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Glenn Tamblyn at 07:37 AM on 17 January 2013Ridley, Murdoch, and Lomborg Attempt to Greenwash Global Warming
An important principle in Agricultural science is Liebig's 'Law of the Minimum'. Essentially that a plant's growth is limited by whichever resource is most restricted. So adding any resource (CO2, Potassium, whatever) may not do much if that resource isn't the limiting factor for that plant. So knowing how plants will react in the future is nowhere near as simple as the 'CO2 is Plant Food' meme suggests -
BaerbelW at 07:03 AM on 17 January 201316 ^ more years of global warming
@eon - I just checked the video script and the narration at 01:20 states the following: What's left is the human contribution to climate change plus some wiggles due to weather. This is different from what you assert at #69 (as well as in some other comments) "and then bundled the remainder all as "caused by humans"." -
Alex The Seal at 06:48 AM on 17 January 2013Ridley, Murdoch, and Lomborg Attempt to Greenwash Global Warming
I disagree that Murdoch wants GW to be a non-issue. The topic is an emotional one which sells news. He loves to keep the pot well stirred. -
Rob Honeycutt at 06:33 AM on 17 January 201316 ^ more years of global warming
eon... It seems to me, again, that you're thinking the point of the video is to validate that warming is man-made. It's not. The video merely validates that the past 16 years of warming are consistent with the prior 16 years when you remove ENSO and volcanoes. Validation of the human contribution to warming comes from the overwhelming body of scientific research. This video is a direct response to all the places in the news media where "skeptics" are saying that there's been no warming over the past 16 years. This video neatly puts that myth to rest. -
ubrew12 at 06:28 AM on 17 January 2013Ridley, Murdoch, and Lomborg Attempt to Greenwash Global Warming
World is growing greener with CO2? Was it not green enough before? -
dana1981 at 06:17 AM on 17 January 2013Ridley, Murdoch, and Lomborg Attempt to Greenwash Global Warming
John Russell @1 - indeed, failing to account for any but the best possible scenario seems to be a constant problem for Ridley in many different areas. Maybe we'll get lucky - maybe climate sensitivity is on the low end of possible values, maybe the greening trend will continue in the future, etc. But banking (pun intended) on that best case scenario is a fundamental risk management failure. If any but the very best case scenario comes to fruition and we fail to do anything about it, we're in big trouble. Which seems to be basically what happened to Ridley's bank, which probably isn't a coincidence. -
Dikran Marsupial at 06:01 AM on 17 January 201316 ^ more years of global warming
@eon, perhaps I ought to get out my time machine and collect some observations so that we can perform the exercise you suggest? If you want to know what to expect, then look at some control runs from GCMs. GCMs include greenhouse effect, volcanic and solar forcing, the more modern ones also have an ENSO like phenomenon. However, GCMs can't include "unknown unknowns", so your question is rhetorical as I suspect there is no answer that would satisfy you. Note also that we haven't said there are no unknowns, just that there is little reason to suggest they exist. -
eon at 05:49 AM on 17 January 201316 ^ more years of global warming
ok, thanks for responses: I'm not going to reply to every individual comment as it will take too long. But I will rather answer the general theme (ignoring ozone as per mods request):- "yes there unknowns+accuracy issues, but that a) They are small/irrelevant; b) Everything has unknowns, so you can't bury everything in quicksand if it isn't completely conclusive." All i'm saying is that the author of the video has took the temperature readings, then subtracted some known figures, and then bundled the remainder all as "caused by humans". If that is true, can I ask what you would expect to see on the graph for the pre-man-made-global-warming era, if you subtracted all of the (Volcano+Solar+El Nina factors) as has be done in the video? So we have: 1) Removal of all rises due to volcanos, solar, el-ninas. 2) In this era, there would be no human CO2 contributions. 3) It is said there are NO unknown factors (of significance) Since no human contributions, no unknown contributions and all the significant factors have been subtracted/added, then by your arguments, we would see a flat graph (+some noise) ? -
gws at 05:32 AM on 17 January 201316 ^ more years of global warming
eon As scientists we sometimes want to, and at times need to be pedantic. In our science and how we interpret it, but not necessarily in how we communicate it. The moment at 1:22 into the video can make some of us feel a bit uneasy. But this is not because there is any reason to think it is wrong. Considering how much is known about climate forcings, invoking the "unknown unknown" is not just unhelpful, especially with respect to communication, it is also mostly wishful thinking, and as such not goal oriented. All those who wish there were some unknown factor that only makes us think CO2 is a problem (recall that the physical effects of CO2 in the atmosphere are fact) are basically akin to drug addicts who blame everything but themselves for their problems. How does that help? See Dikran @64. Ever asked yourself how likely it is that thousands of scientists have yet to discover a major climate factor after so many decades of research? And indeed, your CFC assertion is odd ... so we are indeed looking forward to some source of that claim. -
John Russell at 05:20 AM on 17 January 2013Ridley, Murdoch, and Lomborg Attempt to Greenwash Global Warming
Ridley is "always assuming the best case scenario, never preparing for the worst." Which is why he totally screwed up his bank. Northern Rock was once a fine building society until it became a bank and under Ridley's leadership was then the first to crash when the financial meltdown came along. [This is all referenced in the second link in the article.] Note the excuse Ridley made to the Parliamentary inquiry when explaining why his bank went down; "we were subject to a completely unpredicted and unpredictable closing of the world credit markets." Doesn't that say so much about his denial mindset? I can just hear him now using similar words, when he's called to account for denying the changing of the world's climate (well, one can dream, can't one?). -
Rob Painting at 04:57 AM on 17 January 2013Ocean Heat Came Back to Haunt Australia
Jake - not sure. John Cook has used the comparison before, but whether it originated elsewhere - I don't know. -
Rob Painting at 04:52 AM on 17 January 2013Ocean Heat Came Back to Haunt Australia
Colinkirk - this heat wave was a record-breaker. See this except from the Australian Bureau of Meteorology hyper-linked in the post: "On Monday the average maximum daily temperature record for Australia was broken at 40.33°C. The previous record, 40.17°C on 21 December 1972, was held for 40 years. The daily average maximum temperature yesterday (8 January 2013) is a close third at 40.11°C. The number of consecutive days where the national average maximum daily temperature exceeded 39°C has also been broken this week—seven (7) days (between 2–8 January 2013), almost doubling the previous record of four (4) consecutive days in 1973," said Mr Plummer. And yes, we're sure most readers appreciate it is summer in the Southern Hemisphere. The point that you are failing to understand is that these heat waves will become more frequent and more severe in the future ( See the hyper-linked SkS posts at the bottom of the post). By mid-century these kind of temperatures are likely to be the norm, with heat waves taking place over and above that. With the Earth's committed warming due its energy imbalance, we've got 3 or more decades of warming to come even if we were magically able to stop burning fossil fuels. Australia is a hot, dry, country. Making it much hotter and much drier will bring with it extraordinarily severe consequences. Good luck adapting to that. Your fellow Australians are going to need it. -
Bob Loblaw at 03:44 AM on 17 January 201316 ^ more years of global warming
eon: You appear to be beating a variant of the drum that says "you don't know absolutely everything, so you can't claim to know anything at all". As we never know absolutely everything, but we frequently know enough to accomplish many things, this is a drum that just adds noise, not signal. If you are going to rest a case on "unknown factors", don't expect to be taken seriously when known factors explain most of what is happening. As for your CFC-ozone dismissal - don't throw out the "hogwash" epithet quite yet. When you find your source that "cast a lot of doubt on the claim" and present it here, I suspect that a scientific analysis will show that your source is the one that's doing the pig-cleaning. That doesn't mean that I won't look at your information with an open mind, but my brain hasn't fallen out yet and there is an awful lot of strong science in the CFC-ozone link that would have to be wrong before you'll convince me.Moderator Response: (Rob P) - talk about ozone is wandering off-topic. The future ozone-depleted world avoided was the subject of a peer-reviewed paper released last year, and also this older paper - discussed at NASA Earth Observatory. Note the total ozone and UV index figures. Dodged a bullet there. Find an appropriate thread to discuss it, if you so wish. -
Rob Honeycutt at 03:14 AM on 17 January 201316 ^ more years of global warming
I also have to object to the term "dumbed down" because I don't think that is what has been done here. This, I believe, is a very sophisticated communication piece. Sometimes making complex issues simple and easy for people to comprehend is the most difficult task a scientist can face. -
Rob Honeycutt at 03:06 AM on 17 January 201316 ^ more years of global warming
eon... What you're perhaps missing is there are fundamental accepted facts like, 1) Humans are releasing vast quantities of CO2 into the atmosphere every year, 2) CO2 is well understood to be the strongest well mixed greenhouse gas, and 3) An enhanced greenhouse effect will act to warm the planet. It doesn't follow that you absolutely MUST restate and reprove every aspect of the science for a simple presentation to be valuable. Given the overwhelming body of scientific evidence showing that humans are having a dramatic affect on the climate system, this presentation is perfectly reasonable. It would also be a mistake to suggest this video is proof of a connection between the rise in surface temperature and human causation. It's not, and it's not presented that way. The lesson of the video is that, the surface temperature record is noisy but if you remove some of the known noise (ENSO and Volcanoes) then you can clearly see the trend of the past 30 years is consistent. -
Dikran Marsupial at 02:35 AM on 17 January 201316 ^ more years of global warming
@eon - it isn't "dumbed down", it is just missing a caveat regarding something likely to be of no real importance. Sadly many discussions of climate get bogged down in sophomoric discussions about scientific method, usually claiming something is not testable. You have provided nothing to support the idea that the "unknown component" is plausible non-negligible, and until you do, all you are doing is engaging in pedantry. The fact that you have strong views on CFCs that are not supported by scientific literature suggest that your adherence to scientific method is somewhat inconsistent! -
Daniel Bailey at 02:18 AM on 17 January 201316 ^ more years of global warming
eon, claims not appearing in the primary literature seemingly contradicting the current understanding of science (which is supported by the primary literature) can scarcely be construed as "it cast a lot of doubt on the claim". Such thinking is hardly scientific. -
eon at 02:15 AM on 17 January 201316 ^ more years of global warming
@Dikran. OK - I guess I just don't like "dumbed down" science (working in a scientific field myself). I can understand the requirement for estimations / best-guesses and to a certain level assumptions. But just find it alarming that the 'unknowns' / 'inaccuracies' have been conveniently grouped together with the 'human contributions' as one big catch-all. I get the purpose of the video. But unfortunately, dumbed-down quickly becomes 'fact' in a lot of people's head. I would argue that is it neither a fact, a theory or a hypothesis because it is not 'testable'. It is a 'theory' in the more general-speak use rather than the scientific use of the word theory. Apologise - I don't have details on the CFC - I try dig out what I read. It wasn't a journal - so I shouldn't say "hogwash". But it cast a lot of doubt on the claim, coupled with more recent discoveries that have been referenced in the news. I was mostly trying to illustrate an example of where this kind of assumption has proved very wrong in hindsight and how it could/can be avoided if we avoid 'dumb science' -
Composer99 at 02:09 AM on 17 January 201316 ^ more years of global warming
eon: Positing substantial "unknown unknowns" affecting surface temperature trends is usually an exercise in what is nicknamed here climastrology. IMO it's a waste of time, especially for communicating science to the general public (such as myself). Although off-topic, since it's one of the key planks of your argument, please provide citations to peer-reviewed literature to support your assertions regarding the contribution of CFCs to stratospheric ozone depletion. -
meher engineer at 01:40 AM on 17 January 2013Ocean Heat Came Back to Haunt Australia
@4,i first heard Earth's Energy Imbalance being compared to exploding Hiroshima bombs at such and such a rate in a video of Jim Hansen's TED talk (Feb 29, 2012). Less than halfway through the talk, he refers to ARGO float measurements of the Current Ocean Heat content, which amounts to 0.6 W/sq.meter when spread out over the Earth's surface, and equates that to the energy released by exploding 400,000 Hiroshima bombs a day. The video of the talk is available here.Moderator Response: [PW] Hot-linked URL -
Dikran Marsupial at 01:23 AM on 17 January 201316 ^ more years of global warming
@eon writes "really should read "Whats left is the human contribution + the unknown contributions that we have yet to discover". Yes, technically that is true, but there is little evidence to suggest that the "unknown contribution" is not negligible, and so it isn't worth mentioning in a video aimed at a general audience. Of course this particular analysis cannot show that the "unknown contribution" is negligible, but the history of climate research goes back a couple of hundred years, and the gross features of climate are pretty well explained by the factors we do know. All scientific results are subject to the "unknown unknowns" so should that caveat be placed on every scientific statement, or just ones relating to anthropogenic climate change? Can you give me a reference to a journal paper that shows CFCs were not responsible for the hole in the ozone layer? -
pekka.lehtikoski at 01:13 AM on 17 January 201316 ^ more years of global warming
Hi Vrooomie Thorium reactors might be a better choice. There has been many low power test reactors, most of which closed before 1990. A couple of thorium reactors are currently operating in India (source: wikipedia, reliability: low). Fission reactors being constructed now (and accepted near future ones) are not thorium reactors. Yes. Burning carbon will cause carbon-14 emissions, which are radioactive. This releases much more radioactivity to environment than nuclear power plants. Anyhow carbon-14 has a relatively short half-life of 5730 years, thus it is not a long term problem (just for next 30000 years or so). I do not see nuclear power plants themselves as a problem. End placement of high level waste is the long term problem, and the uranium mining is short term problem. High level waste will stay radioactive for very long time, and toxic even after that. I do not understand how we could contain it safely for millions of years. Besides I do not have faith that all corporations around the world will handle high level waste in very expensive responsible manner, when it can be simply dumped in ocean, with no cost. Short term problem is uranium mining. In Finland (my birth country) Talvivaara cleaning pool dam broke again for the third time, leaking material to rivers and lakes. Even natural uranium has very low radioactivity, it is still toxic heavy metal. If only ITER would succeed and provide fission power. Even fission generates radioactive waste, it is only short lived. We would have to worry about containment only for very short time, like a few thousand year. -
eon at 01:05 AM on 17 January 201316 ^ more years of global warming
@ Dikran. I don't claim to know much on the current state climate change research (its something I'm looking into it), but I do know about correct scientific methodology. It really should read "Whats left is the human contribution + the unknown contributions that we have yet to discover". You are parcelling all the unknowns under the banner of "human contributions". I could equally walk through this video and do: and what we are left with is "volcanic contribution", thus parcelling all the unknown stuff under volcanic. If you are saying that there is absolutely no unknowns of major influence. We are 100% sure of this - then that is fair enough. You should be tackling this from the other end. - Estimate/Calculate volcanic (i dont know how but you have done it) - Estimate/Calculate el-nino - Estimate/Calculate human contributions - Take all 3 from the graph, then what you are left is is the unknowns. Why isn't that more accurate? If you don't think this is important, then consider the ozone/cfc 'scare' of many years ago. Recently, it was admitted that the cfc actually didn't have much effect. Even more recently, it is found that there is emissions from the oceans that have a huge effect on the ozone layer. My point is: What seemed 100% certainty back then. Turned out to be absolute hogwash. Similarly, this video's content is a "theory" not a "fact" because it is inconclusive due to some basic level assumptions about we are 100% certain we known everything -
Dikran Marsupial at 00:42 AM on 17 January 201316 ^ more years of global warming
@eon, so what identifiable forms of natural warming/cooling were not included (provide evidence to suggest it has a non-negligible effect on surface temperatures)? In my opinion, given this is a video intended for the general public, rather than a scientific journal, I think it is being a bit pedantic to quibble about the definition of "fact". It is fundamentally impossible to gain certain knowledge from experiment or observation (Hume), so if you really wanted to you could say that nobody could state any facts about causal relationships in climate. However, that would be just silly, so you have to draw a line somewhere and use a bit of common sense. -
eon at 00:23 AM on 17 January 201316 ^ more years of global warming
I hate to point out the obvious, but at 1:20 when you say "whats left is the human contribution....." How do you know what is left is the human contribution. To be scientific, it should be: 1. Remove volcanic activity. 2. Remove el nina activity 3. Remove all other forms of natural warming/cooling 4. Whats left is the human contribution You seemed to missed out step #3, and just jumped to the conclusion that what is left is ALL human contribution. This isn't following a scientific methodology. You cannot assume something and then say it is fact. -
vrooomie at 00:19 AM on 17 January 2013Ocean Heat Came Back to Haunt Australia
colinkirk, here's but one response to the so-called "facts" that Jo Nova spews. -
colinkirk at 23:45 PM on 16 January 2013Ocean Heat Came Back to Haunt Australia
I lived in Australia for over 30 years and it's a hot country in January! (perihelion was in early Jan). With regards to 'records': http://joannenova.com.au/2013/01/australia-was-hot-and-is-hot-so-what-this-is-not-an-unusual-heat-wave/ Thoughts? -
jake7351 at 23:18 PM on 16 January 2013Ocean Heat Came Back to Haunt Australia
Just out of interest, is the HB/s comparison an sks invention? First heard it from John Cooke speech and found it a good way to give a large number some context. -
CBDunkerson at 19:33 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Smerby wrote: "As Bernard and others have said, the last 10 years of global surface temp trend could only be noise and I have no problem with that. However, based on the past global surface temperature record since the late 1880s, one could also argue that the global surface temperature trend over the past 10 years could continue for another 20 years." So, you have just acknowledged that 10 years is too short a time period from which to draw any conclusion on the global temperature trend. Thereby directly refuting your own central premise that the past 10 years indicates 'warming has stopped'. That said, examination of the factors known to cause temperature changes shows (as others have demonstrated) that natural factors were slanted towards cooling over the past ten years, but offset by continued greenhouse warming from human fossil fuel burning. If we look at statistics alone while ignoring our understanding of the underlying physical processes then the past 10 years is insufficient data to determine anything. On the other hand, if we apply our measurements of those underlying processes and their associated impacts on temperature then we see that AGW has continued as expected. -
Dikran Marsupial at 19:15 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
@smerby wrote "one could also argue that the global surface temperature trend over the past 10 years could continue for another 20 years." well one could argue that marsupials will take over as the dominant form of life on Earth, but is there any good physical reason to think that they will? So what is the physical reason that the trend should continue for another 20 years. Include in your explanation the reason why the enhanced greenhouse effect will not result in warming. -
Dikran Marsupial at 19:11 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
@smerby, all the regressions show you is that the rate of warming has varied over the last 150. We can see that just by looking at the graph. However it does not tell you why the rate has changed, more specifically, it does not tell you that there is any sort of cycle present (for which you would need an analysis that actually involved a cyclical component of the regression). As I have already pointed out, there are good physical explanations for quite a lot of the observed behaviour (for example aerosols), which you are completely ignoring. For your hypothesis of cyclic behaviour to be correct, climatologists knowledge of aerosols must be wrong, but you have not addressed that point at all. I suspect that you won't. -
Doug Hutcheson at 18:30 PM on 16 January 2013Greenhouse Gas Concentrations Reach New Record
scaddenp @ 9, thanks for the link to Ch.10: I will study it with interest. I had not thought through the effect of the phase change from CO₂ to CH₄, which of course creates a forcing. Always glad to learn new stuff "8-) -
Philippe Chantreau at 17:41 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Smerby, although you are being somewhat polite about it, your posts are nothing but sloganeering. You hope I see a cycle too? I don't. Show the data analysis yielding the conclusion that a cycle is present and I could change my mind. You've been asked by me and others how many 10 years periods can be found that show a "flatlining" of temps anomalies. You haven't answered that question. You were asked how the past 10 years can show a "trend" that is statistically significant and different from the longer record. You haven't answered that question either. You keep on repeating the same stuff and offer nothing in response to the objections that were posted. You keep on saying that your eyecrometer tells you stuff and you have nothing to back it up. Zilch. You say you're learning but you are not. You haven't even learned the basic comment policy and what sloganering is. I am unimpressed. -
scaddenp at 17:21 PM on 16 January 2013Greenhouse Gas Concentrations Reach New Record
Ruminants add a methane phase to the carbon cycle with a consequent forcing that isnt there if without the ruminants. If you change the population of ruminants then you get a climate forcing. FF use is just FF use whether its farm machinery to taking the family to the beach. Calculating the effect of livestock on climate is a complex and imperfect calculation. See here for more detail. -
Doug Hutcheson at 16:35 PM on 16 January 2013Greenhouse Gas Concentrations Reach New Record
I'm having an interesting conversation with Alex Cannara, over at The Conversation, where the discussion is centring on the contribution of livestock emissions. My position is that emissions from animals are just recycling carbon already in the biosphere, but Alex is saying that the use of FF in manufacturing fertiliser and in powering farm machinery, means domestic livestock emissions are adding to the total of human emissions. What does the team think: are livestock emissions part of the problem? -
DSL at 15:02 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Smerby, what you're doing amounts to saying, "There's a 30-year cycle. I have no physical mechanism to explain it, and I'm going to ignore all the usual components (ENSO, solar variation, various oscillations, aerosols, enhanced GHE, etc.)." -
dana1981 at 14:50 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
smerby @108 - a global temperature change has to have a cause (or multiple causes). For example, in the early 1900s there was an increase in solar activity, an increase in human GHGs emissions, and low volcanic activity. In the mid century solar activity was flat, human aerosol emissions rose. In the late century, human GHG emissions took over. It's just a coincidence that these events were each roughly 30 years in length. Wait another few years and the last one won't fit that mould. -
smerby at 14:40 PM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Thanks again for the feedback, I am learning here.
When I observe the graph above I see repeating ~30 year trends and I hope you can see them too. There is a relatively flat period from 1880 through around 1910 followed by a warming trend from 1910 into the early 1940s. There is another flat period from the early 1940s through the mid 1970s followed by a second warming trend from around the mid 1970s through the mid 2000s. When I look at this graph these are the things that jump out at me. I see that the overall trend is up but there are embedded and repeating ~30 year trends. It is not proper, and you all are correct, to just make a claim that global surface temperatures have followed such a path since the late 1880s. I will cross check these repeating trends with linear regressions. Below is the outcome.
The linear regressions support my hunch and even show a bit of cooling in the flatter periods, especially in the 1880-1910 frame, which was pointed out that Krakatoa had something to do with this. A question I have is do these ~30 year trends represent noise or climate signal. Given the length of each trend, they represent climate signals. As Bernard and others have said, the last 10 years of global surface temp trend could only be noise and I have no problem with that. However, based on the past global surface temperature record since the late 1880s, one could also argue that the global surface temperature trend over the past 10 years could continue for another 20 years.
Moderator Response: [RH] Fixed image width. May I ask you to review the methods for limiting image width so as to make sure it doesn't break the page formatting? Thx. -
Alpinist at 12:04 PM on 16 January 20132012 Shatters the US Temperature Record. Fox, Watts, and Spencer Respond by Denying Reality
Whenever there’s a discussion about the accuracy of the temperature record, I’m reminded of Tamino’s punishing takedown of AW’s Surface Stations.Org site http://web.archive.org/web/20080613192826/tamino.wordpress.com/2007/07/30/surface-stations/ -
vrooomie at 09:50 AM on 16 January 201316 ^ more years of global warming
pekka.lehtikoski, I'm in a bit of a blinding rush, so cannot link you to the relevant data, but they are out there, in droves: -Thorium reactors are much more safe and reliable than standard 1st/2nd generation NPPs; -The amount of radioactivity released from the burning of coal--if that is what you're concerned about--is WAY more, in a cumulative sense than all the radioactivity from all the nuclear accidents combined. -I'm no huge fan of even 3rd/4th gen. NPPs but they must be considered, if we insist on being 7+ billion souls. Frankly, I personally think it irresponsible to future generations to insist on such, and that to maintain the viability of our species, and the survival of many others, we must do *everything* in our power to address our insatiable need for energy: Not the least of those is conservation. -
skywatcher at 08:53 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
smerby, I asked in #91, the following question: Q: Is there a statistically significant change in the warming trend over the past decade? If you think there is, please show your working. You've returned with more short-term plots that show absolutely no assessment of statistical significance. Furthermore, you stubbornly insist that you can identify significant trends with your lying eyes, despite being repeatedly shown how and why your eyes might be lying to you. I am thus led to believe that you do not actually want to apply the normal scientific conventions of mathematically evaluating the significance of given trend lines in surface temperature data. Why is that?
From Tamino's Open Mind, where you can really learn about statistical methods.
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Tom Curtis at 08:45 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
smerby @101 asks: "Something different has been happening for the past 10 years. What is causing this?" Yes, something different has happened. We went from a period dominated by El Ninos (note negative SOI indicates El Nino conditions):
to one dominated by La Ninas, including two of the deepest La Ninas on record:
We also went from the fifth strongest solar maximum of the last 150 years to the lowest solar minimum since 1910:
Given these two natural factors, we should expect global temperature to plummet over that period. Instead temperatures were, as you point out, near constant. It is possible to remove the impact of those factors from the record, as has been done most recently by Kevin C at SkS (where this discussion should continue).
When you do so, you see that the underlying trend continues unabated. Even should insolation and ENSO levels not recover, they do no provide an ongoing cooling effect. Consequently the warming must be expected to resume. It is likely, howver, that a new El Nino will come along soon, causing a very rapid rise.
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Bob Loblaw at 08:42 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
smerby: I'll re-emphasize KR's comment that "it doesn't mean anything now". To help illustrate, think of the significance of the calculated slope, which is essential to the "is it meaningful?" test. A t-test is one way of looking at the significance of the slope. nearly everyone first thinks that the null hypothesis is a slope of zero, but that is not the only test that you can make. The more general test is comparing "observed minus expected" - see this Wikipedia entry. "Expected" can be zero, but need not be. In this case, it can also be the long-term trend. Sure, a test against an expected value of zero shows "not statistically significant", but so does a test against an expected value that matches the long-term trend. This means that the data can't distinguish between continuing the trend and "no warming". -
Bernard J. at 08:17 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Seriously Smerby, reconsider your last graph. How many flat ten year intervals do you think could be constructed within its range? All you are doing is demonstrating that one can stay motionless on any step of the up escalator. It's a game beloved of children: one expects more (statistical) decorum from an adult... -
Resolving Confusion Over the Met Office Statement and Continued Global Warming
smerby - "...the other data sets clearly show no surface warming for the last 10 years. This supports my first claim but it won't mean a thing..." It doesn't mean anything now. To repeat a portion of previous discussions, until you have sufficient data to separate the observed longer term trend from the null hypothesis of zero trend with statistical significance, you are only looking at noise. And for this data, that hasn't happened, and you're only looking at noise. You are going to need 20-25 years of raw data to make that statistical separation - not 10. "Something different has been happening for the past 10 years." No, there has not. Short term variations can lead one to believe that the underlying trend has changed, but as discussed here, this is demonstrably just a confluence of short term variations, not a change in the underlying warming trend. -
Bernard J. at 08:14 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Smerby. If you "look at graphed variables for a living" you should be able to understand the magnitude of the noise versus the overall signal, and understand the length of time required for signal to emerge from noise. The decade intervals that you insist on considering are far too short for signal to emerge from noise. This point has been made so frequently on this post and on others that one wonders if you are deliberately ignoring it - the only other explanation is that you don't require any statistical strigency when you "look at graphed variables for a living"... -
smerby at 08:02 AM on 16 January 2013Resolving Confusion Over the Met Office Statement and Continued Global Warming
Hi All, thanks again for the feedback and I am learning more each day. I dig the optical illusions but they are much different than a temperature graph showing global surface temperatures for past 130 odd years. At least to me they are. I look at graphed variables for a living and can pick out trends by sight and be pretty confident about it. I also agree that it is just as important to run a statistical analysis. I ran a linear regression for the last 10 years. Other than the UAH showing an insignificant amount of warming, the other data sets clearly show no surface warming for the last 10 years. This supports my first claim but it won't mean a thing if global surface temperatures start trending up again over the next 10 years.
I also did a 10, 20, and 30 year regression of the last 30 years GIS global sfc temperatures and the 20 and 30 showed pronounced warming as expected. Something different has been happening for the past 10 years. What is causing this? Could it be build up of heat in the deeper oceans, the cold PDO buffering El Ninos, aerosols from India and China? Will the lack of global surface warming continue or is it just a temporary bump in the road. What do you all think?
Moderator Response: [RH] Fixed image width. -
pekka.lehtikoski at 06:57 AM on 16 January 201316 ^ more years of global warming
Climate warming caused by human activity (CO2) may not be the worst long term problem. Public perception of need to limit CO2 emissions, has lead to demand and acceptance of alternate energy production. Nicely this would mean wind, solar, etc, just these not yet cost efficient enough for a normal person to pay for. Practically this means rebirth of fission. About 63 new fission reactors are currently in construction, and many more projects have been approved (source: internet, reliability: uncertain). Using fission may have much longer lasting ill effects to future life than burning fossil fuels. -
StBarnabas at 06:45 AM on 16 January 20132012 Shatters the US Temperature Record. Fox, Watts, and Spencer Respond by Denying Reality
Cornelius @23 The Express is below my radar. Even further in the gutter than the mail. The UK system is by no means perfect! I thought Corbyn had lost credibility years ago, still a colourful character. Should have taken up Astrology -
villabolo at 06:41 AM on 16 January 20132012 Shatters the US Temperature Record. Fox, Watts, and Spencer Respond by Denying Reality
Somewhat off topic but it was mentioned in the article - what's Steven Goddard's real name?
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