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Enough scientific certainty exists on climate change to challenge media sceptics

It is difficult to make a conclusive link between human-caused climate change and the record drought in California, record freezes in parts of Canada and the US, Britain’s wettest-ever winter and Australia’s…

Of some things there is no doubt. Danny Lawson/PA

It is difficult to make a conclusive link between human-caused climate change and the record drought in California, record freezes in parts of Canada and the US, Britain’s wettest-ever winter and Australia’s hottest summer.

But there’s no doubt that they have pushed climate change back up the agenda, and will add pressure to the need for a deal at the Paris climate talks next year.

Directly experiencing such extreme weather can make a (small) difference to public sentiment too. Researchers at Cardiff University found that those affected by flooding in Wales in 2012 were more likely to believe climate change is happening now than those who hadn’t (74% versus 65%).

There is similar recent research in the US, which reveals that for every degree the temperature rises above the 12-month average, there is a 7% increase in belief in climate change, especially amongst those without strong convictions. Cold snaps can have the opposite effect.

But an aspect of this weird weather that gets less discussion is how the widespread uncertainties around the nature of such extreme weather, and of climate science itself, hand golden opportunities to those sceptical of climate change to spread doubt.

Who’s nobody, and what do they know?

A classic example is the recent debate on the BBC Today Programme between Lord Lawson of the Global Warming Policy Foundation and Professor Sir Brian Hoskins of Imperial College. Lawson managed to use the phrase “nobody knows” three times in the first minute, and criticised mainstream climate scientists for “pretending they know when they don’t”.

Lawson himself was widely criticised for misunderstanding the science and misrepresenting the scientists. But the general public often misunderstand uncertainty, interpreting it as a complete rather than relative lack of knowledge.

Some scientists have found it helpful to make the distinction between what might be called “school science” (as popularised by the likes of Brian Cox), which is a source of solid facts and reliable understanding, and “research science” where uncertainty is ingrained and is often what drives the direction of further investigation.

So when sceptics stress the “nobody knows” narrative, they are misrepresenting the existence of any uncertainty at all as meaning that, for example, no action to reduce carbon emissions is necessary. It’s the nature of climate science that there are lots of uncertainties, but this doesn’t mean scientists know nothing, or are simply speculating. But it can be difficult to do this in a sound bite.

Some uncertainty is standard

Rather, they try to assess what degree of certainty they have about different aspects of the science. For example, authors of the IPCC reports spend a lot of time trying to assess the degree of uncertainty and level of confidence they have in each of their statements. These are difficult concepts to get across to the general public and to legislators.

Take for example the headline finding of the last IPCC report in September that the authors are now “95% certain that humans are mostly to blame for temperatures that have climbed since 1951”. On the day the report was published, one IPCC author was asked by a BBC presenter: “so what do the other 5% of scientists believe?” In other words, there was a confusion between what the authors of the IPCC report collectively had concluded was true with a very high degree of certainty, and what percentage of scientists were in agreement with the statement.

For scientists, 95% certainty is taken as a gold standard, likened to the degree of confidence scientists have in decades’ worth of evidence that cigarettes cause lung cancer. So the same degree of confidence holds for something like melting of Arctic sea ice or the amount the world has warmed, but there is less confidence in for example explaining the lack of increase in global surface temperatures since 1998.

Scientists and journalists need to get better at explaining the way these uncertainties work. They don’t know everything but they know enough to be able to assess the risks of not acting.

A matter of risk

During the Today programme the presenter also implicitly introduced the concept of risk management, comparing 95% scientific certainty to a 95% chance, or risk. With high odds of 95% – or even equal odds of 50% – it would seem to make sense to take action to lower the risk.

Framing the climate challenge as risk assessment has been gaining considerable traction among some politicians. Lawson’s response to the question was to argue that even if there is a problem of global warming, it will have only marginal effects.

It is worth asking how he can be so certain of this low likelihood, what his level of confidence is and on what science it is based. This is what would be required by any risk assessment: he would have to show how he had come to this risk evaluation and why he was so confident in it, when so many other scientists are saying the impact could be huge. In any case, merely saying “nobody knows” doesn’t make his case.

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124 Comments sorted by

  1. Phillip Bratby

    Retired physicist

    "For scientists, 95% certainty is taken as a gold standard". I don't think you really mean that. Ask those working at the LHC.

    I don't think you understand the meaning of risk, as you seem to think it is the same thing as chance. In fact I don't think you understand the difference between any of the terms you use, such as uncertainty, confidence, probability, chance and risk.

    I think you should stick to journalism and leave these concepts to scientists and engineers who work in the field.

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    1. John Russell

      logged in via Twitter

      In reply to Phillip Bratby

      Maybe if more scientists were better at explaining the facts to the general public—and more willing to come forward to communicate with the public—it wouldn't be necessary for journalists to write such articles.

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    2. Mike Hansen

      Mr.

      In reply to Phillip Bratby

      Dr Phillip Bratby is a climate skeptic. He describes himself as having a doctorate in physics from Sheffield University, and is a semi-retired energy consultant [1]
      He made a written submission to Parliament during the inquiry into climategate and bizarrely claimed "I have no financial interest in the climate change debate." despite being an energy consultant.

      Quotes
      "Man-made global warming does not exist."[3]

      http://www.sourcewatch.org/index.php?title=Phillip_Bratby

      Perhaps you should stick to "energy consulting" and leave the science to people who work in the field.

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    3. Phillip Bratby

      Retired physicist

      In reply to John Russell

      We do our best to communicate to the public. You will see many of us writing in the newspapers. The fact that we are not allowed on the BBC is not our fault.

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    4. Phillip Bratby

      Retired physicist

      In reply to Mike Hansen

      I am now retired and my work was never impinged on by "climate change".

      There is still no scientific evidence that the human influence on the global climate is detectable or has been detected.

      My science has been heavily involved in those physical processes that describe climatic behaviour, so I am well quafified to talk on such matters - more so than the thousands with no scientific qualifications who spout utter rubbish on the science of the earth's climatic behaviour.

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    5. Mike Swinbourne

      logged in via Facebook

      In reply to Phillip Bratby

      "....The fact that we are not allowed on the BBC is not our fault...."

      Yes it is Phillip. The BBC can not be seen to be broadcasting lies, so if you stuck to the truth you could probably get on.

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    6. David Arthur

      resistance gnome

      In reply to Phillip Bratby

      "There is still no scientific evidence that the human influence on the global climate is detectable or has been detected." Oh, stuff and nonsense!

      At the very least, the amount of warming observed post-1950 warming cannot be due to anything other than warming due to anthropogenic additions to atmospheric greenhouse gases.

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    7. Phillip Bratby

      Retired physicist

      In reply to David Arthur

      This is your best scientific response is it: "the amount of warming observed post-1950 warming cannot be due to anything other than warming due to anthropogenic additions to atmospheric greenhouse gases"? For about half of the earth's history there has been natural warming and for about half of the earth's history there has been natural cooling. Suddenly only humans can cause warming! Tell me where you got your scientific training.

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    8. John Doyle

      architect

      In reply to Phillip Bratby

      Man, what a non-sequitur. Where ever did your notion of matching warming and cooling come from? Someone lost in his own arguments? You have no way of knowing that. In fact knowing the sun has brightened by a third every billion years should send you a warning signal that you don't have a clue.
      Regarding the last sentence it just proves that as a physicist when you retired your retired your common sense too or your training was imaginary. Of course humans can cause warming. We don't know the degree but as the only supplier of ancient carbon into the world it doesn't require being an "expert" to know wewill alter the atmosphere.
      In any event our civilization is travelling along a path so quickly going downhill we'll hit crisis point before climate change does.

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    9. David Arthur

      resistance gnome

      In reply to Phillip Bratby

      " when you have eliminated the impossible, whatever remains, however improbable, must be the truth" - Sherlock Holmes in "The Sign of the Four"

      Has it been the sun? No.
      Has it been cosmic rays? No.
      Has it been continental drift? No.

      We've excluded all other possibilities, leaving only the rise in atmospheric greenhouse gases remains. If you have any other possibility, Mr Bratby, pray tell: we'd love to hear it.

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    10. David Pearce

      logged in via Facebook

      In reply to David Arthur

      It cannot be true that all other possibilities have been excluded because the current hiatus in warming remains unexplained. In all likelihood the sun has not been properly considered, along with other factors such as cloud cover and periodic oscillations in ocean currents.

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    11. David Arthur

      resistance gnome

      In reply to David Pearce

      Thanks Mr Pearce.

      1. "Is global warming in a hiatus?" Err, no, as explained by Andy Pitman: https://theconversation.com/is-global-warming-in-a-hiatus-18367, in which it is suggested that decadal variability in rate of atmospheric warming is ascribable to variations in ocean currents.

      2. Evidence for Dr Pitman's suggestion may be found starting with "Global warming stalled by strong winds driving heat into oceans", https://theconversation.com/global-warming-stalled-by-strong-winds-driving-heat-into-oceans-22954

      3. With support from volcanic eruptions: "Volcanoes cool climate predictions"https://theconversation.com/volcanoes-cool-climate-predictions-23646

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    12. David Pearce

      logged in via Facebook

      In reply to David Arthur

      Plausible ex post facto explanations are not really very convincing, and sound to me like epicycles. The basis point still remains: if there are newly found mechanisms that caused the hiatus, it must also be the case that the same mechanisms were in play before the hiatus. Estimates of sensitivity to CO2 are therefore too high.

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    13. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Global warming has reached a plateau. Temperatures over the last 7 years are now on the down slope. The volcano excuse is never going to fly in the face of the evidence out there. Strong winds do not and can not drive heat into the oceans.

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    14. goldminor sanchez

      logged in via LinkedIn

      In reply to John Doyle

      Here is another way to look at co2. Human emissions of co2 equal approximately 4% of the yearly release that goes into the atmosphere, the other 96% is natural. Co2 itself constitutes 400 parts per million of the atmosphere. So we have only added a tiny fraction of the total amount of a fractional gas. If the Earth was that sensitive to such a tiny change, then man and most life forms would have been wiped out many billions of years ago. That is something to consider.

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    15. goldminor sanchez

      logged in via LinkedIn

      In reply to John Doyle

      ""We don't know the degree"". Think about what you said with those words. Climate scientists are so positive about this doomsday scenario, yet they do not know to what degree co2 alters the climate. Yet, they are all set to turn the world upside down, when as of yet have no idea to what degree co2 affects the system. Does that thought instill confidence in you as to the reliability of their assessment?

      I can fully agree with your last sentence. That is exactly what I see as being likely to happen.

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    16. David Arthur

      resistance gnome

      In reply to David Pearce

      "Plausible ex post facto explanations are not really very convincing, and sound to me like epicycles. The basis point still remains: if there are newly found mechanisms that caused the hiatus, it must also be the case that the same mechanisms were in play before the hiatus. Estimates of sensitivity to CO2 are therefore too high." Bollocks.

      Look at last time atmospheric CO2 was ~400 ppm, in the early Pliocene.

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    17. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      You didn't read my reply to David Pearce, did you? It refers you to the evidence of how and why your fantasy that global warming has stopped is a load of tosh.

      BTW, we use our real names on this site, not hide behind screen names.

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    18. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      That is my last name. I have used the screen name 'goldminor' for the last 6 years. I continue to use it as I have grown attached to it. My first name is Mark. I have nothing to hide. What would I be hiding from? That is nonsensical.

      I read all of the comments that were here 6 hours ago. So unless you posted something in between, then I have read all of the earlier comments. Perhaps, you overlooked what I had said. I can plainly see what the temp charts are showing. I stated that there has been no further increase in the warming. Obviously the world is still warm. So what? We should all pray for warmth vs the cold that may soon arrive.

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    19. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      The IPCC has lowered their estimate of cs. Further studies by other scientists now point to a cs of 1.3 approximately. So, I agree with your above statement that estimates of cs to co2 are too high. We are on the same page in that regard.

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    20. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      The Sun feeds the oceans. Then the oceans distribute the heat load to the higher latitudes. This is how nature provides for all of us. The only time when solar directly influences change on Earth is when the approach of a grand minimum arrives. Then that can last 30 to 60 years in duration. Otherwise it gives us a steady rate of warmth.

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    21. David Pearce

      logged in via Facebook

      In reply to David Arthur

      It is a common mistake to confuse cause with effect. What about the times in the past when CO2 was in the thousands of parts per million? Did the Earth fry? No. There were ice ages then too. Calling my perfectly logical reasoning 'bollocks' is hardly a convincing argument.

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    22. David Arthur

      resistance gnome

      In reply to David Pearce

      Mr Pearce, back when CO2 was ~1000 ppm, the earth was warmer (se levels much higher than present.

      There's a previous discussion thread at 'The Conversation' in which this issue is discussed, after Mike Hulme's "Science can’t settle what should be done about climate change", https://theconversation.com/science-cant-settle-what-should-be-done-about-climate-change-22727.

      The thread starts with a comment by one "Rog Tallbloke", a thread to which Glenn Tamblyn contributes the following.
      ____________________…

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    23. goldminor sanchez

      logged in via LinkedIn

      In reply to David Pearce

      It is his entire argument. Notice that he has no ability to discuss any aspect of climate change using his own words.

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    24. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      There is no way to know what the albedo effects were during the past millions of years. That refutes his entire argument. Not to mention that continental land mass shifts would mean changes in ocean currents, which would lead to different climate patterns then we experience now. All of the above is comparing two very different entities.

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    25. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "Notice that he has no ability to discuss any aspect of climate change using his own words." Here's one I prepared earlier:

      Earth is warmed by absorption of short wave sunlight. Because of this, Earth's temperature can remain unchanged by returning the same amount of energy to space. That is, solar shortwave energy is balanced by the earth re-radiating to space as a 'black body' radiator with a characteristic temperature of ~255K; that is, from space the earth's spectrum is roughly that…

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    26. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "There is no way to know what the albedo effects were during the past millions of years. "

      While detailed albedo specification is difficult, broad albedo variation can be estimated based on what we know of ice and vegetation cover, also how how global average cloud cover varies.

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    27. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Yes, fortunate for us the continents do not jump around much. The closing of the Isthmus of Panama made a large change to the climate. I was pointing out how the climate drivers from the past would have been substantially different than today.

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    28. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Meaning that it is guess work, which comes under the heading of 'possibly', 'might have been', and etc etc.

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    29. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      I have yet to read any study saying that co2 reached 430 ppm in the last several hundred years, is there a link to a study for that claim? I thought the much acclaimed 400 ppm from last year was 'unprecedented'.

      The Arctic has seen lower levels of sea ice in the past. Why is it any different now? To my eye, looking at the sat record the last 12 years of diminished sea ice has stayed in a range. Even with the Arctic cyclone that caused the heavy loss in 2012, the sea ice swiftly rebounded. From…

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    30. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      That is an assumption on your part that current conditions will negate the return to glaciation. Even if it were true, which would be worse for man, glaciation or a warmer world?

      I agree with you on deforestation being a problem that should be addressed. I see that and land use changes as the main negative impact that man has inflicted upon nature. The co2 release is undoubtedly going to be seen as beneficial in future years.

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    31. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Isthmus of Panama closed, and Indonesian Throughflow between Pacific and indian Oceans has changed.

      What hasn't changed is that atmospheric greenhouse gas content remains the master controller of surface climate.

      Speaking of guess work, you've not yet proposed even a singled plausible hypothesis to account for how climate has varied through earth's history, whereas I've furnished you with plenty. Matter of fact, here are a couple more now:
      1) Lacis et al, "Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature", Science (2010), 10.1126/science.1195475
      2) "Infrared radiation and planetary temperature", Raymond T Pierrehumbert, S-0031-9228-1101-010-6, January 2011, Physics Today,
      http://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf

      So it's not so much guesswork and could have been as best estimate and overwhelming evidence for and no evidence against.

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    32. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "That is an assumption on your part that current conditions will negate the return to glaciation. Even if it were true, which would be worse for man, glaciation or a warmer world?" Christ Almighty, just how blitheringly stupid are you?

      From available ice-core data, there has NEVER been a return to glaciation that has not been associated with a drop in atmospheric CO2 levels to <~250 ppm.

      1) Lacis et al, "Atmospheric CO2: Principal Control Knob Governing Earth’s Temperature", Science (2010…

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    33. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      If co2 were the master control know, then why did global temperature stop rising after 1997/98? Especially, since in the years after global co2 emissions rose to new heights. A large portion of 'all time' human emitted co2 was sent into the atmosphere during that 17 year period.

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    34. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      ""Irrelevant question, since we know perfectly well that what we need to do is maintain atmospheric CO2 between 300 and 350 ppm. ""

      There are other scientists who disagree with that.

      I am limited in this discussion in that I do not have the math skills necessary to fully dialogue at all levels. I was very good at math back in the 1960s. I went one year to USF as a chem major, but I dropped out during that time of great social change. I was gifted though. My reading comprehension is as strong as it ever was, which is why I can read and maintain a dialogue in science related material with in certain parameters. I am going to work at rejuvenating my math skill.

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    35. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      If co2 were the master control know, then why did global temperature stop rising after 1997/98?

      Gloabal warming didn't "stop" after 1998, but ocean currents changed to La Niña mode so that a much greater proportion of accumulating heat went into oceans and from there was transferred to Poles to melt ice, rather than just stay in the atmosphere.

      1. "Is global warming in a hiatus?" Err, no, as explained by Andy Pitman: https://theconversation.com/is-global-warming-in-a-hiatus-18367, in which…

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    36. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "There are other scientists who disagree with that [maintain atmospheric CO2 between 300 and 350 ppm to ensure climate remaining as we've known it and to which our civilisation and all ecosystems are adapted].

      No, there would be no scientific disagreement with that - at least, not among scientists who've studied climate.

      I was passingly good at maths in the 1970's, and completed a degree in Phys Chem at USyd in 1983. However, it's only been in the last decade that I've been looking in detail…

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    37. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      I joined the climate conversation 6 years ago. I am the kind of person who finds this type of exercise fun and stimulating. I used to debate both sides of the story in the first several years. I am an open minded individual. There is so much to read, though. So far I must have around 6,000 hours into this. Not all of that being fully science based, though. I have a long list of saved links from the places I have read, which include different universities from around the world. Each link means that I read at least one article/paper from that site. I am on Social Security now. So my time is my own. I plan to spend the rest of my time following this path, which I should have never left all those many years ago. I am off now. It is getting late here,.... to be continued!

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    38. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      That book and the book by Hansen are firmly committed to the catastrophic global warming premise. Why would I want to read those books when I fully disbelieve in the premise of CAGW. They are blind to anything else that happens in the real world. You appear to do the same. Look out the 'window'. You can see the world at a glance now. What a great tool the internet is for all to use, especially being that NOAA, NSIDC, Cryosphere , and everything else under the Sun can be viewed on a daily basis. That is what I do. As I already said, I don't have the maths skill as of yet, but I can observe in real time all the major components that drive the weather and thus the climate of the world. Your physics can not explain what is happening in real time around the globe. Nature shows this beyond the shadow of a doubt.

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    39. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Let me be frank, Mr Sanchez.

      Physics and chemistry are such that it is not even possible for atmospheric CO2 to NOT have a major influence on climate. Ergo, it is not even possible for anthropogenic changes to atmospheric CO2 content to NOT have a major influence on climate.

      In other words, AGW is NOT something in which we can choose to 'believe', or to 'not believe'. If you think that it in't real just because you yourself have 'chosen' to not 'believe in it', then you are deluding yourself…

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    40. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Nature disputes what you claim. I realize that co2 has an effect, but it is not doing what the cagw believers says it does. The next 3 years will prove that.

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    41. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Mr Sanchez, I don't give a tinker's cuss for whatever you imagine these "cagw believers" might say. I'm telling you what the observations oblige us to experience, and hence compel us to accept.

      Nature might behave differently on Acid Planet Sanchez to how it behaves on earth; this article, and the ensuing conversation, pertains to the latter planet, not the former.

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    42. David Arthur

      resistance gnome

      In reply to John Doyle

      Thanks for this, Mr Doyle.

      The Mother Jones article is based on Marcott et al's recent paper in Science, "A Reconstruction of Regional and Global Temperature for the Past 11,300 Years", Science 8 March 2013: Vol. 339 no. 6124 pp. 1198-1201 DOI: 10.1126/science.1228026. It's already been posted to http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_Global%20Temperature%20Reconstructed.pdf, but there seems to be no link to it from the parent directory ... hmm.

      Marcitt et al's Holocene…

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    43. John Doyle

      architect

      In reply to David Arthur

      Sure, but it does show that the argument offering a stop in climate change because there has been no temp increase in 7 years, is just weather.

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    44. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      The typical cagw believer, always having to attack the character of the opponent in an argument. That doesn't speak well for your argument.

      When the observations no longer fit with your argument is nature then wrong?

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    45. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "When the observations no longer fit with your argument is nature then wrong?" Err, name one such observation, and I'll point you to how and why you're wrong.

      As I've previously mentioned to you, have a look at the exchange between myself and one 'Jim Inglis' at https://theconversation.com/scrapping-eu-renewable-targets-after-2020-makes-no-sense-22284. That'll let you rule some of the more prominent Denialist memes out for yourself.

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  2. Paul Matthews

    Mathematics lecturer

    You could try reading Lawson's book on the subject. There is a chapter about risk and uncertainty.

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    1. John Russell

      logged in via Twitter

      In reply to Paul Matthews

      Then he has no excuse for trying to mislead the public, does he? In other words his distortion is wilful rather than unwitting.

      Lawson has no qualifications for arguing about the science and in doing so it's clear he has only one agenda: to obfuscate and distort the facts in order to ensure the conversation does not move on to policy. This is strange as policy is the one area in which he <i>is</i> qualified to speak. Perhaps he knows that once the science has been accepted by all, it will be much more difficult to defend a policy of 'business as usual'?

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  3. Alistair McDhui

    Retired

    Have you ever considered that the so-called 'consensus' was achieved by a clever fraud? Here is how it was done. By the early 1970s, Manabe and various students had developed successful atmospheric heat transfer modelling. <b>They assumed on average 160 W/m^2 net IR warming of the lower atmosphere by surface IR</b>. This lives on in the US military programme 'MODTRAN', which models the Radiation Field at any position in the atmosphere.

    In 1981 Hansen et al claimed a -18 deg C. zone in the upper…

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    1. Mike Hansen

      Mr.

      In reply to Alistair McDhui

      You are a conspiracy theorist with ideas that would make a scientific crank blush!

      You say "Sagan's aerosol optical physics is wrong: the sign is reversed."

      The Real Climate blog did a mildly amusing April Fools Day joke post about this a couple a years ago.
      http://www.realclimate.org/index.php/archives/2012/04/wrong-sign-paradox-finally-resolved/

      It was a joke Alistair. They were not serious!

      Have you read this article. You may find it useful.
      http://www.theatlantic.com/health/archive/2012/09/tin-foil-hats-actually-make-it-easier-for-the-government-to-track-your-thoughts/262998/

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    2. Alistair McDhui

      Retired

      In reply to Mike Hansen

      I wrote a paper on this and submitted it 2 years' ago. It was routed to Physics' publications. In it I have established the second optical effect, plus multiple experimental proofs. The US' top cloud physicist made the same observations, about 10% greater albedo for bimodally dispersed clouds from satellite observations.

      Sean Twomey had also made the same observations, warning people not to use Mie scattering theory for thicker clouds. In 2004 NASA buried Twomey's physics. So, cloud cooling does not hide CO2-AGW. It has been a convenient myth to hide bad IR physics. Sagan misinterpreted van der Hulst's observations.

      Go away and do what I and others have done: look at real cloud data. Thunderclouds are dark underneath because most of the 90% albedo is from backscattering by large droplets in the first few 100 meters. Venus' 90% albedo is from the same cause.

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    3. David Arthur

      resistance gnome

      In reply to Alistair McDhui

      On the other hand, Mr McDhui, we know the following:

      The sun warms earth with energy, primarily between wavelengths of 0.1 and 4 microns.

      Earth dissipates energy to space, primarily between wavelengths of 4 and 40 microns.

      Greenhouse gases disrupt transmission of the latter, not the former.

      If earth dissipates more energy to space than it receives from the sun, it cools down; if earth dissipates less energy to space than it receives from the sun, it warms up.

      Humans have increased and are continuing to increase the atmosphere's greenhouse gas content, which is unavoidably increasingly disruptive of transmission of energy from earth to space.

      In other words, it is not even possible that anthropogenic global warming isn't occurring.

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    4. Ross Barrell

      Aikido Student

      In reply to David Arthur

      We also know the following:

      In order to support a case for denial, one has to impune (believe and convince others that the science - and working scientists is/are corrupt) every major scientific institution in the world. This of course includes many universities, the Australian Academy of Science, CSIRO, US National Academy of Science, The Royal Society, and ad nauseam.

      Sorry. This simply is not sustainable.

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    5. David Arthur

      resistance gnome

      In reply to Ross Barrell

      As with many people who cleave to fallacies long after all objective evidence refutes their belief, climate science Denialists are acquiring delusions indistinguishable from clinical insanity.

      One wonders the extent of destruction necessary to restore them to mental health.

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    6. David Pearce

      logged in via Facebook

      In reply to David Arthur

      Accusing people who disagree with you of being mentally ill sounds to me like a classic case of projection. You should see a psychiatrist.

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    7. David Arthur

      resistance gnome

      In reply to David Pearce

      With respect, Mr Pearce, it's not me with whomn these folk disagree, it's reality.

      The sun warms earth with energy, primarily between wavelengths of 0.1 and 4 microns.

      Earth dissipates energy to space, primarily between wavelengths of 4 and 40 microns.

      Greenhouse gases disrupt transmission of the latter, not the former.

      If earth dissipates more energy to space than it receives from the sun, it cools down; if earth dissipates less energy to space than it receives from the sun, it warms up.

      Humans have increased and are continuing to increase the atmosphere's greenhouse gas content, which is unavoidably increasingly disruptive of transmission of energy from earth to space.

      That is, it is not even possible that global warming isn't occurring.

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    8. David Pearce

      logged in via Facebook

      In reply to David Arthur

      The argument is not about the infrared absorption characteristics of carbon dioxide, which are easily determined and not in dispute. It is about the extent to which this will have an effect on atmospheric temperatures. The observational evidence (as opposed to computer model results) points towards the sensitivity being low, which would mean that CO2 emissions are actually nothing to be concerned about since a small amount of warming should be generally beneficial. Scaremongering about large temperature rises become less credible each year, as the global temperatures continue to not rise according to the computer model projections.

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    9. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      The planet has cycles that can be seen through any and all of the temp records that exist. Look at the CET, which is the longest instrumental temp record in the world. Germany has a good one. The Czech republic has a good one, and there are others. All of them show warm to cool and back again. This current warming has been as strong one. Keep in mind though, that the Sun has experienced a Modern Solar Maximum from the late 1940s through to the 1990s. Since then the Sun has now entered into a new…

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    10. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Who is denying that climate changes? I keep reading this comment, yet I never see anyone saying that they deny that climate changes. Could you be more specific in who has said this? Could you point out the guilty party and his words spoken, as evidence?

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    11. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      I'll be a little more specific: there are people commenting here, demonstrably non-cognisant of climate science, who for whatever ridiculous reason of their own are denying that the present changes to atmospheric greenhouse gas concentration occurring as a consequence of human activity, are well outside natural variability.

      If you have a look further down the page, you'll see that I've provided a couple of corrections to errors in your own comprehension of what's happening.

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    12. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Timing may be right for next grand solar minimum, but it's not going to stop warming. With atmospheric CO2 at 400 ppm, but with climate still approximately that of equilibrium with atmospheric CO2 ~340-360 ppm, the planet is going to continue warming until it approaches early-Pliocene climate conditions; Hansen et al, "Assessing ‘‘Dangerous Climate Change’’: Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature", PLoSOne, 2013, http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0081648.

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    13. David Arthur

      resistance gnome

      In reply to David Pearce

      "It is about the extent to which this will have an effect on atmospheric temperatures" Not just atmosphere, Mr Pearce, but also ocean and cryosphere (including cryosphere extent).

      We already know what the climate is going to be like, if atmospheric CO2 stays at 400 ppm: it will be like the early Pliocene, ~4 million years ago, which was the last time atmospheric CO2 was ~400 ppm. Global average temperatures were ~2-3 deg C above pre-Industrial, sea levels were ~10-20 m higher than present…

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    14. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Yes, I have read those dire predictions before. There is zero proof for any of those claims. The planet has already cooled slightly over the last 7 years. Yet co2 is being emitted at ever higher levels. Mainly because the Chinese do not have proper regulations to control emissions.Hopefully the Chinese will get wise and put on the scrubbers which will clean all of the dirty components of coal.

      The warming stopped rising 17 years ago.

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    15. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Thanks for being more specific about what you meant. I am also a denier then, because I do not believe that co2 poses any danger to the future. Mankind already experienced a warmer clime during the early part of the Holocene. Yet here we are today.

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    16. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      There is no proof of any sort to claim that the current level of co2 will drive us into a Pliocene environment. Sea levels are not going to suddenly spurt up to inundate us. I grew up alongside the ocean. I see no change in that time worth mentioning. The rest of your comment is fairy tales meant to scare little children.

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    17. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "There is no proof of any sort to claim that the current level of co2 will drive us into a Pliocene environment." Err, we have all the proof we need to make decisions: atmospheric CO2 at levels not experienced since Pliocene, and absolutely no reason, not even the merest skerrick of supporting evidence, to suggest that global climate is NOT reverting to Pliocene conditions.

      Further, the changes are all in exactly the direction we'd expect from what Tyndall first proposed in the 1850's.

      "Sea levels are not going to suddenly spurt up to inundate us." True, it will take a millennium or so - but even later this century, we can expect local weather events and tides to cause large destruction in coastal cities.

      The remainder of your comment speaks of its own veracity, and hence worth.

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    18. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "Mankind already experienced a warmer clime during the early part of the Holocene." True, but mankind has never experienced climate like the Pliocene - and we've expended so much of our accumulating wealth on cities right beside the sea. Kind of dumb, really.

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    19. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      ""The remainder of your comment speaks of its own veracity, and hence worth.""...as does yours.

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  4. John Doyle

    architect

    One doesn't need to be an "Expert" to be considered credible. If vested interests want to seem credible they employ Experts to sign off on their own profit supporting theories. This has been egregious in the food, tobacco and pharmaceutical industries. So being "an expert" requires caution and an open mind.
    Me, I look at information such as that we are adding ancient carbon to our atmosphere over and above the standard emissions in the current world and I can confidently say it will have an effect…

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    1. goldminor sanchez

      logged in via LinkedIn

      In reply to John Doyle

      We should be putting our attention and efforts to reduce and mitigate the effects from true pollution sources. Co2 is not a pollutant. That is where the co2 scare actually hurts efforts to clean up real problems from industrial waste and land use changes, where land and water sources have been impacted by the advance and growth of mankind. All of this wasted money spent on chasing after a gas that aids crops in increased yields, is money that should have been spent to alleviate real pollution, and also with foresight plan ahead for droughts, flood control, and similar real time issues that impact the health and well being of society.

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    2. goldminor sanchez

      logged in via LinkedIn

      In reply to John Doyle

      Co2 is plant food. The satellites have been showing an increased greening all around the world. This is due to the increase in co2. Crop yields have risen due to the co2 also. That is important in today,s world of 7+ billion people.

      The greatest danger to civilization right now is this mad push to switch from a reliable energy source to a technology that can not carry the load which fossil fuels carry.

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  5. Peter Sinclair

    logged in via email @petersinclair.co.uk

    The first paragraph in this article is correct. The rest is opinion.

    AR5 finds that there is no evidence to link extreme weather events with climate change. Independent weather data shows that many forms of extreme weather have become much less frequent in recent years.

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    1. Mike Hansen

      Mr.

      In reply to Peter Sinclair

      Never trust a man who claims to know something about the IPCC reports but is unable to provide a quote.

      Chances are he has not read the reports directly but has got his information from a climate crank blog

      From the Summary for Policymakers, p5
      "Changes in many extreme weather and climate events have been observed since about 1950 (see Table SPM.1 for details). It is very likely that the number of cold days and nights has decreased and the number of warm days and nights has increased on the…

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  6. John Carter

    logged in via Facebook

    You make the very reasonable case that the science is not fully understood and then go on, as so many do, to ignore that statement and the real evidence and make up your own version of the truth. When Nigel Lawson said what he did, he was right. Nobody, in spite of billions of $ spent on hunting the CO2 witch, can point to a direct causal link between anthropogenic CO2 emissions and increases in global temperature. The opposite is true. In spite of increasing levels of CO2 in the atmosphere, the…

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    1. Mike Hansen

      Mr.

      In reply to John Carter

      Another climate science denier.

      "Nobody ... can point to a direct causal link between anthropogenic CO2 emissions and increases in global temperature
      " the global temperature has remained flat for the last 17 years "

      That is nonsense. You obviously do not read science publications.

      Like to tell us which climate crank blogs you get your information from?

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    2. David Arthur

      resistance gnome

      In reply to John Carter

      On the other hand, Mr Carter, we have reality:

      The sun warms earth with energy, primarily between wavelengths of 0.1 and 4 microns.

      Earth dissipates energy to space, primarily between wavelengths of 4 and 40 microns.

      Greenhouse gases disrupt transmission of the latter, not the former.

      If earth dissipates more energy to space than it receives from the sun, it cools down; if earth dissipates less energy to space than it receives from the sun, it warms up.

      Humans have increased and are continuing to increase the atmosphere's greenhouse gas content, which is unavoidably increasingly disruptive of transmission of energy from earth to space.

      In other words, it is not even possible that global warming isn't occurring.

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    3. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      There is no question that the globe warmed. All temperature records clearly show the warming. It helps to get a better perspective by looking further back in time. The IPCC and related others like to say 'look what has happened since the 1850s'. What they don't tell everyone is that the centuries preceding that point in time were known as the Little Ice Age. Why should it be surprising that the globe warmed after a drastic cooling? Why doesn't the IPCC mention this little detail to aid others in understanding exactly what has happened over time, and what it might mean for the future? The better way to get a proper perspective is to also look at the detail from long term charts such as this 2,000 tree ring study from JG/U....http://www.sciencedaily.com/releases/2012/07/120709092606.htm

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    4. goldminor sanchez

      logged in via LinkedIn

      In reply to Mike Hansen

      What exactly is he denying? Could you be more specific?

      Why has the IPCC admitted that the global temps stalled out for the last 17 years? Are they deniers also?

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    5. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "Why should it be surprising that the globe warmed after a drastic cooling?"

      Because the Little Ice Age was actually part of the earth cooling down from the peak warm period (6-8 millennia ago) of the Holocene Epoch (from ~12 kya up until 200 ya) , as part of the long slow cooling trend towards the next reglaciation (Ice Age) that would have occurred except that a particularly clever ape struck coal and reversed the trend: http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png

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    6. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      The link which is sitting 2 comments down from here shows a 2.000 year chart. On that chart it is plain to see that both the Medieval and Roman Warm periods were warmer than today. That chart also shows multiple swings in temps along the way. There are other studies which show similar. This study has a very high resolution, particularly in comparison to what Wiki is showing, which is a very low resolution chart. So your claim is wrong.

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    7. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Err, what you've found (Esper et al, Orbital forcing of tree-ring data. Nature Climate Change, 2012; DOI: 10.1038/nclimate1589) is N European tree ring data, which is only regional, not representative of the entire world.

      1. N European climate is strongly influenced by N Atlantic transfer.
      2. Modern tree growth has been strongly affected by industrial pollution. You're probably too young to remember concersn in the 1970's and 1980's about acid rain.

      The representation reproduced in Wikipedia uses proxy records from multiple sources.

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    8. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      I understand that it is a regional study. If you take that one and compare it with the many other regional studies out there, a good picture develops of how climate moves and shifts around the globe.
      Of course, Northern Europe is heavily influenced by the Atlantic.

      What would modern pollution have to do with that tree ring study? You keep tossing these meaningless quips out there, as if there is some deep significance to them.

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    9. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "I understand that it is a regional study. If you take that one and compare it with the many other regional studies out there, a good picture develops of how climate moves and shifts around the globe."

      Yes, and the good picture of climate that you develop is summarised and encapsulated in http://en.wikipedia.org/wiki/File:Holocene_Temperature_Variations.png.

      What would modern pollution have to do with that tree ring study? Acid rain stops trees growing - as observed in China. Elsewhere you…

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    10. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      If you had read the JG/U tree ring study, then you would have noted that the trees used were sub fossil pine trees that had been submerged in water. Your mistake for not reading what was presented and thus jumping to conclusions.

      There are much superior charts than the one you are showing from wiki.

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    11. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      "If you had read the JG/U tree ring study, then you would have noted that the trees used were sub fossil pine trees that had been submerged in water." Submerged in water? Irrelevant. The pine trees for post-1900 data can't have been submerged that long.

      "There are much superior charts than the one you are showing from wiki." Perhaps. But they would present pretty much the global average temperature for the Holocene a per the one from Wikipedia.

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    12. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      You are not seeing the picture properly. Obviously, none of the pine trees are 2K years old, right? So they had to use a source that gave them preserved trees to reach that far back in time. They were a collection of preserved trees which had fallen into local lakes at the edge of the taiga. Conditions in the area aided in the preservation of the trees, which is what gave them such a high resolution. The graph is beautiful for the detail which it shows. You can see all of the GMs for the last 2,000…

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    13. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      I really like this site, and I do so enjoy the conversation. I am looking forward to having more discussions with you. How else would I gain in understanding?

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    14. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Not only do they get tree rings out of the swamp, but they calibrate them with trees that haven't fallen into the water but were growing in the same time.

      eg if you have a standing tree that germinated in 1850, then you can calibrate the preserved record from a tree that grew from 1700 to 1900 by correlating them for the period 1850 to 1900.

      I don't think you quite understand about how sulfate aerosols (the industrial air pollution that gets washed out of the sky when it rains, turning the…

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    15. goldminor sanchez

      logged in via LinkedIn

      In reply to David Arthur

      Take a look at thier graph. Line it up with studies done elsewhere around the world and then tell me that there isn't a correlation that can be seen. I have already looked at many studies. This is why I bring it up. There is a Chinese study taken from the Himalayan region, it has correlation to this. The CET has correlation to it. Studies from North America have correlation with it. Within each and any of the individual studies there are obvious regional variations, yet the main part of the graphs show a common structure running through them. The Southern Hemisphere runs different though. The vast expanse of oceans vs land down under, explain that more than likely.

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    16. David Arthur

      resistance gnome

      In reply to goldminor sanchez

      Southern hemisphere probably more better, since the world's surface is 70% ocean, and northern hemisphere has been much more affected by air pollution over the last century.

      Anyway, there are ample instrumental records over the last century or so, that diverge from tree ring proxies for pretty much the reasons I've described. Probably one of the best is that of the National Climate Data Center http://www.ncdc.noaa.gov/ghcnm/.

      I understand the Koch brothers (petrochemical billionaires, and major funders of climate misinformation) contributed to funding an independent audit of meteorological records from all around the world. The result is the Berkeley Earth Surface Temperature project (BEST; http://www.berkeleyearth.org/), which found no evidence of data falsification. Among their conclusions (http://berkeleyearth.org/summary-of-findings) is that "Global land surface temperatures have increased by 1.5 degrees C over the past 250 years".

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  7. David Pearce

    logged in via Facebook

    It's interesting that the author of this article chooses the idea that 95% certainty is the 'gold standard'. I wonder what he thinks about the current global average temperature anomaly being outside of the 95% confidence limits set in previous IPCC reports? See here for more: http://climateaudit.org/2013/09/24/two-minutes-to-midnight/

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    1. Mike Hansen

      Mr.

      In reply to David Pearce

      "current global average temperature anomaly being outside of the 95% confidence limits "

      So this is what climate science denial has come to?

      Instead of the usual cherry picking of a starting year, you vaguely refer to something you call "**current** global average temperature anomaly" and then point to a climate crank blog in the vain hope that you have an argument.

      Sorry - no cigar.

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    2. David Pearce

      logged in via Facebook

      In reply to Mike Hansen

      If you actually read the article, Mr Hansen, rather than just spouting uninformed abuse, you will see that all of the data is accurately sourced from the IPCC reports themselves. Steve McIntyre is hardly a climate crank. If you want to see what a climate crank is, you should take a look at Michael Mann's work, or perhaps take a look in the mirror.

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    3. Ross Barrell

      Aikido Student

      In reply to David Pearce

      Sorry David, the author didn't choose the idea that 95% certainty is the gold standard. What he correctly said was, "For scientists, 95% certainty is taken as a gold standard, likened to the degree of confidence scientists have in decades’ worth of evidence that cigarettes cause lung cancer." So it is scientists who look for the 95
      5 confidence limits, not the author of this piece.

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    4. Ross Barrell

      Aikido Student

      In reply to Ross Barrell

      Sorry that last sentence should read (as if it's not obvious), "So it is scientists who look for the 95% confidence limits, not the author of this piece."

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    5. David Pearce

      logged in via Facebook

      In reply to Ross Barrell

      I think you misunderstand my point. The author's use of 95% certainty, regardless of whose choice it is as some kind of 'gold standard', is contradicted by the fact that global temperature anomalies (which are the only real way of assessing whether there is any global warming at all) are now, and have been for some time, outside of the 95% confidence limits set in previous IPCC reports.

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    6. Mike Hansen

      Mr.

      In reply to David Pearce

      You have no point.

      You are vaguely referring to "global temperature anomalies". What anomalies, what time period, what confidence levels - is that an exercise for the reader?

      You obviously have no knowledge of statistics. You are waving your hands about in the hope that no one will notice.

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    7. David Pearce

      logged in via Facebook

      In reply to Mike Hansen

      I am assuming some kind of basic knowledge of the science. If you don't have even that, I do not understand why you are pretending that you have an argument.

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    8. goldminor sanchez

      logged in via LinkedIn

      In reply to David Pearce

      Yes, there are those pesky little details that most of the media does not like to discuss. Like not mentioning that almost all of the climate models failed to predict the current trend. Nor will they ever mention that the tropospheric hotspot, which was a major prediction by the IPCC has never been seen.

      I notice that temps in Australia have been subdued this year as opposed to the recent past. A look at sst anomalies in the oceans around Australia show a very different heat load than last year…

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    9. goldminor sanchez

      logged in via LinkedIn

      In reply to David Pearce

      Allow me to point out a part from this article which mentions the Arctic melting. Historical records show that the Arctic has seen low levels before in the past. In fact there are regular cycles that drive this change in the growth or reduction of the sea ice. Just like there are regular warming to cooling cycles on a global scale that also drive global temperature changes throughout the historical records.

      One clear and easy to understand point about what is occurring in the Arctic has to do…

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    10. goldminor sanchez

      logged in via LinkedIn

      In reply to Mike Hansen

      There is nothing vague about what he has pointed out. Since 1997, global temperatures have flat lined. If you take the last 7 years, then there has been a slight cooling in that short time period. Obviously, one can not project to much with that short a time sequence, but that does not negate what the time period does show. How can there be a 7 year cooling trend in a world that is supposedly on fire? Especially, that it comes after the previous 10 years of a flat line.

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    11. goldminor sanchez

      logged in via LinkedIn

      In reply to Ross Barrell

      Ahh, the infamous tobacco analogy. That is always a sure sign of one who knows little about the details of the climate change debate.

      Isn't it amazing that the IPCC can still maintain a 95% certainty, when they have had to downgrade their initial claims several times now. How does that work when one says 'well our models have been wrong, the climate sensitivity can not be as high as we thought, the plateau was a complete surprise. Yet we can now say with greater certainty that we are right'. This is what they are saying. Does that make sense to you?

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    12. goldminor sanchez

      logged in via LinkedIn

      In reply to Mike Hansen

      You should stop smoking those cigars, cancer and all you know. I quit almost 4 years ago after 40 years of smoking. I feel great. Bet that I could outrun and outwork you.

      Back to the story, though. Current global temps are not vague. there are multiple sources for global temps, RSS, GISS, UAH, HADCRUT plus a few others. You can look up any of these. there is variation between the data sets, but they all run fairly close together.

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  8. goldminor sanchez

    logged in via LinkedIn

    One reason why it is hard to draw a line between the California drought and catastrophic global warming, is that California has always had drought throughout it,s historical record. The only people unaware of this fact seemed to be the leaders of this state. Blaming everything under the Sun on CAGW is why doubt about the premise of CAGW has spread. Anyone can get online and look up historical data and see at a glance that much of this has all happened before.

    Look at the current deep freeze across…

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  9. Alistair McDhui

    Retired

    The premise of this article is that the IPCC version of climate modelling is correct. It isn't, 13 mistakes in the physics.

    In reality, the AGW we did have was the reduction of cloud albedo by the sudden Asian industrialisation producing vast quantities of aerosols.

    Furthermore, the atmosphere ensures, by a heat engine, that the effective climate sensitivity of CO2 is near zero.

    This is proved by the experimental data: warming above the warming ENSO rate, then the hiatus. The next stage is the new Little Ice Age, caused by the fall in the Sun's magnetic field. This will accelerate after 2016.

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  10. Robert Antonucci

    Prof of Physics, Univ of Cal, Santa Barbara

    It's astounding to me that climate change skeptics think uncertainty is a reason
    not to take action. Uncertainty is a reason for extra caution and precaution.

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