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TonyW at 17:22 PM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Thanks to dana and scaddenp but I'm struggling to find the quoted passages (as mentioned by dana @42) or the figure (mentioned by scaddenp @43). All I can find is the summary for policymakers, as provided in the link in the article above. It has no figures included and doesn't contain the quotes mentioned by dana.If the quoted passages are accurate, I'm still not sure how they result in the claim that "the IPCC says that humans have most likely caused all of the global warming over the past 60 years." One may be able to infer that for one's own opinion but not as a statement of fact.I guess I'll have to wait for the final draft to be made available on-line to check on this. -
scaddenp at 16:47 PM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
TonyW - it would seem to be the logical conclusion to draw from looking at figure SPM-6 in the just released report.
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ajki at 16:39 PM on 29 September 2013Secretary of State Kerry and Senator Boxer Remark on the IPCC Report
"... In reaction to the report, [EU] Climate Action Commissioner Connie Hedegaard said: ''The issue is not whether to believe in climate change or not. The issue is whether to follow science or not. The day when all scientists with 100% certainty warn you against climate change, it will be too late. If your doctor was 95% sure you had a serious disease, you would immediately start looking for the cure. Why should we take bigger risks when it's the health of our planet at stake?"..." [source]
Moderator Response:[JH] Thank you for your contribution.
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dana1981 at 14:51 PM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
TonyW @40 - see the quotes from the IPCC report in the Current Global Warming Caused by Greenhouse Gases, Not Nature section above.
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John Hartz at 14:46 PM on 29 September 2013Secretary of State Kerry and Senator Boxer Remark on the IPCC Report
For the record, Dana was kind enough to put together this post while I was busy working on a third edition of this week's News Roundup. It's chocked full of objective articles on the just released IPCC report.
I invite readers to post any statements made by the world's policy makers on the IPCC report on this thread. Plesase cite source and provide a link.
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Stranger8170 at 12:13 PM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Thanks so much Dana. I've been an everyday lurker from almost day one on this site. I've had no science training beyond chemistry 101. The fact is I’ve learned so more about climate science then I ever wanted too, but you guys make it the most interesting.
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Jim Hunt at 10:45 AM on 29 September 2013Latest myth from the Mail on Sunday on Arctic ice
I have some modest success to report at long last. We have contrived to persuade The Mail to retract the most outrageous of the headline numbers concerning Arctic sea ice that they published on September 8th. They have of course endeavoured to blame the NSIDC for their own shortcomings:
http://GreatWhiteCon.info/2013/09/the-mail-makes-modest-amends/
Next we'll try and persuade The Telegraph to follow in the Mail's illustrious footsteps. Then of course there's all those other inaccuracies that they both still need to make amends for!
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TonyW at 09:19 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
dana,"it's very likely more than half, most likely 100%."But where does the IPCC summary state this, as you claimed at the start of your post? Is it just your opinion (which I happen to agree with, by the way) or does it come from AR5 somewhere? I think it's important not to give contrarians ammunition when relaying the (very conservative) assessment of the IPCC. -
Tom Curtis at 08:40 AM on 29 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
RobertF @45, I have responded elsewhere, where the comments will be on topic.
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Tom Curtis at 08:38 AM on 29 September 2013Foster and Rahmstorf Measure the Global Warming Signal
Elsewhere, RobertF writes:
"I am a sub-beginner and probably a bit skeptical of both sides. Recently, I saw a graph from Rahmstorf showing a continuing warming. A denier friend informs me that Rahmstorf cooked the books by adjusting for ENSO, in part. The rationale given is that ENSO has no direct global impact and thus surface temperatures cannot be adjusted for what is a local phenomenon. As justification, the denied offered a citation from Trenberth: "Although it is possible to use regression to eliminate the linear portion of the global mean temperature signal associated with ENSO, the processes that contribute regionally to the global mean differ considerably, and the linear approach likely leaves an ENSO residual."
What am I missing? Thanks in advance!"
Your "denier friend" is being no friend in feeding you such nonsense.
To begin with, the link between fluctuations in ENSO and changes in mean global surface temperatures is well established - and is the dominant short term (1-2 year) influence on global temperatures. This has been established by (among many more credible sources), the noted "skeptics", McLean, Carter and DeFreitas, who produced this figure comparing detrended middle atmosphere temperatures with the Southern Oscillation Index (SOI):
As you can see, except where there is volcanic cooling, the correlation is very close. Consequently there is no doubt that ENSO is responsible for most of the interannual variability in GMST. A fact so well established that even leading "skeptical" scientists are publishing on it is hardly one we should disagree with on the word of an anonymous friend.
(Note, use of this figure should not be taken as endorsement of McLean et al's ludicrous claim that because they show a correlation with the detrended GMST, therefore ENSO is responsible for the long term trend in GMST.)
So, given that there is an correlation, what are we to make of Trenberth's claim? You will note that he does not say there is no correlation, only that "a linear approach is likely to leave a residual". And if you look closely at the Foster and Rahmstorf adjusted data above, you will see exactly that residual. It is most obvious in the peak at 1998, and the trough in 2008 corresponding to the 1998 El Nino and the 2008 La Nina respectively.
"Leaving a residual" does not mean that there is no relation between ENSO and GMST as your friend would have you believe. It merely means that the effect is not a simple multiple of the strenght of the ENSO signal. Therefore any approach which treats it as such (including F&R) will leave a small part of the ENSO signal in the data, ie, a residual. The effect will be that such approaches will understate the effect of ENSO on short term temperature trends. Had F&R used a more sophisticated approach, they would have shown still stronger long trends over the last two decades than they actually show (although probably within statistical error of the trends they do show).
Of course, you do not need a sophisticated statistical method such as F&R to see what recent temperature trends would have been without the effect of ENSO. You merely need to group like with like - El Nino years with El Nino years, La Nina years with La Nina years - and thus determine the trend largely without any ENSO influence. John Neilson-Gammon has done exactly that:
As you can see, the trends for different types of years are approximately the same. Unsurprisingly, that trend, 0.16 C per decade, is very close to that found by F&R. (The slight difference is partly accounted for in that this method does not account for the recent cooling of the Sun.) More importantly, recent years fall very close to there respective trend lines. Therefore there has been very little recent cooling beyond the switch to a La Nina dominated pattern.
ENSO may not be the whole story in the recent lower trends in GMST. Scientists, being scientists, explore every possibility. But clearly ENSO is the dominant factor, and the other factors which scientists are exporing are additional effects - effects without which we would have seen an acceleration in global temperature rise. "Skeptics" like to drag those other studies across the trail to suggest ENSO is not a clear and dominant factor. The want to treat the diligence of scientists in exploring every factor as proof that no factor explored by scientists explains the recent lowered trends. But that is a simple pea and thimble game. Scientists know that ENSO is a dominant factor in the recent reduced trends. All that is at issue is how much of an effect it has had, and how much influence (if any) other less certain factors have had.
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dana1981 at 08:16 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Stranger @29 - those people are probably referring to the fact that the IPCC AR5 only provides a range of equilibrium sensitivity estimates (1.5 to 4.5°C for 2xCO2) and not a best estimate. This is because while paleoclimate and model-based estimates agree (2 to 4.5°C, most likely 3°C), estimates based on using recent observational data in simple models (Otto, Lewis, etc.) arrive at somewhat lower estimates. So basically two methods agree, one disagrees, so they don't have a consensus best estimate anymore and instead just put the range.
Were I a betting man, I'd put my money on the former two methods. Not only is it 2 against 1, but the latter method has large uncertainties, discussed by Andrew Dessler here.
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dana1981 at 08:11 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
chriskoz @28 - somewhere in there the IPCC says that roughly half the increased anthro forcing estimate is due to the rise in GHGs over the past 6 years, and roughly half is due to the decreased aerosol negative forcing estimate (decreased meaning smaller in magnitude).
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dana1981 at 08:08 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
TonyW @26 - it's very likely more than half, most likely 100%.
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grindupBaker at 07:36 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Me #35 I mean ...and I state +137 ZettaJoules in last 10 years....
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grindupBaker at 07:35 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Need many more temperature measuring contraptions in the oceans, so that interpolation requirement is minimal and fine-grained. As long as it`s possible (rational) for one of you sensible commenters to argue with me when I reference Balmaseda, Trenberth, Kallen (the graph from same) and state +137 ZettaJoules in last 10 years (which one of you did a few weeks back) and you say maybe still +5 to +6 per year into oceans there will be substantial doubt. Need that incontrovertible annual ocean heat increase, year by year as it happens, actually measured.
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John Hartz at 06:22 AM on 29 September 2013Climate's changed before
@justmoi #366:
In response to your question, I decline to engage you in a game of "Gotcha."
BTW, I just realized that your comments are "off topic" for this thread. Please post your comments on the thread to an article which directly relates to your concerns.
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justmoi at 06:10 AM on 29 September 2013Climate's changed before
Oops, sorry for the duplicate (F5 shouldn't do this, computer science is really one!). John, what is science about if not making really sure that the "other side" isn't right when assuming theories about the future? Tagging their arguments as "myths" to begin with is not what I'd call a scientist approach. And I'm glad you admit that not all (let's say 95% ;) of "their" research is rubbish, dare to enlighten me on the remaining 5%? Thanks!
Moderator Response:[JH] Your duplciate comment has been deleted.
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RobertF at 05:43 AM on 29 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
I am a sub-beginner and probably a bit skeptical of both sides. Recently, I saw a graph from Rahmstorf showing a continuing warming. A denier friend informs me that Rahmstorf cooked the books by adjusting for ENSO, in part. The rationale given is that ENSO has no direct global impact and thus surface temperatures cannot be adjusted for what is a local phenomenon. As justification, the denied offered a citation from Trenberth: "Although it is possible to use regression to eliminate the linear portion of the global mean temperature signal associated with ENSO, the processes that contribute regionally to the global mean differ considerably, and the linear approach likely leaves an ENSO residual."
What am I missing? Thanks in advance!
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engineer8516 at 05:14 AM on 29 September 2013Ivar Giaever - Nobel Winning Physicist and Climate Pseudoscientist
Appeal to authority happens from both sides. SkepticalScience itself did a study and wrote an article about a 97% consensus among climate scientists about global warming. On the flip side, opposers of AGW point to people like Lindzen, Frietas, Dyson, Giaver, etc ( admittedly I don't know all the scientists who have dissenting opinions, but that's not the point).
Appeal to authority ultimately doesn't reveal to us how nature is actually behaving. The debates about "well so and so won a Nobel Prize and he thinks blah blah so it must be false" or "there are this many scientists who believe that whatever is true. how many do you have" are pointless.
Just stick to predictions vs observations. What are the predictions of AGW and compare it observations. If it disagrees with observations then there's something wrong with the underlying hypotheses. If it agrees then AGW is strengthened. That's all there is to it. Sorry for the rant, but I see appeal to authority alot and this happens in other fields as well.
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John Hartz at 04:47 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Lei: Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.
Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Note: This is Warning #1. SkS Moderators adhere to a "three-strikes, you're out!" process.
Moderator Response:[DB] Note that if behavior is egregious enough, strikes 1-3 may be combined into just strike 3.
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John Hartz at 04:36 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
All: I have deleted Lei's most recent comments. They are all "off-topic slognaeering".
Concern trolling by Lei or anyone else will not be tolerated.
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John Hartz at 04:20 AM on 29 September 2013Climate's changed before
@ justmoi:
In response to your question, Nope, that is not what science is all about.
The vast majority of "skeptic research" is pseudo-science poppycock.
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Dikran Marsupial at 04:13 AM on 29 September 2013Climate's changed before
justmoi - try clicking on the tab to see the intermediate version of the article and/or look at the notes at the bottom of the page, there are plenty of references to the peer-reviewed research.
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justmoi at 04:08 AM on 29 September 2013Climate's changed before
Sorry if it's been replied to on other pages, but where is the link to the peer-reviewed research? And where is the skeptics research on the same subject, so I can pick whichever suits my beliefs better? Isn't what science is about?
Thank you.
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Albatross at 03:45 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Shoyemore @25,
Exactly! People must not confuse a scientists speaking outside their area of expertise but basing their comments on experts' research in the field (as Hansen does), with someone like Curry making unsubstantiated and unsupported comments in areas outsider her area of specialization.
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Albatross at 03:41 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Hi all,
Dana's position on Dr. Curry is, I'm afraid, spot on. As a fellow scientist in her field I have given up on her. People need to remember that Dr. Curry appears to be more concerned with soliciting attention and obfuscation nowadays than she is with making facually-based or scientifcally-credible or scientifically-defensible arguments.
Dr. William Connolley states the problem with bluntly and accurately:
"Judith Curry’s understanding of climate is not helped much by climate models
Or so she says. Personally, I find that my understanding of the deeper aspects of General Relativity [GR] isn’t helped by me not taking the time to concentrate on the maths. But at least I’m able to realise that’s a flaw in me, not GR.
Mind you, Curry’s comment does help explain why some of her papers are crap – if you write a paper in which “the model simulations … were the main source of data used in the analysis” and yet you don’t think the models help, you’re not really going to write anything sane."
This highlights Curry's double standard, logical fallacies and even hypocrisy when it comes to using climate model data.
Sadly, this is but just one of several problems when it comes to Dr. Curry's musings in the media and to journalists concerned with fabricating disinformation (see here and here)for a couple of examples. Curry did not even bother to check Rose's fallacious claims about the Arctic sea-ice extent, nor do I recall her calling him out on it when his egregious error was highlighted.
Again, Dana is spot on.
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John Hartz at 03:22 AM on 29 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
@Stranger #29:
In response to your question, it's complete B.S.
Have your read Dana's OP?
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desertphile at 01:50 AM on 29 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
A fine article: thank you. Though "disinformation" fits better than "misinformation."
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Stranger8170 at 23:37 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
One of blogs I was reading claimed that the IPCC could not agree on the level of climate sensitivity and this is backing away from the earlier reports. I can't find any evidence of that. Is this some kind of play on words or something?
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chriskoz at 22:48 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Having downloaded & now looking at the report, I find figure SPM.5 especially interesting (I'd like to paste it here but dunno how:().
It is much better detailed than equiv. figure from AR4. The differences worth noting:
- the best estimate of negative aerosol forcings (direct + cloud formation) has been lowered from (-0.5;-0.7) to (-0.27;-0.55) respectively. I don't yet know what it means & be interested in hearing other opinions on that
- total antropo radiative forcings since 1750 increased from 1.6 to 2.29 (in 2011) ARF was only 1.25 in 1980. What does it mean? That AR4 was underestimating ARF a bit that 6y of CO2 increase caused the forcing numbers to grow that much?
Moderator Response:[DB] Here is SPM.5:
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Why is the IPCC AR5 so much more confident in human-caused global warming?
TonyW, the "all" is in the math lower in the article. One could say "more than half" just based on the summary box, but what does "more than half" mean? Well now we know. If Dana is being biased, it's only in choosing not to count those natural +0.1 to -0.1 ranges as positive values. It's very clear from the math that "more than half" means nowhere near 51%. And, of course, it's extremely clear from the existing literature that the human contribution is nowhere near 51%. I do think the IPCC could have been stronger in the box -- "nearly all" would have been representative (if still conservative).
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TonyW at 20:42 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Dana, you wrote that the latest IPCC summary says it's extremely likely that humans caused ALL of the observed warming. However, from the section you quote, it only says that it's extremely likely that humans have caused MORE THAN HALF the observed warming.Did I miss something? -
shoyemore at 20:06 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
ptbrown31, #24,
I once had a lump in a dangerous spot and went to my doc. He knew my fears and said "You are older than the age group for that type of cancer. I think it is just a cyst, but I will refer you to a consultant". He was right, I was relieved to find. His opinion/ gut feel was correct, but he did not 2nd guess the expert.
Hansen does write about species extinction in his book, but he refers to documented cases of mass extinctions in the past, and mentions the work of biologist E.O.Wilson on 20th century species extinction. While he might have given better references, he gives enough for anyone to follow up and find out how justified his opinions are on a topic outside his expertise.
I think anyone can give an opinion, as long as he or she points out where expert knowledge can be consulted. There must be grounds other than the "gut" of the speaker for a calibration of the opinion. The impression with Judy Curry is that she conceals where her own expertise begins and ends, and does not point to evidence or reference, thereby committing the Argument from Authority fallacy.
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ptbrown31 at 18:59 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
@13 Doon9000
Well Said. I agree with almost everyingth you wrote. I guess I just think its a bad argument to discredit an opinion because its slightly outside someonse area of expertise. For example, James Hansen writes about the possibility of specieces exticntion in the next 50 years in "storms of my grandchildren". Do you think that his opinion should be dismissed becaouse James Hanses is not an ecologist?
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shoyemore at 17:20 PM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Zen , #9.
Thomas Stocker did indeed say what you quote, but in my recollection (I listened to the webcast live) he was referrring to the length of time over which observations have been taken, and not to the coverage or reliability of the measurements.
www.theguardian.com/environment/2013/sep/27/ipcc-world-dangerous-climate-change
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scaddenp at 17:14 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
Was simply calculating from energy accumulaton and heat cpacity of atmosphere. I agree that if the CIMP models really did ignore accumulation of heat on land and ocean then your characterisation of what the model would look like is better.
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grindupBaker at 15:14 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
@nhthinker #32 The transfer of heat to the oceans IS "global warming". The combined land/ocean surface and air temperatures are a proxy for it, even those measured today. Climate scientists could not study historical ocean heat content because what they had was historical surface temperature proxies and they must compare apples with apples so they are stuck with surface temperature when it comes to historical comparisons. Also, humans have developed more of an interest in surface temperatures and their effects, especially land, on growing food and whatnot, as opposed to developing huge overarching interest in ocean bottom temperature effects on the lifestyle and prospects of those funny glowing fish. Beats me why. Oceans have 1,100 times the heat capacity of air and 1,200 times the heat capacity of land if you go with Dr. Randall or 3,800 times the heat capacity of land if you go with Dr. Trenberth's land penetration. Either way, all of the ecosystems heat is either in oceans or 1/40th of it is in water that came from oceans (rain) and will return one day. So it is patently absurd to say that "global warming" is only an increase in atmospheric heat content and when I find that climate scientist you say told IPCC to say that I'll chastize him/her severely.
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grindupBaker at 14:48 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
@scaddenp #35 "predicted us frying" I disagree with though I'm in agreement with your statements and rationale otherwise. I find this topic fascinating. Surface temperature increase is not "global warming" (GW is heat content increase). Surface temperature is (1) a symptom flora & fauna outside below-surface oceans are affected by (2) the Earth "trying" to stop "global warming". In a very rational sense surface temperature increase is the antithesis of "global warming" (how about the fever with flu analogy, it's your body trying to slow/kill the real enemy virus but it's really unpleasant and, I seem to recall, can damage your brain if too hot too long). So if the oceans really did have polystyrofoam insulation 1 cm down (I understand some of them do now) and if land surface also was covered by more coffee cups then atmosphere would be continuously in radiative balance and "global warming" last 100 years would be negligible, right now would be ~+1.5C air/surface symptom (BerkeleyEarth land increase plus an estimated tad) and therefore "global warming" would today be a truly trivial 8 ZettaJoules. With CO2x2 and no feedback changes from last few decades would be +3C air/surface and +16 ZJ. No "frying". In reality Balmaseda, Trenberth & Kallen estimate +250 ZJ so far and it'll keep increasing because those freezing cold pesky oceans over the entire planet are just not going to allow the surface and air to stop this"global warming" like it keeps trying to do. I strongly suspect you know the preceding very well and you threw a "frying" phrase in for its delicious sound.
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grindupBaker at 13:10 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
nhthinker #21 your 4th paragraph is entirely incorrect. I cannot respond on a point-by-point basis because you demonstrate no understanding of the topic so it would take effectively a small book be written in the comment to get you in at the ground level and it`s ureasonable for others to do this for your benefit. There are endless videos of actual educational lectures on multiple aspects of this topic, even text books. Suggest you study and learn to get just the basics.
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grindupBaker at 12:51 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
Me @#38 My "Me @#27" S.B. "Me @#37". I'm attempting a Gosh Gillop, Gallup, Gollop attack on myself.
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grindupBaker at 12:46 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
Me @#27 My nhthinker #9 S.B. nhthinker #18.
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grindupBaker at 12:44 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
nhthinker #9 Your understanding of the English language is incorrect. The posting would need to state "Like the relationship between gravity and plate tectonics, the basic tenets of the relationship between greenhouse gases and climate change..." to have the meaning that you incorrectly ascribe to it. As written it compares separately gravity and plate tectonics with "the basic tenets of the relationship" and I believe this is what is intended, and I certainly agree with that intent.
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grindupBaker at 12:37 PM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
@miffedmax #12 you are much correct if logic is applied because it has the appearance of a fairly solid temperature decline getting started, maybe even the 8C drop over a few thousand years to next "Ice Age"getting a tiny start (we'll likely never know now) then a jolting Coolus Interruptus happening the last few decades for some bizarre, weird, mysterious reason that seems to have no possible explanation that humans can figure out and defies all logic, apparently. However, the crack (crevasse) in your logic is that so-called "deniers" target audience is not you, it's a very large group of, not to put too fine a point on it, basically <<the rest of this comment has been severely and properly snipped out by moderator response, except the last bit>> who only need to be primed with buzz phrases and most certainly will not be intelligently analyzing them.
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Tom Curtis at 11:52 AM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Further to my post @22, I would like to draw attention to this plot of global temperature using just 85 rural stations, with an average annual coverage of 50 stations:
The rural stations were selected by an algorithm ensuring only that they were dispersed so as to not generate biases in location, and that they were the longest records available in their region. Details are here. As Caerbannog sumarizes:
"1) UHI is a non-issue (I used only rural stations).
2) Data "homogenization" is a complete non-issue (I used only raw temperature data).
3) The global temperature record is incredibly redundant and robust -- you can really throw away ~98 percent of the temperature stations and *still* confirm the NASA/GISS global temperature estimates."
More importantly for this discussion, it shows clearly that the limited number of thermometers is not an issue. Geographical bias, however, is an issue. For that reason all global temperature series prior to 1880 are suspect (ie, HadCRUTx, and for Land only, BEST), and the HadCRU series is not as good as that of either NCDC or GISS.
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Tom Curtis at 11:25 AM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
First, given their chosen name, it is very likely that Ali G is simply winding us up. People using as a net name, the name of a well known satiricist should not be given the benefit of any doubt as to whether or not they are trolling IMO.
Second, contrary to Ali G's claims, there are reliable temperature records over much of the ocean for far longer than is the case over land. This is due to the practice of ships taking multiple daily temperature readings and recording them in their logs, thereby giving a consistent temperature record along major shipping lanes since the 1850s, whereas reliable temperature records on land from that period are largely restricted to Europe and the North East US. For what it is worth, here is the record of HadCRUT4 coverage (annual means) since the start of the record:
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adamski5807 at 11:14 AM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Ali G - how about having an honest conversation and responding in kind to the points made to you by Brian and Zen
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scaddenp at 11:12 AM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
"But the IPCC predicted atmospheric temperature rises over the next century intentially assume most of the heat imbalance staying in the atmosphere instead of being absorbed by the deep oceans and other masses of the Earth"
That is demostratably false. The models used in IPCC reports calculate that most of the heat is going into the world's ocean. If it was assumed that it was accumulating only (or even mostly) in the atmosphere, then the models would have predicted us frying long ago. Do the calculation yourself. You can see the the GISS-ER model prediction for OHC here. Given all the comments on ocean heating, heat balance etc throughout the IPCC reports, I am loss to understand how you gained such an impression.
And to be pedantic, the IPCC predicts nothing. It merely summarizes and reports on the published science. The GCM models used are a diverse lot from climate modelling groups in many parts of the world.
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Ali G at 11:05 AM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
And so what theory did I propose?
I have walked away - but am still listening!
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Don9000 at 09:37 AM on 28 September 2013Why is the IPCC AR5 so much more confident in human-caused global warming?
Satire alert.
Dana--you or anyone at Skeptical Science is more than welcome to delete this for being inappropriate, too long, or just plain absurd.
Taken to the extreme, Ali G's theory is fascinating. I think I can expand on it.
I have a thermometer in my room that has an internal column diameter of less than one millimeter. For the sake of the argument, let's assume the cross-section of the glass thermometer tube occupies a 1 mm x 1 mm square. Well, it turns out that to cover just a single square meter of the earth's surface with similar vertically positioned thermometers, we would need one million similarly sized thermometers.
Now, the earth's surface area is 510,072,000 square kilometers, or 5.1 x 1014 m2, or 5.1 x 1020 mm2. My calculations--done without a government grant, and non-peer-reviewed I might add, like the "science" on WUWT--indicate that two-thirds of this area is approximately 3.4 x 1020 mm2. This number also gives us the number of thermometers necessary to cover the same area with thermometers (I believe this correlation is true because of Lord Kevin's Fifth Law of Thermometers, but don't quote me on that). Also, while I'm not a mathematician, I think the number translates into 340 quintillion thermometers. Admittedly, that's a somewhat large number of thermometers to reach even the two-thirds level of coverage, but if we want to be reasonably certain global warming is really happening, we surely shouldn't quibble over a few hundred quintillion thermometers. We can probably order them on Amazon and get a quantity discount and free super saver shipping.
Now, I need to put the current dire situation into context. Shockingly, NOAA NOAA link, one of the world's most reliable sources of global surface temperature data, currently uses only 1500 weather stations around the world to monitor the earth's surface temperature! With all this in mind, I can really see why some skeptics are concerned about the lack of data. Even if we dare to assume that each of these 1500 stations has two thermometers, each of which occupies a square millimeter in cross-section, this still only lets NOAA monitor the earth's temperature on the equivalent of slightly less than a 55 mm2 section of the earth's surface! For the non-scientific in the audience, that is actually a smidge less than a third of the earth's surface by my calculations. Why, the area of my main vegetable garden covers approximately 96,000,000 mm2! Despite this shockingly inadequate coverage, a bunch of crazy climate scientists are telling us to cut our carbon emissions! What nerve!
Clearly, the world's nations shouldn't do anything rash until they have rectified this unacceptable situation. Surely it isn't too much to ask that governments cover a mere two-thirds of the planet's surface with simple thermometers, and then take the earth's temperature for thirty years so we have enough data to find a clear trend.
Of course, as we can all see, and before a skeptic feels the need to raise the point, it wouldn't be a complete and accurate record if we didn't take the temperature from each and every one of those 3.4 x 1020 thermometers almost constantly for those thirty years. I'd say one reading per thermometer per second would satisfy most skeptics that enough data was being recorded, though I suppose some hardcore WUWT scientists might want to record the temperature a hundred times a second, or a million times, just to be on the safe side--as they might point out, you never know when the temperature is going to drop a fraction of a degree after all, and it might just turn out that, because we are not sampling continuously we have missed some kind of colossal hidden temperature decrease due to our faulty non-continuous sampling methods which may mean we have all been frozen solid for the last thirty years and are just imagining that global warming is happening. That could be true. I dunno.
Still, I want to be practical, so I'm going to stick with the 1 sample per second option. That would work out to (pardon me if my math is a bit off) 3.2 x 1029 data points at the end of the thirty years of data gathering. Such a robust data set surely is necessary to have before we actually do anything crazy like cut global emissions of greenhouse gases on the word of a few thousand scientists, who, by the bye, if they have an average cross-sectional area of 594 cm2 each, only occupy a tiny fraction of the earth's surface . . . but I digress.
Next, scientists would have to analyze the data. They should obviously do this without the aid of computers, since we all know that the models are all wrong, and Al Gore has programmed all computers running Microsoft Windows to yield data supporting his theories (he also gets a penny every time you access the Internet, but that's another story).
By my admittedly rough estimate, scientists should have the definitive answer on whether or not the earth is warming in approximately 5.34 x 1045 years, assuming they work 40 hour weeks and take only two weeks of vacation per year.
I could go on, but I'm sure I've made some kind of point already!
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shoyemore at 09:07 AM on 28 September 2013Understanding the pre-IPCC Anti-Climate Science Misinformation Blitz
nhtinker,#27
Yes, you may have a child scientist check Newton's Laws, but ask the same child to solve a problem of three moving masses in space with gravitional attraction between them, and they would need a computer, and the assistance of a whole Maths Dept. The Three Body Problem is a famous one since the days of Newton.
In practice the motion of small bodies in the solar system is chaotic because of gravitional fluctuations from other small bodies, small planets and larger planetary masses. Large-scale behaviour is predictable, but can we pick out the asteroids that might crash to earth decades in the future? No, not until they are almost on us.
It is much the same with the climate. We can do small scale heat flows but the large scale problem of many variables is much more difficult and needs elaborate computer models.
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