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Tom Curtis at 10:35 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Russ R @6, I have already explained that in my second point @2. That you choose to ignore it is no reason for me to repeat myself (or to waste time on an elaboration that will be equally ignored by you if it does not serve your rhetorical interests).
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Russ R. at 08:51 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Hello Tom Curtis,
If you agree that:
- GHG =0.9±0.4°C
- OA = -0.25±0.35°C
- ANT = GHG + OA
Could you please explain how the uncertainty of ANT can be lower than that of either of its components?
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Tom Curtis at 08:47 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Thankyou Leto. I did indeed misplace a decimal point, and that should be to the nearest 0.05 degrees.
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Leto at 08:29 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Tom,
I don't think you mean "to the nearest half degree" (i.e. 0.5 degrees) - perhaps to the nearest half graph-interval, where the graph-intervals (gap between axis ticks) are 0.1 degrees.
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97 hours of consensus: caricatures and quotes from 97 scientists
@ Tom Curtis at 06:43 AM on 12 September, 2014
"Therefore we no longer include classics scholars among the people we relly on to understand physics. Instead we relly on scientists."
If we rephrase this argument you say that: "We rely on scientists to understand physics." I will say that there is much more to it than that. For important matters we are not likely to rely on scientists. We will likely require to see independent data demonstrating that the result of applying the physics is ok. When the product is a measurement result or a prediction, the responsible will likely require to see data demonstrating the uncertainty of the prediction and that it is without systematic errors. The application of physics rapidly becomes extremely complex also to the scientists applying it. This complexity implies that nobody can be sure that end product is ok without testing it. That is why testing and experimenting is an extremely important part of physics.
Imagine constructing a complex instrument, like a new electronic weighting scale or a much more complicated instrument. To build the instrument you depend on hardware components, electronics, software, primary measurements, correctly set parameters, physical models etc. Many scientists are required to design the instrument, develop the models, build the instrument, develop the software and test it. The instrument is based on physics, but still, there is an enormous amount of possible errors which can be made when designing and building the instrument. Hence you do not know the uncertainty of the instrument or if there is a significant systematic error in the instrument before you perform a calibration. A calibration is performed by letting the instrument perform measurement on a number of test weights traceable to international standards. The central information on the calibration certificate consist of the measurement result from the weighting scale, the mass of the test weights and the uncertainty of the mass of the test weights.
Even if no single person has all the competence that is required to design and build the instrument, the calibration certificate is very easy to understand. The calibration certificate can be completely understood by a person without any of the competencies required to design and build the instrument. Hence the capabillities of the instrument can be completely understood without having to rely on the scientists required to design and build it. There are also other ways to demonstrate that a complex construction works for its intended use. Even if I have no clue how it is made, I can still tell if a television works. There is also more to it, because, even the scientists who built the complex instrument cannot be sure about the uncertainty of the instrument and that it is without systematic errors without also using the same kind of data a layperson can use to comprehend the capabilities of the instrument. Hence I think it is more valuable to say that we rely on other scientists, text book´s and data tools to understand physics and construct a product or a model, we rely on testing to se if it works. A properly performed test and properly presented test results can be easy to comprehend. To summarize I would say that We do not rely on scientists in physics, we rely on data from calibration, testing and experiments. In that respect, I would also like to quote William Edwards Deming:
“In God we trust; all others bring data.” -
Tom Curtis at 07:48 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Further, to Russ R @1, I did not note Russ R's absurd treatment of error where he merely added the error bounds of Greenhouse and OA. That would be mathematically in error even if the uncertainties are independent, which they are not as explained above.
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Tom Curtis at 07:46 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
Russ R @1, here are the relative contributions as determined from Fig 10.5 by pixel count:
(Press on figure for larger version).
I note first that the Anthropogenic contribution (Anthro) has a far more tightly constrained uncertainty than does either the Greenhouse gass contribution (Greenhouse) or the Other Anthropogenic contribution (OA). Further, the Anthro contribution has a mean (and median) contribution of 107.7% of the total increase in temperature. Therefore you are using the less certain data in preference to the more certain data to make your case, which is the wrong way to go about it.
Second, the uncertainty of Anthro is substantially less than the uncertainty of the other four (including Natural forcings (Nat), and Internal Variability (Intern Var), which have an uncertainty about that of Anthro, but centered on, or very near zero) because their uncertainties are not independent. If we estimate Greenhouse to be higher, it follows that OA, Nat, or Intern Var, or some combination of them are lower, and vice versa. Further, estimates of the relative contribution of Intern Var are inversely depedent on the estimated strength of all forced responses together.
Because of this interdependence, you cannot simply add mean or median values for Greenhouse and OA to determine the mean or median value for Anthro.
That is particularly the case because, third, the uncertainty of Greenhouse (almost definitely) and of OA (probably) are slightly right biased. This shows up in the pixel counts of Fig 10.5, but is so small a bias (1 or 2 pixels at 150% magnification of the large version of the image on the IPCC site) that I (and probabily Real Climate) ignored it for mathematical simplicity. The bias in both cases, however, is a right skew meaning that the simple addition of their means will underestimate the total anthro contribution.
Further, that the Anthro, Greenhouse and OA contributions are normally distributed is just a simplifying assumption made by me and Real Climate. Often in these cases the PDF is log normal with a right skew, rather than normal. If that is indeed the intent of the IPCC, then that would further bias the results of simple addition. Of course, a log normal distribution would also greatly reduce the probability of a low (50-75%) Anthro contribution and represents a conservative assumption for the AGW case.
Fourth, and most simply, you neglect the probability of rounding errors. If the IPCC has rounded figures to the nearest half degree (likely given that all values amount to half degree figures in the table), then the difference may be due to rounding error alone. In that case the mean (or median) Anthro contribution may be as little as 100%, but may be as much as 116%, with the additional uncertainty due to rounding error. That is an additional level of uncertainty not accounted for in my graph (nor, I suspect, in Real Climate's graph), but it will only negligibly increase the probability of low (50-75%) attributions, while equally increasing the probability of high (140-165%) attributions.
For the record, ignoring any rounding errors, and assuming a normal distribution, the lower bound of the 99% confidence interval of Anthro is approximately 78%, and of the 99.9% confidence interval it is 62%. Therefore merely shifting the confidence interval 8% lower will leave a lower bound of the 99.9% confidence interval 57%. That would be an absurd response to the additional error from rounding, but even it does not result in substantial probabilities of less than 50% anthro contribution.
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Russ R. at 06:27 AM on 16 September 2014The 97% v the 3% – just how much global warming are humans causing?
The probability density function shown relies on an estimate that warming due to anthropogenic forcings was 0.7±0.2ºC (5-95%), while observed warming was 0.65ºC, (citing IPCC AR5 Figure 10.5).
However, the actual chart in Figure 10.5 displays something rather different.
By the IPCC's definitions, combined anthropogenic forcings (ANT) equals greenhouse gas warming (GHG) plus other anthropogenic forcings (OA), or ANT = GHG + OA
And (reading off the scale) they show GHG =+0.9±0.4°C and OA = -0.25±0.35°C.
So, by simple math, ANT = 0.65±0.75°C.
So, the PDF would would be centered around 100% (not 110%) of the observed warming with (5-95%) uncertainty of ± 115%.
How would that change the shape of the PDF, and what would be the likelihood of ANT/Observed being less than 50%?
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Phil at 20:52 PM on 15 September 20142014 SkS Weekly News Roundup #37B
@1 From Peru asks "What do you think" ?
Given your quote, there are three seperate statements made by Modi:
- "On climate change, the Prime Minister said exploitation of nature was a crime.
- “At best, you have the right to milk nature. You can milk a cow, but you can’t kill the cow.”
- “Climate change? Is this terminology correct? The reality is this that in our family, some people are old... They say this time the weather is colder. And, people’s ability to bear cold becomes less.
In Statement 3 he suggests that the temperature record is not accurate, i.e. he questions whether the planet has warmed at all
Statement 2 seems to imply that we can continue BAU if the planet hasn't warmed (because we are only "milking" the cow)
Statement 1 seems to imply that because we are only "milking the cow" then BAU is not exploitation and so not a crime.
Thats how I read it.
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From Peru at 15:21 PM on 15 September 20142014 SkS Weekly News Roundup #37B
My point was that the Guardian article attacked Modi suggesting he has turned into a climate skeptic, just few years after expressing strong concerns about global warming and supporting a "renewable energy revolution" in his country, like giving solar panels to every family in the 1000 billion people federation.
That seemed a lot strange to me, and in effect, I saw abolutely no hint of anti-environmental statements in the original source (The Hindu).
I have one concern about the Guardian article: Modi is a right-wing politician, so he strongly supports private investments instead of a state-dominated economy. One could agree with that or not, but one should praise the right policies no matter of what political end of the spectrum is involved.
In the Anglo-American world the political right seems to be highly anti-environmental, pro-pollution, but elsewere in the world that it is not the always the case:
- Germany, governed by a centre-right coalition has been leading Europe in the Energy transition away from fossil and nuclear fuels
- In Latin America some of the worst polluters are the petro-states like Venezuela (that have the world top tar sand reserves) and Argentina (that is developing a giant shale oil and shale gas in Patagonia), both left-wing, and in the case of Venezuela, we are talking about an authoritharian stalinist regime.
I hope my concern is wrong.
N.B.: I belong to both the left-wing and the libertarian end of the spectrum (google "political compass" where is shown the 2-dimensional political spectrum)
Moderator Response:[JH] Your points are well taken. Only time will tell if Modi is a champion for tackling climate change or not.
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chriskoz at 14:17 PM on 15 September 20142014 SkS Weekly News Roundup #37B
From Peru@1,
I find quoted Modi’s arguments non-sequitur: is he commenting about the human causality of AGW or about climate change impacts on humans or the old age impact on an aging human individual? Those 3 observations are independent issues and each should be commented on separately. By mixing those 3 in a single comment, Modi is making a logical error and the resulting statement is a fallacious bubbling rather than a reasonable opinion/assessment. Unless the true sense of his statement was lost in translation but that possibility is low in case of Modi who speaks fluent English and must have pronounced his comment in English rather than in Hindu or his other native tongue.
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Thousands of ‘Nameless Short-Lived Lakes’
MA Rodger @ 12.
Absolutely agreed. I wanted to edit my post @10 and add the caveat that there is to little data to decide wether the trend is linear or exponential (but I needed a break from my heroic struggles with the foreign language monster).
I think Hansen himself says that in the first paper you linked to. But as you show with your projection, even the SLR from a constant acceleration would be quite substantial. Thanks for that.
I guess it is time to buy a boat, a rubber boat will have to do it for now ... "Way hay and up she rises, ..." :-)
Have a nice day -
MA Rodger at 19:20 PM on 14 September 2014Thousands of ‘Nameless Short-Lived Lakes’
noa @10.
Thanks for the info. Sad to hear that Tom & Jerry the two GRACE satellites are running out of umph.
The GRACE data at the NOAA's 2013 Greenland Report runs up to July 2013 and it looks from the graph in the link you provide to the Polar Portal that the last 4 moths after March 2013 have been pulled.
The IMBIE/ICESat/CryoSat data does show a doubling, but so indeed does the GRACE data. The numbers scaled from the NOAA graph show 2011-13 averaging ~415Gt/yr loss, while the 2003-2009 data gives a ~210Gt/yr loss. But I do not see this, a doubling in 6 years, as being inconsistent with even a constant acceleration of ~30Gt/yr/yr as illustrated in the graph I link to @6.
Not that such a linear trend is small. If sustained to 2100 we will still be receiving 420mm SLR from Greenland alone.
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Thousands of ‘Nameless Short-Lived Lakes’
I just remembered that the Morlighem paper was covered on SkS here, of course. ;-)
An other paper re SLR projections is this one from Spence et al. 2014 (free PDF). They seeked to improve the modeling of the consequences from the poleward shifting westerlies in the SH, which is - according to them - projected to persist under continued anthr. forcing. They find that the westerlies weaken the Antarctic Slope Front (a counter-current on the outer antarctic shelfs, if I am not mistaken) and this opens the doors for the relative warm circumpolar deep waters. From that they project a warming of the waters near the grounding lines of some outlet-glaciers up to 2 degrees till 2100. This feedback is, as they say, not included in the AR5 SLR projections, because the resolution of the CMIP5-models is not high enough to account for the changes of the Antarctic coastal waters.
(Please bear with me if I made some basic errors in my summary - I am just an interested layman).
Well, I'll better quote the abstract of the paper:
The southern hemisphere westerly winds have been strengthening and shifting poleward since the 1950s. This wind trend is projected to persist under continued anthropogenic forcing, but the impact of the changing winds on Antarctic coastal heat distribution remains poorly understood. Here we show that a poleward wind shift at the latitudes of the Antarctic Peninsula can produce an intense warming of subsurface coastal waters that exceeds 2°C at 200 – 700 m depth. The model simulated warming results from a rapid advective heat fl ux induced by weakened near-shore Ekman pumping and is associated with weakened coastal currents. This analysis shows that anthropogenically induced wind changes can dramatically increase the temperature of ocean water at ice sheet grounding lines and at the base of fl oating ice shelves around Antarctica, with potentially signi fi cant rami fi cations for global sea level rise.
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Thousands of ‘Nameless Short-Lived Lakes’
@6 MA Rodger
As far as I know there seem to be some issues with the GRACE data for 2013. See repley 156 here on the ASIF. Answer from the DMI Polar Portal (see here there GRACE chart):
Your question is really good, and the answer is actually quite simple: The GRACE mission is already way past the originally intended duration, but the satellites are still flying. But systems do fall out once in a while and, as an example, the 2013 summer data are unavailable due to power system problems. The 2013 summer data are thus missing from the Polar Portal GRACE figure. The linear interpolation across the summer negative peak suggests an extremely low (even no) loss summer and therefore is very misleading. We will work on a different way of representing this.
Recent GIS MIB estimates derived from CryoSat-2 published in TC (Helm 2014) do not look that promissing (within doubling rates faster than 10 years). From p. 13 table 4:
IMBIE 2003-2008: −189 ± 20 Gt
ICESat 2003-2009: −146 ± 13 Gt
CryoSat 2011-2014: −375 ± 24 Gt
See also McMillan (2014)
Reagarding the SLR projections of AR5. Here is the latest paper from one of the lead authors of chapter 13 SLR, Anders Levermann, albeit just for the AIS. His new estimates seem to be 3 times as high as the ones in the AR5 (but still with very big error margins).
re stability of GIS, an interesting papers is (I am sure most here are aware of it):
Abstract: "... Here, we combine sparse ice-thickness data derived from airborne radar soundings with satellite-derived high-resolution ice motion data through a mass conservation optimization scheme5. We infer ice thickness and bed topography along the entire periphery of the Greenland ice sheet at an unprecedented level of spatial detail and precision. We detect widespread ice-covered valleys that extend significantly deeper below sea level and farther inland than previously thought. Our findings imply that the outlet glaciers of Greenland, and the ice sheet as a whole, are probably more vulnerable to ocean thermal forcing and peripheral thinning than inferred previously from existing numerical ice-sheet models.
@sidd thanks for the link.
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sidd at 14:19 PM on 14 September 2014Thousands of ‘Nameless Short-Lived Lakes’
Hansen is more often right than wrong. Here is a tidbit to chew on:pulling one plug on WAIS drains more than one basin http://www.the-cryosphere-discuss.net/8/4885/2014/tcd-8-4885-2014.pdf
Moderator Response:[PS] Fixed link per later message (and again, checked this time)
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Hyperactive Hydrologist at 09:16 AM on 14 September 2014Thousands of ‘Nameless Short-Lived Lakes’
Where did the 1m per year figure come from? Jason Box stated that the yield of SLR from Greenland alone would be 1m in total by 2100. Jason is just extrapolating current melt acceleration, which is perhaps an over exaggeration, as it would mean the entire Greenland Ice sheet would be gone by 2130.
The question I would like answering is how much ice mass would Greenland need to lose before all the major glacier snouts are grounded? I think once that occurs melt rates will begin to slow quite significantly due to a lack of carving by the sea and a decrease in basal lubrication. By then however, it will probably already be too late.
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From Peru at 07:58 AM on 14 September 20142014 SkS Weekly News Roundup #37B
The guardian article about India says:
"Modi was also vague on global warming and its causes in an interview with The Hindu a few days earlier.
“Climate change? Is this terminology correct? The reality is this that in our family, some people are old ... They say this time the weather is colder. And, people’s ability to bear cold becomes less,” he said.
“We should also ask is this climate change or have we changed. We have battled against nature. That is why we should live with nature rather than battle it,” he said.
Both sets of comments are at variance with Modi’s earlier views on climate change, set out in an e-book, published in 2011 when he was chief minister of Gujarat."
I don't understand the article comments. They do not seem like what a so-called skeptic would say. The actual article from The Hindu says the following:
"On climate change, the Prime Minister said exploitation of nature was a crime. “At best, you have the right to milk nature. You can milk a cow, but you can’t kill the cow.”“Climate change? Is this terminology correct? The reality is this that in our family, some people are old... They say this time the weather is colder. And, people’s ability to bear cold becomes less.
“We should also ask is this climate change or have we changed. We have battled against nature. That is why we should live with nature rather than battle it,” he said.
The Prime Minister commended a book written by him on climate change called “Convenient Action” while pointing out that former US Vice-President Al Gore’s book was entitled “An Inconvenient Truth”. The Prime Minister said his book was available online"
The section quoted by the Guardian is underlined.
My apologies for the extensive quoting, but I want to share my impression that the original article from The Hindu is much less worrying than the Guardian one. Modi actually used very strong words against polluters (suggesting they are "criminal exploitators") and his latter words sound more like a criticism against common public opinion than a re-wording of pseudo-skeptic arguments.
What do you think?
The news about the ongoing energy reform in India seemed to good to be true, but at least are most self-consistent than the arguments show in the Guardian article.
Moderator Response:[JH] Don't read too much into these quotes. Modi has just assumed the reins of government in India. We need to wait and see how his government's policies and programs re climate change and energy unfold.
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One Planet Only Forever at 07:10 AM on 14 September 20142014 SkS Weekly News Roundup #37A
Here is a link to the basis for my previous comment about Canada not meeting its promises (CTV item here)
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One Planet Only Forever at 07:01 AM on 14 September 20142014 SkS Weekly News Roundup #37A
Not only have the developed economies failed to offer to adequately address the global requirement to limit human CO2 emissions impacts to 2 degrees C, many of those nations, like Canada, appear to be failing to keep pace towards their inadequate promises.
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One Planet Only Forever at 06:50 AM on 14 September 20142014 SkS Weekly News Roundup #37A
There definitely should be no new coal power generation facilities built. And there should be CO2 capture and storage systems added to every existing coal plant, even though those would cost money while reducing the energy production. CO2 capture and storage may increase the coal burning per megawatt, but the followiong article indicates it may be a 30% increase in coal burned per megawatt while up to 90% of the CO2 could be capotured (See CBC article here). That would be less CO2 per megawatt than electricity generation from natural gas since natural gas generation produces half the CO2 of coal generation. (See EIA item here).
It would also appear that CO2 capture would be beneficial on natural gas fired generation.
And, of course, all the impacts of the entire set of activities related to the different types of electruicity generation need to be considered, not just the CO2 emissions. Those considerations make coal and fracking to get gas less desireable than easier to get gas.
The simple reality is that energy is actually more expensive than the unsustainable and harmful ways that the developed and developing economies have been getting away with benefiting from.
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Philip Shehan at 02:18 AM on 14 September 20142014 SkS Weekly Digest #36
Thank you again to KR and Dikran for additional comments.
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MA Rodger at 01:50 AM on 14 September 2014Thousands of ‘Nameless Short-Lived Lakes’
The statement of 1 metre per year SLR "from Greenland alone" by the end of the century isn't entirely correct (when it should be squeeky clean give it is so controversial). Also the Hansen argument mentioned @1 is a long long way from the statement by Jason Box in the post/video.
The simple arithmatical progression described in the post would lead from a 2010's rise of 1mm pa today to a 1m pa in the 2110's which is actually a significant period after "the end of this century."
The Hansen thesis was 1 metre per decade SLR from both Greenland and Antarctica, and certainly not 1 metre per year from Greenland alone.
There is however a little ambiguity in Hansen's position. And I am not convinced by his 5m SLR by 2100, although his warning that humanity shouldn't be complacent about SLR is surely correct. The potential delivery of ~80m SLR with just a few degrees of global temperature rise is convincing and that would inundate 90% of human endeavour. That is not trivial, even if it were a 2,000 year process.
I take issue with Hansen when he argues that a 5m SLR by 2100 is not unrealistic. He makes plain that there is a negative feedback that will prevent a continued doubling of SLR. "Our simulations (Hansen and Sato, 2012) suggest that a strong negative feedback kicks in when sea level rise reaches meter-scale, as the ice-melt has a large cooling and freshening effect on the regional ocean." (From Hansen & Sato (2012a) Update of Greenland Ice Sheet Mass Loss : Exponential ? here)
Yet, his Figuree 8 of 21st century SLR showing 5m SLR by 2100 in Hansen & Sato (2012) Paleoclimate Implications for Human-Made Climate Change (here) shows rates of rise that are well above 'reaching meter-scale' SLR. In Fig 8, the last metre SLR before 2100 taking 3.25 years, a rate of 3.1m per decade. And this is not me being picky in my literal interpretation of 'reaching meter-scale'. Hansen & Sato (2012) talks of "...a negative feedback that comes into play as ice discharge approaches a level of the order of a meter per decade."
The only basis I can see for Hansen's argument for 5m SLR by 2100 is the accelerating mass loss of Greenland and Antarctica as shown by GRACE. If the data is updated to include 2013, the accelerations are a lot less worrying than those curves graphed by Hansen & Sato, with doubling rates faster than per 10 years looking unlikely. Indeed, the Greenland mass data from NOAA Report Card 2013 yields a graph of rate-of-loss (two clicks down here) that could easily show a linear acceleration, although that 30 Gty^-2 (from data centred on 2008) is steeper than the 21Gty^-2 in Hansen & Sato (2012a) Figure 1 (from data centred on 1999) suggesting linearity isn't entirely on a solid footing.
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AuntSally at 01:10 AM on 14 September 201497 hours of consensus: caricatures and quotes from 97 scientists
Objection! Roy's caricature doesn't have a pithy quote. How about "No it aint', shut up!"
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AuntSally at 01:04 AM on 14 September 20142014 SkS Weekly News Roundup #37A
I'd like to register an official objection to 97 in 97. It appears the warmist fear-mongers intend to completely ignore the other 3%. To remedy, I'd like a cartoon caricature of Roy and a short pithy statement: "No it ain't. Shut Up!"
: )
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ubrew12 at 21:32 PM on 13 September 2014Thousands of ‘Nameless Short-Lived Lakes’
World's largest Slip-n-Slide...
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Rob Painting at 19:26 PM on 13 September 2014Thousands of ‘Nameless Short-Lived Lakes’
Tom - a few things:
1. I was simply drawing attention to recent research on the topic. There is no suggestion that this was even available for consideration for inclusion into the latest IPCC assessment. As is normally the case, this was presented at a scientific conference earlier this year and will likely find it's way into the scientific literature in due course. Regardless, cutting edge research is unlikely to find it's way into the IPCC reports given the panel's conservative nature. That seems a reasonable stance.
2. Previous ice sheet modelling work by Pollard and DeConto is often cited in the scientific literature as a reason for caution over the semi-empirical methods. By incorporating better understood physics into the model, that may no longer stand.
3. Modelling now is a much better fit to paleo sea-level records and the physical evidence (ice-rafted debris in sediment cores for instance) around the Antarctic continent. Rates of sea level rise near 1.2 metres per century are not uncommon in the last few glacial/interglacial cycles.
3. Riduna brought up the 5 metre sea level rise this century claim, not me. There is no evidence AFAIK to support such high rates of sea level rise, and such a scenario seems implausible according to all the literature on the topic that I have read.
4. If you use the IPCC as a guide then you will have noticed that your projections of future sea level rise have often been at the upper bound.
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Tom Curtis at 18:41 PM on 13 September 2014Thousands of ‘Nameless Short-Lived Lakes’
Rob P inline @2:
First, google search shows the paper to not yet have been published, but only to have been presented at a conference in 2014. Therefore it cannot have been considered by the IPCC for AR5. If asked (and sometimes if not asked), I consistently advise non-climate scientists to accept IPCC findings as the best statement of the consensus on the science at time of writing. As non-experts, they are certainly entitled to their own opinion but should be aware that their own opinion is likely to have been formed by making a number of subtle (and not so subtle) gaffes from looking at limited and often non-representative data. As in any area where we consult experts, they are far wiser to accept the expert opinion even when they, with their little knowledge, disagree.
Given that, I would be hypocritical to not accept the IPCC consensus in areas where I or my friends think there is a reasonable chance the IPCC has been too cautious. Even if I am told they have been too cautious by some climate scientists, I know I can find others who do not think so (and who are well within the 97% consensus on the attribution issue). Nor am I, and nor can I be in a position to judge which of the individual experts has it right unless I first get up to speed on the issue by an intense reading of relevant textbooks, and keep up to speed by reading something in the order of 10 relevant scientific articles a week, while maintaining regular communication with a network of peers to keep up with what is current.
Jason Box has done, and continues to do the equivalent of that. He is a genuine expert and is entitle to disagree with the IPCC. I have not, and have not the time to do that (unless I want to restrict my commentary solely to icesheet dynamics), and so must stick with the IPCC - even, indeed especially, when giving greater weight to a subsection of the experts would appear to warrant more urgent action.
(I understand that you are far more up on the sea level literature than I am, and are thus far more entitled to a different opinion to the IPCC - but at best that just makes you one more expert on the more alarmed side of the IPCC opinion to me. Further, I do not think even you would claim to be expert on the topic, as opposed to well informed.)
2) More directly, the IPCC explained in detail the prospect of rapid collapse of the WAIS ice sheet, so is not in disagreement with the new study per se. In particular, they showed the following image:
The key factor show is the increased depth increased distance shoreward. That ensures the process does not ground out, and indeed can become self sustaining even in the event that we control surface temperatures to current levels. That is the key difference between the WAIS and the Greenland Ice Sheet where the water becomes shallower as the shore is approached, thus limiting the extent of any rapid collapse induced by other means.
Therefore the only thing new added by the as yet unpublished study is the quantification of "up to" 9 meters sea level rise "within the next five centuries". That equates to "up to" 1.55 meters of sea level rise by the end of this century assuming a constant rate, and much less assuming (as it must) the rate accelerates from a slow start. That would raise sea levels by more than the process based estimates, but by about the same amount as the semi-impirical based estimates. It does not justify belief in a 5 meter sea level rise by 2100, or of 1 meter sea level rise from Greenland alone by 2100.
3) I would love for SkS to publish an article by Jason Box in which he explains not only the processes that are accelerating the ice loss from Greenland, but also the processes that might limit the acceleration, and gives a median estimate of sea level rise from the GIS by 2100 taking all factors into account. Given such a fuller account, he might persuade me to change my personal opinion - although I would still recommend accepting the current IPCC position for formulating policy even if my opinion was changed.
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Tom Curtis at 18:07 PM on 13 September 2014Climate sceptics see a conspiracy in Australia's record breaking heat
Asthon, Graham Lloyd repeatedly misrepresents the situation. When he says "The official station record said there had been no site move at Rutherglen", he is referring to the "Station Summary" section of the metadata for Rutherglen which states:
"No summary for this site has been written as yet."
Alternatively, he may be referring to the "Station Equipment History", for which we have the note:
"Historical metadata for this site has not been quality controlled for accuracy and completeness. Data other than current station information, particularly earlier than 1998, should be considered accordingly. Information may not be complete, as backfilling of historical data is incomplete."
In a later section, on the "reliability of the metadata", we read:
"The Bureau is part way through a task of entering historical information held on paper file into the corporate database. Until this process is completed there will remain large gaps in the information contained in these metadata documents and considerable caution should be used when deriving conclusions from the metadata. As an example, two consecutive entries about a rain gauge dated 50 years apart may appear in the equipment metadata. This may either mean that nothing happened to that instrument over the 50 years, or that information for the intervening period has yet to be entered into the database. Similarly, if no information was available about instruments at a site when it was first established, fields which were required to have a value present may have used the earliest information available as a best-guess estimate. Sometimes this was the metadata current when the database was established in 1998. In some instances there may be gaps in metadata relevant to the post 1998 period.
For the above reasons it is recommended that all metadata prior to 1998 be considered as indicative only, and used with caution, unless it has been quality controlled. The Bureau of Meteorology should be contacted if further information or confirmation of the data is required."
Clearly the station record does not treat an absence of record of a move as an absence of such a move - but that is how Lloyd interprets it.
Of course, the BOM have asserted that the station used to be in one place, and was later located at a different place, but that they have no record of the time of the move. I know this because Graham Lloyd reported it:
"However, the official catalogue says “there have been no site moves during the site’s history”. Former Rutherglen workers said the site had not been moved.
Asked further about Rutherglen, BOM said “statistical analysis of minimum temperatures at Rutherglen indicated jumps in the data in 1966 and 1974”.
“These changes were determined through comparison with 17 nearby sites,” it said. “The biases detected in the temperature data for Rutherglen were deemed large enough to require adjustment, based on the statistical tests alone.
“The site records indicate that at least one site move took place between 1958 and 1975. It is likely but not confirmed that this move took place in 1966. The site records also indicate that the weather station was substantially upgraded around the time of the 1974 break in the temperature record.”"
(My emphasis)
Note that the "site records" are the detailed documents on which the metadata for the official station record (linked above) are based. Note also that Lloyd says the "official catalogue", ie, the document linked above literally said that "there have been no site moves during the site’s history" (note the quotation marks). That is a fabrication, as you can easily verify by reading the original document.
There has been absolutely no basis to question the intergrity of the BOM in this episode. The integrity of Jennifer Marohasy, who makes accusations of fraud based on disagreements about such easilly checkable stations as Amberley without bothering to have made the checks, and of Graham Lloyd who has run strongly on this story based on the word of a known climate change denier, a failure to check basics and a series of misrepresentations of the BOM and its documents, are certainly in question
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Ashton at 16:30 PM on 13 September 2014Climate sceptics see a conspiracy in Australia's record breaking heat
From the recent reactions of the BoM to the series of pieces by Graham Lloyd in The Australian (http://tinyurl.com/pxzzopc) it may be that those questioning the integrity of the BoM might, just might, not be miisguided conspiracists judging from this paragraph from Lloyd's piece:
"BoM was unable to provide The Australian with details to substantiate their claim of a site move at Rutherglen in Victoria where the minimum temperature trend had been changed from a cooling trend of 0.35C in the raw data to 1.73C warming after homogenisation. The official station record said there had been no site move at Rutherglen."
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Tom Curtis at 14:49 PM on 13 September 2014Thousands of ‘Nameless Short-Lived Lakes’
Riduna @1, the IPCC discusses these issues in FAQ 13.2, saying of Greenland:
"In Greenland, mass loss through more surface ablation and outflow dominates a possible recent trend towards increased accumulation in the interior. Estimated mass loss due to surface ablation has doubled since the early 1990s. This trend is expected to continue over the next century as more of the ice sheet experiences surface ablation for longer periods. Indeed, projections for the 21st century suggest that increasing mass loss will dominate over weakly increasing accumulation. The refreezing of melt water within the snow pack high up on the ice sheet offers an important (though perhaps temporary) dampening effect on the relation between atmospheric warming and mass loss.
Although the observed response of outlet glaciers is both complex and highly variable, iceberg calving from many of Greenland’s major outlet glaciers has increased substantially over the last decade, and constitutes an appreciable additional mass loss. This seems to be related to the intrusion of warm water into the coastal seas around Greenland, but it is not clear whether this phenomenon is related to inter-decadal variability, such as the North Atlantic Oscillation, or a longer term trend associated with greenhouse gas–induced warming. Projecting its effect on 21st century outflow is therefore difficult, but it does highlight the apparent sensitivity of outflow to ocean warming. The effects of more surface melt water on the lubrication of the ice sheet’s bed, and the ability of warmer ice to deform more easily, may lead to greater rates of flow, but the link to recent increases in outflow is unclear. Change in the net difference between surface ablation and accumulation is projected to contribute between 10 and 160 mm to sea level rise in 2081-2100 (relative to 1986-2005), while increased outflow is projected to contribute a further 10 to 70 mm (Table 13.5).
The Greenland ice sheet has contributed to a rise in global mean sea level over the last few decades, and this trend is expected to increase during this century. Unlike Antarctica, Greenland has no known large-scale instabilities that might generate an abrupt increase in sea level rise over the 21st century. A threshold may exist, however, so that continued shrinkage might become irreversible over multi-centennial time scales, even if the climate were to return to a pre-industrial state over centennial time scales. Although mass loss through the calving of icebergs may increase in future decades, this process will eventually end when the ice margin retreats onto bedrock above sea level where the bulk of the ice sheet resides."The most important points are the uncertainty as to whether the large increase in ice loss is due to the NAO or to global warming, and the fact that any runaway process will ground out (last sentence in the quote).
As it happens, Jason Box was a contributing author to that chapter. That does not mean the chapter reflects his views, but it does mean his views were given due consideration. Therefore to the extent that his views differ, they do not reflect the consensus of relevant experts.
Having said that, there is a divide among the relevant experts between those favouring "process based" and those favouring "semi empirical" based projections. The later give consistently higher projections than those obtained by the process based methods (on which the IPCC headline results are based, as shown in the IPCC Fig 13.12:
Figures a, b, c and d are for RCP scenarios 2.6, 4.5, 6.0, and 8.5 respectively. The black line is the median process based projection with the likely (66%) range shown in grey. Blue estimates are based on temperatures, red on forcings, with the bars showing the "extremely likely" (95%) range.
Based on that, sea level rise one or even two meters greater than IPCC projections cannot be excluded, but there is no basis in the literature for Hansen's projection of 5 meters. It should be noted that the IPCC preffers the process based projections because they are assessed as having medium confidence, while the semi emperical projections are assessed as having low confidence.
Moderator Response:[Rob P] - Tom, recent ice sheet modelling, (yet to be published in the peer-reviewed literature AFAIK) that incorporates new physics, simulates a collapse of parts of the Antarctic ice sheet over the next half-millennia.
"The new model simulates an Antarctic contribution to sea-level rise of ~15m during peak mid-Pliocene warmth and ~4.25m during the LIG, in approximate agreement with (albeit uncertain) geological sea-level indicators. When applied to long-term future simulations assuming extended RCP greenhouse gas emission scenarios and using high resolution atmosphere and ocean components, the same model physics show a dramatic retreat of Antarctic marine-based ice over the next 500 years, beginning within a few decades in the Pine Island Bay sector of West Antarctica. In the most extreme RCP scenarios, subsequent retreat of the Siple Coast margin results in the near-total collapse of the West Antarctic Ice Sheet (WAIS) within a few centuries, followed by retreat into the deep subglacial basins underlying the East Antarctic Ice Sheet (EAIS). Antarctica is shown to contribute up to 9m of sea level rise within the next five centuries."
This seems more consistent with marine sediment core samples taken from around Antarctica which imply swift dynamic responses to warming.
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Riduna at 10:12 AM on 13 September 2014Thousands of ‘Nameless Short-Lived Lakes’
The article concludes that … By the end of the century, at that rate, [decadal doubling of ice loss] Greenland alone would be accounting for about one meter per year [of sea level rise].
This is akin to the conclusion reached by Dr Hansen in 2007 – one which has been studiously ignored by glaciologists and rejected by those contributing to 2013 IPCC report on sea level rise this century. Why? Apparently because of doubt that doubling of ice sheet mass loss per decade will be sustained over the rest of this century.
Hansen was referring to mass loss from both the Arctic and Antarctic, concluding that consequential average global sea level rise of 5m by 2100 should be an expected outcome. IPCC rejection of this does smack of common agreement by contributing scientists to ignore Hansen. In the absence of cogent scientific refutation of Hansen, does this amount to cherrypicking on their part – or is it just a healthy “concensus”?
Given the observations referred to in the article, the expectation that greenhouse gas emissions associated with permafrost thawing, on-going aerosol soot deposits on the Greenland ice sheet and loss of albedo due to sea-ice depletion – should we really cling to the notion that average global sea level will rise by no more than one metre by 2100?
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wili at 07:39 AM on 13 September 201497 hours of consensus: caricatures and quotes from 97 scientists
So what is the post-mortem on this project? Was it a success? Did it get out into the internet? Has there been a strong response one way or the other? Do we think it persuaded some of those it was designed to persuade?
Moderator Response:[Rob P] - John Cook is very busy at the moment, but will have a post up in the next few days. I can say that it looks to have been a very successful project.
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franklefkin at 00:27 AM on 13 September 20142014 Arctic Sea Ice Extent Prediction
5.35 million sq km looks to be a winner!
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Dikran Marsupial at 19:44 PM on 12 September 20142014 SkS Weekly Digest #36
Just to answer Philips question more directly, no, McKitricks method is not a legitimate way of determining the length of the hiatus. The correct way would be to use changepoint detection, also known as piecewise regression, which attempts to see if there is evidence for a change in the slope of the regression function at some particular point. If there is, then the point identified would be the inferred start date of the hiatus. The major problem with this is that the standard methods (e.g. the Chow test) do not account for the autocorrelation of the time series, which means that it will tend to identify suprious changepoints.
Using the statistical test with the null hypothesis being that the underlying rate of warming has continued unchanged would also be a valid approach, and as KR says, in this case the null hypothesis would not be rejected and there would be insufficient statistical evidence to claim that there has been a hiatus.
I don't think anybody disagrees that there has been a hiatus, that much is evident from just looking at the data, however that does not mean that climate change has stopped, or is called into question, as it seems that it is likely to be due to a change in the redistribution of heat between the oceans and surface. Such redistribution is noise, not signal, but naive statistical tests do not properly account for the full range of unforced variability.
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Dikran Marsupial at 17:14 PM on 12 September 20142014 SkS Weekly Digest #36
Philip Shehan There are two ways in which the scientific community deal with journal papers which contain fundamental errors. The most usual way is for scientists to read the paper, raise their eyebrows, think "boy, the reviewers have let that author down!", and then ignore it. The result of this is that the paper rarely gets cited and the authors' academic reputation slips somewhat. The second way is that someone writes a comment paper (a "letter to the editor") pointing out the errors, and then the scientific community continues as in the first way.
I suspect in this case, nobody will be very interested in Prof. McKitricks paper, I doubt it will get many citations (outside e.g. Energy and Environment), and it won't change anything. The fact that Prof. McKitrick published it in a lowly journal that few people read and rarely contains ideas worth using (c.f. h-index mentioned by Tom) suggests that even Prof. McKitrick doesn't think his method has much value. If he did, he would have sent it to a more prestigeous journal.
So asking you to write a journal paper on this is basically their way of saying "we have no answer to your criticism, but we are not going to admit that, and we are not going to change our minds". In this case, there is little value in publishing a comment as the journal is not sufficiently prestigeous for the paper to attract much scientific interest, and it is unlikely that the skeptics on the blogsphere would pay any attention to the comment anyway.BTW I have written several "letters to the editor", and whether they are effective depends on the nature of the audience. I wrote a paper explaining why Prof. Essenhigh's argument about the residence time of atmospheric CO2 does not mean the rise is not anthropogenic. However that has not stopped the skeptics from citing Prof. Essenhigh's paper and ignoring the refutation and not also citing my paper (e.g. the NIPCC report). I wrote another explaining the flaws in a paper about estimating the body mass of dinosaurs from their long bone measurements. While the authors of the original study were unable to accept their method was incorrect for this particular application, the research community often cite my paper, whenever the original one is cited. This rather shows a difference between some skeptics in the climate debate and the way in which scientists generally behave.
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2014 SkS Weekly Digest #36
Philip Shehan - Sounds like a basic misunderstanding of statistics. Failure to reject the null hypothesis of no warming does not mean no warming has occurred, merely that you have insufficient data to exclude it.
To perform a frequentist test of 'no warming', you need to posit a null of warming continuing at previous rates and show that it is excluded. That simply hasn't happened.
Examining any time-span starting in the instrumental record and ending in the present:
- Over no period is longer term warming statistically excluded.
- Over no period is the hypothesis of "no warming" statistically supported against a null hypothesis of the longer term trends.
- And over any period with enough data to actually separate the two hypotheses – there is warming.
The people at JoNova's blog, not to mention JoNova herself, simply don't understand statistics or the evidence you can gain from it. Their misperceptions lead them to false (i.e., wrong) conclusions.
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Philip Shehan at 12:59 PM on 12 September 20142014 SkS Weekly Digest #36
I might add that on Jo Nova's blog, when I raised these points, i was challenged to submit a manuscript for publication to the journal and see what the reviewers made of them.
This is a typical "skeptic" response and I pointed out that a few observations on a paper do not constitute 'original research' worthy of publication, but it did cause me to check on the Open Journal of Statistics (the 'open' in the title is enough to raise suspicions).
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Philip Shehan at 12:53 PM on 12 September 20142014 SkS Weekly Digest #36
I will say at this point that I suspected on viewing the paper and comparing the results with those provided by the excellent skeptical science trend calculator that McItrick was converting 'warming no longer statistically significant (that is, the trend error margins include values below zero)' to a statement that this constitutes evidence for a pause, but as I noted previously, his statistics is beyond my level of expertise (limited to applications in biomedical research).
I have previously said on skeptic blogs that the requirement for statistical signficance for warming or cooling (the error margins do or do not cross the zero trend line) is "unfair" as far as a hiatus is concerned. By definition, a hiatus means that the trend is (or is very close to) zero, so any error margins no matter how small will include positive and negative trend values. It is difficult to see haow you can get a "statistically significant" pause by this criterion.
So I was wondering whether McItrick's stistical manipulations (not meant pejoratively) were a legitmate way of dealing with this problem, but considering the comments here, I remain unconvinced.
Any further comment welcome.
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Philip Shehan at 12:11 PM on 12 September 20142014 SkS Weekly Digest #36
Thank you to all those who responded to my request for opinions on this.
It will take me some time to properly read and consider your answers, but in the meantime, thanks again very much.
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Bob Loblaw at 09:53 AM on 12 September 201497 hours of consensus: caricatures and quotes from 97 scientists
"No person growing up has time or ability to check every fact they accept for themselves."
This jives with a saying (from the Canadian Aviation Safety Letter) I have used many times over the years: learn from the mistake of others - you won't live long enough to make them all yourself.
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Tom Curtis at 06:43 AM on 12 September 201497 hours of consensus: caricatures and quotes from 97 scientists
dhf @40:
"Very many are trained through education and profession to recognize and disregard arguments containing logical fallacies."
Being in fact trained in formal logic, and having some practical experience in rehtoric, I can recognize your argument as an "argument from assertion".
Of course, that does not make it a logical fallacy. A logical fallacy is formally described as an "invalid argument", ie, and argument for which the premises can be true, and the conclusion false. Clearly, the argument by assertion, as the formal form of p⇒p (read as p, therefore p, where p is any proposition). That is so far from being a logical fallacy, it is in fact a tautology. It also in no way gives us more reason to believe that "p" than we had initially, and is thus a rhetorical fallacy (or from some points of view, a strong rhetorical move if you can disguise what you are doing.
Unfortunately, that which you argue for by assertion is false.
I know that becuase both induction and abduction are also logical fallacies. (I leave aside mathematical induction, which may be formally valid, but cannot be shown to be formally valid without assuming that it is.)
In the classic example of induction is the argument that because all (non-albino) crows that we have seen are black, therefore all (non-albino) crows are black. Clearly the proposition that all members of a set, S, have a given property is not logically entailed from the fact that all members of a proper subset of S, S', have that property. But the argument from induction asserts that inference to be valid. Ergo the argument from induction is a logical fallacy.
To take a practical example, it is a universal experience of humans that not all points of the Earth's surface are directly visible from one location no matter how high. It does not follow logically from that that tomorrow no human will directly see the entirety of the Earth's surface from one location. Assuming that they will is a logical fallacy, known as the argument from induction.
An even more practical example is the belief that that asperin has a high probability of reducing the pain from a headache (supported by a vast body of experience) will continue through tomorrow. It is logically consistent with all past experience that from tomorrow asperin will cause humans to die after 48 hours of excruciating agony. Any time you take asperin in the confident belief that it will reduce your headache and cause no appreciable harm, you are indulging in the logical fallacy known as induction.
Abduction (the inference to the best explanation), is even more fun in that it has the apparent form of a named fallacy, ie, that of affirming the antecedent. It is none-the-less the basis of all science. Admitedly, some scientists try for a Popperian science, but as even Popper admitted, falsification is a matter of convention - and hence even Popperian science is inductive. Indeed, as Imre Lakatos has pointed out, the inductive leap based on the fact that a theory has not been falsified is always false. As he says,
"In the distorting mirror of naive falsificationism, new theories which replace old refuted ones, are themselves born unrefuted. Therefore they do not believe that there is a relevant difference between anomalies and crucial counterevidence. For them, anomaly is a dishonest euphemism for counterevidence. But in actual history new theories are born refuted: they inherit many anomalies of the old theory. Moreover, frequently it is only the new theory which dramatically predicts that fact which will function as crucial counterevidence against its predecessor, while the "old" anomalies may well stay on as "new" anomalies"
It is clear from that last example that the very professions you probably had in mind (medical doctors, engineers) are not trained to ignore arguments based on logical fallacies. Rather, they base their careers on at least one logical fallacy, and probably many. Indeed, certainly many if they are any good.
Appeal against an argument because it is a "logical fallacy" really amounts to the old classical cannard of assuming all knowledge is certain - that only that which can be known deductively can in fact be known. In fact, in real life most of what we know is known inductively - from arguments that are not formally valid, but are reliable. That is necessarilly the case, or our knowledge would be restricted to logical tautologies, and mathematics. Indeed, at a most fundamental level, did we not accept the argumentum ad populum in our youths, we would speak no language. It is only because all around us (or nearly all) call crows "crows" and swans "swans" that we know the meaning of those words.
The reason some (at least) of the "logical fallacies" have such a hold on our minds is that they are in fact reliable ways to obtain knowledge, or at least were so under the conditions in which we evolved. Under those conditions the knowledge base of all the people was based on their every day experience of the world over generations, and within its limits was reliable (although it could sometimes be false). We did not need to check that black mambas were poisonous because we were told so by "all the people", and trusting them was a far more reliable way to obtain that knowledge (even if less certain than direct experimentation).
Not only were they reliable, they were essential. No person growing up has time or ability to check every fact they accept for themselves. That was true in the past and is even more so in modern societies with a substantial scientific and technical base.
What has changed with the development of science is not that we need no longer rely on "arguments from authority" or "arguments from all the people", but that we have realized the reliability of the people on whom we rely depends essentially on the type of experience they have. We have realized with respect to science that reading ancient greek classics is not a reliable source of knowledge, but that detailed experimentation and scientific reasoning is. Therefore we no longer include classics scholars among the people we relly on to understand physics. Instead we relly on scientists.
Doing so, of course, remains a 'logical fallacy'. It is also a reliable guide to knowledge. The key is we must ensure that scientists do not themselves relly on the argumetum ad populem in the area of their specialization. Rather, they should relly on those other 'logical fallacies', induction and abduction. So, unless you are yourself a climate scientists, you are a fool to not relly on the 97% in determining your knowledge on science. You are giving up the most reliable source of knowledge to which you have access. You are even more a fool if you do so based on myths about "logical fallacies" which have no bearing on the real world.
Climate scientists themselves, on the other hand, should not be persuaded one iota in any direction from the fact that they are in the 97%, or the 2% or the 1%. And from my experience of their works, they are not.
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Earth Encounters Giant Speed Bump on the Road to Higher Sea Level
sailingfree, yes. However, you have to keep in mind that the "hiatus" is for surface temperature and starts roughly in 2007-2008. Not much of the accumulating energy (global warming) is going into warming the troposphere/surface. Most is going into the oceans. Not much of a hiatus there.
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sailingfree at 05:31 AM on 12 September 2014Earth Encounters Giant Speed Bump on the Road to Higher Sea Level
From a newbie: Does the continued rise in SL during the recent temperature hyiatus show continued GW?
Moderator Response:[Rob P] - Yes, that's how very simple this is. Sea level rise is a combination of extra water volume from the melt of land-based ice, and the expansion of seawater as it gets warmer. The ongoing rise in sea level, although complicated by a number of factors, is a clear indication the oceans are continuing to warm.
As for surface warming, the rate appears to have slowed over the past decade or so, but one needs imagination to describe it as a pause or hiatus. Plenty of people possess the necessary imagination of course......
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knaugle at 05:10 AM on 12 September 201497 hours of consensus: caricatures and quotes from 97 scientists
I fully accept that all but a very few climate scientists are convinced AGW exists, and is of concern, and has strong science behind it. Even Richard Tol admits 90+% of scientists are convinced. Still the 97% number has been around as long as Naomi Oreskes and hasn't changed in 11 years. Numbers that constant (pi notwithstanding) usually make me suspicious, not of the science but how we are communicating it.
Moderator Response:[Rob P] - Richard Tol only accomplishes a lowering of the consensus to 91% by magicking up 300 extra rejection papers - he camouflages this with technobabble in his paper. IIRC only 78 were found in the entire rating process of Cook et al (2013). To my knowledge, not even one extra rejection paper has been found let alone 300.
As for 97% & Oreskes; I think you may be misremembering - Oreskes (2004) found no papers at all that rejected the consensus.
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Phil at 04:52 AM on 12 September 201497 hours of consensus: caricatures and quotes from 97 scientists
dhf @36 and 40
You are incorrect, the argument is only an "appeal to the masses" if the argument is being presented to the 3%, i.e. if someone used this argument to try to persuade Lindzen, Spencer, Pat Michaels, etc.
However it is being used to convince a much wider, less knowledgable, audience, and thus is, in fact, an appeal from authority ( http://en.wikipedia.org/wiki/Argument_from_authority )
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Atom at 03:36 AM on 12 September 2014Water vapor is the most powerful greenhouse gas
I have a question. Since warming causes more atmospheric water vapor and more atmospheric water vapor causes warming, why doesn't the water vapor feedback become self sustaining as a result of any natural change in global temperature, such as an El Nino? The effect must be self limiting or the planet would just keep heating up. What breaks, interrupts or stalls the feedback loop?
Moderator Response:[TD] Good question! See the answer in the post on positive feedback.
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Tom Curtis at 00:29 AM on 12 September 20142014 SkS Weekly Digest #36
Dikran @30, indeed. Number 405 on the list.
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Dikran Marsupial at 23:38 PM on 11 September 20142014 SkS Weekly Digest #36
Tom, I understand it is also on Beal's list of predatory open access (author pays) publishers - more or less academic vanity publishing. I definitely won't be sending any papers there! ;o)
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Ferroequinologist at 23:22 PM on 11 September 2014We didn't have global warming during the Industrial Revolution
Alan Titchmarsh was correct when he said you couldn't have seen across the street in the early days of the Industrial Revolution for all the carbon emissions and crap- If you take Carbon emissions literally- i.e. NOT CO2; just soot!
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