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    A crisis of epistemic overconfidence I’ve just completed rereading Vol I of the NCA4. There is so much here of concern that it is difficult to know where to start." - Fixed the following “Assessments of confidence in the Key Findings are based on the expert judgment of the author team. Confidence should not be interpreted literally, as it is distinct from statistical likelihood.“ - The message being pushed is not the level of confidence but the need to have a level of confidence to persuade people to believe.

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    The IPCC position is stated in AR5 Chapter 6 (1) as: The removal of human-emitted CO2 from the atmosphere by natural processes will take a few hundred thousand years (high confidence). Depending on the RCP scenario considered, about 15 to 40% of emitted CO2 will remain in the atmosphere longer than 1,000 years. This very long time required by sinks to remove anthropogenic CO2 makes climate change caused by elevated CO2 irreversible on human time scale. [original bold] This high confidence statement has been falsified by Harde 2017. The IPCC also says that all of the recent rise in atmospheric CO2 content is caused by human activity. Harde and others have shown this to be erroneous.

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    As a degreed and registered mechanical engineer, I have a professional, legal and financial obligation to get it right. 1) 33 C warmer with atmosphere is rubbish. By reflecting 30% of the ISR the atmosphere cools the earth, i.e. it’s hotter without an atmosphere not colder. https://www.linkedin.com/feed/update/urn:li:activity:6473732020483743744 2) The 333 W/m^2 GHG energy loop is thermodynamic nonsense. Not because of the 2nd law regarding entropy, but because it appears out of nowhere violating the 1st law of energy conservation. 3) The surface upwelling 396 W/m^2 LWIR as a BB that powers the GHE is not possible. Because of the non-radiative heat transfer processes radiation’s share, 63/160 = 39.4%, presents an effective emissivity of 63/396 = 0.16 and demonstrated by experiment. https://principia-scientific.org/debunking-the-greenhouse-gas-theory-with-a-boiling-water-pot/ 1 + 2 + 3 = no GHE & no CO2 warming & no man caused climate change. Bring science, prove me wrong. Nick Schroeder, BSME CU ’78, CO PE 22774 https://www.linkedin.com/feed/update/urn:li:activity:6466699347852611584

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    Rather incoherent v8. Cliff Mass doesn't need you to read his mind or call him politically motivated. His accomplishments speak for themselves. You don't seem to understand how science works through hearty debate.

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    BTW v8, People would be more likely to wade through your verbose comments if you used proper grammar and sentence construction. Most people haven't the time to fill in the blanks in your decidedly bad writing style. I gave up on this one after the first paragraph.

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    I'm not confident that you have assessed the overconfidence in a robust repeatable way. "This statement really struck me, since it is at odds with the conclusion from the IPCC AR5 WG1 Chapter 5 on paleoclimate: “For average annual NH temperatures, the period 1983–2012 was very likely the warmest 30-year period of the last 800 years (high confidence) and likely the warmest 30-year period of the last 1400 years (medium confidence). While my knowledge of paleoclimate is relatively limited, I don’t find the AR5 conclusion to be unreasonable, but it seems rather overconfident with the conclusion regarding the last 1400 years. " 1. without the requisite knowledge it seems rather unreasonable to asses the claims or the confidence in those claims. What are we juding when we judge the stated confidence in the claim? I'll return to this below 2. For NH temperatures over the past 1400 years, they only claim likely for where such an assessment is possible. You missed some critical text in the SPM. "Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. The period from 1983 to 2012 was likely the warmest 30-year period of the last 1400 years in the Northern Hemisphere, where such assessment is possible (medium confidence)." It is likely (medium confidence) that you didnt read the whole IPCC text. The IPCC statement doesnt seem--highly likely--the least bit overconfident . And I am highly confident of that. A group of experts considered the publications about the past 1400 years in the NH. They conclude that publications show its likely (66% +) that the NH was warmer in the 1983-2012 time period. And they only have medium confidence in this assesment. To tell if this is OVER confident I have to at least do the same work they have. I have to at least read everything they read. And then I have to give reasons why I think Medium confidence is over confident. If I dont do this I cant be confident in my assesment of their confidence. Their confidence results from engaging in a behavior: reviewing all the relevent science. I kinda have to walk a mile in their shoes. You for example have some confidence after working with ECMWF. That confidence is the result of your experience. If I wanted to seriously question your confidence, at a bare minimum I would have to share some of your experience and see if I came to the same conclusion And it would help ( for traceability) for people to explain WHY their confidence is Medium. Few studies? Studies with shakey assumptions? new methods? untested methods? Why medium confidence? If you dont know why Medium confidence, then its very hard to say why medium is too high. If you don't have knowledge in a field and they dont explain why they have medium confidence, then its over confident to claim that that they are over confident. The simple truth is you may just not know why they say medium confidence and may not know whether that is too much or too little confidence

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    I have a simpler way of approaching it. An assessors confidence level should be justified by the evidence they use (and cite), and be consistent with the language the use to describe their evidence and the uncertainties and ambiguities associated with their evidence.

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    JBM, A valid free 'market-driven innovation strategy' is the opportunity for anyone to get rich quick by entering into the science of mineral exploration. Go out there, find the makings of a new mine, sell it for a profit. I worked with a modest team for decades in this environment, with success, a dozen new mines and sales to date of $65 billion. The biggest impediment was unwanted and unsought government intervention. Mineral royalties, property rights, health and safety, aboriginal land rights, export licences, costs of services like electricity and water, etc. None of these was needed as a legislated intervention. We could have navigated with ease. Society now suffers because these 'frontier' type activities are over-regulated to the point of being unattractive. It is easier to turn a quid now by subsidy mining, thus making economic activity a drain, when once it was a benefit. We now have a mindset that says too often 'This project could never happen because it would be too hard to write the regulations for it'. That is a social sickness of the mind, like saying that a vaccine is worse than the disease because it is so hard to regulate the vaccine inventors/makers/sellers. With regret, I can but point out this problem while offering no solution that has a chance of success with current generations and they ways they think. I have a crisis of underconfidence. Geoff.

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    Hayhoe is one of the most irrational ideologues in climate science. The fact that they have given her the megaphone is reason enough to ignore the assessment as political theater.

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    Uncertainties and ambiguities were classically handled by the use of statistics on measurements resulting in error analysis and mathematical bounds to express uncertainty. Sadly, few recent climate papers show any comprehension of the formal treatment of errors, despite established methodologies such as those written by the Bureau of Weights and Measures. Some might argue that climate research is different, because of the common impossibility of replicating a climate event to measure, for example, a bias so derived conventionally. That might be so, but it does not excuse the lack of formal error analysis in a multitude of other more ordinary endeavours, like finding the temperature of a portion of the atmosphere from time to time adequate to make quantitative descriptions of it and its variations. The classic, formal approach to uncertainty has no place for subjective assessments or expert opinion. Nor should it have. Disrespect for such formality about errors and uncertainties is one of the prime reasons why I personally have so little trust of the climate field. Much of it is at a child-like level of intellect, is known to be so, yet is allowed to continue and to grow, with horrible, predictable outcomes. Geoff.

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    Nick, I am a P.Eng, mechanical ‘74 with post grad courses in heat transfer, with the same obligations to be correct. The amount of heat being radiated from one surface to another is q/a= [k/(1/ehot+1/ecold-1] x (Thot^4-Tcold^4). The ground is at Thot due to being warmed by sunshine, If the atmosphere was only N2 and O2, it would be completelely transparent to Infrared. The “surface” the ground would radiate to is outer space at -270 C. But CO2 and H2O readily absorb and reradiate IR. Because the H2O and CO2 are the same temperature in the atmosphere as the N2 and CO2, the “surface” the ground radiates to is “the sky”, and the “sky” is much warmer than outer space. You can take an IR thermometer and typically read the temperature of clouds at about freezing and blue sky down to -80, but $40 IR guns do not have proper emissivity settings for this job. Anyway my point is that the ground temp has to get warmer as it heats in the sunshine in order for Qout and Qin to be equal, when there are radiating gases between the ground and outer space. Yes, it is foolish to assume a constant Albedo of .3 to come up with the often stated 33 C number, when Albedo is so dependent on clouds and clouds are made of water, but people who make this generalization are only trying to show how the radiative gas effect works,

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    The epistemological problem is we don't even know what we don't know about CO2 and climate. The only crisis is the deflation of the 16' blow up mickey mice posturing as scientific savants. They lie on the lawns like morning deflated Santas., even as their workshops continue to crank out toys no one will ever bother to look at. There never was any basis for confidence that we understand the climatic effect of CO2. The proxies are unequivocal. In deep time CO2 shows no relation, except possibly to follow temperature into the Ordovician glaciation. In ice core time, CO2 follows temperature like a poodle on a leash. These are proxies, with all the attendant uncertainty. Our historic measurements are fraught with uncertainty. Dismal coverage, questionable dedication, and poor quality instruments. In the sober early days of the new year, we should resolve to better understand why temperature still controls the variation around the trend of increasing atmospheric CO2; but CO2 does not control the variation around the trend in increasing temperature.

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    The fundamental precept of ecology - environmental science is something different - is the richness and profusion of life occupying every available niche. But nature is red in tooth and claw and there are food webs with some sort of dynamic balance. e.g. https://www.clatsopcc.edu/sites/default/files/file/rbeveridge/mth252/Sugihara_Fish_Modeling.pdf

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    "Global-scale multidecadal variability missing in state-of-the-art climate models" - https://www.nature.com/articles/s41612-018-0044-6 - and in JCH's intellectual microverse. https://wol-prod-cdn.literatumonline.com/cms/attachment/51a17b52-58d5-4424-b569-2bfcdc8dafef/grl25658-fig-0001.png "(top) Synchronization as measured by the root‐mean‐square correlation coefficient between all pairs of modes over a 7‐year running window. Note the reversed ordinate; synchronization increases downward in the plot. High synchronization at the p = 0.95 level is denoted by shading, tested by generation of surrogate data as described by Tsonis et al. [2007]. (middle) Coupling as measured by the fraction of consistently increasing or decreasing mode time series as described in the text. The shaded region denotes coupling at the p = 0.95 level as calculated from the surrogate data used for the confidence intervals in Figure 1 (top). (bottom) HadCRUT3g global mean temperature over the 20th century, with approximate breaks in temperature indicated. The cross‐hatched areas indicated time periods when synchronization is accompanied by increasing coupling." I know I said that attribution was of minor scientific interest - but we are working on more than half of warming in the last 40 years. "The global-mean temperature trends associated with GSW are as large as 0.3 °C per 40 years, and so are capable of doubling, nullifying or even reversing the forced global warming trends on that timescale." op.cit. That's Global Stadium Wave for the cultural agnotologists.

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    Mosh The Met Office, The Dutch Met Office and various other scientists have concluded that CET is a reasonable, if not perfect proxy for the Northern Hemisphere. From the instrumental record we can reasonably conclude that there was a remarkable temperature rise from around 1695 and that, according to Lamb and Jones, the 1730's were the warmest decade until the 1990's. From the extended record (my own) to 1535 plus the observations from a variety of scientists and historians it would appear that the few years centred on 1540 were probably the warmest and driest in our history, from any reasonable record until the Domesday book. I have not examined the early part of the 1500's so can not comment how long lasting the extreme heat and drought lasted in the English record. I have examined the 1200's and whilst there were periods of extreme warmth they were relatively short lived so I doubt if there were a very warm 30 year consecutive period as most of this century was rather cool. There were certainly some extended warm periods in the 1300's which was quite a turbulent century but as yet I have not examined it in detail, nor the 1400's. The medieval warm period is well represented in English literature and records for both architecture,(churches and castles) sea levels (high) altitude of tilled fields and habitation. I would say that any claim of the warmest in the past 1400 years would need to ignore the works of Lamb Groves and many many others. The high point of the MWP -generally warm and settled with less wind-was around the 750 to around the 1050 period, with a century either side being generally fairly characteristic of the warm period but with undoubtedly some extremely cold periods mixed in. So we need to explain the 1730's warm decade, various other decades or longer periods in a variety of centuries and certainly the MWP with its history of exploration, extension of settlements to heights not currently possible, abundance of crops etc which would seriously challenge the IPCC claim of the warmest 30 year period since around the 6th Century. At that point of course we have abundant evidence of the Roman warm period but the period from around 450 to around 650 or later seemed cold but not as cold as the intermittent little ice age. The last couple of hundred years illustrate a continual increase of warmth with the starting point being around 1700 rather than 1850. Manley noted the general retreat of the glaciers from around 1750 and Ladurie noted in great detail their sporadic retreat and advance back to the 11th century. So, the 30 year claim is unproven as yet tonyb

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    Figure 2 from NCA4 Executive Summary is an excellent example of graphical overconfidence: https://science2017.globalchange.gov/img/figure/es-2.png <i>"Global annual average radiative forcing change from 1750 to 2011 due to human activities, changes in total solar irradiance, and volcanic emissions. Black bars indicate the uncertainty in each. Radiative forcing is a measure of the influence a factor (such as greenhouse gas emissions) has in changing the global balance of incoming and outgoing energy. Radiative forcings greater than zero (positive forcings) produce climate warming; forcings less than zero (negative forcings) produce climate cooling. Over this time period, solar forcing has oscillated on approximately an 11-year cycle between −0.11 and +0.19 W/m2. Radiative forcing due to volcanic emissions is always negative (cooling) and can be very large immediately following significant eruptions but is short-lived. Over the industrial era, the largest volcanic forcing followed the eruption of Mt. Tambora in 1815 (−11.6 W/m2). This forcing declined to −4.5 W/m2 in 1816, and to near-zero by 1820. Forcing due to human activities, in contrast, has becoming increasingly positive (warming) since about 1870, and has grown at an accelerated rate since about 1970. There are also natural variations in temperature and other climate variables which operate on annual to decadal time-scales. This natural variability contributes very little to climate trends over decades and longer."</i> All they did was to take figure 8.18 from Chapter 8 AR5 and add all the radiative forcings since 1750. According to that best knowledge there hasn't been any significant natural contribution to climate change since 1750. The error bars do not permit any other conclusion except that for the last 270 years nearly all climate change has been anthropogenic. If we ask climatologists how many believe this is true, we know based on past polls that a majority of them would respond that they believe natural climate change has played a significant role since 1750. After all they have answered they believe it has done so since 1950. https://i.imgur.com/6IUuIht.jpg This is from a poll published by Verheggen et al., 2014, where only 17% spoused the IPCC belief that GHG had caused more than 100% of the observed warming (compensated by aerosol cooling). 50% believed it had caused more than 75%, and 66% believed it had caused more than 50%. If instead of recent warming you would ask them about since 1750, do we think a majority of them would be more convinced that human contribution is likely to be >95%?

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    At the basis of this figure is the root of the problem. The IPCC has decided that climate change can only be defined and quantified in terms of radiative balance, and any climate factor that has a small impact on radiative balance cannot play a significant role. This essentially rules out anything but GHGs from affecting climate. By accepting that paradigm, the IPCC crowd, that makes a great majority of climate scientists, has painted itself into a corner where it is impossible to understand climate change. Surprises are guaranteed. Until the paradigm is rejected climate science cannot advance.

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    Thank you tony b

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    There would not be much future loss and damage from … [pro-nuclear] policies designed to prevent climate change.

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    "“Overconfidence” is actually more akin to hubris" Hubris, it's been said, tempts nemesis; let's hope it (a cooling trend) happens soon, before developed countries go further down the renewables rathole.

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