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Albatross at 13:35 PM on 9 February 2012Michaels Misrepresents Nordhaus and Scientific Evidence in General
Oamoe, One should look at all the metrics and consider the big picture. But given that people have been speaking about OHC. Here is the 0-700 m and the 0-2000 m OHC data from NOAA-- note this represents the analysis from one of about seven groups who analyze the OHC data. Nevertheless, these figures refute claims made by Pielke and fake skeptics that the oceans have not been accumulating heat in recent years-- global warming continues, albeit it at varying rates (as it is expected to do). It is interesting Pielke Senior insists that THE metric for quantifying global warming is the OHC (well that is when he thought it supported the argument that the warming had stopped and by cherry picking a short time window). In contrast though, Michaels is using the error plagued satellite estimates of lower tropospheric temperature and he too has had to cherry pick a statistically insignificant short time window starting with a super El Nino and ending with a moderate/strong La Nina to hide the incline. So the fake skeptics cannot even decide amongst themselves which metric to use to quantify global warming. What they they are consistent in doing and what they are in agreement on is cherry pick those data which at any give time support their ideological agenda and cherry picking statistically insignificant short time windows.
With error bars for 0-2000 m:
With error bars for 0-700 m:
[Source]
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skywatcher at 13:32 PM on 9 February 2012Global Sea Level Rise: Pothole To Speed Bump?
Steve Case, your argument from incredulity is just that. Just because you have a hard time imagining the collapse of an ice sheet, and the resulting pulse of sea level rise, does not negate the plausibility of it happening. Meltwater Pulse 1A had 20m SLR in ~200 years, a mean of 0.26mm/day for two hundred years. Assuming a sigmoidal curve for the pulse, which is certainly reasonable, the peak sea level rise was quite possibly close to, or even larger than, 1mm/day. This is a matter of palaeoclimatic record, and we presently have two ice sheets (Greenland and West Antarctica) that have been known to be a great deal smaller in global conditions with this much CO2 in the atmosphere. -
bill4344 at 13:25 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Dale - evidence for the following, please.It's obvious that both "sides" are going in and contaminating the waters. The negative reviews slamming Mann and the book in my opinion are the same as the positive reviews literally fawning over Mann like he's a deity.
Oh, I see -the book looks to be more about Mann's sob story than any real science,
No, you really haven't read it, have you? I put it to you that what we have here is "Fake Skeptic Adopts 'View from Nowhere' Strategy in Unconvincing Attempt to Claim Evenhandedness" tone-trolling! Anyone shocked? -
skywatcher at 13:19 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
So Dale, did you read the reviews? Did you notice the difference between the comprehensive and thorough reviews giving it 5*s by people who evidentially had read the book, and were even not afraid to critcise aspects they didn't like. On the other hand you have 1* reviews that compare Mann to a "turd", usually a short paragraph, giving no indication they'd actually read the book. If you can't spot the difference between the two, I suggest you go to Specsavers... -
Tom Curtis at 13:17 PM on 9 February 2012Medieval Warm Period was warmer
Composer99 @71, it is true that some fake skeptics of climate science argue explicitly or implicitly that it was warmer throughout the MWP than it has been over the last two decades. Such a claim is implicit, for example, in any claim about the vikings "growing vinyards in Greenland". Leaving aside the fact that that claim is false, and conflates two true claims (there where viking settlements in Greenland, and wine was grown in the MWP in England); farmer and particularly medieval farmers did not switch cropping practices on an annual or even decadal basis. They where very conservative because a failed innovation literally meant starvation. Therefore, for the vikings to have grown crops in Greenland, Greenland must have been warmer than current temperatures not just for a decade or two, but for centuries. In fact, the comparison above (intermediate level) does show that that Greenland was as warm as the current decade for centuries in the MWP. Of course, some of that time, it would have been cooler, but some of that time it would be warmer. But the implicit claim that the MWP was globally warmer than the last two decades for the entire period of the MWP is refuted by the same comparison. Never-the-less, the more informed fake skeptics (and some uninformed or misinformed genuine skeptics) are arguing that because decades within the MWP where warmer than the last two decades, there is a prima facie assumption that the current warming is natural rather than anthropogenic. The conclusion is a non-sequitor, but the premise is not refuted by the comparison above for exactly the reasons jzk gives. We need to recognize that and not make the erroneous argument that the comparison between three centuries of data and one to three decades could show that no decade in the three century period was warmer than any decade in the two to three decades. That argument is not made above, although it has been in comments and it is an invalid argument. Because the argument has been made in comments, it is clearly a misunderstanding people are prone too, and the intermediate article should be revised to explicitly caution against it. -
Dale at 13:05 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
As a reader of both sites (SkS and WUWT) and having read the Amazon reviews, I must admit to being disappointed by both sides. It's obvious that both "sides" are going in and contaminating the waters. The negative reviews slamming Mann and the book in my opinion are the same as the positive reviews literally fawning over Mann like he's a deity. To be honest, if I were looking to buy this I would be ignoring all of the reviews as it's obvious posturing by both "sides". But since the book looks to be more about Mann's sob story than any real science, I wouldn't have read it regardless. -
Steve Case at 12:47 PM on 9 February 2012Global Sea Level Rise: Pothole To Speed Bump?
Hi Barry, nice to see you here. #52 Barry
That's right, Dr. Hansen is not saying the 5 meter rise is the likeliest outcome, he just says it's plausible. I've run the numbers on his 5 meter every ten years rate doubling scenario and have determined that sea level would be going up at a rate of nearly one millimeter per day by 2100. Further comment is not necessary, it stands as its own testimony. -
Alex C at 12:47 PM on 9 February 2012Michaels Misrepresents Nordhaus and Scientific Evidence in General
Oamoe @7: Afterthought, no - I agree with both you and KR in that OHC is an important metric of heat accumulation. If I can offer the narrative that was going through my head as I wrote this: 1) Dr. Michaels presented surface temperature data (actually, he presented a satellite temperature record for the lower troposphere), and as such the surface/atmospheric record should be addressed first; 2) Michaels gave the data implying that the warming had abated, but provided no sort of even basic analysis, instead citing a paper from Susan Solomon that came based on HadCRUT temperature data only up to 2009 (which John has discussed at the link below); 3) the surface and atmospheric temperature records cannot be properly evaluated in such short time intervals without accounting for exogenous factors; 4) and not as an afterthought, but as a key point to whether warming has abated, the surface record doesn't tell the full picture. I can see though where the way I phrased the section may have seemed like the point wasn't played up to the role it could have been, and thanks for that feedback. (FWIW, the graph from von Schuckmann is scaled more or less how it appears in the paper. However, thank you for the link to that very useful source at NOAA). http://www.skepticalscience.com/news.php?n=129 -
NewYorkJ at 12:35 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Given the assault on the Amazon page from those who obviously didn't read the book (note all the 1-star ratings occurred on the same day as the Watts post) it seems to confirm much of what Dr. Mann is saying. -
Albatross at 12:22 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Its appears that Anthony Watts and his fellow fake skeptics are taking lessons in "Guerilla Internet Tactics". I recommend watching the video, it is quite an eye opener. Unfortunately, the climate system does not care one iota about fake skeptics trying to fix opinion polls. It will just keep responding to the ever increasing radiative forcing from adding greenhouse gases to the atmosphere as dictated by the physics. -
dana1981 at 12:20 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
apirate - as Rob @7 notes, I did. Unfortunately some people who haven't read the book are posting 1-star reviews just because they have personal issues with Mann. -
Rob Painting at 12:20 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Yes, Bill. The fake-skeptics seem to think they can opinion poll away the physical laws of nature. -
Rob Painting at 12:14 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Pirate - check out the Amazon link, Dana's review is there. -
bill4344 at 12:13 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
NB in saying 'one of our problems' I'm not suggesting we should adopt the same tactics, I'm saying we're at a distinct disadvantage in a truly trashy propaganda war. In the short-term, anyway. Also, Albatross is right: all the stampeding klutzes are virtually assuring best-seller status for the book... -
bill4344 at 12:09 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
I'm reading it in the Kindle version, and thoroughly enjoying it. I also note the complete absence of 'Mann the fanatical Activist' as portrayed by the Denier camp. All the uncertainties of his research are made very plain indeed. One of our problems is, I believe that we're substantially less inclined than folks like the WUWT mob - and I use that term deliberately - to unfairly review material we actually haven't read and devote a lot of time to trashing the reviews of others. It all feels undignified and rather 'dirty' for most of us, I suspect. George Monbiot has had something interesting to say on this phenomenon generally recently. -
Albatross at 12:09 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
What the fake skeptics at WUWT fail to understand (besides the science) is that spamming the Amazon site is going to only generate a controversy and controversy sells :) Additionally, the vitriol, rhetoric and conspiracy theories that they are filling their "reviews" with in their zeal to dismiss this book will set off reasonable peoples' BS filters. It is also going to show that they are frantically swarming and spamming the site without having even reading the book. That is a pretty desperate and disingenuous ploy, but I suppose such desperate antics are all they now have given the vacuity of their scientific arguments. Sadly, it is altogether completely unsurprising that they would stoop this low. Finally, the WUWT followers and fake skeptics swarming the Amazon site only goes to demonstrate one again that this is yet another episode in an ongoing ideological and zealous attack on Dr. Mann by fake skeptics. -
apiratelooksat50 at 12:06 PM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
Dana at 2 How about reading the book itself and then posting reviews? I first learned about this book from a post on WUWT and wouldn't dream of reviewing it without reading it. I won't spend money on it, but I am first in line at my local library. -
dana1981 at 11:16 AM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
It really is a very interesting book. It's a shame the fake skeptics are writing bad reviews without reading it, and rating all positive reviews as unhelpful. I strongly encourage people to follow John's link to Amazon, read the reviews for yourself, and rate them as you feel appropriate to try and counteract the WUWT behavior. -
kaustubh at 11:00 AM on 9 February 2012Book review of Michael Mann's The Hockey Stick and the Climate Wars
As my research deals with the AMO, I was always under the impression that Rich Kerr coined the term [http://www.sciencemag.org/content/288/5473/1984.full] - interesting... -
skywatcher at 10:56 AM on 9 February 2012Global Sea Level Rise: Pothole To Speed Bump?
Though I've not read the paper, I'd suggest it is that it is because, of these two ice sheets, the West Antarctic Ice Sheet (almost a physically separate entity from the East Antarctic Ice sheet because of the Transantarctic Mountains) has a great deal more potential for rapid melt/collapse than the Greenland Ice Sheet. Both contain broadly comparable potential sea level rise components, but Greenland has a lot of mountains round the perimeter to buffer the ice sheet, which the WAIS does not have. The WAIS is also grounded well below sea level, and so warmer sea water can readily melt it from the base (Greenland also, but sea water access is mostly limited to the narrow fjords). If the WAIS begins to go, there's a lot less to stop it, and a consequently rapid sea level rise. Having said that, I think Greenland has more melting on its surface, and an observed flow acceleration already, so is not immune to significant melt! -
Pete Dunkelberg at 10:49 AM on 9 February 2012NASA scientists expect more rapid global warming in the very near future (part 1)
OK, clicking on the image goes to http://www.skepticalscience.com/Description of page you're linking to which is not helpful. But right click / copy image location works: http://64.19.142.13/earthobservatory.nasa.gov/Features/ElNino/Images/sst_depth_1-97.jpg http://64.19.142.12/earthobservatory.nasa.gov/Features/ElNino/Images/sst_depth_4-97tn.jpg http://64.19.142.12/earthobservatory.nasa.gov/Features/ElNino/Images/sst_depth_7-97tn.jpg http://64.19.142.13/earthobservatory.nasa.gov/Features/ElNino/ It looks like an old but good NASA page that IanC found somehow. -
Was Greenland really green in the past?
jatufin - Ah yes, marketing... -
Michaels Misrepresents Nordhaus and Scientific Evidence in General
oamoe - The oceans are an excellent measure of total energy, but unfortunately detailed data only goes back about 50-60 years, with considerable uncertainty early in the record. With atmospheric temperatures, on the other hand, we have >150 years of instrumental data and numerous proxies going back over a thousand years. Personally, I think it best to continue to evaluate all of the data, take full advantage of the uncertainty reduction from redundant measurements, and define the state of the climate from every perspective possible. -
scaddenp at 10:41 AM on 9 February 2012Volcanic Influence on the Little Ice Age
LIA appears to be global but much less pronounced in the Southern hemisphere than in NH (based on comparative glacial geomorphology). MWP varied globally in timing and strength as described in Mann et al, 2009 -
chirhophoros at 10:39 AM on 9 February 2012New research from last week 5/2012
Thanks Ari :-) CC -
jatufin at 10:34 AM on 9 February 2012Was Greenland really green in the past?
And about the naming of the place, why not to look at the original source: Þat sumar fór Eiríkr at byggja land þat, er hann hafði fundit ok hann kallaði Grænland, því at hann kvað menn þat mjök mundu fýsa þangat, ef landit héti vel. 1880 translation: In the summer Eirik went to live in the land which he had discovered, and which he called Greenland, "Because," said he, "men will desire much the more to go there if the land has a good name. -
oamoe at 10:27 AM on 9 February 2012Michaels Misrepresents Nordhaus and Scientific Evidence in General
In you discussion you cite the atmospheric temperature record as adjusted by Foster and Rahmsdorf. You then, almost as an afterthought, note that heat is accumulating elsewhere as well and show a y-axis squashed graph of ocean heat content. Why should ocean heat content be an afterthought? I would suggest we define global warming, first and foremost, as the accumulation of heat in the ocean. Since 90% of the global energy imbalance goes into the oceans, and since its heat capacity makes ENSO based heat exchanges far less important, it seems the ideal metric. Let's just use the NOAA 0-2000 meter global OHC frfom 1955-present as out standard graph, taking data from (http://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/basin_data.html) -
Sascha Tavere at 10:14 AM on 9 February 2012Global Sea Level Rise: Pothole To Speed Bump?
(novice question) "Summer melt on West Antarctica has received less attention than on Greenland, but it is more important" says M. Mann in his reticence paper. Because of ocean temperatures or are the other or more reasons? -
Fred Staples at 10:00 AM on 9 February 2012Skepticism About Lower Atmosphere Temperature Data
I use the data, Tom, not the charts, which stop at 2002. However, the charts are interesting. Consistently significant cooling at all altitudes between 1958 and 1978, before the satellite data. We are discussing the impact on the satellites’ field of vision of the stratospheric temperatures. The weights of the relevant altitudes are shown on Roy Spencer’s chart, at your post no. 20. So, what does the TMT blue line see of the stratosphere? We are looking for the altitude at which the relative area under the blue line ceases to be significant. Would you agree that there is nothing significant above 15 kms, and little above 10kms, the point where the stratosphere might be said to commence? If so, Tom, you can download the HADAT data and repeat my calculations with EXCEL. My results have surprised you, so you suggest that they are in error. You will find that you are wrong. There has been no significant cooling for more than 50 years at 11.74 kms, which is the most influential altitude. At 15.75 kms the cooling has been more pronounced, but you still have to go back 22 years to achieve significance. What can we conclude from these facts. At the higher level the effect on the TMT line is marginal, both as to the trend itself and its possible impact. At the higher impact level, 10kms, there is almost no cooling trend. In between, a cooling trend of 1.0 degrees per century, but nothing significant for 50 years. So Tom, if your second and third points (29) are wrong, why (on what grounds) do we reject the mid-troposphere satellite data?. -
MattJ at 09:47 AM on 9 February 2012Volcanic Influence on the Little Ice Age
Typo: "ice caps exhibit little or now flow, " should read, "ice caps exhibit little or no flow, "Moderator Response: [DB] Fixed; thanks! -
skywatcher at 09:42 AM on 9 February 2012Antarctica is gaining ice
#120 muttkat: There's no evidence for vineyards in Greenland in the MWP, temperatures were nowhere near warm enough for that! The only evidence for crops are a few grains of barley found in a Viking-age midden, but that does not confirm whether they were locally-grown or imported. Local growing of barley is maybe possible in the warmest years of the Greenland MWP, but the most sensible explanation is that the Norse Greenlanders imported it, due to a combination of low temperatures and poor soils. It would be a commodity worth trading for, as the Norse were partial to beer! There are a few active volcanoes in Antarctica, but not enough volcanism to do much damage to a whole ice sheet (ice sheet big, volcanoes small). Iceland is a good example, where Vatnajokull survives happily despite having several active volcanoes under it, notably Grimsvotn and Bardarbunga. -
JMurphy at 09:34 AM on 9 February 2012Antarctica is gaining ice
muttkat, have a look at the Greenland used to be green myth. I doubt there would have been any vineyards there, though. As for underwater volcanoes, presumably they would be very noticeable, being as how the water temperature would get warmer the deeper you go towards those volcanoes ?Response:[DB] NSIDC has a FAQ on undersea volcanoes here:
http://nsidc.org/asina/faq.html#volcanoes
"The heat from the volcanoes would have dispersed over an enormous volume and had little effect on ocean temperature, much as a bucket of boiling water emptied into a lake would have little effect on the lake's temperature."
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muoncounter at 08:48 AM on 9 February 2012Volcanic Influence on the Little Ice Age
Neukom 2009 reports on southern South America: The reconstructed SSA mean summer temperatures between 900 and 1350 are mostly above the 1901–1995 climatology. After 1350, we reconstruct a sharp transition to colder conditions, which last until approximately 1700. MWP appears much more variable; hence the controversy over whether it really was a 'warm period' or just a 'climate anomaly.' -
EliRabett at 08:25 AM on 9 February 2012Still Going Down the Up Escalator
Eli, takes no position on whether the temperature is rising in jerks or ramps, but even if you hold for jerks, why are all of the jerks are positive? and jerks are bigger trouble because the damage comes all at once. -
Composer99 at 08:22 AM on 9 February 2012Medieval Warm Period was warmer
jzk: The purpose of this post is to refute the contrarian claim that the Medieval Climate Anomaly was globally warmer than the present day, where 'the present day' is, effectively, any given year in which someone asserts this claim. The SkS-created graphic to which you object (thank you for the correction, by the way) does exactly this by showing both the MCA global temperature reconstruction (to the extent that such a thing is possible given the proxy data used) and a (not quite) present day global temperature anomaly, both calibrated to the same climatological baseline. Indeed, the present day data is already a few years out of date. Since the contrarian claim is about the present day, it is IMO sufficient to show that the present day is much warmer than the MWP/MCA. If you want a more complete picture, there are always the Moberg et al 2005 reconstruction with instrumental data in the 'Basic' version of this article and the various other graphs provided by Daniel Bailey upthread (comment #20). Given the inclusion of these graphs in this post (to say nothing of other posts with additional information) I think SkS has satisfactorily minded the ps and qs.Response:[DB] The Basic tab article in the OP above shows the SkS version of the graphic from Moberg et al 2005. The original is here:
With a zoomed-in version of the pertinent section here:
It is left for the viewer to demonstrate a substantive, non-pedantic difference between the SkS version and the original graphic from Moberg.
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Klaus Flemløse at 08:16 AM on 9 February 2012Volcanic Influence on the Little Ice Age
Until now I have understood that LIA and MWP are not global. Is this still correct ? -
Paul D at 08:11 AM on 9 February 2012Michaels Misrepresents Nordhaus and Scientific Evidence in General
"Wall Street Journal rapped over climate change stance": http://environmentalresearchweb.org/cws/article/opinion/48528 -
Don9000 at 08:08 AM on 9 February 2012NASA scientists expect more rapid global warming in the very near future (part 2)
Tom@42 Tom, I never meant to criticize the use of "implies" in Dr Hansen's paper. I have looked through my post and don't see such a criticism, but perhaps it appears to be implied. Again, it was not intended to be. On your second point, I readily concede that many people use the English language far too loosely. I try to buck that trend to the best of my ability, but I also concede I am far from perfect. To be fair to native English speakers, the language's marvelous flexibility does render it at times rather illogical or inconsistent or prone to errant constructions. That said, I suspect Latin as actually written and spoken by plebeians and senators alike back in the day had its own issues.--Don -
EliRabett at 08:02 AM on 9 February 2012Still Going Down the Up Escalator
If Briggs is arguing that (as Robert S said)Briggs argues that most people aren't actually interested in the uncertainty in unobservable model parameters, but the uncertainty in the unobserved observables - the temperature at places where averaging techniques (statistical models) attempt to predict, and where we don't have measurements (though theoretically we could).
Then he simply is ignorant (and Eli uses that word advisedly) of the research underpinning all global climate records. Remember that the prequel to GISSTemp was a study by Hansen and Lebedeff showing that there was significant correlation in temperature trends out to 1000 km. That conclusion has been confirmed by a large number of more recent publications and never falsified. So indeed, the global surface temperature anomaly records DO provide significant, statistically useful information about the anomalies at places where there are no thermometers and about the variability in those records. (you can, of course, verify this further by holding out stations from the calculation and then comparing, in essence BEST does this as a lumped study with the 36K stations) -
muttkat at 07:55 AM on 9 February 2012Antarctica is gaining ice
On the Antarctica ice melting issue aren't there some underwater active volcanos that would melt ice? Being there were crops and vineyards grown in Greenland between the 9th & 12th more or less how warm would temperatures have to get for that to happen again? What caused the temperatures to rise to that point before? -
Rob Painting at 07:52 AM on 9 February 2012NASA scientists expect more rapid global warming in the very near future (part 2)
Don 9000 - I'm sure a once-in-a millenium event is aptly described as 'monster.' See Barriopedro (2011). -
Rob Painting at 07:46 AM on 9 February 2012Medieval Warm Period was warmer
"How can you compare centuries of data that include both a warm and cool period to a decade of warm data? By using 1711, I would be unfairly averaging in cooler years to the recent warmer ones to bring down the significance of the recent warming" No by including 1711 you would be including a period where global warming had not even begun. The question is: how does present warming relate to the MWP? Present warming is the period affected by human-added greenhouse gases. So how does that compare to a period without large human perturbation? You know, the natural background state. If, as is claimed, the MWP was warmer why does a compilation of the ENSO data indicate that the tropical Pacific was much cooler than present? As I'm sure you are aware ,the tropical Pacific has a huge effect on the global climate through the sea surface-atmosphere heat exchange. And once again, why is the ITCZ anchored further south during the MWP? That indicates an Earth cooler than present too. Maybe it was globally warmer during the MWP, but the evidence thus far indicates otherwise. "That is my exact point for not doing it in the MWP either. Otherwise the comparison has no meaning." And for consistency you'll be telling the fake-skeptic blogs that a comparison is utterly meaningless too. Right? -
Don9000 at 07:42 AM on 9 February 2012NASA scientists expect more rapid global warming in the very near future (part 2)
Rob, Your clarification and the news from Dr Hansen works for me regarding the missing word "implies." In fact, I have no problem with that word as Dr Hansen used it. My only small objection was that you used the word "state" and then inserted the word "monster" into your paraphrase. Rather small beer.--Don -
william5331 at 07:23 AM on 9 February 2012Volcanic Influence on the Little Ice Age
If the freshening of the North Atlantic due to the export of ice from the Arctic ocean leads to the shutdown of the Gulf stream and therefore the extension of cold conditions in the North, the same effect could occur if the Arctic ocean becomes ice free. In this case, an accelerated melting of the Greenland ice sheet could occur as the now warm air from the ocean is sucked down katabatically over Greenland, melting the ice. We would possibly have a flickering back and forth between cold and warm periods, followed, when much of the ice is gone, to a very much warmer climate. This very cold winter in Europe may be a harbinger of things to come. How long does it take for the Gulf Stream to respond to a change in its driving force. -
jzk at 07:06 AM on 9 February 2012Medieval Warm Period was warmer
"Of course, but then the Industrial Revolution had not even begun in 1711." Yes, of course that is the point. How can you compare centuries of data that include both a warm and cool period to a decade of warm data? By using 1711, I would be unfairly averaging in cooler years to the recent warmer ones to bring down the significance of the recent warming. That is my exact point for not doing it in the MWP either. Otherwise the comparison has no meaning. -
Alex C at 06:38 AM on 9 February 2012Michaels Misrepresents Nordhaus and Scientific Evidence in General
John: Thanks for the notice, will remember down the road.Response:[dana1981] It's probably an issue of copying from a Word document or something. If you just type the post straight into the SkS blog post box, the default font size is what we normally use.
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Tristan at 06:31 AM on 9 February 2012Medieval Warm Period was warmer
I think I understand what jzk is trying to say. If you took the temperature reconstruction and randomly generated noise for it (in line with the expected distribution) to show examples of what the year to year temp might have looked like, some examples would have years (possibly multiple consecutives) as high as the decade just passed. -
Rob Painting at 06:26 AM on 9 February 2012Medieval Warm Period was warmer
jzk -"How about this. Take Mann's chart and compare it to one of the last 300 years (1711-2011). Would the chart be different than the decade one? You bet it would" Of course, but then the Industrial Revolution had not even begun in 1711. Fake-skeptics make the false claim that the MWP was warmer than today, not 1711. So some comparison is necessary in order to demonstrate that that is wrong. It would be nice if an apples-to-apples comparison could be made, but that isn't possible. -
jzk at 06:17 AM on 9 February 2012Medieval Warm Period was warmer
Yes I understand the proxy data, and I am not expecting to plot temperatures from May, 975. But certainly a more narrowed view can be taken. If not a decade, how about half a century? One can see from Mann's data that half of that period was warmer and the second half cooler. And besides, it is not Mann that is comparing a decade of our warmest weather so far to any of his data. It is this site. How about this. Take Mann's chart and compare it to one of the last 300 years (1711-2011). Would the chart be different than the decade one? You bet it would. -
muoncounter at 06:09 AM on 9 February 2012Volcanic Influence on the Little Ice Age
Oppenheimer 2003 on the 1258ish volcano. Palaeoclimate reconstructions indicate very cold austral and boreal summers in AD 1257–59, consistent with known patterns of continental summer cooling following tropical, sulphur-rich explosive eruptions. This suggests an eruption in AD 1257, producing a stronger climate forcing than hitherto recognized. A figure from a summary of Crowley 2000:
Clearly these volcanic events were known; I'm still not seeing convincing evidence that they initiate cooling lasting hundreds of years.
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