AM on 23 August 20142014 SkS Weekly News Roundup #33B
"If it is connected to deep thermogenic gas, then no problem. No possibility of a methane apocolype from that kind of cause."
I admire your certainty, so soon after the appearance of this new cold eruption phenomenon. But, you've actually been quite helpful, and have helped advance the "cold eruption as a cause of the circular lake phenomenon associated with Siberian gas fields" hypothesis.
I'm afraid, though, I cannot agree with your statement about "no possibility". The permafrost weakening mechanism could likely produce cold eruptions from any high pressure source, and it may be that the thermogenic gas fields have the highest pressure.
So, thanks for your help.
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Dikran Marsupial at 21:41 PM on 22 August 20142014 Arctic Sea Ice Extent Prediction
billthefrog If you look at the call for contributions, you will find it talk about the September minimum right at the top of the page
"The Sea Ice Outlook provides an open process for those interested in arctic sea ice to share ideas about the September minimum sea ice extent. The monthly reports contain a variety of perspectives—from advanced numerical models to qualitative perspectives from citizen scientists. A post-season report will provide an in-depth analysis of factors driving sea ice extent this summer as well as explore the scientific methods for predicting seasonal ice extent"
but September mean much further down. Presumably that is where the confusion arose, mea culpa (I don't appear to be the only one to make that mistake). Thanks for pointing this out, I'll update the page to reflect this.
What difference does it make? Well not much really, if you have a 95% credible interval (note: it is not a frequentist confidence interval), it means you should expect the observations to lie outside the intervals 5% of the time, even if the model is perfect. If the observations lie very slightly outside the CI they are only slightly more unexpected than if the lie very slightly within. The important thing the model learned from the last two years (where the observations were at opposite ends of the interval) was that it was probably underestimating the variability, which is why the credible interval is a bit wider this year. If you look around 1995, you will see that the observations were outside the CI then, even though that is in the calibration period. This sort of thing does happen from time to time, especially if the model is non-physical - you know it is "wrong" (in the GEP Box sense) a-priori.
Now, nobody is claiming the model is perfect, or even good, just a simple statistical baseline that expert opinion or physical models ought to be able to improve upon. -
billthefrog at 21:08 PM on 22 August 20142014 Arctic Sea Ice Extent Prediction
@ Gavin & Franklefkin,
Hi guys,
Perhaps it might help if we go through this one step at a time. Gavin correctly points out that, in previous years, this exercise was carried out under the Study of Environmental ARctic CHange umbrella (ie SEARCH).
However, I think Gavin is mistaken in the assertion that the criterion requested for 2013 was the daily minimum recorded in September. In the SEARCH background page, it clearly states that...
An integrated monthly report is produced that summarizes the evolution and expected state of arctic sea ice for the September mean arctic sea ice extent, based on the observations and analyses submitted by the science community. (My underlining)
More specifically, the SEARCH Report for June 2013 states...
With 23 pan-arctic Outlook contributions, an increase over the last two years (thank you!), the June Sea Ice Outlook projects a September 2013 arctic sea extent (defined as the monthly average for September) median value of 4.1 million square kilometers, with quartiles of 3.8 and 4.4 million square kilometers (Figure 1). (Again my underlining)
If the submission was made mistakenly thinking that the daily minimum had been sought by SEARCH, then we are into the realms of chalk and cheese. Should this be the case, then the projection of 4.1 +/- 1.1 million sq kms does indeed encompass the observed NSIDC daily minimum of 5.1 million sq kms. (Especialy as NSIDC have, I believe, an uncertainty figure of around 50,000 sq kms.) However, that was not what the SEARCH team was looking for.
On the other hand, if, as Franklefkin suggests, the 4.1 million sq kms daily figure is somehow derived from an intermediate calculation giving the projected monthly average, then we are in the dark as to the value of this hypothesised monthly mean.
A third alternative is that the 4.1 million figure does represent the monthly mean. In that case - barring Snowball Earth and Hothouse Earth intervals - it is impossible, both physically and mathematically, for the daily mean to equal the monthly mean.
Sorry about this guys, but if got to sign off and go exploring ancient ruins on Dartmoor. I will log in again later this evening to explain my "jangling nerves" comment further.
Cheers Bill
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Tom Curtis at 13:44 PM on 22 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
To the moderator, I know I probably provoked him by posting a sensible post on a related topic, such that Donny had to rush in to fill the space with distracting nonsense, but surely Donny's quota of irrational, unsupported online "arguments" is used up. If he cannot state a cogent case, with clearly linked supporting evidence, why is he permitted to waste our time?
Moderator Response:[JH] As long as you and others choose to respond to Donny's "distracting nonsense" before a Moderator can take action to delete his post, the problem will persist.
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Tom Curtis at 13:41 PM on 22 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Donny @71, the total cost of the Conservation Reserve Program from 1995-2012 was 31.5 billion dollars, for an average payment of 34 thousand dollars per recipient, or 1.9 thousand dollars per annum per recipient.
For comparison, farm commodity subsidies amounted to 177.6 billion dollars over the same period, for an average of 60 thousand dollars per recipient, or 3,356 per annum. Further, there were only 1.4 million eligible recipients for the CRP, compared to the 2.9 million recipients of commodity subsidies. In all, the CRP represented only 13.3% of US farm subsidies. The 1.75 billion payed out in CRP in 2012 represented just 0.4% of gross farm income in the US, and 1.3% of net income.
Given these statistics, the claims made about the CRP at the site to which you link are hardly credible. Having acreage under cultivation results in higher net subisidies for the farmer, which are more easilly obtained. Once income from sale of products is included, it can only be commerically advantagious to have acreage rented under the CRP program if that acreage generates a marginal return in the first event. Further, the CRP does result in a net conservation gain, so that its stated purpose is its most likely actual purpose. (Arguing that a minor tie up of land focussed on degraded land that results in improvement of land quality and recovery in population of threatened species was not introduced for the stated purpose of conservation looks very like a conspiracy theory to me.)
Finally, in total, as of 2014, 5.62 million acres of farmland were tied up by CRP contracts. That is just 0.55% of total US agricultural land. So even it, as per your fantasy, the land tied up by the CRP was as productive as the rest of US agricultural land, releasing it would not compensate other than to a minimal extent to the expected loss in agricultural productivity from global warming.
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Donny at 12:24 PM on 22 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
www.pbs.org/newshour/making-sense/why-does-the-govt-pay-farmers/
Ending CRP would help in the extremely unlikely event that there was a shortage.
Moderator Response:[PS] This is not science. It is not even basically relevant. Other commentators have produced data to support their argument that climate change is not going create new farmland due to warming temperatures at a rate commeasurate with crop decline in other sectors. Things like actual studies, soil maps etc. Change of land use in existing areas of arable soils are not relevant. Expect further offtopic, essentially political points to be deleted.
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Tom Curtis at 11:10 AM on 22 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Further to my post @69, here is a map of the geological regions of Canada:
It is interesting to note that Canadian agriculture is largely confined to the spur in Ontarion between Lake Huron and Lake Erie, and to the Interior Platform in Manitoba, Saskatchewan, Alberta and British Columbia.
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Tom Curtis at 10:45 AM on 22 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Just to put the "new agricultural lands" idea into perspective, and in lieu of boots on the ground, compare the following views from google Earth:
Prime agricultural land north of Saskatoon
This image is centered on Warman. To get the relevant view, tilt twice so that you are looking north, then (while retaining Warman in the forground), scale in to 200 m. Having done so you will see the extensive farmland, which has been plowed, and is evidently intended from growing grains. You will also see the system of small lakes that are a consequence of past erosion from the Laurentide ice sheet.
This map will help you place the view, which is evidently looking north toward the black (best) soil, although whether it is in that belt or just below it I am unsure.
Scrolling the view north you find greener fields, and then forest, but throughout the pattern of extensive lakes persists. Therefore the glacial erosion pattern certainly persists through the best soil of the Canadian Prairie.
Non-Agricultural Land north of Preston Lake
Looking further north within Saskatchewan, we have the view from Preston Lake. Again, tilt twice to look north but focus in till the scale is 500 meters rather than 200 meters, again retaining the main feature (Preston Lake) in the foreground. We focus in to 500 meters because the 200 meter resolution is not available in this part of Canada.
It is interesting to see that here we have a similar pattern of lakes formed by glacial erosion to that found in south Saskatchewan north of Saskatoon. Here, however, the green represents forests. A large proportion of the dry land, however, is taken up by of-white formations that apparently resist tree cover. Comparison with the far whiter sands near lake Athabasca (further north) suggest the of-white formations are not sand, but rock. Indeed, a description of a minereological claim in the area states:
"[The claims] includes a large area of partially exposed pre-Cambrian shield rocks. ... The claims are underlain by Phanerozoic rocks (limestone and sandstone)..."
The of-white exposed portions are, therefore, most probabily the pre-cambrian shield rocks as shown here:
Or possibly exposed areas of the underlying sandstone/limestone as shown here:
Clearly this area, while apparently very suitable for a uranium mine, is not at all suitable for agriculture. The brunisolic soils of the area apparently provide a thin cover over the base sedimentary rocks, with earlier (and harder) exposed pre-cambrian rock covering much of the territory. The soil under actual forested areas is probably thicker than in the photo above (where the clearing is probably a clearing for a reason), but is not thick.
Non-agricultural land in Northern Quebec
Finally, for completeness, is the area around Lac Bienville in northern Quebec. Again, centering the google Earth image on the lake, tilting twice to look north and and focusing in to the highest resolution view (500 meters), we see a similar, but for more intensive glacial erosion pattern. Further, as with north Saskatchewan we see extensive pale regions marking regions, whose nature can be determined from this surface photo taken slightly further north at Bienville Sud:
I do not feel the need to point out why that land is not suitable for agriculture.
I'll make an important caveatte that google Earth and photos found on the internet are no substitute for on ground experience, so that my discussion below is premised on the supposition that anybody with onground experience in these regions agrees with my assessment of them. (In this discussion, by "anyone" I primarilly mean Bob Loblaw, who has previously asserted such experience.)
I think this comparison of agricultural vs non-agricultural shows very clearly why land in northern Canada is for the most part unsuitable for agriculture quite independent of current climate. The past history of climate in the region is relevant because formation of soil would have been far faster in a tropical region (for example), but that is no help over the next few hundred years. Even such soil that does exist in northern Saskatchewan is brunisolic, ie, it is "... a stage in an evolutionary sequence that begins with an unweathered parent material (Regosolic soils) and ends with development of a “mature” forested soil of the Podzolic or Luvisolic orders" and as such is unsuitable for agriculture in any event.
Finally, scaddenp @68 mentions Hobson et al (2002). That paper discusses the conversion of forest to agriculture in a belt across the middle of Saskatchewan, more or less on the latitude of Pince Albert, and hence mostly south of Edmonton. As such, it is mostly in, or on the northern edge of the black soil region shown in the map above (first image). Clearly statistics on clearing forest in regions of known good agricultural soil have no bearing on the potential for conversion from forest to agriculture further north where there are large areas of exposed pre-cambrian rock and the soils are of a much lower quality.
As a footnote, I have found a new online map of canadian soils which has the distinction of also being able to show simultaniously the limits of current agriculture. That feature helps show the importance of soil type in placing the northern limit of agriculture. It shows the limited conversion of luvisolic soils to agriculture in Alberta and Saskatchawan, along with the almost complete absence of conversion of brunisolic soils. In west Ontario, regions with brunisolic soils on the US border are still agriculture free. Anybody arguing the brunisolic soils of northen Aberta and Saskatchewan will suddenly become suitable for agriculture due to climate change need first to explain why equivalent soils on the US border are currently unsuitable for agriculture.
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chriskoz at 10:30 AM on 22 August 2014Climate Change Impacts in Labrador
Robert,
In this movie by Zach Kunuk, that you probably know very well, Inuit elders are saying that bears are not threatened by climate change at all: in fact they are thriving in this dramatically new climate, despite sicetific evidence to the contrary.
What's your opinion about it? How many bears did you see and were they annoying? Perhaps hunger makes bears more desperate and they congregate around human settlements in search for food making the appearance to Inuits as if their population were increasing?
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Dikran Marsupial at 04:22 AM on 22 August 20142014 Arctic Sea Ice Extent Prediction
Billthefrog, thanks for your comments, I'll fix the minor errors when I have a moment (hopefully tomorrow). Last year (2013) the exercise was run by SEARCH, rather than SIPN, and last year, the criterion was the September minimum.
The SEARCH Sea Ice Outlook is an international effort to provide a community-wide summary of the expected September arctic sea ice minimum. Monthly reports released throughout the summer synthesize community estimates of the current state and expected minimum of sea ice—at both a pan-arctic and regional scale.
If it is September mean this year, then that means my model is a better fit to the criterion, but the prediction interval is so large I doubt it would make much difference in practice.
I don't see why the sentence
"Note also that the model actually predicts the mean Arctic sea ice extent for the month of September, and so can be expected to somewhat over-estimate the September minimum."
should jangle the nerves, it is just pointing out a known bias in the model, it isn't excusing anything. This is the norm for reporting science, pointing out the flaws and biases in the model. As you can see from the caveat lector at the end, I am not suggesting my statistical model is anything more than a useful statistical baseline, as it does not take into account any of the physics. It also only uses the annual September means, so it is a prediction based on (a little of) what we knew last September. I would be very surprised if it doesn't turn out to be substantially pessimistic.
Note also in recent years the observations have been first at the very bottom of the prediction interval and then at the very top, so this issue doesn't actually help make the model look any more accurate overall anyway! The bias "helps" in some years, and it "hinders" in others, but it is always there.
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franklefkin at 03:52 AM on 22 August 20142014 Arctic Sea Ice Extent Prediction
billthefrog,
Gavin's method uses past September averages to predict a new September average, which then predicts a one day low - hence minimum extent-----I believe. He is obviously better able to describe his method. Given the above, his prediction for last year was just within the bounds.
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billthefrog at 03:32 AM on 22 August 20142014 Arctic Sea Ice Extent Prediction
@ OP
Gavin,
There's a little proof reading problem in the OP, in that Figures 1 & 3 are reversed from the way they are described in the body text.
Also - and please forgive the pun - but I think you're skating on thin ice as regards your characterisation of your model's prediction for last year. My understanding (not that that's saying much) is that all the figures submitted to the SIPN should relate to the mean September figure, rather than the absolute one-day minimum.
The observed figure for the Sept 2013 average was, as shown above, 5.4 million sq kms. (This is, I think, an upward rounding of the 5.35 million sq kms given by the NSIDC.) That being the case, I'm afraid the observed figure did fall outwith your model's error bar range.
I'm usually reticent about criticising the choice of phraseology that people employ (each to his/her own and all that stuff) but one sentence did seriously jangle the nerves. You wrote that...
Note also that the model actually predicts the mean Arctic sea ice extent for the month of September, and so can be expected to somewhat over-estimate the September minimum.
It may not have been your intention, but that sentence sounds as if you were trying to account for some of the divergence between the observed and predicted values. There would be no problem with that if the model had indeed produced an over-estimate, and it was being compared to the absolute daily minimum. If that was the case, it would indeed explain away some, or perhaps even all, of the divergence.
However, since the model produced an underestimate for the monthly average, it doesn't help at all as a mitigating factor in explaining the divergence from the observed one-day minimum. In fact, if you give some thought to the matter, it has quite the opposite effect!
Please note that I'm not in any way suggesting that there is some significant reversal of the decades-long trend in Arctic Sea Ice. Sadly, it is in no way surprising that, in a breath-taking display of revisionism, the lessons regarding the so-called "recovery" between 2007 and 2009 seem to have already been expunged from the collective memory in some quarters.
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wili at 01:48 AM on 22 August 2014Scientist in focus – meteorologist and climate communicator Paul Huttner
I was just listening to Paul and Kerri broadcasting this excellent program from the first day of the Minnesota State Fair. I second all of John's praise for the program. I hope they expand it.
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Lloyd Flack at 00:36 AM on 22 August 2014Global warming denial rears its ugly head around the world, in English
As several have pointed out here it is usually a waste of time trying to convince a denier. What you have to do is expose them them to their audience.
What I think you have to do is to expose their irrationality. You won't do that by attacking their arguments. What you have to do is get them to display their willful blindness. You have to get them into a position where they have a choice between accepting logic and holding on to their beliefs.
And when they are obviously looking for reasons to keep on believing something try to get then to answer why.
But to effectively do all this you have to actually understand their motives rather than attribute to them motives that are easy to denounce. And that means don't talk about greed. Other things are more important. Some are actually worse or at least more dangerous.
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scaddenp at 00:34 AM on 22 August 20142014 SkS Weekly News Roundup #33B
If it is connected to deep thermogenic gas, then no problem. No possibility of a methane apocolype from that kind of cause.
You cant have methane hydrates at depth since only stable in a narrow pressure range. I cant see any plausible mechanism to have long term high rates of methane flow from hydrates.
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One Planet Only Forever at 00:01 AM on 22 August 2014Global warming denial rears its ugly head around the world, in English
Mancan18,
It is unfortunte that Australia appears to have ended up with a similar situation Canada is currently in, hopefully returning to developing toward a sustainabe better future for all with earnest, if the impending 2015 election unseats a similar group of characters. Polls indicate that the general population in Canada is becoming more aware of the threat posed by such characters, and are not as easily tempted to be fooled by the made-up claims of these people who have 'made-up their minds to never chage their minds' no matter what information is provided that contradicts their interests.
Al Gore's book "The Aussault on Reason" (2007), includes a fairly comprehensive presentation on the problem of consolidation of media power by the likes of Murdoch. And he has some recommendations for actions that might defeat the irrational influence of such arrangements.
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2014 SkS Weekly News Roundup #33B
Leland Palmer - The Yamal craters are quite interesting, and should certainly be studied. However, concern should be weighted by risk, and by analysis, and reasonable estimations of melt rates, emissions, and methane decay indicate that a Shakhova type methane catastrophe is simply not in the cards.
You have posed increasingly implausible scenarios, including permafrost decay and methane percolation rates hugely larger than the physics would indicate, you have conflated thermogenic gases (deep seeps) with biogenic sources (permafrost decay), and from a few crater events have extrapolated ~7 orders of magnitude to a methane catastrophy. You are IMO extending concern far far past what the physics indicate as risks.
Given the decay time of methane, I would be far more concerned about subsea hydrates than permafrost decay - and neither is terribly likely if you actually look at the physics and numbers. In the meantime, going overboard with unsupported "we're doomed" scenarios is a distraction from acting where we can, and focusing on controlling our emissions. A focus, I'll point out, that greatly reduces the already low chances of a methane catastrophy by minimizing total climate change.
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Leland Palmer at 23:39 PM on 21 August 20142014 SkS Weekly News Roundup #33B
scaddenp-
"Leland, the "door to hell" can maintain production over a long period because it is effectively connected by a "pipe" to a very large high pressure reservoir at depth."
The initial gas eruption at Yamal might be pretty good evidence that the same is true at Yamal.
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mancan18 at 14:28 PM on 21 August 2014Global warming denial rears its ugly head around the world, in English
One Planet Only Forever
Sadly, in Australia, the Murdoch press who Andrew Bolt and a number of other deniers write for reaches around 83% of Australia's literate population. Also, the Institute of Public Affairs, of which Maurice Newman and others are associated with, and whose closest American equivalent would be the Marshall Centre, wields a high proportion of business and economic policy influence with the Liberal Party, which currently holds Government. There is very little challenge to their climate change narrative, although the Government does profess to agree that climate change is happening, it then gives the green light to burning more coal as a method of counteracting it, and promotes a policy called Positive Action but then provides it with inadequate funding.
There are a few fringe commentators and comedians who do make cynical and satirical statements regarding the situation in Australia, however, the only place where climate science is reported honestly in the media anywhere Is on the ABC program Catalyst with a few press releases by the CSIRO and the now private Climate Commission. There is very little to offset the bias in the Murdoch press.
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PhilippeChantreau at 13:06 PM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Bob Loblaw has it right. Unfortunately, large masses of people are so undereducated in general that they can't even have a concept of the significance of the stuff they don't know. After years of being nice to everybody and giving points for trying, we end up with countless people who believe that their opinions matter even when they are completely clueless. Isaac Asimov summarized that attitude very well: "my ignorance is just as good as your expertise."
What kind of exchange can happen, in the thick fog of today's bullshit wars with those who live by this motto?
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Leland Palmer at 13:01 PM on 21 August 20142014 SkS Weekly News Roundup #33B
"As Archer has said, our focus should be on our emissions."
No.
This cold gas eruption release mechanism is a new effect, and we should focus on understanding it.
After we understand it, then we can come to some conclusions about how significant it is.
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One Planet Only Forever at 12:59 PM on 21 August 20142014 Arctic Sea Ice Extent Prediction
NSIDC reporting on Arctic Ice extent (here) indicates their expected minimum is between 5 and 5.5 million square kilometers. A range of possible extents from about 5.9 down to about 4.8 based on a variety of projections from the current extent is also presented.
The revised WUWT forecast is indeed still in the race though it is above the upper side of the NSIDC likely range for this year's minimum. But unusual things can and do occassionally happen in the complex climate system of our planet, so we still have to wait to see how this will turn out, and add this year to the total set of information, making no claims based on this year compared to last year.
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Bob Loblaw at 11:56 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Ashton @ 13: "You have to structure the argument for your point of view so "they" can follow it."
That sounds an awful lot like what my sister would call "Sesame Street Learning" - the student just has to sit back and watch/listen, and the teacher has to do all the work. Unfortunately, I've seen too many students with that attitude, even at the university level - they expect to get good marks for just showing up at lectures.
Learning takes effort by the student. People that don't want to learn, won't - no matter how good the teacher is. If they don't want to learn, then their opinions will often be uninformed, as Dikran alludes to @14. If people refuse to learn, then their uninformed opinions are not a positive contribution to the discussion.
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One Planet Only Forever at 11:51 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Ashton,
I provided a comment on the recent sks report about this year's potential El Nino (here), showing that the global temperature record shows that the warming has continued without getting into explanations of how La Nina conditions result in temporarily lower global average surface temperatures as more heat is taken into the ocean. Yet that simple and easy to present case will not 'convence anyone against their will'. So I would disagree with your comparison of convincing students, with convincing the general public. The method of appeal to the general public needs to be both emotional and rational, even though the rational approach has far less chance of success.
Using the points in my earlier comment here, I have had some success delving into 'why a person is reluctant to accept the science'. And by bring up all the other unacceptable consequences and fundamantal unsustainability of benefiting from burning dug up non-renweable hydrocarbons the result is usually a realization by the person that they were deliberately not wanting to understand the science. Some then change their mind and want to learn more. Others dig in further in a fight to preserve their internal justification for something that is clearly unacceptable. Either way, a better understanding has been established.
As for the media attention, does Australia have its equivalents of The Daily Show, Real Time with Bill Maher, the Colbert Report, Last Week Tonight with John Oliver like Canada has This Hour has 22 Minutes and the Rick Mercer Report? There would seem to be a potential market for providing public entertainment in Australia at the expense of all the 'deniers' including Australia's Government-of-the-Moment. And the show could target more than just Climate Change deniers. It could target all the people who deliberately are doing anything they think they can get away with to get more profit quicker for as long as they can get away with.
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mancan18 at 08:17 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
scaddenp, Dikran Marsupial and Ashton
The reason for thinking that in any argument with a denier, you need to reveal their core belief in order to get a baseline for debate (argument).
A few months ago, I had a very heated argument with a denier. It took me half-an-hour for him to admit that CO2 levels had reached 400 ppm, was rising at 2ppm p.a., and another 15 minutes for him to admit that in his lifetime, levels had risen nearly 100 ppm from a situation that has existed for at least a million years. Amongst all this, I never got him to admit that CO2 was a greenhouse gas even using the simple examples of Venus compared to Mercury, and the Earth versus the Moon. Along the way I was called a socialist, Marxist, greenie, and other things and told in no uncertain terms that it was all crap and just some sort of conspiracy. Now this denier usually doesn't believe in conspiracy theories but in this case he does. I probably shouldn't have pushed the argument once I realised he just didn't believe the CO2 argument. I should have simply stated he was wrong and he needs to do more reading.
However, the Bolts and Newmans of this world do need to be challenged because of their wide influence. At a site like Skeptical Science arguing using scientific evidence should win the debate, but in the wider media it won't. Evidence needs to be used selectively and sparingly otherwise it just overwhelmes the wider public. It is probably better to ask deniers the right questions to reveal the unscientific nature of their core beliefs than just arguing from polarised positions. In the non-scientific world, a bit of Socratic questioning is probably better than copious amounts of evidence. In a one-on-one debate with the likes of Bolt or Newman you will probably always lose unless you expose the weakeness of their arguments, which you can do by asking the right questions. In fact, proving the case beyond reasonable doubt in some sort of mock trial would be far more effective in convincing the wider public than just trying to overhwelm deniers with evidence.
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2014 SkS Weekly News Roundup #33B
Leland Palmer - A relevant paper to this topic is Etiope and Klusman 2002, discussing global CH4 emissions from all sources. These include biogenic and thermogenic methane, and the totals from atmospheric CH4 isotopic ratios indicate that such seeps are a rather small fraction of that emitted from biosphere sources.
Reality checking indicates that thermogenic seeps are not major contributors, and that even if there were trapped seeps under permafrost they wouldn't be sufficient to cause a Shakhova type catastrophe - by multiple orders of magnitude. There simply aren't enough seeps globally.
Again, I understand your concerns regarding methane emissions - but the numbers show that a methane catastrophe (from either hydrate or seeks) is very unlikely. Your increasingly hypothetical scenarios are just not plausible.
As Archer has said, our focus should be on our emissions.
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scaddenp at 06:57 AM on 21 August 20142014 SkS Weekly News Roundup #33B
Leland, the "door to hell" can maintain production over a long period because it is effectively connected by a "pipe" to a very large high pressure reservoir at depth. Not so with methane hydrates. They are shallow so there is minimal pressure. You may be aware of experiments to mine methane hydrates. If you could get sustained flow rates that easily from melting hydrates, then mining would be easy.
While I remain skeptical that frozen tundra is capable of sealing a gas seep, even it were so, we know that the amount of methane going into the atmosphere from such sources has little affect since existing gas seeps contribute little of significance. It is unreasonable to expect there are far more leaky natural gas field under tundra than there are in other parts of the world.
However "methane hydrate apocolypse" proposes that warming of the arctic will release huge amount of methane over a sufficiently short period of time to significant increase global warming. Critcs such as Archer note that the existance of such large quantities of hydrate remain hypothetical and that being able to melt them fast enough to have significant impact without other externalities is not yet demonstrated. The Yamal craters at this stage dont appear to provide much support to the methane apocalypse given the quantities of methane involved.
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scaddenp at 06:38 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
I fully agree that getting a message across clearly is important, but getting bad news across is extremely difficult because too many would rather read the anodyne instead. And its not just the "cause" that is lost, because nature doesnt care whether we understand what is happening or not.
The climate change message is complex, and its made more complex by the amount of baloney out there produced by those who have idealogical or economic resistance to any solution proposed.
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Leland Palmer at 06:10 AM on 21 August 20142014 SkS Weekly News Roundup #33B
Hi KR-
"What I believe scaddenp is saying is that thermogenic methane isn't a factor in climate change, because those sources are not changing, and are really quite unaffected by surface temperatures."
The sources aren't changing, much, but the permafrost cap is. That is the concern, I think, that high pressure gas that has accumulated over thousands of years could erupt through a weakened permafrost cap. I think that was also Shakova's concern about the East Siberian Arctic Shelf- that the relict undersea permafrost could be weakened, and release reservoirs of high pressure free methane gas.
It's the accumulate and sudden release possibilities that worry most scientists about methane, in one way or another. Dickens and Hansen, for example, are concerned that the oceanic hydrates, accumulated over millions of years could ultimately be dissociated.
If the permafrost weakening process is what is allowing these eruptions, we could see many thousands of them, I think.
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Dikran Marsupial at 03:40 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Ashton, it was you that pointed out "That is perhaps why "denier" blogs have a bigger following than blogs run by proponents of climate change.". I pointed out that the reason that this is plausibly true is nothing to do with the effectiveness of the communication, but because they are providing an anodyne, comforting message that is appealing a-priori, even though it is not supported by the science. You have evaded that point completely.
Try getting popular support for an action that will bring the greatest benefit to other people in the future, that will have a negative effect on individual prosperity now, and you will find support difficult to find whatever the question happens to be. That is human nature, to expect otherwise is naive. The MORI poll results suggest that the general public has been rather more receptive than I would have expected.
As to soundbites, more baloney is not a good response to baloney, all you would be doing with the ones you suggest would be to open yourself up to accusations of ignoring the uncertainties and lack of unequivocal support for the economics. -
Ashton at 03:08 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Dikran Marsupial. It isn't those who frequent sceptical blogs you need to convince but the average person in the street who neither knows or cares about any blogs on Climate Science.
The MSM puts its message out in short pithy soundbites or alliterative headlines that grab the attention. Here's a couple of, imaginary, examples.
PM in radio interview says "Incomes will fall by 40% unless gobal warming is stopped".
The Daily Gossip "Scientists say fossil fuel use to force pay freeze"
Mancan 18 totally agree it is the wider public that needs convincing but disagree that climate change advocates have to defend their position while deniers can say what they like. Deniers continulally point to the current hiatus in global temperatures in the face of rising CO2 while the scientists say the missing heat is in the oceans although the evidence from the Argo system does not seem tounequivocally support this contention at the moment. More isignificantly perhaps "deniers' get less media time than "advocates" on ABC (Australia) and the BBC and less articles in the Fairfax press but more articles in the Murdoch press. As radio and TV have far wider coverage than print media advocates currently are ahead of deniers as far as exposure to the wider audience is concerned. Whatever, my position like yours is that the MSM is central to and crucial for informing the "man in the street"
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dcpetterson at 01:48 AM on 21 August 2014Antarctica is gaining ice
Jetfuel,
1) Yes the rate of melting of Antarctic land ice is increasing. Simply projecting previous rates into the future is not a useful calculation.
2) A permanent increase in sea level, even a small one, is not comparable to the temoprary increase in tides represented by the position of the moon. In a similar way, a daily variation of +/- 20 degrees F between midnight and noon is normal temperature variation, but a permanent difference of 4-6 degrees worldwide can trigger an ice age or eliminate all glaciers and ice caps.
I think there is a thread dealing with arguments that ciimate change isn't that bad. Perhaps this would be better discussed there.
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Dikran Marsupial at 01:08 AM on 21 August 20142014 Arctic Sea Ice Extent Prediction
franklefkin the prediction exercise targets the NSIDC September minimum extent, so I use the NSIDC data to calibrate my model (although I use the mean rather than the minimum).
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Leland Palmer at 01:05 AM on 21 August 20142014 SkS Weekly News Roundup #33B
michael sweet-
Yes, the information is very preliminary, and they seem to be making the wrong measurements, or making the right measurements in the wrong way.
If there is a bouyant plume, what matters to the long term release calculation is the methane concentration at the top center of the crater, I think.
The best way to do such a calculation would be a fluid dynamics calculation, of course, or computer modeling.
I still think it's possible that these craters could be a signifcant long term source of methane, and that the chronic releases might end up being more significant than the initial eruption event- even much more significant, by a large factor.
The significance of the "Door to Hell" image is that it makes the methane entering that crater visible. The methane entering that crater, looking at it visually, could be on the order of ten to 100 cubic meters per second. Turkmenistan, according to Wikipedia, wants to increase its exports to 75 million cubic meters of gas per year, so like Yamal, the ultimate reservoir of gas available is very large.
It might be possible to get some idea of the chronic emissions by looking at natural gas wells in the area, and seeing what their output is in tons per day.
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2014 SkS Weekly News Roundup #33B
Leland Palmer - What I believe scaddenp is saying is that thermogenic methane isn't a factor in climate change, because those sources are not changing, and are really quite unaffected by surface temperatures. Deep thermogenic methane isn't going to bubble out through the permafrost or anything else without unrelated fracture paths going much much deeper.
I understand your concern on the impact of methane emissions - but at this point I believe it has been made sufficiently clear that while permafrost melt/decay and methane release will have an impact on total forcing and (after the ~7 year decay time for methane) CO2 levels, it's not going to be a catastrophic impact simply due to the rate of melt, decay, and methane conversion to CO2. The numbers are central to this understanding, and I have to say I consider Archers calculations far more reasonable than yours.
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Leland Palmer at 00:34 AM on 21 August 20142014 SkS Weekly News Roundup #33B
scaddenp-
I get what you are saying, now. But I think climate change is still relevant to the release of methane, whatever the source.
It's the melting of the permafrost cap that allows the eruption event, the hypothesis goes. Frozen permafrost is strong and able to resist pressure from below, melted permafrost is weak and susceptible to eruption events. So as the permafrost melts, high pressure reservoirs of free methane gas from any source built up in the last few thousand years will start to erupt, if these three events are the start of a trend.
If the source of the gas is methane hydrate dissociation, that could be more serious, I think that makes sense.
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mancan18 at 00:21 AM on 21 August 2014Global warming denial rears its ugly head around the world, in English
Dikran Marsupial and Ashton
A reality of the debate is that you will not convince a dedicated denier. However, it is possible to marginalise the hard core deniers like Bolt and Newman with good arguments based on the basic science. What is more important is convincing the wider public. At the moment it seems to me that in the wider debate in the popular media, climate change advocates are always expected to justify their assertions while the deniers never seem to have too. Now in a scientific information forum like Sceptical Science, the debate is scientific, so there is little problem. However, in the wider media it isn't and climate change advocates are continually required to defend their position while the deniers can just take potshots using any cherry picked piece of information they want to support their argument without having to justify anything else they say. Good arguments based on the basics of the science are needed so that deniers are always constantly challenged. Also, good metaphors related to everyday life, like microwaves warming food to describe the interaction of CO2 and infrared radiation, or although interest rates are small you can end up with a large amount money, are also needed to convince the wider public in realtion to what you are saying. There is probably little you can do if you encounter a denier who does not even beiieve that CO2 is a greenhouse gas and having it increase in the atmosphere is not going to warm the planet. The only thing you can do is show the absurdity of their argument using basic science.
For instance the latest effort by deniers to discredit increasing CO2 as an argument is that somehow it doesn't matter because CO2 reaches a certain saturation point in the atmosphere so no further warming will occur. However, all you need to do is to point Venus. While there is no suggestion that we will cause runaway greenhouse gas heating like Venus, even if we burn all known fossil fuels, it certainly shows that the so called CO2 saturation argument is not what the deniers say.
There is also an old saying "never argue with fools, because people mighten know the difference". What climate change advocates need to do is show that deniers are fools, particularly when they deny the basics of the science.
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franklefkin at 23:53 PM on 20 August 20142014 Arctic Sea Ice Extent Prediction
Dikran Marsupial,
rocketeer actually brings up a good point, sort of, what source do you use as your reference/comparisson? JAXA, NSIDC or other?
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Dikran Marsupial at 22:57 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
Ashton wrote "No Dikran Marsupial it desn't matter how "right" the sciece is, if you are unable to communicate its rightness to others then your cause is probably lost."
Nonsense. The fact that the rise in CO2 is anthropogenic has been communicated perfectly well, the fact that many denizens of climate skeptic [sic] blogs still don't accept it is because they are unable to accept it, a-priori, no matter how well it is explained. It is not something that is seriously questioned outside skeptic [sic] blogs. Therefore if skeptic [sic] blogs is where you get your view of the public debate on climate, you are getting a rather biased and unrealistic view.
What I wrote is not at all insulting to the 43% (or whatever, the MORI poll suggests it is more than 50% even in the US) who do accept that the science is correct. Far from it, it is a complement to their rationality that they do accept something, even though it is not something the want to hear. It seems to me that your grasp of idiomatic English is perhaps a bit of a problem. If I said that somebody did want to hear that their fossil fuel use was going to cause hardship to others less fortunate than themselves, that would be an insult! There is something deeply wrong with you if you want to hear you are indirectly harming others who have done you no harm.
The British government accepts the IPCC reports, having held a committee to look into it. If the government is incompetent, that is generally the fault of the electorate, and they should avail themselves of the next opportunity (election) to correct their mistake.
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Ashton at 22:40 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
No Dikran Marsupial it desn't matter how "right" the sciece is, if you are unable to communicate its rightness to others then your cause is probably lost. I've been a university lecturer, in biochemistry, for many years and if, after a lecture on, say, the way steroids interact with cells, more than 50% of the students don't understand then it's my poor communication that is at fault. Communication is essential when you're selling a message, whatever that message might be.
And your comment "Unfortunately what the science says about climate change is something that nobody in their right mind will want to hear." is rather insulting to the 43% or so who do accept that the science is correct. Are they not in their right mind? Your communication, at least on that point is hardly conducive to selling your message or to enhancing the convictions of those that do accept it. If you can't get at least 60% to accept that somethig must be done then it probably don't happen. In conclusion why is it that the conferences in Bali, Copenhagen and Doha have not found general support? It would seem largely because those opposed to new measures have not been convinced why they should not oppose these measures. If the IPCC can't convince governemnts the science is right then who can?
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Dikran Marsupial at 21:57 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
Ashton wrote "They don't have to do anything" they do if they want to make an informed contribution to the discussion. If instead they just want to reduce the signal to noise ratio, then you are correct.
The logic about the popularity of blogs is also rather shaky. Unfortunately what the science says about climate change is something that nobody in their right mind will want to hear. Providing comforting but specious arguments that suggest we don't need to do anything will always attract an audience. It doesn't matter whether you are a good communicator or not, if you are dscussing science, you first need to get the science right (c.f. repeated discussions on skeptic [sic] blogs on whether the rise in CO2 is anthropogenic, e.g. Salby, which we know beyond reasonable doubt it is).
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Ashton at 20:41 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
scaddenp@10 You comment " if someone can't follow the summary arguments in WG1 SPM, then frankly they have to trust the viewpoint of those who can. I dont think it is as simple as "CO2 is greenhouse gas, GHGs warm the planet" is extremely patonising
They don't have to do anything. You have to structure the argument for your point of view so "they" can follow it. If you can't or won't, do that then your cause is probably lost. Good communicators are those that can get their message across to all not just to a select few. That is perhaps why "denier" blogs have a bigger following than blogs run by proponents of climate change. If that is not the answer then pesumably it must be that more believe the deniers than believe the warmists
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scaddenp at 20:23 PM on 20 August 20142014 SkS Weekly News Roundup #33B
"This simply does not compute, sorry to say".
The speculation is that crater is result of shallow methane hydrate melting due to global warming and releasing methane. The pressure of methane builds up till it blows out the cap rock. There are no vents involved and the origin of the methane is in immediate sediment around the hole. If this is correct, then the crater is related to global warming since it depends on warming of the sediments to release the methane. I would note that there is no mention of any vents in descriptions of the craters so far.
If the methane is thermogenic, then it is finding its way to the surface via fractures from a reservoir, probably at around 50Mpa, 2km below the surface. This is the origin of the "Door to Hell" seep. I struggle to see how global warming can have any impact on this process. Furthermore, I would expect a gas seep at the bottom of the crater linked to a fracture system. Gas from such a system would continue to leak as it does in numerous other places at rates entirely unaffected by climate, at least on human scales.
For my money, I would back the shallow methane hydrates as source, caused by warming of the tundra, that the sources are local and temporary. (after the pressure release surrounding sediment would quickly give up biogenic and hydrate methane but the sediment permeability would be unlikely to allow a large area to drain).
I looked more carefully at Archer's calculation. He not using the 9% measurement. He is assuming bubble is the same volume of the hole and that it is 100% methane at pressure of 10 atmospheres. That is surely an upper bound.
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michael sweet at 20:10 PM on 20 August 20142014 SkS Weekly News Roundup #33B
Leland,
I doubt that an estimate of the gas flow into the crater can be made from the very limited data that has been released. Presumably the scientists who made the measurements will release their estimates when they finish their calculations. It will be interesting to see what they find.
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Dikran Marsupial at 18:48 PM on 20 August 20142014 Arctic Sea Ice Extent Prediction
rocketeer the WUWT estimate was the one they submitted for the June round of the prediction exercise, I suspect the predictions submitted in later months were lower. My method only uses the September mean sea ice extent measurements from previous years, so my prediction doesn't change as the Arctic summer progresses.
Having investigated, I don't think WUWT made a submission for July; their August submission of 5.6 million square kilometers is "still in the race", I would be very happy for them to be right, but I think they are being rather too optimistic!
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mancan18 at 18:39 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
scaddenp and One Planet Forever.
I am not disagreeing with you and I am not saying forums like Sceptical Science are not important, but I am saying that the argument is already lost if you cannot even get through to a denier/skeptic about the basic idea that increasing greenhouse gases and its significance, has warmed and will continue to warm the globe.
In Australia, the likes of Andrew Bolt, a prominent newspaper opinion writer for the Murdoch press and host of a "current" affairs show that has a wide following, gets away with the most outrageous comments regarding climate change, and influences a lot of people. He does this without challenge and he reaches a wider audience than anyone from the climate science community does. His tactic is to pick trite points irrelevant to the arguments being made and bury anyone who is trying to make a factual point. The problem is that he conducts a political interview rather than a scientific one. He needs to be challenged about his view of the science and to do this, you need to go back to the basics of the science and not try to argue about the significance as to why it's been hot, whether climategate was a scam or not, and what needs to be done; because he and his audience don't believe there is a problem anyway.
Also, which is even worse, one needs wonder why someone as obiviously intelligent as Maurice Newman is a denier. He's been Chair of the ABC, Chancellor of Macquarie University and a key Government business advisor for over a decade, so he obviously has a few brains. He is still steadfastly a denier and he influences many of his other business mates to the same way of thinking. Again, whenever he makes a denier argument, you need to make arguments and challenge him from the basics so he doesn't have room to move. Expecting ordinary people with little knowledge or interest to follow the debate in its entirety is a bit much to expect, and most are not going to read the IPCC report anyway. However, they are going to listen to the likes of Andrew Bolt and Maurice Newman. If Bolt and Newman are confronted with the basic tenets of the science of global warming, everytime they try to make an argument, then their ridiculous statements, like the one Bolt uses about CO2 being harmless, can be put to rest and he can be shown to be the fool that he is and, hopefully, leave people who are just trying to understand a little less confused.
Hopefully, by going back to the basics of the science, will relegate the likes of Bolt and Newman and climate change denial to the realm of such myths as the "Earth being 6000 years old" and "we didn't land on the moon" fads. You need to remember the overwhelming majority of scientists are reasonable people whereas the politcal ideologues who argue against the science aren't and will use any political tactic in their arsenal to get their views across. Climate change advocates, despite their overwhelming arguments, will always lose against climate change deniers, because deniers by and large are never directly challenged to prove their stance, while the advocates always are.
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shoyemore at 18:36 PM on 20 August 2014Global warming denial rears its ugly head around the world, in English
One point about the "in English" is that if you look at "these islands" (aka the British Isles), how much public climate change denial correlates with British, in fact English, Conservative politics.
The "Celtic Fringe" (Ireland, Scotland, and as far as I know Wales) is almost entirely climate-change-denier-free as regards politicians. While neither the Scottish Nationalists who are in government in Scotland, or the Centre-Left Coalition in office here in the Republic of Ireland, are paragons when it comes to carbon, at least they do not have full-on deniers in their cabinets or in powerful back bench factions.
Nor has climate change denial or opposition to renewable energy any traction with the electorate, other than wind farms as an environmental-aesthetic issue.
It highlights the alignment of climate-change-denial with a particular brand of "business-friendly" right-wing politics. At least politicians of the centre or left talk the talk, whatever about walking the walk.
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Leland Palmer at 16:41 PM on 20 August 20142014 SkS Weekly News Roundup #33B
Hi michael sweet-
Yes, of course a bouyant gas will rise, until it becomes well mixed with the atmosphere.
Inside the Yamal crater, I suspect that what is going on would be a bouyant plume of methane that would rise, until it clears the rim of the crater, and it would then be mixed with the rest of the atmosphere. I suspect that the bouyant plume would be concentrated toward the center of the crater. I suspect that air would flow down the sides of the crater, to fill the space left by the exit of the bouyant plume. I suspect that the air flowing down the sides of the crater would help melt the walls of the crater, and increase the erosion rate- part of the natural process of evolution of the crater, leading ultimately to a circular lake.
It may be that my calculation was too high - I was assumng that most of the volume of the crater was 9% methane. If that 9% figure was only around some vents at the bottom of the crater, then the bouyancy driven circulation would be less. By the way, my calculation results in gas flows of 4 miles per hour, or so - walking speed.
I suspect that methane concentration measurements around the rim of the crater would be low- likely this is in the influx stream of air leading down into the crater. What I would be interested to know is the concentration of methane in the bouyant plume toward the center of the crater, and the rate of flow in a cross section across the top of the crater.
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