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Comments 751 to 800:

  1. How sure are climate scientists?

    Nigel @1: There is no doubt that denialists will misconstrue what is in that video ... surprised? Since when do we care about their BS? they will do so anyway, regardless of what we say or what the video contains.

    Instead, it is the broad middle, the cautious, disengaged, and doubtful we need to reach, and for them, the video will be helpful.

    I do not agree with everything in it either, but I think it is one of the best outreach videos I have ever seen.

    There is one important point in there, that requires repeating. In his nice (book form) summary from 2015, Andrew Hoffman calls it the need to "address the process by which the message was created". Aka, don't just endorse expertise (miscontrued as "authority"), endorse the scientific process through which we arrived at the "message" (here: we need to address climate change by eliminating GHG emissions).

    SkS does this. So SkS shares this video. Thank you!

  2. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Hopefully the guys'n'gals here at SkS will find this as amusing as my Arctic alter ego did?

    Tucker Carlson interviewed Steve Koonin for Fox News. Fox displayed lots of stock footage of melting sea ice in the background. Needless to say neither Tucker nor Steve broached the subject of the 800 pound canary in the Arctic coal mine.

  3. How sure are climate scientists?

    It's worth noting that uncertainty cuts both ways, and I hope his next video, on renewables, does this.  Renewable power plants are temporary structures, while emissions from fossil fuel power plants are essentially permanent.  The former thus comes with much less risk than the latter: you can take down a wind turbine, you can't take down an excess of carbon dioxide.  Thus, the uncertainty about our climate future, so often used against climate action, actually favors renewable energy, and disfavors the fossil status quo.

  4. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Eclectic @13 - Thanks for your kind words

    Al @15 - Might I humbly suggest that in future you refrain from posting live links to the dark side from SkS? IMHO links to an archive like the one below are infinitely preferable for a variety of reasons:

    Thanks for your suggestions, which may well come in handy in due course. For the present I am still trying to persuade Judy et al. to take on board my prime proposition. See for example:

  5. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Jim Hunt @12,

    I think you missed a trick in your interchange with Judy @ClimateEtc on the subject of Koonin & Arctic Sea Ice. Judy chips in "If you think that the consensus is that this decline is 100% caused by AGW, then you disagree with the IPCC SROCC report (which estimates ~50%). Very weak base for criticizing Koonin."

    But come on,  Judy is just flying arround on Occam's broom.

    So I think the reply should be "Judy, have you read IPCC SROCC and the references it bases that "est ~50%" on?  I ask because if you had, I think you would be less quick with your "very weak base" comment."

    IPCC SROCC says "Approximately half of the observed Arctic summer sea ice loss is driven by increased concentrations of atmospheric greenhouse gases, with the remainder attributed to internal climate variability (Kay et al., 2011; Notz and Marotzke, 2012) (medium confidence).  ...   A lack of complete process understanding limits a more definitive differentiation between anthropogenic versus internal drivers of summer Arctic sea ice loss (Serreze et al., 2016; Ding et al., 2017; Meehl et al., 2018)."

    So at first cut, the ~50% value appears to be based on some rather old references. Of these references, Kay et al (2011) which provides a 40%-50% value says "The conclusions we draw are only as reliable as the underlying climate model processes," which isn't the sort of finding you would lay great store by. Their conclusion is "Thus, consistent with early studies, this [study] should be seen as another reminder of the need to account for internal variability in the assessment of recent sea ice loss and the fidelity of global climate model simulations."  It is thus not a reliable quantification of the contribution of internal variability.

    And Notz and Marotzke (2012) basically says that internal variability is not the cause of the post-1979 trend in SIE decline. "1. Internal variability as estimated from pre-satellite observations cannot explain the recent retreat of Arctic sea ice. 2. The observational record shows no signs of self-acceleration and hence no signs of a possible ‘tipping’. 3. The satellite record is well described by a linear trend onto which internal variability is superimposed. The magnitude of this superimposed internal variability is very similar to that of the pre-satellite record. 4. The most likely explanation for the linear trend during the satellite era from 1979 onwards is the almost linear increase in CO2 concentration during that period."

    Of the later references, Serreze et al (2015) says nothing on the subject,
    Ding et al (2017) is saying the internal variability is being driven by sea ice loss in a two-way street [so this is AGW creating internal variability] and comes up wiht a 30%-50% value, while Meehl et al (2018) suggest the extra oomph in Arctic SIE decline 2000 is due to forced tropical SST.

    So I see nowhere any reason to dismiss half the 1079-2020 SIE loss as being due to one of Judy's wobbly trends.

  6. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Jim Hunt . . . an addendum :-

    I got a smile, from someone saying you were "a denier of consensus".


    In another direction, there was also a neat comment by Joshua :-

    "the basic science implies danger (within a range of uncertainty)"

    ~ and I shall try to remember that quote.  Very neat.

  7. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Jim Hunt @12  :-

    Well congratulations and bravo, Jim, for your multiple comments in the Judith Curry blog (Post titled:  Climate book shelf , on 10 May 2021).

    Your droll ironies were entertaining/enjoyable.  Such as: "It seems safe to assume that Dr. Koonin has heard of NASA ... [which is mentioned] once in the body of the book."

    Meanwhile the "opposition" [the usual suspects] were parading themselves in typical form.  Such as Turbulent Eddie's face-palming fatuosity about arctic maxima/minima.  Others were in good form too ~ one stating the certainty of massive cooling due in the coming century or two.  While another stated that the present arctic warming was, yes, caused by humans . . . but even in the absence of humans, the same amount of warming would have occurred in a few decades' time anyway!   Others were deeply into "cycles" explaining all climate variation . . . yet they never seem to understand that there must be an underlying physical cause of every variation (cyclic or otherwise).

    In some ways, Curry's blog "ClimateEtc"  is more fun than the proverbial barrel of monkeys.   But it is partly rescued by sane contributions from JH, Willard, and the very deft Joshua, plus some (erratic) others.

    Curry herself (and likewise Koonin, who uses a partly similar style) is like a magician making a stage presentation.  Rhetorical vagueness and obfuscation, like smoke and mirrors.  All designed to keep the audience's attention away from the physical realities.

    Yet overall so far, the deniosphere's response to the Koonin book is somewhat more muted than I expected.

  8. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Eclectic @10 - "[Koonin] took a rather aggressive/persistent attack on the mainstream position."

    Allegedly that has now changed. I'm endeavouring to point this out to the thick skulled denizens at Judith Curry's blog, but they seem incapable of taking this message on board:

    It seems that I need to repeat myself very slowly.

    1) On page 21 (of the Kindle edition) of Prof. Koonin’s magnum opus it states:

    "Along with its comprehensive AR series of assessments, the IPCC also publishes more focused special reports, such as those on Extreme Events, the Ocean and Cyrosphere (sic), or Climate Change and Land."

    followed on page 22 by:

    "The assessment reports literally define The Science for non-experts. Given the intensive authoring and review processes, any reader would naturally expect that their assessments and summaries of the research literature are complete, objective, and transparent—the “gold standard.” In my experience, the reports largely do meet that expectation, and so much of the detail in the first part of this book, the science story, is drawn from them."

    The final clause should of course read:

    Much of the detail in the first part of this book, the science story, is cherry picked from them."

  9. How sure are climate scientists?

    Thanks for this! I will absolutely share it and even include it as a reference in my projects! Brilliantly done!

  10. How sure are climate scientists?

    The movie does have some good features like that graphical time line. It talked a lot about uncertainty in science, and quoted some big medical science mistakes, and although it tried to explain why climate science is different, it did this rather weakly for me. It could leave a lot of people feeling "uncertain" about climate science and whether action is required. It seems like a gift to the denialists.

  11. Overshooting 2C risks rapid and unstoppable sea level rise from Antarctica

    The link to the article in carbonbrief is incorrect. The correct link is

    correct link :



  12. There is no consensus

    The argument presented by hedron @896 is entirely anti-science in that it is saying any area of scientific study can be fake as it can be created to sustain fallacious findings based purely on the belief of those who initiated that area of study and not based on the scientific evidence. If this fake science were possible, all science would be at risk of being slowly stacked full of undebunked nonsense.

    Of course, that is not to say that an individual or small group of resrearchers cannot go off and create a pile of undebunked nonsense. Indeed, many researchers do effectively spend their whole careers so employed. Such work is not of itself anti-scientific as, through the act of bebunking it by others or eventually by those initially involved, the science learns what is and what is not nonsense. The 97% consensus is thus healthy and healthier than 100% as the missing 3% provides an arena for testing the veracity of the 97% and specific to AGW healthy because that 3% is better seen as comprising 30 x 0.1% (as those testing the 97% do not present a singular criticism).

  13. Is Nuclear Energy the Answer?

    Replying to micheal sweet 247

    If you or anyone else are interested, there's an extremely long thread here ( rivalling this one ) where Ben Sovacool responds to some rather trenchant criticism of his two papers on bird deaths, and then to further criticism of his response. Warning - Sovacool makes 36 entries in reply to an even larger number from various critics.

    Moderator Response:

    [BL] Link activated.

    The web software here does not automatically create links. You can do this when posting a comment by selecting the "insert" tab, selecting the text you want to use for the link, and clicking on the icon that looks like a chain link. Add the URL in the dialog box.

    It has been suggested that you re-read the comments policy. With regard to this current comment, please note the following section. If you feel that a link is relevant, do not just ask people to go and read it - provide some sort of indication of what you expect people to see. Your current comment is a bit light in that regard.

    No link or picture only. Any link or picture should be accompanied by text summarizing both the content of the link or picture, and showing how it is relevant to the topic of discussion. Failure to do both of these things will result in the comment being considered off topic.

  14. One Planet Only Forever at 12:42 PM on 11 May 2021
    SkS Analogy 22 - Energy SeaSaw

    Evan, I try to learn as I try to help other people understand what is happening. I appreciate your attention to my comments, and your feedback.
    I have a few more suggestions for your consideration starting with the last point you made in your comment @16 (potentially only my comments “Regarding 10 years of temperature data being a sufficiently long time to provide a degree of technical rigour” affect what you have presented in your See-Saw item).

    I find it helps to expose people to the fuller record of basic data like CO2 levels and Global Average Surface Temperature. That can help them see how unusual or unnatural the recent values are and that CO2 and Temperature are related. That is why I recommend looking at the history of Temperature and CO2 data:

    • back to 1880 for the surface temperature which shows that one of the biggest See-Saws was a warm bump in the 1940s that many “global warming - climate change” doubters mistakenly believe was Globally warmer than now because it was very warm in parts of the USA (And some people experienced that or knew someone who was alive back then similar to your “Winter recollections”).
    • back to 1979 for the satellite data (to see that, though satellite temperatures are not the surface temperature, the pattern of temperature is similar)
    • and back 800,000 years for CO2 levels, like the animation by NOAA that allows the details of recent decades to be seen along with the final full length record. It shows that:
      • several 100 to 120 ppm changes happened in the previous ice-ages
      • the high level of CO2 of 300 ppm was only reached once in all that time, until recently
      • for the past 4000 years the CO2 level has been between 270 and 280 ppm.
      • CO2 levels are now at 420 ppm, 140 above the pre-industrial level of 280 ppm, and continues to increase, and indeed an increase of 100 ppm since 1960.

    The higher recent rates of warming do indeed over-whelm the impressions of the See-Saw. However, the magnitude of the warming is more important. Even if the decade rate was only 0.10 degrees C, eventually the warming would be clear in spite of the larger swings of the See-Saw.

    Regarding how people will perceive a message

    There is a diversity of awareness, understanding and perspective. Not everyone will see things the way you intend.

    You asked: “Many people feel a difference in winters now than during their childhood (1970's or earlier). Can you tell how old I am? :-)”

    What I can tell is how far North you likely live. You are likely part of the small portion of humanity who live north of, or near to, 60 degrees N latitude. The arctic regions have warmed faster than the rest of the global surface. People may legitimately recollect that Northern winters were different decades ago. But global average warming since the 1960s is far less than 1 degree C with non-arctic areas warming less than the average (and there is more warming at night than the daytime. So, people in non-arctic areas may not recall a difference. I was born before 1970 and have lived between 50 an 55 degrees N. In spite of my bias of being aware of the warming and climate change that has occurred, I cannot claim a clear recollection that winters were significantly different when I was younger. So there are likely many people who do not have a legitimate recollection that winters were different decades ago.

    Regarding 10 years of temperature data being a sufficiently long time to provide a degree of technical rigour

    I do agree you may want to reconsider what you say about the adequacy of a 10 year set of temperature data.

    As KR suggests, unless the data has had significant variable influences like ENSO and volcanic impacts scrubbed out of the data, which raises questions about how those impacts are “scrubbed out”, temperature data sets longer than 20 years may be needed to avoid unintended interpretations.

    I spent a little time learning about “decades of temperature data using the SkS Temperature Trend Calculator. I looked at the Trend values for sets of 10 years in the GISTEMPv4 and UAHv6.0 TLT data starting in 1979 (everyone can do this to verify the results):

    • The Satellite data set shows a negative trend for the decades starting in 1987, 1998, 2000, 2001, 2002, 2003, and 2004.
    • There are also many decades where the Positive Trend is less than 1/10th of the 2 sigma range of variability starting in 1980, 1986, 1997, 1999, and 2005 (decades with almost no clear warming, like the set starting with 1997 being 0.015 +- 0.445 degrees C per decade meaning a value range from -0.430 to +0.460, or 2005 being 0.005 +- 0.376 meaning -0.371 to +0.381).
    • In the Surface Temperature data set only the decade starting in 1987 had a negative trend. There were no decades with a positive trend that was less than 1/10 of 2 sigma.

    This may explain why the likes of Dr. Roy Spencer focus on their satellite data manipulations and try to claim the superiority of that data over surface temperature data. That run of values from 1997 through 2005 was a long period of being able to claim that the warming had appeared to have ended even though CO2 levels continued to increase (the UAHv6 data set trend for the 19 year period of 1997 to 2015 is negative. In the UAHv5.6 data set the longest negative Trend was for the 11 years 1998 – 2009, and in the RSSv4 TLT data set the longest negative trend is the decade starting with 2003). So shorter sets of data, rather than the fuller story, can be the “Friend” of the likes of Dr. Roy Spencer (and updated manipulations of the data can also be “Friendlier to the likes of Dr. Roy Spencer.).

    A final point about presenting decade averages

    I do like the presentation of the averages of the 70s, 80s, 90, 2000s, 2010s when a graph cannot be shown. And I agree that such a presentation is not improved by adding earlier decades. But I also consider a “moving average” presentation to be better, but it needs to be Graphed (referring to the SkS Temperature Trend Calculator works). The moving average values can’t be described in words the way the decade averages can be. However, the discrete decade averages are a 120 month "moving average" with the data points being every 10 years (on a graph the decade averages would be points in the middle of each decade). As you can see from the investigation I summarized above, any set of 10 years of data can be a Decade average. And when those averages are done for each new month of data the series of points will look like a line (note that Dr. Roy Spencer presents a 13 month moving average because that makes it easier to present the data points. They go on the middle point of the data set – no need to set the graphic up to present a 12 month average between the middle two months of a 12 item data set).

  15. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Eclectic @10

    "I am sourly amused by the repeated crocodile tears of denialists claiming that we (the West) should first supply coal-fired generators to bring electricity to the suffering poor of Africa..."

    Me too. Very sourly amused. Funny how these  conservative leaning fossil fuel loving  denialists suddeny find all this sympathy for poor people when its usually so absent. The more usual rehetoric is "pull yourselves up by your own bootstraps".

    That said, there is a group of liberal leaning denialists and luke warmers that appear driven by genuine sympathy for poor people and worry that they will be hurt by climate mitigation. For example while Mike Moore accepts AGW, he is opposed to renewables because he (falsely) believes they are a capitalist scam to enrich the corporate sector. He produced an anti renewables movie, but I can't remember the name. And Bjorn Lomberg is a lukewarmer who appears driven by genuine concern for poor people. This may be at least part of he source of his luke warmerism. He doesn't appear to have business or libertarian  motives or links to the fossil fuel industry. Of course none of this justifies his luke warmer position.

    The question is which group does Koonin fall into. We will probbaly never know. He seems to avoid discussions about his world view

  16. There is no consensus

    hedron states "Of course, 97% of climate scientists believe in global warming, the field of climate science itself was created by a group of people who believed in climate change".

    This, of course, is complete bollocks. Studies into the nature of climate date back at least as far as the 1800s,

    If hedron wants to inform itself of the history, it can go to Spencer Weart's The Discovery of Global Warming. Based in its brief posting history here, I doubt that hedron will make the effort, though.

  17. Philippe Chantreau at 05:15 AM on 11 May 2021
    There is no consensus


    It is a little difficult to understand your convoluted reasoning and the analogies you provide don't help. There is such a field as the scientific study of hurricanes, it is a specialized area of work for meteorologists. It probably was started by specialists who believed that hurricanes were real. If you don't believe that it is legitimate, substitute your own advice to theirs next time a storm is barreling down the coast of Florida, but to keep honest, leave yourself open to litigation in case your advice leads to loss of life or property.

    "Academies of science from 80 countries" and "many scientific organizations" does not equate to "97% of climate scientist." Furthermore, your analogy does not hold because scientific inquiry is a process whose very purpose is to uncover the stuff that is not a matter of opinion. 

  18. There is no consensus

    That humans are causing global warming is the position of the Academies of Science from 80 countries plus many scientific organizations that study climate science. 

    This is a disingenuous statement.  Of course, 97% of climate scientists believe in global warming, the field of climate science itself was created by a group of people who believed in climate change.  It's literally no different than claiming capitalism in bad, because 97% of communists say so.  It would be similar to creating an academic discipline of hurricane-ology.  It's a one trick pony.  When you have an entire academic discipline dedicated to a single political cause which is funded by a wealthy elite, I tend to be highly skeptical of the intent or motive.

    So, this article has been officially DEBOOONKED!!!

  19. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Nigel :-  Koonin's attitude to mainstream climate science is not a new development.   If you go back 7 years and read the transcript of his verbal contribution to the 2014 American Physical Society climate statement review, you will find he took a rather aggressive/persistent attack on the mainstream position.   Clearly it was not a skeptical, but a prejudiced attitude he took with his carping.

    Nigel, I am sourly amused by the repeated crocodile tears of denialists claiming that we (the West) should first supply coal-fired generators to bring electricity to the suffering poor of Africa.  Thus raising their economic well-being . . . and only after that has been accomplished, would we be justified in pursuing our own renewable energy goals.

    The poor of this world have have been suffering for many decades, with precious little help from the denialists.  When even a 10% diversion of our global armaments expenditure could have made a colossal difference in helping the poor.  But this hasn't been done ~ nor even suggested by the same denialists.  Apparently we must not consider donating solar panels to African villagers for charging their (increasingly widespread & useful) cellphones etcetera ~ but we must first go to donating centralized coal-fired generation of electricity.

  20. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Nigel @8,

    Whilst Steve's apparently undimmed "scepticism" may well have been firmly debunked in the past it seems that the task needs to be undertaken yet again.

    The latest episode in the Wall Street Journal's "Unsettled Science" propaganda campaign includes a video interview with Prof. Koonin that includes references to those well known climate scientists Al Gore and Joe Biden, as well as the cover of his new book in the background:

    So there you have it. Al Gore is a mere straw man, easily knocked down with a cherry pick without even bothering to mention any of the underlying science.

  21. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    MA Rodger @6

    "So Koonin presents a wibbly-wobbly argument against AGW science." 

    He sure does.

    "And if anybody sees in this reason not to brand Koonin a nought but a vaccuous blowhard, I'd be interested to hear that reason."

    And he sure comes across like a vacuous blowhard. He is getting on a bit in age which might have something to do with it. What also troubles me is the way he is content to quote examples of how the weather is not changing, eg frequency of droughts and tornadoes but is happy to leave out evidence of where it is changing eg frequency and intensity of heatwaves and heavy rainfall events. In other words very selective, done like this for whatever purpose.

    His climate views also seem to have been quite changeable, for whatever reason

    Anyway I was googling about him briefly,  trying to track down his political and world views, but nothing came to light, in fact a curious lack of a single thing, but I did find the quote about poor people in this article here.

    “For me,” Koonin concludes, “the many certain downsides of mitigation outweigh the uncertain benefits: the world’s poor need growing amounts of reliable and affordable energy, and widespread renewables or fission are currently too expensive, unreliable, or both.”

    More from that article. He might also fancy himself as a great contrarian truth seeker:

    "Earlier in Koonin’s career, in 1989, that inclination led him to prominence, as one of a group of scientists who successfully debunked the claims of a University of Utah team who reported that they had discovered “cold fusion”—a breakthrough that, had it proved real, would have transformed energy production. "

    And he comes out with the standard republican party climate views:

    "While at BP Koonin, as he does today, advocated research into approaches typically favored by oil companies and Republicans opposed to fundamental change in energy supply. They include carbon capture and storage, advanced nuclear energy, and biofuels and geoengineering ideas, like seeding the atmosphere with aerosol particles to increase Earth’s reflectivity."

    Although elsewhere he is supportive of solar power. His positions on mitigation thus also seem a bit changeable. 

    Yet he says he doesn't support Donald Trump. So who knows what drives the man. I think my original contention is still possible, but his real motivation and political beliefs and personal world view remain pretty much unknown. What is certain is that his scepticism on the climate issue is misleading, out of date,  and has been firmly debunked.

  22. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Al @6,

    They don't brand Dr. Koonin "a nought but a vacuous blowhard", and it sounds as if they weren't sent a copy of his book for reveiw. However based on a review of the book in the Wall Street Journal the science content has been assessed as "very low" by Climate Feedback:

    Scientists who reviewed the article found that it builds on a collection of misleading and false claims. For instance, Koonin states that “Greenland’s ice sheet isn’t shrinking any more rapidly today than it was eighty years ago”. Contrary to the claim, scientific studies using airborne and satellite altimetry observations show considerable thinning has occurred along the margin of the Greenland ice sheet since 2003. As explained below by Twila Moon, from the National Snow and Ice Data Center, the Greenland ice sheet lost more mass during the 2003-2010 time period than during the entire time period from 1900 to 2003. Furthermore, this melting has generated a measurable sea level rise over the last 20 years.

    Koonin also claims that “the rate of sea-level rise has not accelerated”. Contrary to the claim, scientific studies show that rates of global sea level rise have changed over time and accelerated, notably since the 1990s, primarily due to glacial ice melting and the expansion of seawater as it warms. As pointed out by Zeke Hausfather, Director of Climate and Energy at The Breakthrough Institute, sea levels are rising faster now than at any point since records began in the early 1900s

    etc. etc.

  23. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    nigelj @5,

    If you believe Koonin, in his recent NY Post OP he tells us he was fully-signed-up to the science of AGW until he took part in the 2014 APS Climate Change Review Workshop which he chaired. The APS found nothing in this workshop to change its stance on AGW which pitted the science against the grand theorising of John-boy Christy, Judy Curry & Dicky Lindzen, a falsely-balanced debate that had been exposed as nonsense for decades. So why Koonin was so strongly convinced by the denialist arguments, indeed his role in setting up the event (he has been advocatng the use of such a process ever since), does need more explanation from Koonin, explanation which is simply absent.

    His work with BP back in the 2000s involved biofuels which do present a problem with high land-use but it would be a fool who took a decade to spot that truth and, then without pause jump to the view expressed in his Sept 2014 OP. While the usual take-away from this Sept 2014 OP is his denial of the science, it is actually a call to resolve the divide (the unresolvable divide) between AGW "belief" and AGW "hoax", to resolve through re-directing scientific effort, as this resolution "should be among the top priorities for climate research." But I neither see any emphasis being made by Koonin in 2014 that the cure (a zero carbon economy) would be a worse outcome that AGW. Nor do I see any emphasis by Koonin in 2021 any message calling to re-direct the scientific effort. The only sign of his continued holding of this view is his involvement in the RedTeam/BlueTeam initiatives, not the most scientific methods of tackling science.

    A year later as the Paris climate talks draw near, Koonin is advocating AGW adaptation because mitigation cannot be achieved in time, a new slant on things again.

    Now his 2021 OP (and presumaby his grand book) he brands talk of a climate emergency and the policies to address it as being fallacy, basing this on some very silly denialist nonsense.

    So Koonin presents a wibbly-wobbly argument against AGW science. And if anybody sees in this reason not to brand Koonin a nought but a vaccuous blowhard, I'd be interested to hear that reason.

  24. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    I read somewhere that Steve Koonin is worried that renewable energy will be allegedly too expensive and will hurt poor people. I wonder if this is why hes a luke warmer. There appears to be a small but genuine group of left / liberal leaning people like that. If so, he should check the numbers. Solar and wind power have plumetted in cost in the last 20 years, and are are now very cost effective (Lazard energy analysis).

    He did work at British Petroleum about 20 years ago (according to his wikipedia entry) , and this was developing renewables. He may have lost track on the more recent trends in renewables. Of course he might have other motives for his luke warmerism. The motives of these people intrigue me. I get a bit obsessive about it.

  25. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Bob @3 - Thanks for mentioning the work of my Arctic alter ego.

    dmyerson @1 - I have a copy of the Kindle version of Dr. Koonin's new book. Here's a brief extract from my initial review at Great White Con:

    I was compelled to acquire my own review copy, and have just purchased the electronic version. I eagerly searched the virtual weighty tome for the term “Arctic sea ice”, and you may well be wondering what I discovered?

    Nothing. Nada. Zilch. ничего такого. Nic.

    What more would you like to know?

  26. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    I have not read Koonin's book,. but I am aware of some that have. Seems to be the same old misinformation he usually peddles.

    A recent post over at And Then There's Physics talks about it briefly with links to previous criticisms of his work.

    A couple of posts from an Arctic perspective:

    ...and general background on Steve Koonin

  27. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Tenth item from the top: "Dissecting ‘Unsettled,’ a Skeptical Physicist’s Book About Climate Science"

  28. michael sweet at 04:57 AM on 10 May 2021
    Is Nuclear Energy the Answer?

    John ONeill:

    A free copy of the Sovacoll article concerning brds is here.  From the abstract:

    "The study estimates that wind farms and nuclear power stations are responsible each for between 0.3 and 0.4 fatalities per gigawatt-hour (GWh) of electricity while fossil-fueled power stations are responsible for about 5.2 fatalities per GWh. While this paper should be respected as a preliminary assessment ..."

    Your claim that Sovacool "claimed that nuclear power was responsible for three times as many bird deaths per watt hour delivered as wind turbines." is false.  Your description of Sovacool's work is so far from reality it is a waste of my time to address the facts.   Sovacool describes his study as preliminary.  He notes that all sources of energy are bad for birds.

    You present material that is completely false.  Keep in mind that your comments can be checked for accuracy.

  29. 2021 SkS Weekly Climate Change & Global Warming News Roundup #19

    Would be good to get a book review of the recent Koonin book, Unsettled.

  30. michael sweet at 22:51 PM on 9 May 2021
    Is Nuclear Energy the Answer?

    John ONeill:

    Here is a free copy of the Sovacool paper apparently my previous link is broken.  It took me 15 seconds to find.  If you read the literature you would be able to do this yourself.  You are welcome to think anything you want.  The peer reviewed literature contradicts you.  You are sloganeering.

    At 236 you claimed:

    "If we really try to build out wind and solar there will be a substantial decrease in carbon emissions in a short period of time.' That's something I haven't seen, though I rather obsessively scan for examples of it." italiced is a quiote of me

    I provided Uruguay as an example of reduction of carbon emissions from renewable energy.  I found this clear example in less than 5 minutes on your reference.  This proves that you do not "obsessively scan" for examples.  You are simply trolling us.

    At 236 you claimed "The BN600 and BN800 in Russia seem to be operating without any leaks or fires"   I showed that the BN600 has had at least 14 fires.  You are trolling us again.

    At 238 you stated:

    "'These reactors cost even more to build than normal reactors. They will never be economic. No more are planned worldwide.' - Apart from the one Gates' company is developing, there's one being built in India, and one in China." Italics is you quoting me.  

    The reactors you cite in 245 are a completely different design and are new, experimental builds financed entirely by the government.  They are liquid sodium reactors, but are a different design.  As one design fails, nuclear supporters give it a new hat and claim it will finally work.  Your current claim that they are the same is false.  Construction of the Indian reactor begun in 2007 for completion in 2012.   Now due in 2022.  Every year they extend the operational date another year.  Typical nuclear build.

    More renewable energy was installed last year than all other power systems combined. 

    "IRENA’s annual Renewable Capacity Statistics 2021 shows that renewable energy’s share of all new generating capacity rose considerably for the second year in a row. More than 80 per cent of all new electricity capacity added last year was renewable, with solar and wind accounting for 91 per cent of new renewables." source

    At 245 you say:

    "Exponential growth [of renewable energy] is easy enough from a small base"

    In 2021 wind and solar power generated will surpass nuclear power worldwide.  Nuclear currently has a smaller base to ridicule than renewable energy, after 60 years of operation.  Nuclear generated less power in 2020 than in 2004.  They are not buiding enough nuclear power worldwide to replace retiring reactors.  You are trolling us again.

    Moderator Response:

    [BL] Although countering repeated claims can be frustrating, please keep it civil.

  31. John ONeill at 18:04 PM on 9 May 2021
    Is Nuclear Energy the Answer?

    michael sweet at 242
    'Sovacool is a peer reviewed scientific study.'

    The paper you linked is behind a pay wall, but examples I have given show emissions from electricity generation, at least, are considerably lower in some nuclear-reliant countries than in comparable countries without it. For example, from 2000 to 2019, Germany's electricity generation from fossil fuels went down by 29%, France's ( to 2020) by only 1% ( from 'Our World in Data'). Nevertheless, in absolute terms, Germany was still getting 248 TWh from fossil fuels to France's 50 TWh. The difference in emissions would be even greater, since so much of Germany's power is from lignite, and even their 'renewable' thermal generation has a fairly hefty carbon footprint. The UK, which, unlike Germany, chose to close its coal plants instead of its nuclear ones, saw power from fossils fall by 49% over the same period. In 2020 the UK generated 5 TWh from coal, France 4 TWh, and Germany 134 TWh. (Denmark also made 4 TWh from coal, but it only has a twelfth the population of France or the UK.)

    My scepticism of Ben Sovacool's work stems from a paper he wrote, also peer reviewed, which claimed that nuclear power was responsible for three times as many bird deaths per watt hour delivered as wind turbines. This was based on a single incident of geese hitting cooling towers at a coal plant, and another isolated case of waterfowl dying in a copper mine waste pond. ( His estimates of lifecycle CO2 emissions from nuclear, in another paper, are rather higher than the IPCC's, but not as outrageous as some of the other authors he considers. )

    'Uruguay produced 40% of its electricity from wind in 2020 while Sweden produced only 30% of its electricity from nuclear power. If you claim Sweden as a nuclear success than Uruguay has to be a wind success.' I would say that Uruguay is a wind success, but the circumstances allowing that are limited. The world currently gets 86% of its energy from coal, oil and gas, and has done for the last forty years. Wind backed by hydro will not replace that - the gaps in wind power would simply be far greater than hydro could fill. I can't show you a grid running on SMRs yet, but likewise you can't show me one with significant battery storage.

    'I provided proof of at least 14 fires at the BN600 plant. Your claim of no fires was false.' I didn't claim they had not had any fires, I said they weren't having any currently. The last leak at the BN600 was in May 1994.

    'The World Nuclear Organization does not show any of these reactors under construction. Please provide evidence to support your claim that two are under construction.'

    'The CFR-600 is a sodium-cooled pool-type fast-neutron nuclear reactor under construction in Xiapu County, Fujian province, China, on Changbiao Island...Construction of the reactor started in late 2017...A larger commercial-scale reactor, the CFR-1000, is also planned...On the same site, the building of a second 600 MW fast reactor CFR-600 was started in December 2020 and four 1000 MW CAP1000 are proposed.'

    The Indian Prototype Fast Breeder Reactor, also sodium-cooled, is scheduled to go critical in October 2022 - though it's been delayed multiple times before. It's intended to close the fuel cycle from India's heavy water reactors, and allow the use of thorium, which India has very large reserves of.

    'Worldwide installation of renewable energy is increasing exponentially. Your cherry picking a handful of countries that are not increasing wind or solar this year is simply an attempt to distract which will not work. Any cursory look at data shows that installation of renewable energy is increasing rapidly while nuclear plants are not being started up.'

    Exponential growth is easy enough from a small base, but in the real world, it will eventually hit natural limits. In nearly every case, growth in solar has started falling, i.e. it's no longer exponential, when solar provides between five and ten percent of total generation. Wind has double the capacity factor, doesn't regularly drop to zero, and is usually less seasonal. Where there's plenty of hydro as backup, it does, in a few areas, help lower emissions to levels approaching those of a nuclear + hydro grid. In places like Texas or California, where it's backed by gas, average emissions stay higher. Since replacing current power fossil generators is only a small first step - we also need to provide clean power for much of the third world, and we've hardly started on industry and transport - it would be ill judged to rule out the world's second largest combustion-free energy source ( after hydro.) Nuclear can be installed as a plug-in replacement for coal plants, a role unsuited to power sources which spend much of the time powerless.

    Moderator Response:

    [BL] Please make note of the fact that you are repeating claims and not addressing points made by others.

    I suggest that you re-read the Comments Policy, taking particular note of the sections on excessive repetition and sloganeering:

    • Comments should avoid excessive repetition. Discussions which circle back on themselves and involve endless repetition of points already discussed do not help clarify relevant points. They are merely tiresome to participants and a barrier to readers. If moderators believe you are being excessively repetitive, they will advise you as such, and any further repetition will be treated as being off topic.
    • No sloganeering.  Comments consisting of simple assertion of a myth already debunked by one of the main articles, and which contain no relevant counter argument or evidence from the peer reviewed literature constitutes trolling rather than genuine discussion. As such they will be deleted. If you think our debunking of one of those myths is in error, you are welcome to discuss that on the relevant thread, provided you give substantial reasons for believing the debunking is in error.  It is asked that you do not clutter up threads by responding to comments that consist just of slogans.
  32. Is Nuclear Energy the Answer?

    I case people missed it buried in the text from MA and michael, the web site Our World In Data has quite a bit more than just nuclear data. The main web site is:

  33. michael sweet at 22:23 PM on 8 May 2021
    Is Nuclear Energy the Answer?

    Hey MA Rodger:

    Your link to Our World in Data is a great site.  I have been having trouble finding energy data updated to 2020 and they have everything!  It is easy to search.  Thanks for the link.

  34. michael sweet at 22:09 PM on 8 May 2021
    Is Nuclear Energy the Answer?

    John Oneill at 238:

    Sovacool is a peer reviewed scientific study.  You are attempting to substitute your personal opinion unsupported by any data or analysis at all.  This is a scientific site.  You must provide peer reviewed data to support your wild claims.  You are simply sloganeering.

    Uruguay produced 40% of its electricity from wind in 2020 while Sweden produced only 30% of its electricity from nuclear power.  If you claim Sweden as a nuclear success than Uruguay has to be a wind success. (Our world in data linked below).  Both have high hydro.

    Nuclear electricity generation is (2020 TWh, 2000 TWh) World 2,616, 2498, France 355, 414 Canada 95, 69 and Sweden 50, 57 TWh our world in data Generation of electricity from wind is (2020 TWh,2000 TWh) World 1590, 31, France 39,0.04, Canada 34, 0.16, Sweden 27, 0.46, US 336, 6, Uruguay 5.5, 0, Denmark 16, 4. IBID

    This data shows that worldwide nuclear is reducing or flat and everywhere is building out wind.  Solar is much the same.  Sweden and France are slowly shutting nuclear plants as renewable energy comes online.  That allows them to progressively reduce carbon emissions while switching to renewable energy.

    Talk to me about small modular reactors when they have a working pilot plant.  That will be in 2029 at the earliest.  Utilities are backing out of the NuScale project because of cost.  Safety questions remain.

    At 236 you said:

    "The BN600 and BN800 in Russia seem to be operating without any leaks or fires - unlike some of the new grid storage battery plants,"

    I provided proof of at least 14 fires at the BN600 plant.  Your claim of no fires was false.  I have to Google everything you say.  They have to build expensive, duplicate cooling systems so that they can repair the fire damage without shutting down the entire plant.  It is uneconomic to build duplicate cooling systems.  The World Nuclear Organization does not show any of these reactors under construction.  Please provide evidence to support your claim that two are under construction.

    Worldwide installation of renewable energy is increasing exponentially.  Your cherry picking a handful of countries that are not increasing wind or solar this year is simply an attempt to distract which will not work.  Any cursory look at data shows that installation of renewable energy is increasing rapidly while nuclear plants are not being started up.

  35. SkS Analogy 22 - Energy SeaSaw

    Whatever the technical merits of what you're saying OPOF (I'm not disagreeing with anything you're saying), it has to be personal for people to feel it enough to move them to action. The problem with going back to 1880 is that we cover a period where other signals were on the same order of magnitude or larger than the warming signal. Although industrial output cranked up after WWII, the warming signal was still muddled by other signals. But ince about 1970 the warming signal has emerged from the noise. It is also convenient that 1970 is within the consciosness of many people alive, so this is not a matter of history but of personal experience. Many people feel a difference in winters now than during their childhood (1970's or earlier). Can you tell how old I am? :-)

    For me one of the most striking statistics is this. During the last deglaciation cycle CO2 rose 100 ppm in 10,000 years. CO2 has risen that much in my lifetime!

    Perhaps the largest benefit of going back to1880 with the temperature record is to show how strong the variability was compared to the underlying warming signal prior to 1970, and by comparison, how strong the warming signal is now compared to the variability.

  36. garyjenkins at 19:11 PM on 8 May 2021
    Welcome to Skeptical Science

    M A Rodger @90

    Very helpful, thank you. I'll use your numbers in the thing I'm writing. And I've just found a paper that agrees with what you say.

  37. John ONeill at 10:28 AM on 8 May 2021
    Is Nuclear Energy the Answer?

    Philippe Chantreau - I was actually looking for another item that Thunberg linked to. The relevance is that nuclear is always contasted with 'renewables'. In theory, at least according to Mark Jacobson's 'Solutions Project' scheme, that would be over 90% wind and solar - for everything. In practice, at present, it also covers the burning of various forms of biofuel and biomass. These are welcomed by some W & S advocates as covering the obvious gaps in energy supply from weather, and also by owners of fossil fuel businesses, who can claim various percentages of emission reduction, by putting corn ethanol in petrol, woodwaste in coal feed, or biodiesel in fossil diesel. The island of Bornholm, for example, cited by Michael Sweet as 100% renewable, uses farm waste for power when the wind drops. The website we both referred to lists biomass as having CO2 emissions of 230 grams per kw/h, versus 45 for solar, 11 for wind, and 12 for nuclear. 

    We have history for societies running on 100% renewable energy. In Britain in 1700, for example, there were about five million people, there was a desperate shortage of wood, and so eventually coal extraction led to the steam engine and the industrial revolution. Now there are 60 million people on the same islands, with much higher levels of energy use. Even just to cover steel manufacture, there is no way to go back to relying on growing our power, and any effort to do so will decimate remaining natural sanctuaries just as it did 300 years ago.

  38. Why scientists shouldn't heed calls to 'stay in our lane'

    Jim Hunt @30 :  thank you for that.  I won't be purchasing a copy of Koonin's book, for I have zero hope that it would contain anything other than Points Refuted A Thousand Times.   But I shall be grateful if you can unearth anything at all which will prove me wrong about that.

    From the snippets of the book so far received at second hand, it is disappointing that someone of Koonin's education & intelligence could produce such a book.   If I were a certain cartoon character, I would describe the book as "dethpicable".   ;-)

    As mentioned in an earlier comment, Koonin seems (at first glance) to be rather different from the usual nutty denialists and the run-of-the-mill rightwingers who care only for their own short term interests and who have no compassion or charity for their fellow citizens.   His mindset puzzles me ~ perhaps we need a psycho-analyst to delve into his early childhood traumas etc etc.

    Jim, it would be great if you would provide more insights into Koonin and his book.   Interesting - and as expected - the elephantine omissions in his Propaganda Piece.    (As a frequent visitor to WUWT,  it is very noticeable to me that the question of summer minimum sea ice volume is unmentionable there.  Among various other perpetual omissions.)

  39. One Planet Only Forever at 09:16 AM on 8 May 2021
    SkS Analogy 22 - Energy SeaSaw

    Evan and Bob,

    We appear to be discussing the same things from different perspectives.
    I appreciate that using the term Trend for the impression a person would get from seeing the red-line presentation of the moving-average is not “Technically the Trend”. My perspective is that many people will accept a Trend like a Fashion Trend, something that they can see changing, more readily than the result of a statistical analysis of data.

    The SkS Temperature Trend Calculator presents what is being discussed: Trend, Moving Average, and the See-Saw.

    Images from the SkS Temperature Trend Calculator would help explain my perspective. But I am not skilled at “image” inserting, so I will try to present it with words.

    The difference between the Statistical Trend and a 360-month moving average can be seen when looking at the full set of surface temperature data from 1880 to 2021. The Statistical Trend for the full data set does not show what is happening as well as the moving average. The moving average line shows that the recent temperature Trend is steeper than the Statistical Trend of the full data set.

    And the See-Saw effect can be seen by using a shorter moving average like 60 months. So the use of a longer moving average with the full data set provides a visual impression of what is happening that is better than the statistical Trend calculations that are the “Scientifically more precise” way to determine if there is a Trend in the Data. And that presentation does not require the further manipulation of data, and related questions about how it is done, to "attempt to remove variables that create the See-Saw effect".

  40. Why scientists shouldn't heed calls to 'stay in our lane'

    Eclectic @28 - Having purchased my very own copy of Dr. Koonin's tome I have now personally, if rather hastily thus far, reviewed it:

    We eagerly searched the virtual weighty tome for the term “Arctic sea ice”, and you may well be wondering what we discovered?

    Nothing. Nada. Zilch. ничего такого. Nic.

    Evidently there are some areas of climate science that Dr. Koonin tells his eager readers nothing whatsoever about. It seems likely that he is also well aware that Arctic sea ice is the canary in the climate coal mine, which is why he has chosen to make no mention of it in his magnum opus.

  41. Philippe Chantreau at 23:29 PM on 7 May 2021
    Is Nuclear Energy the Answer?

    John O'Neill,

    The Guardian article you cited is about Sweden's forestry practices and has nothing at all to do with its energy generation, or policies. It does not support any part of your argument. The "article" (mostly a succession of pictures with captions) mentions the country's export of paper, pulp and sawn timber, it does not allude to energy policy or energy from biomass at any point. It does make a good point that the forestry practices are less than ideal. Similar practices exist in the US and Canada, unfortunately.

  42. Is Nuclear Energy the Answer?

    Quoted @237 & 238 - "After 60 years nuclear generates less than 5% of world energy."  The 2019 nuclear contribution to world primary power was 4.3% according to the BP Review but OurWorldInData shows nuclear did manage 6.5% back in the 1990s, so after 30 years. Since that time nuclear has failed to keep up with demand, with output stalling at 2,600TWh/yr since 2005. Given the need for carbon-free energy, the failure of nuclear to deliver can have no excuses.

    Meanwhile OurWorldInData shows the renewable contribution continues to grow, with solar & wind reaching 2,400TWh/yr in 2020, an increase of 14% on 2019. 

  43. John ONeill at 21:24 PM on 7 May 2021
    Is Nuclear Energy the Answer?

    'Countries that build nuclear as a group do not reduce carbon emissions. Countries that build out renewables do.'

    By restricting his study to emissions reductions over the last 25 years, Sovacool omits the period when nuclear build massively replaced oil and coal power generation. The legacy plants left over from this period are still making far more power than wind and solar, and most of them are light water reactors, which have been licensed to eighty years in the US, and should be in most other places too.

    '.. looking at Uruguay 100% renewable mostly wind.

    North east Brazil 95% renewable, mostly wind. And

    Bornholm, Denmark 100% renewable, no hydro'

    Uruguay gets 60% of its power from hydro. It also resembles Denmark, in being a small country in between two much larger ones, to which it can export its surplus wind, and from which it can import during calm periods. North East Brazil also has quite a lot of hydro, and can import much more from North Brazil when needed. Just now it is getting 43% from wind, the rest from local or North Brazil hydro. I'd also note that it's running at about 10 to 12 GW for a population of 50 million people, well below the level associated with places with a high human development index, and that without replacing fossil fuels for uses like transport and industry. Bornholm has no hydro, but imports up to 95% of its power from Sweden at times, usually mostly hydro and nuclear. ( Sweden has wind turbines too, but when they're not spinning in Bornholm, they're usually not doing much on the mainland either.) Bornholm's power emissions would also be much lower if it wasn't burning so much biomass.

    'Sweden closed 2 of their 8 remaining nuclear reactors in the last 18 months..... Hydro will provide more than enough backup when the wind does not blow.

    Sweden provides clean power not just for itself, but also for Denmark, Germany, Finland and the formerly Soviet Baltic countries. It's likely that if they close their nukes, these other countries will have to burn more fossils, even if Sweden doesn't. Greta Thunberg recently posted a link to an article describing how much damage biomass harvesting is doing to Sweden's forests. Nuclear is a much less land-hungry, and lower carbon, alternative for power independent of weather conditions. 

    'France is planning to shutter 14 nuclear plants in the near future (they also closed two last year) and install renewables.' -Macron closed the two reactors at Fessenheim, which had received 2 billion Euros worth of upgrading in the last few years, making them effectively the country's most modern plants. This fulfilled a campaign promise by his predecessor, President Hollande, whose Energy Minister (and former lover), Segolene Royale, had offered to donate them to Elon Musk to turn into Tesla car factories. She also vowed to build a thousand kilometres of solar roadways. Macron has subsequently stated that further reactors will not be closed if the result would be a rise in emissions. It certainly would be.

    'Ontario's nuclear plants are old and they are installing wind.' Ontario is refurbishing its heavy water reactors in the Darlington and Bruce plants, and the Canadian government is actively promoting new Small Modular Reactor designs. The province has not tendered for any new wind since 2014.

    'I noticed you forgot links to descriptions to the Russian nuclear reactors. According to Wikipedia, the BN600 has had 27 sodium leaks resullting in 14 fires...The BN 600 runs only 70% of the time because of required maintenance.' In its early years, the BN 600 did suffer a number of leaks, but since this was expected, it had been given three independent cooling systems, each capable of 50% of the thermal load, so that any one could be worked on with the reactor still operational. The BN 800 had no leaks. Operational status of the BN 600 over the last six years averaged 85.1 % capacity factor - roughly double a wind plant.

    'Both reactors have three complicated triple part cooling systems to isolate the radioactive sodium coolant from water since sodium is flammable in water.' Bill Gates' sodium reactor directly heats nitrate salts, for energy storage.

    'These reactors cost even more to build than normal reactors. They will never be economic. No more are planned worldwide.' - Apart from the one Gates' company is developing, there's one being built in India, and one in China. Nasa is also working on a similar design for use in space, and a company called Oklo has just received the first US licence for a non-light water SMR. Two other designs are under licence review in Canada. With no water adjacent to the hot fuel, they should be able to run much hotter than LWRs, greatly increasing thermal efficiency, while avoiding any danger of a steam explosion, and thus most of the cost of containment.

    'After 60 years nuclear generates less than 5% of world energy.' -In 2019, wind made up 2.2%, and solar 1.1%.

    'In 2020 more than 80% of new electrical capacity added world wide was renewable. ' -Since wind and solar have the second lowest and the lowest capacity factors of any generation source, their contribution to world energy was much lower, proportionally, than their increased nameplate capacity.

    'In the future renewables will dominate all new construction.' In places such as Italy and Spain, solar installations boomed till they reached between five and ten percent of total power generation, by which time the costs, and the stresses to reliable power supply, led to a dramatic decline in growth. Japan's solar installations peaked in 2015, at which point they were generating 3.5% of the country's power ( Wikipedia ). Since then, yearly additions have been gradually declining, even though prices are still falling. In 2019, solar made 7.6% of electricity generated there, still far below the third from nuclear pre-Fukushima. Most of the shortfall since then has been from increased coal and gas imports. Japan has also recently suffered massive power spikes in winter, as LNG availability fell during cold spells. The government wants to reopen more reactors to reduce power costs. It would also reduce emissions - a win-win.

  44. SkS Analogy 22 - Energy SeaSaw

    scaddenp@12 You make a valid point, and perhaps we should plot ocean temperatures together with air temperatures to emphasize their link and that they are driving each other upwards.

    michael sweet@13, thanks for your comments. It's good to get affirmation of what is and is not connecting with readers (e.g., concept of decadal averages). The point of these analogies is certainly not to educate the experts (which I am not), but rather to communicate what the experts know to non-technical people.

    I appreciate the time all of the experts have given to adding their comments here. Thanks.

  45. michael sweet at 13:33 PM on 7 May 2021
    SkS Analogy 22 - Energy SeaSaw


    I thought your post has an interesting perspective.  I don't have anything to add there.

    I think one additional reason that ten year averages are used is because of the Sun's cycle.  The Sun gets stronger for a while and then gets dimmer.  This pattern is clearly seen in the temperature record.  Most of the highest temperatures are at the height of the Sun cycle.  The average Sun cycle is about 11 years.  That means that a 10 year average removes most of the Sun cycle effect. 

    I think your point that 10 years is meaningful to the person on the street is a good one also.

  46. SkS Analogy 22 - Energy SeaSaw

    In the Argo age, you could argue that OHC is both a less noisy dataset (and so significance of trends is established over shorter time frames), and a better indicator of climate.

  47. SkS Analogy 22 - Energy SeaSaw


    "Dana did a post here about results of an analysis by John Nielsen-Gammon, which plotted independent lines for El Nino, neutral, and La Nina years."

    We did something similar with our Christmas Dinner analogy where we plotted a trend line through annual temperatures and a trend line through decadal maximum temperatures.

    Plot showing annual temperatues fitted with one line and decadal maximum temperatures fitted with a second line. The two lines are parallel, indicating that the trend indicated by decadal average temperatures is the same as the trend of annual temperatures.

  48. SkS Analogy 22 - Energy SeaSaw

    Running means represent smoothing, but they are highly auto-correlated and normal significance testing cannot be used.

    Decadal averages do provide a clear step-by-step indication that things are warming.

    Another convenient tool is looking at the list of warmest years - so many of the top 10/15/20 years are the recent ones.

    One last link to an interesting analysis to remove some of the variation: Dana did a post here about results of an analysis by John Nielsen-Gammon, which plotted independent lines for El Nino, neutral, and La Nina years.

    The key graphic:


  49. SkS Analogy 22 - Energy SeaSaw

    OPOF@7 and Bob@8

    I am not suggesting that we need to wait until 2030/2031 to assess current trends. Just that it seems that talking about decadal averages is more intuitive for non-technical people than refering to moving averages. That may change now in the age of Covid, because we are hearing more and more about 7-day moving averages, for obvious reasons. If moving averages move into and stay in the modern lexicon, I will consider using them. But decadal averages seems like a concept that is easy to understand, and accurate: for about 50 years each decade has been warmer than the previous, and with CO2 accumulation in the atmosphere continuing its 60-year, upward acceleration, there is no idication this trend is going to stop anytime soon.

    I appreciate all of the references that you are suggesting and will consider additional modifications to my messaging.


  50. SkS Analogy 22 - Energy SeaSaw


    "Is the record long enough?" is a characteristic of the data, not so much the method. A rule of thumb for global surface air temperature is that you need to have somewhere around 15-20 years of data to determine a trend - but that is deterimed from the noise characteristics of surface air temperature. It is not generally applicable to other data sets.

    In addition to statistical significance, you also need to look at the power of the test. For a small trend, you need more data than for a large trend. With low power, a non-significant result may just be a lack of data, whereas if you have high power, no significant result is more likely to mean no relationship. Dikran Marsupial did a good post on this four years ago:

    In addition to this, we are no longer in a position where the significance of our temperature trend is in question. We are clearly in a warming trend. When we encounter someone claiming "the warming has stopped!" or "No warming since 1998 2006 2010" (or whatever year they pick), asking if the trend is significantly different from zero is the wrong statistical test.

    A statistical test involves evaluating the significance of the difference between "observed" and "expected". When testing if the trend is non-zero, the "expected" is zero. When testing if the existing trend has stopped, the "expected" value is the previous trend, not zero. So that is the comparison you need to make when determining something like a t-statistic.

    So, to try to directly answer your question, any 10-year period should be looked at in the context of  what preceded it. For the "warming stopped in..." argument, the easiest statement to make would be to say "the last 10 years shows the trend continuing".

    The Foster and Rahmstorf paper that KR mentions is very good. Foster is the person that writes, where you will find lots of excellent posts on statistics and climate (He's been on hiatus for while now, but the archives are a treasure-trove of good stuff.)

    The approach taken in the Foster and Rahmstorf paper is to quantify known sources of variation and remove them from the data, leaving the long-term trend showing clearly. If you leave that variation in, it is treated as unidentified noise in a regression, which makes the trend harder to see. (It would be wrong to reduce the noise by averaging - that just deceives the regression test. You need to be able to independently say "yes this causes variation and I know how much".)

    ...and we always can make use of the SkS Escalator image:

    The Escalator

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