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Search for Nir Shaviv

Comments matching the search Nir Shaviv:

  • From the eMail Bag: a review of a paper by Ziskin and Shaviv

    Bob Loblaw at 10:14 AM on 3 August, 2022

    Hello, yanirdz. Welcome to Skeptical Science, and I hope that this is a useful resource.


    The short story is that the model used by Ziskin and Shaviv introduces an "indirect solar effect" that is based on an index (the AA index) that starts positive and grows over time (figure 4). All other forcings (direct solar, CO2, aerosols, etc.) represent a departure from equlibrium - i.e., they would have a value of zero in a stable climate, and a non-zero value would push temperatures away from that equilibrium (warmer, or colder, depending on whether the value is positive or negative).


    Since the AA index is always positive, it is always "causing" a warming trend in the model output of temperature. And since the AA index increases over time, it pushes the temperature warmer and warmer. The AA index never has a value of zero, so it can never not contribute to warming in the model.


    ...and as a result, the observed warming over the past century gets "explained" by the "indirect solar effect", because the model is created in such a way that the "indirect solar effect" absolutely must cause warming. And since the "indirect solar effect" must cause warming, the fitting of the model to actual observations must reduce the warming effect of anything else (e.g., CO2).


    Really short version: they assumed continuous warming due to the "indirect solar effect" when they built the model, and therefore their "conclusion" is not a conclusion, it is their original assumption.


    Minor point: they have a multiplier (fudge factor) for the "indirect solar forcing" that hypothetically could have a zero value, making the AA index always zero, or even negative (see the last row in table 2 in their paper). The fitting process, though, finds it easier to use the always-positive AA index to "explain" the warming, instead of CO2 or direct solar, etc.


    Feel free to ask any further questions.

  • From the eMail Bag: a review of a paper by Ziskin and Shaviv

    Bob Loblaw at 03:56 AM on 4 February, 2022

    DesmogBlog's entry on Shaviv now has a link to this blog post....

  • From the eMail Bag: a review of a paper by Ziskin and Shaviv

    Bob Loblaw at 23:28 PM on 1 February, 2022

    Yes, Shaviv is well-known in that area. He also has a DesmogBlog profile:


    https://www.desmog.com/nir-shaviv/


    I tried to stick to the paper itself in the review, letting it stand (or die) on its own. There is lots more wrong with it than I had room for - what I've written about is enough, I think.


    You can always ask questions about the parts that need more explaining. You probably won't be the only one.

  • From the eMail Bag: a review of a paper by Ziskin and Shaviv

    nigelj at 18:39 PM on 1 February, 2022

    Thanks Bob for the appraisal. I don't know enough physics to follow all of it, but I got something out of it, and I can see some of the flaws.


    Did a quick google search on Nir J. Shaviv. The name was familiar: He routinely minimises affects of CO2, has links to Heartland Institute and GWPF, and supports websites like WUWT and Jo Nova, believes CO2 is plantfood, is sceptical of measures to control covid 19 pandemic, promotes nuclear power.


    The complete classic package of a typical climate change denier. Almost textbook. Its almost a personality type. It always seems to include the same range of things and same leanings, spanning not just climate, but energy systems and covid issues and other things.


    Not remotely surprised. Doesn't mean his paper is necessarily wrong, but it sure suggests dont take it at face value.


    en.wikipedia.org/wiki/Nir_Shaviv#Rejection_of_human-caused_climate_change


    sciencebits.com/GWPseudoScience


     

  • It's cosmic rays

    citizenschallenge at 06:51 AM on 22 December, 2017

     

    He's baackk, 

    H. Svensmark, M. B. Enghoff, N. J. Shaviv, J. Svensmark. Increased ionization supports growth of aerosols into cloud condensation nuclei. Nature Communications, 2017; 8 (1) DOI: 10.1038/s41467-017-02082-2

    https://www.sciencedaily.com/releases/2017/12/171219091320.htm

    December 19, 2017
    Source:
    Technical University of Denmark
    Summary:
    The study reveals how atmospheric ions, produced by the energetic cosmic rays raining down through the atmosphere, helps the growth and formation of cloud condensation nuclei — the seeds necessary for forming clouds in the atmosphere.

     

    Henrik Svensmark confidently broadcasts and hundreds of astroturfers are busy spreading the word: "Finally we have the last piece of the puzzle explaining how particles from space affect climate on Earth. It gives an understanding of how changes caused by Solar activity or by super nova activity can change climate." says Henrik Svensmark, from DTU Space at the Technical University of Denmark, lead author of the study. Co-authors are senior researcher Martin Bødker Enghoff (DTU Space), Professor Nir Shaviv (Hebrew University of Jerusalem), and Jacob Svensmark, (University of Copenhagen).

    ===========================

    Links to serious critiques of this paper and ther authors claims would be appreciated.

  • There is no consensus

    MA Rodger at 19:49 PM on 8 January, 2015

    The Forbes story amhartley asked about @650 is rather strong in its assertions. It asserts that Cook et al (2013) involves "egregious misconduct" and was "a deliberate misrepresentation designed to intimidate the public." These claims are backed up by a mis-description of the Cook et al method and the comments of some well-known scientists - Richard Tol, Craig Idso, Nicola Scafetta and Dr. Nir Shaviv, this last one being a not-so-well-known climate change denier compared with the other three.

  • How we discovered the 97% scientific consensus on man-made global warming

    barry at 16:25 PM on 23 November, 2013

    Question:

    Of the scientists that were surveyed to rate their own papers, did you include Alan Carlin, Craig D. Idso, Nicola Scafetta, Nils-Axel Morner, Nir J. Shaviv, Richard S.J. Tol, and Wei-Hock "Willie" Soon?

    I ask because Anthony Watts, referring to a PopTech article regarding those scientists' comments on the paper, says that they were not contacted. But the scientists themselves say nothing about that.

    Do you have a list of the scientists you attempted to contact, perhaps in supplementary material?

    Any leads appreciated.

    Barry.

  • Shakun et al. Clarify the CO2-Temperature Lag

    OneHappy at 12:53 PM on 15 March, 2013

    On ScienceBits 21 April 2012 Nir Shaviv raised this objection to the Shakun et al. paper: "in order to recover their average "global" temperature, I needed to mix about 37% of their southern hemisphere temperature with 63% of their northern hemisphere temperature." So he is accusing them of deliberately manipulating the data by weighting it to get the result they wanted (ie that globally on average temperature lags CO2). I am interested in two aspects of this objection. 1) Is he correct, and if so how much does this compromise Shakun's results? 2) Assuming Shaviv is correct, would this mean that temperature does not lag CO2 only during the start of a period of warming (but it would during the mid and latter period), or would this apply across the entire period?

  • Global Surface Temperature: Going Down the Up Escalator, Part 1

    Tom Curtis at 07:03 AM on 24 November, 2012

    Setit-Bargain @115:

    1) Your temperature chart is derived from a reconstruction by Jan Viezer which is known to not account for the effects of ocean acidification on its temperature proxy. This introduces a cool bias to the temperatures during periods of high CO2, a known cause of ocean acidification. Once corrected, the temperature record looks like this:



    It should be noted that in response to the paper which pointed out this correction, Nir Shaviv and Jan Viezer acknowledged the correction to be accurate. (They unconvincingly argue that, despite the accuracy of the correction, in determining CO2/temperature correlations, you should use the uncorrected temperature record, which has a cooling bias based on the level of CO2 concentration.)

    2) Although you make much of the existence of other forcings in addition to that from CO2, you neglect the largest known forcings over the period since the first evolution of arthropods and vertebrates (ie, the Phanerozoic). Of these, by far the largest is the gradual warming of the sun by 4.1%, which has resulted in a forcing of 9.75 Watts per square meter over the period from 500 million years ago to today. That would require a forcing from increasing CO2 to is the equivalent of 1750 ppmv just to maintain a constant forcing, relative to preindustrial levels. Once both changes in the solar constant and in CO2 levels are taken into account, the forcing history of the phanerozoic is as follows:


    (As modified from Royer et al, 2004 by Tony Noerpel. The red line represents current CO2 forcing relative to preindustrial levels of 1.8 W/m^2.)

    Comparing known solar plus CO2 forcing shows that the two combined are responsible for the broad pattern of temperature change over the phanerozoic.

    You also neglect the crucial impact of continental positions. Throughout the phanerozoic, glaciations have occurred only when there have been large continental masses at, or very near the poles.

    Importantly, neither of these two other major factors can have any impact over the next half million years or so because of the very slow rate of change of the solar constant, and of continental drift. In other words, while you have neglected the two other most important factors over the phanerozoic; you paradoxically insist that effects of similar magnitude must exist (without evidence) to counter CO2 when the two other major factors are known to not be in play.

    (More later.)
  • Climate sensitivity is low

    cjshaker at 18:39 PM on 23 October, 2011

    You may be interested in Professor Shaviv's writings about climate sensitivity. He explains why he comes up with a lower number

    http://sciencebits.com/OnClimateSensitivity

    From: http://sciencebits.com/about

    "Prof. Nir J. Shaviv, who is a member of the Racah Institute of Physics in the Hebrew University of Jerusalem. According to PhysicaPlus: "...his research interests cover a wide range of topics in astrophysics, most are related to the application of fluid dynamics, radiation transfer or high energy physics to a wide range of objects - from stars and compact objects to galaxies and the early universe. His studies on the possible relationships between cosmic rays intensity and the Earth's climate, and the Milky Way's Spiral Arms and Ice Age Epochs on Earth were widely echoed in the scientific literature, as well as in the general press."

    Chris Shaker
  • It warmed just as fast in 1860-1880 and 1910-1940

    Adam at 03:53 AM on 15 April, 2011

    Okay I'm back.

    KR I have never claimed that CO2 is the only driver of climate change. Could you please point out where in my comments I said that?

    Sphaerica you are completely misunderstanding what the authors did in the paper I provided. The top graph is of tropspheric temperature compared with changes in cosmic rays.

    The radiosonde data shows a lot less warming over the past 30 years than the surface station data.

    The bottom graph is the removed effects of el nino, volcanoes and the NAO. The removal of the effects caused the slight warming trend to disappear. You completely misunderstood what they did. They didn't get rid of the warming for no reason. The removal of those effects (natural forces) simply effected the total trend after they were removed.

    Daniel Bailey, once again blog posts are not published. Tamino didn't really provide proper evidence that the AMO was the result of the warming. In Chylek's paper they theorised that Arctic temperature was caused by the AMO which makes much more sense.

    Albatross, once again the graph you showed is ignoring Svensmark's cosmic ray theory and using surface data. Cosmic rays can indeed still be the major cause of warming of the past three decades. Read Svensmark and Friis-Christenson's paper. See also here

    Sphaerica I think you're the one who needs to read papers more carefully, since you completely misunderstood what it did.
  • Meet The Denominator

    muoncounter at 07:49 AM on 17 February, 2011

    Here are two papers from the list's 'cosmic rays' section that have nothing whatsoever to do with climate change; the phrase does not even appear in the text.

    The Spiral Structure of the Milky Way, Cosmic Rays, and Ice Age Epochs on Earth (New Astronomy, Volume 8, Issue 1, pp. 39-77, January 2003) Nir J. Shaviv

    Ice Age Epochs and the Sun’s Path Through the Galaxy (The Astrophysical Journal, Volume 626, Issue 2, pp. 844-848, June 2005) D. R. Gies, J. W. Helsel

    The ice age epochs in question in each paper are on the million year (Myr) time scale. That's why they're called 'epochs,' a word specifically used in geology to denote a longer period of time than what we normally refer to as an 'ice age'.

    Another: Hale-cycle effects in cosmic-ray intensity during the last four cycles (Astrophysics and Space Science, Volume 246, Number 1, March 1996) H. Mavromichalaki, A. Belehaki, X. Rafios, I. Tsagouri

    This paper is about cosmic ray dynamics in the heliosphere; the abstract makes no mention of earth climate.

    None of these papers support any form of AGW skepticism, 'alarm' or phobia. It is not sufficient to simply gather papers with the words 'cosmic rays' in their titles and assume that they support the unsubstantiated Svensmark-style hypotheses. We now see concrete proof that '850 papers supporting skepticism' is another one of those malleable phrases that must have an alternate PopTechian definition.
  • The question that skeptics don't want to ask about 'Climategate'

    Marco at 05:01 AM on 21 November, 2010

    Chris Shaker, if Nir Shaviv is surprised that an editor rejects a paper without forwarding Shaviv's response to the reviewers, Nir Shaviv does not understand the publication process. The Editor has the final word on what gets published, and what not. Plain and simple. In fact, I know several journals that due to page restrictions have to reject up to 75% of all submissions.

    This poor understanding by Shaviv puts significant doubt on his other claims. Sounds to me to be the Galileo-syndrome.
  • The question that skeptics don't want to ask about 'Climategate'

    cjshaker at 18:43 PM on 20 November, 2010

    Phillipe:

    Given what has been reported in the press about suppression of articles critical to the AGW premise,
    criticizing someone for not having a peer reviewed article may be a circular argument.

    Given what Dr. Muller says on his website, I'm not surprised that M&M were unable to get a paper published.

    http://muller.lbl.gov/

    "Some people may complain that McIntyre and McKitrick did not publish their results in a refereed journal. That is true--but not for lack of trying. Moreover, the paper was refereed--and even better, the referee reports are there for us to read. McIntyre and McKitrick's only failure was in not convincing Nature that the paper was important enough to publish."


    Here is one from Israeli Astrophysicist, Nir Shaviv:

    "I witnessed how an editor rejected a paper I wrote without forwarding the reviewers my detailed response to their comments (he was perhaps afraid that the reviewers would actually be convinced with my detailed response which included detailed referrals to published results proving my points).

    I saw another rejection (perhaps by the same editor...), this time of a paper written by a colleague that included the punch line: "any paper which doesn’t support the anthropogenic GHG theory is politically motivated, and therefore has to be rejected"

    I saw how proposal reviewers bluntly reject funding requests, based on similar beliefs in the global warming apocalypse. I even know of someone who didn't get tenure because he advocated non party line ideas. "

    From

    http://www.sciencebits.com/node/211

    Chris Shaker
  • It's the sun

    cjshaker at 09:24 AM on 20 November, 2010

    If you're interested in reading the opposing viewpoint, Nir J. Shaviv, Isreali Astrophysicist, writes about Solar Forcing. He is quite readable.

    Carbon Dioxide or Solar Forcing?

    http://www.sciencebits.com/CO2orSolar

    Chris Shaker
  • What does past climate change tell us?

    shawnhet at 07:58 AM on 21 October, 2009

    Just for the record, I think here is a contrary view, where solar activity is amplified(it is not increased by a positive feedback).

    http://www.friendsofscience.org/assets/documents/Shaviv-Ocean%20as%20calorimeter-solar%20forcing.pdf

    Using the oceans as a calorimeter to quantify the solar
    radiative forcing
    Nir J. Shaviv

    Over the 11-year solar cycle, small changes in the total solar irradiance (TSI) give riseto small variations in the global energy budget. It was suggested, however, that different mechanisms could amplify solar activity variations to give large climatic effects, a possibility which is still a subject of debate. With this in mind, we use the oceans as a calorimeter to measure the radiative forcing variations associated with the solar cycle. This is achieved through the study of three independent records, the net heat flux into the
    oceans over 5 decades, the sea-level change rate based on tide gauge records over the 20th century, and the sea-surface temperature variations. Each of the records can be used to consistently derive the same oceanic heat flux. We find that the total radiative forcing associated with solar cycles variations is about 5 to 7 times larger than just those associated with the TSI variations, thus implying the necessary existence of an
    amplification mechanism, although without pointing to which one.

    Cheers, :)


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