Of buckets and blogs
This last week has been an interesting one for observers of how climate change is covered in the media and online. On Wednesday an interesting paper (Thompson et al) was published in Nature, pointing to a clear artifact in the sea surface temperatures in 1945 and associating it with the changing mix of fleets and measurement techniques at the end of World War II. The mainstream media by and large got the story right - puzzling anomaly tracked down, corrections in progress after a little scientific detective work, consequences minor - even though a few headline writers got a little carried away in equating a specific dip in 1945 ocean temperatures with the more gentle 1940s-1970s cooling that is seen in the land measurements. However, some blog commentaries have gone completely overboard on the implications of this study in ways that are very revealing of their underlying biases.
The best commentary came from John Nielsen-Gammon's new blog where he described very clearly how the uncertainties in data - both the known unknowns and unknown unknowns - get handled in practice (read that and then come back). Stoat, quite sensibly, suggested that it's a bit early to be expressing an opinion on what it all means. But patience is not one of the blogosphere's virtues and so there was no shortage of people extrapolating wildly to support their pet hobbyhorses. This in itself is not so unusual; despite much advice to the contrary, people (the media and bloggers) tend to weight new individual papers that make the news far more highly than the balance of evidence that really underlies assessments like the IPCC. But in this case, the addition of a little knowledge made the usual extravagances a little more scientific-looking and has given it some extra steam.
Like almost all historical climate data, ship-board sea surface temperatures (SST) were not collected with long term climate trends in mind. Thus practices varied enormously among ships and fleets and over time. In the 19th Century, simple wooden buckets would be thrown over the side to collect the water (a non-trivial exercise when a ship is moving, as many novice ocean-going researchers will painfully recall). Later on, special canvas buckets were used, and after WWII, insulated 'buckets' became more standard - though these aren't really buckets in the colloquial sense of the word as the photo shows (pay attention to this because it comes up later).
The thermodynamic properties of each of these buckets are different and so when blending data sources together to get an estimate of the true anomaly, corrections for these biases are needed. For instance, the canvas buckets give a temperature up to 1ºC cooler in some circumstances (that depend on season and location - the biggest differences come over warm water in winter, global average is about 0.4ºC cooler) than the modern insulated buckets. Insulated buckets have a slight cool bias compared to temperature measurements that are taken at the inlet for water in the engine room which is the most used method at present. Automated buoys and drifters, which became more common in recent decades, tend to be cooler than the engine intake measures as well. The recent IPCC report had a thorough description of these issues (section 3.B.3) fully acknowledging that these corrections are a work in progress.
And that is indeed the case. The collection and digitisation of the ship logbooks is a huge undertaking and continues to add significant amounts of 20th Century and earlier data to the records. This dataset (ICOADS) is continually growing, and the impacts of the bias adjustments are continually being assessed. The biggest transitions in measurements occurred at the beginning of WWII between 1939 and 1941 when the sources of data switched from European fleets to almost exclusively US fleets (and who tended to use engine inlet temperatures rather than canvas buckets). This offset was large and dramatic and was identified more than ten years ago from comparisons of simultaneous measurements of night-time marine air temperatures (NMAT) which did not show such a shift. The experimentally-based adjustment to account for the canvas bucket cooling brought the sea surface temperatures much more into line with the NMAT series (Folland and Parker, 1995). (Note that this reduced the 20th Century trends in SST).
More recent work (for instance, at this workshop in 2005), has focussed on refining the estimates and incorporating new sources of data. For instance, the 1941 shift in the original corrections, was reduced and pushed back to 1939 with the addition of substantial and dominant amounts of US Merchant Marine data (which mostly used engine inlets temperatures).
The version of the data that is currently used in most temperature reconstructions is based on the work of Rayner and colleagues (reported in 2006). In their discussion of remaining issues they state:
Using metadata in the ICOADS it is possible to compare the contributions made by different countries to the marine component of the global temperature curve. Different countries give different advice to their observing fleets concerning how best to measure SST. Breaking the data up into separate countries' contributions shows that the assumption made in deriving the original bucket corrections—that is, that the use of uninsulated buckets ended in January 1942—is incorrect. In particular, data gathered by ships recruited by Japan and the Netherlands (not shown) are biased in a way that suggests that these nations were still using uninsulated buckets to obtain SST measurements as late as the 1960s. By contrast, it appears that the United States started the switch to using engine room intake measurements as early as 1920.
They go on to mention the modern buoy problems and the continued need to work out bias corrections for changing engine inlet data as well as minor issues related to the modern insulated buckets. For example, the differences in co-located modern bucket and inlet temperatures are around 0.1 deg C:
(from John Kennedy, see also Kent and Kaplan, 2006).
However it is one thing to suspect that biases might remain in a dataset (a sentiment shared by everyone), it is quite another to show that they are really have an impact. The Thompson et al paper does the latter quite effectively by removing variability associated with some known climate modes (including ENSO) and seeing the 1945 anomaly pop out clearly. In doing this in fact, they show that the previous adjustments in the pre-war period were probably ok (though there is substantial additional evidence of that in any case - see the references in Rayner et al, 2006). The Thompson anomaly seems to coincide strongly with the post-war shift back to a mix of US and UK ships, implying that post-war bias corrections are indeed required and significant. This conclusion is not much of a surprise to any of the people working on this since they have been saying it in publications and meetings for years. The issue is of course quantifying and validating the corrections, for which the Thompson analysis might prove useful. The use of canvas buckets by the Dutch, Japanese and some UK ships is most likely to blame, and given the mix of national fleets shown above, this will make a noticeable difference in 1945 up to the early 1960s maybe - the details will depend on the seasonal and areal coverage of those sources compared to the dominant US information. The schematic in the Independent is probably a good first guess at what the change will look like (remember that the ocean changes are constrained by the NMAT record shown above):
Note that there was a big El Niño event in 1941 (independently documented in coral and other records).
So far, so good. The fun for the blog-watchers is what happened next. What could one do to get the story all wrong? First, you could incorrectly assume that scientists working on this must somehow be unaware of the problems (that is belied by the frequent mention of post WWII issues in workshops and papers since at least 2005, but never mind). Next, you could conflate the 'buckets' used in recent decades (as seen in the graphs in Kent et al 2007's discussion of the ICOADS meta-data) with the buckets in the pre-war period (see photo above) and exaggerate how prevalent they were. If you do make those mistakes however, you can extrapolate to get some rather dramatic (and erroneous) conclusions. For instance, that the effect of the 'corrections' would be to halve the SST trend from the 1970s. Gosh! (You should be careful not to mention the mismatch this would create with the independent NMAT data series). But there is more! You could take the (incorrect) prescription based on the bucket confusion, apply it to the full global temperatures (land included, hmm…) and think that this merits a discussion on whether the whole IPCC edifice had been completely undermined (Answer: no). And it goes on - once the bucket confusion was pointed out, the complaint switched to the scandal that it wasn't properly explained and well, there must be something else…
All this shows wishful thinking overcoming logic. Every time there is a similar rush to judgment that is subsequently shown to be based on nothing, it still adds to the vast array of similar 'evidence' that keeps getting trotted out by the ill-informed. The excuse that these are just exploratory exercises in what-if thinking wears a little thin when the 'what if' always leads to the same (desired) conclusion. This week's play-by-play was quite revealing on that score.
1 juin 2008 at 11:27 AM
good job
Thank you
1 juin 2008 at 12:22 PM
Nice!
1 juin 2008 at 12:45 PM
I would count Roger Pielke Jr. out. Take a look at his latest post.
As you can see, Pielke Jr. is not afraid to bring in the heavy thinkers when it’s required.
1 juin 2008 at 2:33 PM
Gavin,
I would be careful if I was you. Citing Roger Pielke Jr. only gives him respectability, creates doubt, and results in complacency.
The Arctic sea ice is rapidly disappearing with a time scale of years rather than decades, and it is becoming increasingly likely that the with the Greenland ice sheet will also collapse rapidly. Droughts are contributing to food shortages, and destructive cyclones and hurricanes seem to be increasing. Wild fires, a symptom of desertification are being reported from Alaska to California, and from the north Mediterranean coast of Europe to the main populated regions of Australia. We should be concentrating on the dangers happening now and in the future, not allowing ourselves to be distracted by minor inconsistencies in the past with no relevance to the future.
Arguing about a 0.1C difference in SSTs during 1945 is totally irrelevant and only leads to a false optimism that the main problem of cutting fossil fuel use by 90% can be left for the next generation. The Arctic sea ice will have vanished long before then
Cheers, Alastair.
1 juin 2008 at 3:45 PM
Re #4. although you are right Alastair you cannot keep optimists down and the world abounds with peope in positions of influence who are optimistic about everything. Realism aint their thing but optimism is, if the world aint as they want it to be then change it and make it that way.
1 juin 2008 at 4:06 PM
Sorry for being off-topic. I read a number of alternative financial sites. Along with being contrarian about economic issues, most posters reject AGW. One in particular is TickerForum. The site is owned by Karl Denninger, who posts as Genesis. In a thread from a couple weeks ago, he has posted what seem like softball questions. If my math were better I would debate him myself. If anyone has the energy to get into it with another denier I think it would be beneficial if you could change his mind as he is fairly influential with the people who read his site.
A link to the thread below and his questions.
You will need to register with the site to post.
http://www.tickerforum.org/cgi-ticker/akcs-www?post=44720&page=3
—————————————–
1. The percentage of contribution for each greenhouse gas out of the whole.
2.The measurement for man’s contribution to CO2, expressed as a scientific measurement (pick your units but they must match the first answer), and that measurement must include an uncertainty.
We’ll ask some tougher questions (which I suspect you won’t like) once you produce the first two answers.
——————————————
Again - how much of the CO2 generated in a given year is man-made?
In scientific form please.
Same for methane.
—————————————–
[Response: It’s a set up since the questions are ill posed, but he thinks he’s knows the answer (but he will be wrong). For the current situation CO2 provides about 20% of the greenhouse effect (water vapour is about 50% and clouds about 25%, ozone and other minor gases make up the rest) (defined as the net reduction in the difference between longwave emitted from the surface and the longwave emitted to space, uncertainties are a few percent maybe). For CO2, the anthropogenic component is about 27%, methane it’s 60%, N2O it’s about 13%, CFCs it’s 100% (uncertainties of a couple of percent). His second set of questions are either irrelevant or make no sense. Last year, we emitted about 9 GtC, and increased concentrations by ~2ppm CO2. Your chap will most likely respond with a reference to a website run by mhieb (see here for more debunking). - gavin]
1 juin 2008 at 7:04 PM
I respond to this post here:
http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001446real_climate_on_mean.html
[Response: Roger, when you’ve calmed down please do let us know when you: a) work out the difference between the ocean and the global temperature, and b) realise that there is difference between getting criticised for asking questions, and for getting the answer wrong (the latter being the central point here). Thanks! - gavin]
1 juin 2008 at 7:06 PM
Re #5 Hi Pete,
I felt I was being rebuked when you wrote:
I am trying to change it, but no one listens. Besides it was Professor Martin Parry who wrote “A curious optimism …” not me.
But I am no longer optimistic about the future. Only tonight I heard a Russian scientist say about global warming: “People claim that there is not enough evidence to act. I say there is not enough time.”
Optimism is fine when things are going well. Now is the time for realism
Cheers, Alastair.
1 juin 2008 at 7:29 PM
Why is it when I read this posting I think of an episode of “Yes Minister”. The minister asks Sir. Humphrey what to since the figures used by the ministry have been shown to be clumsily and obviously incorrect. Sir Humphrey responds by noting that while the figures could be considered incorrect that they are incorrect in a very complicated and learned way. That while strictly speaking they are wrong’ tey are wrong in a very educated way
1 juin 2008 at 7:29 PM
Re #7
Just as I predicted. Roger Pielke is luring you into a slanging match with inviting remarks like “There is a lot of science and civil discussion there, with a healthy mix of assorted experts and a range of ordinary folks” but absolutely no science at all in his post at: http://sciencepolicy.colorado.edu/prometheus/archives/climate_change/001446real_climate_on_mean.html
HTH,
Cheers, Alastair.
1 juin 2008 at 7:57 PM
>luring
That’s like trolling, but with simulated rather than edible bait.
1 juin 2008 at 8:24 PM
Hi Gavin-
I’d be happy to work from a proposed adjustment directly from you, rather than rely on the one proposed by Steve McIntyre or the one you point to from The Independent.
Thompson et al. write: “The new adjustments are likely to have a substantial impact on the historical record of global-mean surface temperatures through the middle part of the twentieth century.”
It is hard to see how temperatures around 1950 can change “substantially” with no effect on trends since 1950, but maybe you have a different view. Lets hear it. Give me some better numbers and I’ll use them.
[Response: Nick Rayner, Liz Kent, Phil Jones etc. are perfectly capable of working it out and I’d suggest deferring to their experience in these matters. Whatever they come up with will be a considered and reasonable approach that will include the buoy and drifter issues as well as the post WW-II canvas bucket transition. Second guessing how that will work out in the absence of any actual knowledge would be foolish. - gavin]
1 juin 2008 at 8:57 PM
One of the things I like about RealClimate is how easy the articles are to read and understand, compared to the slanted ramblings on the denialist-delayer blogs. I went and looked at that post of Roger’s - what a missmash! And of course he reaches into his bag of tricks and …
A. Starts his plot halfway through the data record so that he can argue that there has been a reduction of 20th century warming by 30% - when if he had started the plot before the period in question he would not be able to make that assertion.
B. Takes an adjustment to sea temperatures in a defined period and implies that it impacts the global mean temperatures trend estimates over the entire twentieth century.
C. He attributes the plot to RealClimate!!!
I’m fascinated that he is now accusing RealClimate authors of writing in a ‘passive’ manner, like it is some kind of devious technique.
I suspect that people relying on such sources must think the science is not reliable because it appears to be confused. But it’s the denialist-delayers who are working hard to make it seem so.
—–
It would actually be really interesting to see a series of plots that show how the datasets of measured sea and land temperatures have evolved over time as they have been improved with adjustments such as this.
1 juin 2008 at 9:22 PM
Question as to how this might relate to GISTEMP.
GISTEMP uses Smith et al (1996) and Reynolds & Smith (1994) for SST, but those papers document SST interpolation methods. Who performs the underlying corrections used for the in situ (pre 1982) data in the current GISTEMP analysis? The satellite sst measurements (1982+) are said to be calibrated using “quality controlled” buoy data, so I presume corrections are rarely necessary with them.
Thanks!
[Response: GISTEMP uses HadISST up to 1982 and Reynolds thereafter - there may still be issues in melding the two approaches because small potential offsets between the buoys and other methods of determining SST. - gavin]
2 juin 2008 at 2:08 AM
Cautionary as Nature’s account of this tale of a tub may be,it is hopelessly outclassed by this week’s Culture Of Modeling news-
La Scala has commissioned a full length opera based on
An Inconvenient Truth.
Stay tuned for the encore :
http://adamant.typepad.com/seitz/2008/05/hot-ticket.html
2 juin 2008 at 5:34 AM
re Response to #6
“For CO2, the anthropogenic component is about 27%”
Pre-industrial CO2 c.280ppmv
Present CO2 c.385ppmv
Shouldn’t your 2 be a 3 Gavin? ie
“For CO2, the anthropogenic component is about 37%”
Otherwise, great. Thanks.
[Response: No. 105/385 = 27% of the current concentration is anthropogenic. 37% is the rise over pre-industrial levels, but that wasn’t what was asked for. - gavin]
2 juin 2008 at 5:46 AM
Modifying the adjustments will not change the overall 20 century trend. Modifying the adjustments will, however, change the perception of how much we warmed in the first half of the century, and how much in the second half, possibly invalidating claims that we are warming faster now. And of course any sea-surface temperatures history change will affect global temperature history change to a great extent. Most of the Earth’s surface is ocean.
[edit]
2 juin 2008 at 8:03 AM
You know I was just looking through some old papers and came across a few records… worth reviewing now, I think:
“In 1989, not long after James Hansen’s highly publicized testimony before Congress and shortly after the first meeting of the UN’s Intergovernmental Panel on Climate Change, the Burson Marsteller PR firm created the Global Climate Coalition (GCC). Chaired by William O’Keefe, an executive for the American Petroleum Institute, the GCC operated until 1997 out of the offices of the National Association of Manufacturers. . .
“The GCC has also used “Junkman” Steven Milloy’s former employer, the EOP Group, as well as the E. Bruce Harrison company, a subsidiary of the giant Ruder Finn PR firm. Within the public relations industry, Harrison is an almost legendary figure who is ironically considered “the founder of green PR” because of his work for the pesticide industry in the 1960s, when he helped lead the attack on author Rachel Carlson and her environmental classic Silent Spring…”
“Industry’s PR strategy with regard to global warming issue is also eminently practical, with limited, realistic goals. Opinion polls for the past decade have consistently shown that the public would like to see something done about the global warming problem, along with many other environmental issues. Industry’s PR strategy is not aimed at reversing the tide of public opinion, which may not in any case be impossible. Its goal is simply to stop people from mobilizing to do anything about the problem, to create sufficient doubt in their minds about the seriousness of global warming that they will remain locked in doubt and indecision…”
“In 1991, a corporate coalition composed of the National Coal Association, the Western Fuels Association, and Edison Electrical Institute created a PR front group called the “Information Council for the Environment” (ICE) and launched a $500,000 advertising and public relations campaign to, in ICE’s own words, “reposition global warming as theory, (not fact)…”
“To boost its credibility, ICE created a Scientific Advisory Panel that featured Patrick Michaels from the Dept of Environmental Services at the University of Virgina; Robert Balling of Arizona State University, and Sherwood Idso of the U.S. Water Conservation Laboratory. ICE’s plan called for placing these three scientists, along with fellow greenhouse skeptic S. Fred Singer, professor emeritus of environmental sciences at the University of Virgina, in broadcast appearances, op-ed pages, and newspaper interviews. Bracy Williams & Co., a Washington-based PR firm, did the advance publicity work for the interviews…”
“…According to Peter Montague of the Environmental Research Foundation, “S. Fred Singer is now an ‘independent consultant’ for companies including ARCO, Exxon Corporation, Sheel Oil Company, Sun Oil Company, and Unocal Corporation. Rather than conducting research, Singer “spends his time writing letters to the editor and testifying before Congress….”
“In April 1998…the New York Times reported on yet another propaganda scheme developed by the American Petroleum Institute. Joe Walker, a public relations representative of the API, had written an eight-page internal memorandum outlining the plan, which unfortunately for the plotters was leaked by a whistle-blower. Walker’s memorandum called for recruiting scientists “who do not have a long history of visibility and/or participation in the climate change debate.” Apparently, new faces were needed because the industry’s long-standing scientific front men - Balling, Michaels, Idso, and Singer - had used up their credibility with journalists.”
-”Global Warming is Good For You”, Ch. 10, in “Trust Us, We’re Experts” by Rampton & Stauber (2001)
Well- that’s interesting. I wonder who they decided to go with? I imagine it’s not too hard to find out - just look at the most widely promoted and quoted “climate science skeptics” in the leading press outlets over the past 8 years or so.
2 juin 2008 at 8:55 AM
RE_ #The Article says: The biggest transitions in measurements occurred at the beginning of WWII between 1939 and 1941 when the sources of data switched from European fleets to almost exclusively US fleets (and who tended to use engine inlet temperatures rather than canvas buckets).#
In the Pacific the US shipping dominated since the ambush on Pearl Harbor, but in the North Atlantic most tonnage was under British, Norwegian and Neutral Flag. The specific war situation concerning SST is explained in paper from 1997 and 1998, http://www.oceanclimate.de/English/Pacific_SST_1997.pdf , http://www.oceanclimate.de/English/Atlantic_SST_1998.pdf
2 juin 2008 at 8:59 AM
There is no hint in Rayner06 of a reversion to canvas buckets after WWII. There is a quantitative effect of this error, both on global average calculations up to the 1970’s and on the uncertainty of that number. Your post does not calculate that effect. It would appear that aerosols explaining cooling into the 1970’s has to be revisited, is there a quantative analysis of that (i.e. including actual aerosol measurements)? Another correlation to be investigated is solar since (nonquantitatively speaking) warming started more in the 40’s than in the 70’s as previously thought which is more in line with solar trends (modern maximum).
[Response: Not so - the quoted section clearly refers to that. As for the 40s-70s cooling, this is still seen in the land data and is not tied to SST changes in 1945. The first cut at the revisions linked above has effectively the same match to the model trends as before (maybe a little better) and so no revisions to the models nor to attribution studies are likely. - gavin]
2 juin 2008 at 9:04 AM
In June 2008, Miami artist Xavier Cortada will travel to the North Pole, ninety degrees North (90N), to create site-specific installations exploring our connection to the natural world.
The work addresses global climate change and will include the reinstallation of the “Longitudinal Installation” and “Endangered World” (originally created in the South Pole, 90S, during January 2007 as part of a National Science Foundation Antarctic Artist and Writers residency).
The artist will also plant a green flag at at the Earth’s northernmost point to encourage the reforestation of native trees in the world below.
At a time when melting polar sea ice is causing so many to focus on which political power will place its flag over the Arctic, controlling the Northwest Passage shipping lanes and the petroleum resources beneath the sea ice, Miami artist Xavier Cortada has developed a project that engages people across the world below to plant a green flag and native tree to help address global climate change. Reforestation helps prevent the polar regions from melting.
Cortada will plant a green flag the North Pole when he arrives there on June 30, 2008. On that same day folks from around the world will be asked to also plant a green flag and native tree in their community.
Miami artist Xavier Cortada created Native Flags as an urban reforestation project to help restore native habitats for plants and animals across South Florida. Launched last year at the Miami Science Museum, Native Flags now calls on individuals globally to join the effort.The conspicuous green flag serves as a catalyst for conversations with neighbors and a call to action to help rebuild our native tree canopy. Community leaders can model the behavior by planting a native tree and green flag at their science centers and city halls.
To learn about this please visit the artist’s website at http://www.xaviercortada.com.
2 juin 2008 at 9:20 AM
Gavin, wouldn’t the difference between northern and southern hemisphere trends (e.g. http://cdiac.ornl.gov/trends/temp/jonescru/graphics/nhshgl.jpg) indicate an potential SST sampling error, especially right after WWII?
[Response: Why? Hemispheric trends can differ due to different forcings, different thermal inertia, different impacts of ocean circulation change etc. The sampling issue is much worse in the SH and so the uncertainty there is greater, but you can’t automatically associate a hemispheric difference with an artifact. - gavin]
2 juin 2008 at 11:19 AM
OK, this is a question only about the “blog” part of this topic.
We need help over at Dot Earth, again.
Please see this comment:
#60. June 2nd, 2008, 7:28 am
Tenney,
The graphs are of actual measurements, so it doesn’t matter what our opinions are of Dr. Spencer.
Just exactly how has Dr. Spencer been discredited?
The most important greenhouse gas, water vapor, overwhelms all the others combined, including methane. Apparently, the water vapor is self regulating, more than offsetting all the other greenhouse gases combined. Simple precipitation counterbalances the thermal forcing of much of the growth of CO2 and others.
Why did the globe gradually warm then in the latter part of the 20th century? Increased solar activity.
Why is the globe cooling now? Decreased solar activity, with the current 23rd solar cycle yet to end.
It is only a matter of time before the thermal momentum of the latter part of the 20th century is reversed, and the northern polar cap begins to cool back down, reforming the ice. The southern polar region has already been cooling for several years, with an increasing ice cover.
By the way, did you catch this story?
http://www.theglobeandmail.com/servlet/story/LAC.200805 24.TRIPPING24/TPStory/
The Northwest Passage is not quite as easy to navigate as we have been led to believe.
Eppure, si rinfresca
— Posted by Jack Simmons
That comment was in response to my comment #56, a response to his comment #54.
The link to the blog thread is this one:
http://dotearth.blogs.nytimes.com/2008/05/29/white-house-poor-face-health-risks-from-warming/
I would appreciate your help because you guys are so much better at this than I could ever think about being.
Thank you.
[Response: Your correspondent can’t possibly believe that climate sensitivity is zero (due to some magical stabilisation mechanism) and also claim that the sensitivity to solar is enough to explain the 20th C trend. Either water vapour is stabilising or it isn’t (and it isn’t by the way - as shown by the water vapor changes during ENSO, after Pinatubo, the long term trends etc. - see Soden et al, 2001;2003;2004). And why would anyone think that the NWP is navigable easily in May? Even in 2007, the opening was in the second half of August… more FUD. - gavin]
2 juin 2008 at 11:51 AM
The most revealing item is Gavin’s “Colocated Anomalies” graph showing the relationship between corrected SST (HadSST2 in red) and marine air temperatures (NMAT in green). The air temperatures were not susceptible to bucket or engine inlet artefacts. The first thing that stands out is that the mid-century aberrations are not merely a “dip” after 1945, but also a peak that preceded it. Here, both curves coincide during the ascending and part of the descending limbs of the peak, and the upward and descending limbs may be attributable, at least in part, to El Nino years between 1939 and 1942, a transient downturn in the AMO (Atlantic Multidecadal Oscillation) warm phase and a more persistent shift from warm to cool in the Pacific Decadal Oscillation) in the mid-1940s, among other natural events.
Strikingly, both curves show the post-1945 “dip”, with the main difference residing in the deeper decline of the SST curve, and its more sudden drop. (The differences are even better seen in IPCC AR4, WGI, Chapter 3, p.246, Fig. 3.4a).
It seems plausible, therefore, to conclude that most of the peak and dip were not caused by SST measurement artefacts, and presumably reflected natural events, with the artefactual component mainly limited to the modest excess in depth of the SST curve between 1945 and about 1956, rather than the entire dip.
If this interval is corrected, it appears that the 1945-1975 interval of the SST curve may become slighly flatter, consistent perhaps with a slightly greater aerosol masking of greenhouse gas forcing than previously estimated. Probably more important, most sections of the twentieth century warming curve will not be substantially affected, and should not require significant reinterpretation.
2 juin 2008 at 12:06 PM
Re: comment #23
Dear Gavin,
Thanks for your response. Of course he does not believe what he is writing — he is one of those industry-paid denialists that show up on Dot Earth to confuse the uninitiate. I have to use layman’s language to explain to other readers where he is fantastically incorrect, but as I am not a scientist, it is not so easy for me to do that.
2 juin 2008 at 12:29 PM
Tenney, Your correspondent not only does not believe what he is writing, he doesn’t understand it. It is pure gobbldygook. Water vapor as a stabilizing (negative) feedback–what happens to water content as temperature goes up? Moreover water vapor peters out at cloudtop level, while CO2 stays well mixed into the stratosphere. Then there is the relative lifetime of H2O and CO2–days to hundreds of years.
This guy is just parroting back what he’s heard/read somewhere else, and he’s not even doing a particularly good job of parroting. Go back and read “A saturated Gassy Argument” and Gavin’s posting about greenhouse forcing in 6 easy steps. Understand those and you’ll blow this guy out of the water.
2 juin 2008 at 12:36 PM
#23, Terry, I would like to read that Globe and Mail story (link is a dud). Living next to the Northwest Passage, I must say, if it infers in anyway that it is just as hard to Navigate this passage as with any previous times during the shipping season, it is absolute hogwash. It necessarily might have omitted that it is also easier to snowmobile on the passage during winter, reason: no old ice, virtually none on sight near Arctic communities. RC press rebuttals should be syndicated in every news outlet out there, correct interpretations of climate science is regularly mangled, to the point where I get Arctic visitors, some journalists, who regularly quote bad science from misleading news sources, newspaper stories are considered like science journals, peer reviewed quoted news stories especially, namely that 10 year cooling German model forecast. Like Alastair says. no time to trivialize how serious the disappearance of old multi year ice, but it seems that this mega story gets less attention than a Mars landing. But a rapid response to immediately kill mischievous news stories is apparently, not quick enough, syndicate guys!
2 juin 2008 at 12:41 PM
#23 re. Tenney Naumer “The Northwest Passage is not quite as easy to navigate as we have been led to believe.”
Well according to a Science Journal article it was navigatable enough for two “huge dry docks” to be taken through to the Bahamas in 1999:
http://www.sciencemag.org/cgi/content/full/291/5503/424?ck=nck
2 juin 2008 at 1:29 PM
> navigatable
All I can see is the Abstract, here:
http://www.sciencemag.org/cgi/content/full/291/5503/424
I’d speculate they used icebreakers.
Anyone know for sure?
“… In 1999, Russian companies sent two huge dry docks to the Bahamas through the usually unnavigable Northwest Passage ….”
Science 19 January 2001:
Vol. 291. no. 5503, pp. 424 - 425
DOI: 10.1126/science.291.5503.424
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Arctic Life, on Thin Ice
Kevin Krajick
Field observations from the Beaufort Sea to Hudson Bay are suggesting that the food web in the Arctic Ocean is ailing, causing many species to flounder as a result of the warming environment. Sea ice in the Arctic, on which arctic animals hunt, rest, and reproduce, now covers 15% less area than it did in 1978; it has thinned to an average of 1.8 meters, compared to 3.1 meters in the 1950s. If this trend continues, in 50 years the sea ice could disappear entirely during summers–possibly wiping out ice algae and most other organisms farther up the food chain.
2 juin 2008 at 2:18 PM
I’m sorry but I don’t think the contributors to this website fully appreciate how bad this “bucket” saga really is. As someone who was using a bucket to obtain water samples on a UK registered survey vessel during the years 1981/2, I can testify that the quality of data obtained was not high - be it a wooden, canvas or plastic bucket that was employed. Even if there was a standardised proceedure for measurement- and it’s my understanding there was no universal proceedure- I suspect those proceedures would not have been adhered to on shipboard conditions. It was bad enough slinging a bucket over the side in the North Sea; I would hate to have been the deckhand assigned the job in the South Atlantic. Working at sea, especially in “weather”, has to be experienced to be appreciated.
Further, conscientiously done work could be undermined by slight positional changes by the ship; a vessel could move from a warm current area to a cold current within a few hundred yards and the temperature changes could be of the order of degrees. Off the Outer Banks where the Gulf Stream veers off into the Atlantic is an example. Frankly, when sea temperature measurements were being taken using buckets, few envisaged those measurements would be read as precision readings. I would suggest that much of data collected had errors margins of +/- 2C.
This being the case, I believe the whole area of oceanic temperature measurements should be comprehensively re-examined.
2 juin 2008 at 2:32 PM
Tenney #25, what Ray said.
What you should clearly understand here is that the water vapour doesn’t know what warms the air it is in. Your correspondent effectively claims that the water vapour produces a strong negative feedback (in whatever way; who cares) reducing total sensitivity. But this feedback is mediated through tropospheric temperature. If it happens for CO2 radiative forcing, it will also happen for Solar activity -related (or any other) forcing, which thus would be equally ineffective to explain late 20th century warming. This is Gavin’s argument in layman’s terms (I hope).
…and there is a second impossibility compounding the first one: during the last few decades of accelerating global warming, the Sun has been very precisely monitored from space, and its brightness hasn’t shown any discernable trend. Same for solar activity (sunspots), interplanetary magnetic field, cosmic rays… so you would have to first explain away a known and understood forcing mechanism (CO2) and then replace it by one that cannot even work because it has the wrong time signature.
2 juin 2008 at 2:48 PM
I confess to a little confusion from your post.
Let’s put the details aside fro the moment.
At some time in the past measurements were predominantly by bucket.
At some time in the recent past (arbitraily, say 2000) readings were predominately by water intake.
Buckets apparently read colder than inlets by some amount, possibly .3 degrees.
So the change in the measurement, regardless of the intervening use of different mixes of buckets and other means, overall would be about .3 degrees between the “past” and the “recent past”..
Is this currently factored out of the trends or not?
2 juin 2008 at 3:32 PM
For Richard Ordway, re #28, Google is your friend, albeit not a wise advisor. Tell your friends they did use an icebreaker - and had trouble doing the job:
http://www.cargolaw.com/presentations_casualties_a.html
Russian icebreaker M/V ADMIRAL MAKAROV (14,058 gt, built 1975), towing a dry dock to the Bahamas, had towline break on Oct 14 and the dry dock was adrift off eastern Canada in the Cabot Strait between Nova Scotia and Newfoundland. The dry dock, with 15 people on board, was adrift in heavy seas for 2 days before being taken back under tow by the Admiral Makarov on Oct 16. All 15 crew members were reported in good health. (Mon. Oct. 18 1999)
2 juin 2008 at 3:35 PM
Hank Roberts (29)
>I’d speculate they used icebreakers.
Anyone know for sure?
“…In 1999, the first non-American
passage for commercial shipping pur-
poses took place when a Russian com-
pany sold a floating dry dock based in
Vladivostok. Its new owners decided
to move the dock to Bermuda. With
the aid of a Russian icebreaker and an
ocean-going tug, the dry dock was
successfully towed through the
Passage…”
http://www.navyleague.ca/eng/ma/papers/huebert_e.pdf
2 juin 2008 at 3:40 PM
Re 4 … The Arctic sea ice is rapidly disappearing …
The latest data by NSIDC for Arctic sea ice extent shows that 2008 ice coverage has fallen to 2007 levels for the end of May:
http://nsidc.org/arcticseaicenews/
Also see ice age (Figure 4):
http://nsidc.org/arcticseaicenews/2008/040708.html
2 juin 2008 at 3:45 PM
P.S. for Richard Ordway:
http://www.internationalliving.com/var/ezwebin_site/storage/images/in_country_support/other_countries__1/europe/russia/country_archive/09_19_06_russian/36290-1-eng-US/09_19_06_russian.jpg
It’s a tourist attraction; it used to be a research ship:
http://www.internationalliving.com/countries/other_countries__1/europe/russia/country_archive/09_19_06_russian
“… the Kapitan Khlebnikov, a Russian ice breaker from Vladivostok, now under charter to Quark Expeditions…. (a purpose-built ice breaker, as opposed to merely having an ice-strengthened hull) was a working vessel before she became our cruise ship; cabins previously assigned to scientists and technical staff are now passenger cabins. …”
2 juin 2008 at 4:04 PM
Thank you Gavin, very informative contribution. It also gives a new meaning to the exprssion “kick the bucket”. News that SST temperature readings are kaput because of differences in methods of drawing sea water samples are highly exaggerated, to paraphrase Mark Twain.
2 juin 2008 at 4:38 PM
John Lederer (32)
Before WWII the Brits and others were good about measuring SST. They mostly used buckets. During WWII they had better things to do. Few SST measurements were taken during the war but the Yanks did most of them. They mostly used engine intake measurements that had a slightly higher bias. After the war others once again began to measure the SST using buckets. This caused the Yank’s (warmer) engine room temps to be “diluted” by the (cooler) bucket temps and caused a largely unexplained drop in (average) SSTs after the war. This paper explains the curious drop after the war.
SSTs have continued to rise since the war, and surpassed war levels in the 70’s This paper mostly only addresses the (dip) artifact from 1945-1970.
Does that help?
2 juin 2008 at 5:11 PM
Arch Stanton,
Thank you very much.
But in the very recent past (say 1990- 2000) Igather measurements were largely water intakes?
So after the immediate post WWII reversion to buckets, we changed again, presumably more gradually, to intakes.
So if I look at a trend from say just after WWII (largely bucket) to around 2000 (largely intake), there will be .3 degrees (assuming that is the difference) of warming attributable not to an actual temperature change,but to the switch in measurement method?
Or am I missing something?
I
2 juin 2008 at 6:06 PM
I’m really curious here as I’ve only read a few dozen of the climate-centric blogs, but I’m under the impression that only a small fraction are written by AGW “deniers” and perhaps 5% of the total would fall into the “skeptic” category? In terms of mainstream media it would seem that only a handful of stories (plus uninformed ranters at FOX) are critical of the basic AGW ideas held so dear here.
2 juin 2008 at 7:19 PM
#18 Ike Solem, #27 Wayne Davidson, #25 Tenney Naumer …
This might be an opportune time to remind everyone of how organized tobacco’s astroturf “sound science” movement morphed into attacks on science in other areas like global warming, as ably revealed by George Monbiot, among others: http://opinion-nation.blogspot.com/2008/06/sound-science-and-climate-change-or.html
Whenever I read this stuff I marvel at how little pride some people have.
Thanks again, RC, for providing some balance – and the ammo to fight back.
2 juin 2008 at 7:31 PM
Joseph Hunkins, there are plenty of denialist sites on the Web. There are also sites that say the moon landing was a hoax and that allow posters to compare their anal-probing experiences by aliens. There are a few “skeptic” sites, but most of them are not run by scientists, and the “science” presented there is only of value in terms of entertainment. A very few actually raise some valid points, but grossly exaggerate their importance.
In terms of mainstream media, the proportion of stories that question climate change or the “balance” of the stories (e.g. presenting “both sides”) is grossly out of proportion to the actual level of scientific consensus. And if you look at scientists who actually publish on climate in peer reviewed journals, there is pretty much universal agreement that CO2 has contributed significantly to recent warming and the vast majority say CO2 is responsible for the vast majority.
There are many things we do not yet know about climate. The importance of CO2 is not among these things.
2 juin 2008 at 7:48 PM
Here’s a list that will include a good many:
http://www.sourcewatch.org/index.php?title=Category:Front_groups
+joeduck +climate
2 juin 2008 at 9:07 PM
John Lederer,
Ah, I think I understand your question now. It looks more like .4-.5C (but honestly I am extrapolating from a small graph. I will refer you back up to Gavin’s OP however and ask you to click on the second graph, this will take you to the Nature blog: ClimateFeedback. The first two line graphs are very interesting, although they are somewhat hard to see.
“a” shows SSTs for the century; uncorrected on top, the bottom has had ENSO and COWL (Cold Oceans Warm Land) reconstructions subtracted from it. The dashed vertical line represents the drop after WWII the solid vertical lines represent major volcanic eruptions. It looks to me as though if the drop in temps in 1945 is .3C then the subsequent rise to today must be around .4-.5C (?)
2 juin 2008 at 9:45 PM
Perhaps denialism is waning.
Deep denial is rooted in human nature that wants look at the positive and ignore anything that is not causing real pain right now. AGW is uncomfortable news. No one wants to see it. But any science has to lay out all the models, scenarios, and systems analysis that will butt heads with economies, politics and will-power. The crux is an informed populace. Passive denial is like being asleep. Active denial is often traced to selfish monetary interests - carbon industries, etc. And so much recalcitrance is just momentum.
How does one describe, label and then halt the AGW practices that are too dangerous for civilization? Science can only describe, label, predict and advise. Halting requires political involvement. And the lessons we failed to learn have been repeated. And will be repeated again.
Sometimes I wish RC would be more political. Physics trumps all eventually, but politics and power rules humans - for now.
2 juin 2008 at 9:53 PM
Speaking of the media: Charles Krauthammer wrote a run-of-the-mill denialist diatribe in the Washington Post last Friday in anticipation of the Lieberman-Warner Climate Security bill making it to the full Senate this week. I urge you to respond to that column with a letter to the editor, given this current visibility. And with the NASA IG’s report also in the news, the more and higher-profile NASA scientist signatories to that letter, the better.
3 juin 2008 at 2:34 AM
In his response to 23. Gavin argues “Either water vapour is stabilising or it isn’t (and it isn’t by the way…”
[edit]
“Cloud climate feedback constitutes the most important uncertainty in climate modelling, and currently even its sign is still unknown. In the recently published report of the intergovernmental panel on climate change (IPCC), 6 out of 20 climate models showed a positive and 14 a negative cloud radiative feedback in a doubled CO2 scenario.”
Ref: Wagner, Thomas, S. Beirle, T. Deutschmann, M. Grzegorski, and U. Platt, 2008. Dependence of cloud properties derived from spectrally resolved visible satellite observations on surface temperature. Atmospheric Chemistry and Physics Vol. 8, No 9, pp. 2299-2312, May 5, 2008
[Response: Perhaps if you read what I wrote we’d communicate better. Water vapour feedback is not the same as cloud feedback (clouds are condensate - not vapour). - gavin]
Please see also:
“By comparing the response of clouds and water vapor to ENSO forcing in nature with that in
AMIP simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate of the
strength of the negative cloud albedo feedback and (2) an overestimate of the positive feedback
from the greenhouse effect of water vapor. Extending the same analysis to the fully coupled
simulations of these models as well as to other IPCC coupled models, we find that these two
common biases persist.”
Ref: Sun, De-Zheng, Yongqiang Yu, Tao Zhang, 2008. Tropical Water Vapor and Cloud Feedbacks in Climate Models: A Further Assessment Using Coupled Simulations. Submitted March 2008 to Journal of Climate
3 juin 2008 at 6:41 AM
Re # 4 Alastair McDonald
You claim
“Wild fires, a symptom of desertification are being reported from Alaska to California, and from the north Mediterranean coast of Europe to the main populated regions of Australia”.
You can leave my country, Australia, off the list. Please don’t invent to make a point. Stick to what you know is measured accurately, both as to desertification and fires, and quote your source.
3 juin 2008 at 6:51 AM
Re # 12 Gavin’s response
But Phil Jones knew SST work was wrong early in 2006 but failed to do much if anything about it by the time the IPCC published. Here is what he emailed to me:
“Geoff,
First, I’m attaching a paper. This shows that it is necessary
to adjust the marine data (SSTs) for the change from buckets
to engine intakes. If models are forced by SSTs (which is one
way climate models can be run) then they estimate land
temperatures which are too cool if the original bucket
temps are used. The estimated land temps are much
closer to those measured if the adjusted SSTs are used.
Jonesandmoberg.pdf follandetal200.pdf ”
So how can you justify writing that
“Nick Rayner, Liz Kent, Phil Jones etc. are perfectly capable of working it out and I’d suggest deferring to their experience in these matters.”
[edit]
[Response: Possibly you did not read those papers. They show that the pre-1941 changes because of the Folland and Parker (1995) correction are in much better agreement than the raw data (ie. the correction seen in the first figure above). The changes we are talking about now are much smaller, but yes, they do know what they are doing. Read Rayner et al 2006 for instance. - gavin]
3 juin 2008 at 6:53 AM
Re # 14 Gavin
[Response: GISTEMP uses HadISST up to 1982 and Reynolds thereafter - there may still be issues in melding the two approaches because small potential offsets between the buoys and other methods of determining SST. - gavin]
Is it so hard to use realspeak on realclimate and simply say “At least one is wrong”.
[Response: Well down here in the reality-based community things don’t come in neat packages labelled perfect or useless. Instead everything comes with uncertainties and we use all the available data to get closer to what was likely to be the truth. It’s really not that hard a concept. -gavin]
3 juin 2008 at 7:24 AM
Politics will always be the way we get things done when we work with people (gr=polis). However, politics can be motivated by either ignorance or science. Eventually, I don’t see any way around it but to build a smarter voter. If that means we have to take American Idol of the air, so be it.
The current breed of denialists are not motivated by facts, so it will not matter how strong the case is for climate change. However, on a positive note, a recent poll revealed that most young women would rather talk to a guy at a party with the latest green car than to a guy with a sports car.
3 juin 2008 at 8:00 AM
Geoff,
You wrote:
You can leave my country, Australia, off the list. Please don’t invent to make a point. Stick to what you know is measured accurately, both as to desertification and fires, and quote your source.
You may wish to declare your Australia a global warming free zone but …
Understanding autumn rain decline in SE Australia http://www.csiro.au/news/UnderstandingDeclineAutumnRain.html
“This is the worst bush fire conditions we have ever had in Victoria’s history …”
http://www.sott.net/articles/show/125695-Wildfires+Burn+in+Southern+Australia
Australia suffers worst drought in 1,000 years
Depleted reservoirs, failed crops and arid farmland spark global warming tussle
http://www.guardian.co.uk/world/2006/nov/08/australia.drought
Cheers, Alastair.
3 juin 2008 at 9:13 AM
Roger Pielke Sr. chimes in -
http://climatesci.org/2008/06/03/biased-view-of-the-global-average-temperauture-trend-data-at-real-climate/
[Response: And another example of someone over-extrapolating from the Thompson et al paper in order to promote their pet hobbyhorse. Pretty much underlines the point of my post I think. - gavin]
3 juin 2008 at 10:14 AM
Geoff Sherrington (#48):
Although desertification and fires are related in that they are both exacerbated by increasing average temperatures, I agree that they are not directly related (here in Australia at least) in the manner of fires causing deserts. Desertification on this continent is more the result of land clearance, broad-acre agriculture and grazing in arid and semi-arid regions.
However, if you want information on the impact of climate change and associated temperature rise on fires, then this report by the CSIRO is a good place to start:
Hennessy K, Lucas C, Nicholls N, Bathols J, Suppiah R, Ricketts J. 2006. Climate change impacts on fire-weather in south-east Australia. CSIRO, Australia. [PDF file, 2MB, 91 pages].
3 juin 2008 at 10:40 AM
I’ve been watching these NESDIS arctic ice images:
Here’s the residual ice at the end of last year’s melt season:
By the start of this year, there was clearly multi-year ice north of Greenland and the Canadian archipelago, and thin ice everywhere else apart from in a narrow band stretching roughly from NE Greenland to Severnaya Zemlya:
The transpolar drift has steadily moved that band, and much of the rest of the multi-year ice, towards the Fram Strait:
Today the band is broken. Using this very imperfect observation, I suggest that for the first time in history there is no multi-year ice between the pole and the Fram Strait.
To get a really clear impression of the process, I recommending opening each of these images in a separate browser tab and using Ctrl-Tab to cycle through them.
3 juin 2008 at 12:45 PM
Argh. Links broken in my comment #55. Here are the images:
End of last melt season:
http://manati.orbit.nesdis.noaa.gov/ice_image21/2007/D07250.NHEAVEH.GIF
Start of this year:
http://manati.orbit.nesdis.noaa.gov/ice_image21/D08001.NHEAVEH.GIF
Movement earlier this year:
http://manati.orbit.nesdis.noaa.gov/ice_image21/D08050.NHEAVEH.GIF
http://manati.orbit.nesdis.noaa.gov/ice_image21/D08100.NHEAVEH.GIF
Today’s image:
http://manati.orbit.nesdis.noaa.gov/ice_image21/D08154.NHEAVEH.GIF
3 juin 2008 at 2:38 PM
RE: #30
What type of thermometers were used for these measurements? I can’t imagine a merchant vessel using high-quality scientific types. How were these calibrated? Or are there special thermometers for marine service?
3 juin 2008 at 3:49 PM
Re # 57 Harold Pierce, Jr.
Interesting question. I am curious to know how the Navy’s methods during war time (or even in rough seas) compare with the meticulous methods used by oceanographers (Woods Hole oceanographers, at least):
Nansen-Bottle Stations at the Woods Hole Oceanographic Institution
Corresponding author: Bruce A. Warren
Abstract
Nansen-bottle stations were occupied by ships and personnel of the Woods HoleOceanographic Institution from 1931 to about 1981. Most of these data are in archives, but usingthem intelligently to depict the state of the ocean and to assess time changes in it requiresknowing how the observations were made, what accuracies can be assigned to them, and generally how to approach them. This report describes the evolving methods on Woods Hole stations for measuring temperature, depth of observation, salinity, and dissolved-oxygen concentration, and for determining station position. Accuracies generally improved over time,although estimates from the early years are sparse, and even later there is indefiniteness.Analytical error is to be distinguished from sloppy sample collection and other blunders. The routine for carrying out Nansen-bottle stations, from the late 1950s through the 1970s, is reviewed.
http://64.233.169.104/custom?q=cache:tW194mlD1s8J:https://darchive.mblwhoilibrary.org/bitstream/1912/1691/3/Nansen_Bottles.pdf+Nansen+Bottle&hl=en&ct=clnk&cd=13&gl=us&client=pub-2456819124576563
3 juin 2008 at 4:00 PM
Gavin - Since you are willing to listen to those who have worked with the data, I invite you to answer the weblog on Climate Science today: http://climatesci.org/2008/06/03/biased-view-of-the-global-average-temperauture-trend-data-at-real-climate/
I look forward to you showing that the claim that Real Climate is biased is incorrect.
[Response: Roger, you are not going to be convinced until we agree with everything you think is important. Since that isn’t going to happen, there doesn’t seem to be much point in engaging. I’m perfectly willing to accept that you have different priorities and interests than us and would not dream of curtailing your right to blog about any of them. For instance, should I assert that you are biased because you haven’t blogged about any of my recent papers? I think not. I would expect the same courtesy from you. - gavin]
3 juin 2008 at 5:17 PM
RE: #58
I once saw the term “Kriegsmarine effect”. Presumably it has something to do with the German Navy. Do you know anthing about this?
There is a huge amount merchant shipping still discharging much oily bilge water into the open ocean. Oil on the surface of water would retard its evaporation. Cruise ship can’t do this anymore and have to filter the bilge water to remove oil before discharing it into the ocean.
3 juin 2008 at 5:30 PM
Confused by your response Gavin. You strongly imply that it is not responsible to say these data problems are a big deal. Pielke says the are a big deal, and he provides an analysis to suggest this accounts for a very significant amount of IPCC warming trend.
If Pielke is right are you seriously saying that finding about SSTs would not be a big deal? Why not address the issue rather than spend all this time asserting it’s not relevant?
[Response: You are confusing your Pielkes (it’s easily done). Jr is the one with the trends based on nothing originally, and based on a little something later. Why I should waste time discussing the implications of hypotheses that are certainly incorrect is unclear. All I said above is that the corrections are likely to be limited to the immediate postwar period (based on the paper itself and discussions with people in a position to know). If so, this has little or no relevance to the detection or attribution of climate change and thus no importance to the main IPCC conclusions. Is it meaningful? Of course, but meaning is not limited to the IPCC AR4 SPM. I suggested a wait and see attitude is more appropriate - others appear to disagree. We’ll see who is vindicated when the new analyses are done. - gavin]
3 juin 2008 at 5:34 PM
Re #56: Nick, what’s the URL for selecting those images, and is there any sort of interpretation guide? Thanks.
3 juin 2008 at 6:03 PM
Re # 60 Harold Pierce
Kriegsmarine means “war navy”
(http://en.wikipedia.org/wiki/Kriegsmarine). I don’t know what the Kriegsmarine effect is, but when I googled it I came up with this essay by AGW skeptic, Roy Spencer, of the National Space Science and Technology Center at University of Alabama, Huntsville:
Spencer Part2: More CO2 Peculiarities - The C13/C12 Isotope Ratio
http://wattsupwiththat.wordpress.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/
I couldn’t find any mention of Kriegsmarine effect, though I didn’t read it very carefully.
By the way, Spencer’s first article on this subject (Part 1) was titled: Atmospheric CO2 Increases: Could the Ocean, Rather Than Mankind, Be the Reason?
3 juin 2008 at 6:15 PM
Gavin:
All I said above is that the corrections are likely to be limited to the immediate postwar period (based on the paper itself and discussions with people in a position to know). If so, this has little or no relevance to the detection or attribution of climate change and thus no importance to the main IPCC conclusions
Thanks for this clarification. In fact befor I had misread Pielke Sr. post as talking about SST anomolies when in fact he was looking at other things when he suggests IPCC is running too hot.
3 juin 2008 at 6:56 PM
Steve Bloom @ 62: The images are scatterometry, QuikSCAT daily ice images. You can pick the images yourself from the directory view:
http://manati.orbit.nesdis.noaa.gov/ice_image21/
e.g. D08154.NHEAVEH.GIF: year 08, day 154, northern hemisphere average.
This page provides, and links to, more information about the instruments, data collection, and interpretation:
http://manati.orbit.nesdis.noaa.gov/cgi-bin/qscat_ice.pl
3 juin 2008 at 8:19 PM
> Kriegsmarine
There’s a fellow who will be along any minute to fill you in on his theory. Or you’ll find it at a great many websites — oceanclimate.de and seaclimate.com among others.
3 juin 2008 at 8:19 PM
Perhaps realclimate’s “bias” consists of reporting on what the papers actually say, rather than reporting on what they say and twisting it around to be some new attack on the IPCC and AGW…which the Pielkes seem to be joining the club for doing any chance they can get
Perhaps the authors would not have written this in the abstract:
//Corrections for the discontinuity are expected to alter the character of mid-twentieth century temperature variability but not estimates of the century-long trend in global-mean temperatures.//
3 juin 2008 at 8:32 PM
Re 47 Timo
The Sun et al paper links the WV/cloud bias to ENSO rather than global warming. This is in their paper:
//”These results suggest that at least in the models, the feedbacks of water vapor and clouds estimated
from the ENSO cycle cannot be used as harbingers for the feedbacks of water vapor and clouds
during global warming.”//
Of course, as further evidence of “bias,” (RC’s of course) this didn’t stop Roger Pielke Sr. from declaring so confidently that
//”This study indicates that the IPCC models are overpredicting global warming in response to positive radiative forcing.”//
Silliness.
3 juin 2008 at 9:22 PM
Re 59 - Gavin, I just read Roger’s response. He is really an annoying prima donna. “Dance with me, or you are rejecting the art of dance.” He does not understand that he does not understand. To use the words of a recent Secretary of Defense, he seems to be plagued by unknown unknowns.
3 juin 2008 at 11:18 PM
Re. 33 “Hank Roberts wrote: “The dry dock, with 15 people on board, was adrift in heavy seas for 2 days before being taken back under tow by the Admiral Makarov on Oct 16.”
“and had trouble doing the job” (but is this in the NW passage itself or outside of it?) Is this your opinion or facts?
Note that it might not have been in the NW passage itself that was so bad…the “adrift event” took place off Nova Scotia…which I believe is not part of the infamous north west passage and the Cabot passage “is part of an important shipping route”:
“Cabot Strait, channel connecting the Gulf of St. Lawrence with the Atlantic Ocean, between Cape Breton Island and the island of Newfoundland, southeastern Canada. The channel is 110 km (70 mi) wide. It is part of an important shipping route. Ferries cross Cabot Strait, between Cape Breton Island and the island of Newfoundland. The channel is named after the Italian navigator John Cabot.”
http://encarta.msn.com/encyclopedia_761564151/Cabot_Strait.html
As Arch Stanton found:
“This use of the Passage to
avoid storms in the open ocean demonstrated
its advantage for international
shipping should the ice be reduced.
The fact that the dry dock was
then almost lost in a storm off Newfoundland
seemed to confirm the benefits
of sheltered waters of the Passage
route.”
http://www.navyleague.ca/eng/ma/papers/huebert_e.pdf
So Hank, I wonder if the Northwest Passage itself is really so difficult to navigate…or is it instead the usual shipping lanes that are so hard to navigate in comparison?
In other words, can you now just crank up an icebreaker and go through the NW passage and save ~3000 Km or 5000 miles while in a “calm NW passage”?
4 juin 2008 at 1:39 AM
RE: #66
Hank, thanks for the links. Absolutely fascinating. Do you think that the enormous amount maritime activity with modern ships bigger than most WW II battleships could be having an effect on the oceans or some sections of the oceans. The authors of these articles seem to think so.
Their propellers of htese ships really churn up the sea. Essentially all of their heat energy is released into the ocean enviroment.
Google “P&O Ventura” This ship is just huge and boogles the mind.
Unlike naval vessels, merchant ships usually travel in well-defined sea lanes. Can the satellites see their effects? Know any links?
4 juin 2008 at 2:48 AM
Gavin
Have you see this sentence at the end of the Thompson et al. article?
“However, compensation for a different potential source of bias in SST data in the past decade the transition from ship to buoy-derived SSTs ,might increase the century-long trends by raising recent SSTs as much as 0.1 °C, as buoy-derived SSTs are biased cool relative to ship measurements”
[Response: Yes. I mentioned it above. This would imply that the last few years in ths SST record is biased a little low - but as I said also, it’s probably best to wait and see how this plays out when all the new corrections are made. - gavin]
4 juin 2008 at 3:47 AM
This bunch of sites promoting the naval war climate effect is probably the most bizarre stuff you can find on the entire web.
Anyway - I used it as an excuse to call my grandfather who is well into his nineties and spent WWII on a german submarine as an engineer. He said they had very sophisticated temperature measuring equipment on these ships but of course they never used it to detect the temperature as an absolute but for calibrating various sonar sensors on weapons and the ship itself. He also mentioned that they kept detailed records about the exact depth of temperature layers. Furthermore there apparently were seperate measurements for engine inlet and ballast water temperature used to finetuning the ship’s engine performance and diving behaviour but he doubted they would be much use in research due to lack of absolute calibration and lack of records. When I told him, why I wanted to know all this stuff, he answered that there should be nobody better positioned to know the exact water temperatures at any depth in any part of the oceans than the post-war US and russian sub fleets. Is that true and if so - are these records available for research and already in use for climate science? Considering the degree of sophistication on modern nuclear subs, they should be the most reliable and most traveled water termometers out there - they’re certainly the most expensive.
4 juin 2008 at 4:13 AM
Re 47 Timo
maybe you are aware, that cloud types, properties, distribution, thickness, etc. in the tropics (that is, what the Sun paper is all about, see title) are different from those over the rest of the planet and might react different on global warming. ENSO forcing is not a very good analogon for global warming concerning clouds (as the authors assert).
4 juin 2008 at 6:11 AM
Harold Pierce writes:
Do the math, Harold. The amount released is trivial compared to the ocean’s heat content, or even the upper ocean’s heat content.
4 juin 2008 at 6:15 AM
Roger, in your post you complain, that RC has not commented on a specific paper.
Since it is not possible to comment on any published paper, this complaint is strange.
However, some short comments on your post http://climatesci.org/2008/01/30/a-serious-problem-with-the-use-of-a-global-average-surface-temperature-anomaly-to-diagnose-global-warming-part-ii/ for the readers here (comments on your site are closed), since it concerns my former research field:
The post claims a significant bias in global temperature trends due to a warm bias in nocturnal minimum temperature trends due to the stabilisation (positive temperature with height) of the nocturnal boundary layer during calm nights.
It presents a back-of-the envelope estimation of the possible influence of this bias since 1990.
This estimation has serious problems, e.g.:
1) The temperature trends presented in the IPCC report are based on monthly averages, which are calculated from continuous measurements for a lot of the stations, and not as assumed only from daily maximum and minimum temperatures, especially since 1990. Thus the influence of the daily minimum temperature is smaller than assumed.
2) The discussed problem (the formation of a nocturnal boundary layer) over mid-latitudes only occurs for a number of nights during summer, i.e. for perhaps 30-60 days a year. For stations in high latitudes it will be less, for those in the subtropics it will be more. However, this reduces the effect by a factor of 5-10.
3) The assumption, that in terrain with more relief this effect will be stronger, is strange. Relief causes winds in the discussed situations, which will reduce the effect. The effect is strongest in plains. Thus it concerns only part of the stations. This further reduces the effect.
In addition, there are more fundamental questions (e.g. the trends are about surface temperatures, so why bother about different trends at other heights).
Sorry, that I also have not the time to comment the paper more in depth.
4 juin 2008 at 6:21 AM
Harold Pierce #71:
http://climateboy.blogspot.com/2007/10/shipping-lanes.html
and links therein
4 juin 2008 at 6:57 AM
There must somewhere be explanation how eg GISS makes the global land & ocean temperature averages. Then it shouldn’t be a big deal to estimate how these bucket adjustments change the temperature series? The GISS is so often referred here in RC and by IPCC, which rely just on peer reviewed articles, that there must be a good description how the SST averages are calculated? And which stations are used, how station moves or changes are handled, how UHI effects are calculated and so on for the land stations. Any help?
[Response: http://data.giss.nasa.gov/gistemp though the ocean temperatures are a blend of the HadISST product and the satellites from 1982 onwards (Reynolds and Smith). - gavin]
4 juin 2008 at 7:55 AM
#73
*OT apologies*
what a wonderful response from your grandfather - so acute and clear sounds like he is absolutely on the ball plus I would take his word (”is it true?”) over many others!!
4 juin 2008 at 9:18 AM
> 73, Henning’s grandfather on submarine data
He’s right. Part of the US data set for the Arctic was declassified at the behest of then Senator Al Gore; the Navy has a large climate modeling program and publishes some work steadily. E.g.:
… The area first declassified is called the “Gore box” ….
http://www.realclimate.org/index.php/archives/2006/03/climate- …
www.realclimate.org/index.php/archives/2006/05/more-on-the-arctic/ -
… bear in mind that Maslowski has access to data that none of the other modelers have (the stuff outside the “Gore box”). …
fergusbrown.wordpress.com/2007/12/12/did-someone-stir-the-martini/
4 juin 2008 at 9:23 AM
As a lay person (albeit with a Science degree) I find it interesting that the last 7 posts on this site have been disputing claims by Climate Change skeptics or data/studies that may/may not support their case. If the skeptics and their arguments are so off-the-wall why all the focus. “Doth the lady protest too much???”
4 juin 2008 at 10:05 AM
When discussing sea surface temperatures please see the following new study about sea level rise:
Berge-Nguyen, M., A. Cazenave, A. Lombard, W. Llovel, J. Viarre, and J.F. Cretaux. 2008. Reconstruction of past decades sea level using thermosteric sea level, tide gauge, satellite altimetry and ocean reanalysis data. Global and Planetary Change Vol. 62, No 1-2, pp. 1–13, May 2008
They reconstructed approximately 80 mm sea level rise over 1950–2003, i.e. a rise of 1.48 mm yr−1. This rise is below the estimate of the IPCC and have no acceleration.
And after 2003 sea levels are falling…
4 juin 2008 at 10:31 AM
Re 81. Gee, Patrick, why don’t you take that “science degree” off the shelf where it’s gathering dust and put it to some use learning the science yourself?
Perhaps you have been unaware of the well funded disinformation campaign waged by coal and oil interests to discredit good science and heap calumny on good scientists. Perhaps you are not outraged when ignorant food tubes distort science to support their own pet theories. Perhaps you don’t feel that civilization is under threat in a society where more people believe in angels than believe in evolution. On second thought, go ahead and put that science degree back on the shelf. You’ll never need it.
4 juin 2008 at 10:57 AM
Urs - Thank you for taking the time to comment on the Climate Science weblog on the warm bias [http://climatesci.org/2008/01/30/a-serious-problem-with-the-use-of-a-global-average-surface-temperature-anomaly-to-diagnose-global-warming-part-ii/]. Here are the answers to your very good questions:
1. The monthly mean is obtained as the average of each daily maximum and minimum temperature, so that the warm bias is not reduced by averaging.
2. The nocturnal boundary layer occurs at all latitudes, of course, and in the higher latitudes persists 24 hours a day in the winter. At these high latitudes in the winter, where a significant wamring has been reported,the warm bias results in an overstatement of the warming.
3. In complex terrain, the lower elevations (closed valleys, depressions, ect) have cool air pooling when the synoptic wind and large scale pressure gradient are weak. This results in the stable boundary layer being a common feature, particularly in the winter at middle and high latitudes (e.g. such as the Grand Valley of Colorado).
The result of this warm bias is a significant overstating of the surface temperature warming.
4 juin 2008 at 11:18 AM
Re 83. Ray,
instead of yr political comments on scientists, I see different scientific views in all details of Climatology, worth debatable with scientific courtesy.
In general, I see enormous amount of neutral, ‘mainstream’, alternative, critical and sceptical studies, normally funded and peer-reviewed.
Media and blogosphere are sui generi.
4 juin 2008 at 11:19 AM
“squishy science”
Repeating what Gavin wrote “Every time there is a similar rush to judgment that is subsequently shown to be based on nothing, it still adds to the vast array of similar ‘evidence’ that keeps getting trotted out by the ill-informed.” …
Repepeating what longtime CBS WCCO-TV meteorologist Mike Fairbourne said recently - in the 1970s “we were screaming about global cooling. It makes me nervous when we pin a few warm years on squishy science.”
Fairbourne said he has talked “to a number of meteorologists who have similar opinions” as his, adding that he is concerned about “the extremism that is attached to the global warming.”
I think we need to be concerned about where meteorologists, and many people who listen to them, are getting their educations about climate change and global warming from. NOAA’s NWES meteorologists have made light of and poked fun of global warming for more than a decade, and counting?
http://www.startribune.com/nation/19095579.html?page=1&c=y
4 juin 2008 at 11:39 AM
Re # 81 ” If the skeptics and their arguments are so off-the-wall why all the focus.”
Well, people tend to argue with those with whom they disagree - if there is no disagreement, there is little to argue about (unless you want to nitpick). Now, if you are asking, Why not ignore the AGW skeptics/deniers? it is simple: They (some of them, at least) wield influence far in excess of their scientific credibility on the issue, and some of them are hell-bent on misleading the public, as Ray has pointed out.
4 juin 2008 at 12:04 PM
#73
Henning,
I would like to meet your grandfather and swap a sea story or two. He is a rare survivor of some of the harshest naval warfare on both sides in history. His memory sounds right on the money to me. I spent 15 years as a Cold Warrior, slinking around in much greater comfort on US nuclear submarines and then another 15 training submariners, maintaining the ships and planning their operations.
I cannot speak for the Soviet submarine data gathering practices but the US submariners logged everything. Strategic missile submarines put together extensive data packages after each approximately 60 day patrol. These included almost continuous comparisons of inertial velocity and electromagnetic log velocity. This gives a continuous measure of ocean current (set and drift). Daily XBT traces were taken which provided sound velocity profiles down to 1000 feet or more. At least daily traces of sound velocity from operating depths (a few hundred feet) to periscope depth were submitted. Continuous, highly accurate bottom contour traces were recorded. Sea water injection temperatures were logged hourly. All of this was coupled to very accurate continuous inertial navigation based positions.
Polaris patrols started in 1960 with much the same data gathering that, I think, continues to this day on Trident submarines. Well over 3000 patrols have been conducted. A patrol of 60 days would have between 9000 and 10000 miles of continuous track over chunks of the Norwegian Sea, North Atlantic or Mediterranean about the size of Texas. Similar patrols were conducted in the Pacific from 1964 on. Each data package was submitted for analysis to the Applied Physics Laboratory at Johns Hopkins University. The bottom line for the analysis was whether or not we had maintained continuous target coverage and the ability to launch within national command authority guidelines. Later the data packages were extended to cover more sonar system related data and used to develop better sonar and also confirm that we were not being followed by the “other guys”.
The data reduction effort would be enormous. I think the effort could provide good temperature data over an almost 50 year period and down to depths of at least 100 meters. The ocean current data is unique and should be a valuable input to ocean modeling. Best of all for me would be knowing we contributed to something beyond mutually assured destruction.
Declassifying this data will require strong political leadership—at least as strong as provided by Mr. Gore in breaking loose the Arctic ice data. I can think of no one better to take on this task then my own Representative Jay Inslee (D-Washington). He already has a stellar record on energy and climate.
4 juin 2008 at 1:14 PM
Timo,
Different scientific views? Exactly where in the peer-reviewed literature is there any contention that CO2 sensitivity is significantly less than 3 degrees per doubling (other than, say the ill-fated attempt of a certain scientist from BNL).
Yes, there are areas where uncertainty remains. The role of CO2 is not among these. If you contend otherwise, produce the peer-reviewed literature backing your position.
4 juin 2008 at 1:24 PM
Re 87 Chuck,
Science is not about credibility, but facts. When Climatology is mostly probabilities, there’s always room to debate.
Everyone, whether neutral, ‘mainstream’, alternative, critical or sceptical, who proclaims certainty, only proves poor knowledge, false confidence and lack of scientific understanding (& behavior).
4 juin 2008 at 1:33 PM
#82, Timo, I can’t find that paper, but here are some related charts that show sea level rises overall, but thermal contraction since 2003, perhaps that’s what you were referring to?
http://www.aviso.oceanobs.com/en/news/ocean-indicators/mean-sea-level/science-questions/index.html
4 juin 2008 at 2:01 PM
Yesterday’s Science Times section of the NY Times had a brief piece on this topic. http://www.nytimes.com/2008/06/03/science/03obtemp.html?ref=science
Also pack up all your cares and woes if you’re concerned about the future of renewables, especially solar power, the same section contains an article in which Dr. Ray Kurzweil says in part:
” Worried about greenhouse gas emissions? Have faith. Solar power may look terribly uneconomical at the moment, but with the exponential progress being made in nanoengineering, Dr. Kurzweil calculates that it’ll be cost-competitive with fossil fuels in just five years, and that within 20 years all our energy will come from clean sources.”
http://www.nytimes.com/2008/06/03/science/03tier.html?_r=1&ref=science&oref=slogin
4 juin 2008 at 2:19 PM
Re 89. Ray,
about climate sensitivity please see e.g.
1. Kiehl, Jeffrey T., and Christine A. Shields, 2007. Inter-model climate sensitivity. NCAR Climate Change Prediction Program study 2007, online http://www.cgd.ucar.edu/ccr/shields/posters/ccppsensitivity.pdf
2. Kiehl, Jeffrey T., 2007. Twentieth century climate model response and climate sensitivity. Geophys. Res. Lett., 34, L22710, doi:10.1029/2007GL031383, November 28, 2007
Abstract
Climate forcing and climate sensitivity are two key factors in understanding Earth’s climate. There is considerable interest in decreasing our uncertainty in climate sensitivity. This study explores the role of these two factors in climate simulations of the 20th century. It is found that the total anthropogenic forcing for a wide range of climate models differs by a factor of two and that the total forcing is inversely correlated to climate sensitivity. Much of the uncertainty in total anthropogenic forcing derives from a threefold range of uncertainty in the aerosol forcing used (TH = tuned) in the simulations.
[edit - FUD removed]
5. Seiffert, Rita, and Jin-Song von Storch, 2008. Impact of atmospheric small-scale fluctuations on climate sensitivity. Geophys. Res. Lett., 35, L10704, doi:10.1029/2008GL033483, May 21, 2008
Abstract
Climate change scenarios are based on numerical models with finite spatial and temporal resolutions. The impact of unresolved processes is parameterized without taking the variability induced by subscale processes into account. This drawback could lead to an over-/underestimation of the climate sensitivity. The aim of this study is to investigate the impact of small-scale atmospheric fluctuations on the modeled climate sensitivity to increased CO2 concentration. Using a complex coupled atmosphere-ocean general circulation model (ECHAM5/MPI-OM) climate response experiments with enhanced small-scale fluctuations are performed. Our results show that the strength of the global warming due to a CO2 doubling depends on the representation of small-scale fluctuations. Reducing the horizontal diffusion by a factor of 3 leads to an increase of the equilibrium climate sensitivity by 13%. If white noise is added to the small scales, the climate sensitivity tends to weaken. The largest changes in responses occur in the upper troposphere.
[edit - irrelevant ref removed]
4 juin 2008 at 2:20 PM
Not trying to hijack this thread:
“Our investigation found that during the fall of 2004 through early 2006, the NASA Headquarters Office of Public Affairs managed the topic of climate change in a manner that reduced, marginalized, or mischaracterized climate change science made available to the general public through those particular media over which the Office of Public Affairs had control (i.e., news releases and media access).
NASA internal review June 2008
“The report found credence in allegations that National Public Radio was denied access to top global warming scientist James Hansen. It also found evidence that NASA headquarters press officials canceled a press conference on a mission monitoring ozone pollution and global warming because it was too close to the 2004 presidential election.”
http://www.hq.nasa.gov/office/oig/hq/audits/reports/FY08/IG-08-017.pdf
4 juin 2008 at 4:19 PM
#86 warm Northern re-greetings Pat, Being of Scottish ancestry, I rather go down fighting the good fight, than sit down and watch the show go bad, complacency rules the world, even people in key science positions follow the business as usual flow, but it does not mean we all have to agree to do nothing. Ya TV met guys have for the most part been horrendous on the subject for the longest time. They can’t distinguish the difference between climate and weather forecasting. We got a CBC weather woman who isn’t so bad, try watching CBC National news if you have access.
#84 Roger, Nice arguments, they are trivial at best, of no real consequence aside from flaunting semantics. Why don’t you do a weighted temperature of your Colorado Upper Air Radiosondes, Over the last 3 months, and see if there is a noticeable variation? Just wondering if you have a bit of access, and a bit of curiosity? You may be surprised by what you find.
4 juin 2008 at 7:11 PM
Thanks so much for the fascinating Maritime Archeo-Climatology.
This triggers a thought that there must be a huge amount of data in airline pilot reports. I know that every aircraft has a high quality thermometer or even two or more. And at any moment, there are thousands of aircraft in flight somewhere globally. Sometimes pilots report weather info. With aircraft transponders reporting other data, Shouldn’t all aircraft report temperature too? Seems like an easy way to collect data. And there might be lots of data to mine.
4 juin 2008 at 8:31 PM
> Aircraft
Sounds like special instruments would be preferable, avoiding people blogging about how the Boeing 737 thermometers were known biased and the Airbus temperature gauges were placed downwind of the engines….
But it’s being tried:
“… Moffett Field isn’t generally open to civilian aviation. To get access, Google’s founders, Larry Page and Sergey Brin, along with CEO Eric Schmidt, agreed to pay $1.3 million annually to NASA through a holding company they control and to carry scientific instruments aboard their aircraft….”
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/11/15/BU85SK0QM.DTL
I imagine the radio call.
“Hello, Sergei? Moffett here. We’re diverting your Hawaii vacation flight by a couple hundred miles to get better data on that hurricane offshore of Baja before it hits San Diego. Yes, hurricane. No, you’ll be fine. Fasten your seat belts, this may be a bit bumpy …”
4 juin 2008 at 10:21 PM
Or imagine hundreds of North Atlantic or polar flights — at very specific altitudes and routes - and altimeters are pretty accurate. How about 50 years of temperature data at 30,000 feet? Different planes and different hardware is similar to the bucket problem above. The data may be there in the past, certainly so in the future. Looks like a straight forward study.
4 juin 2008 at 10:22 PM
Re # 90 Timo
Most scientific “facts” are accepted as such based on probability - that’s the reason scientists perform, and report, statistical analysis of their data. And virtually all scientific conclusions are debatable (though some are so thoroughly confirmed that further debate is of little value). In this regard, climatology is no different from any other field of science. Surely you know all of this?
As for credibility, in order to avoid having to repeat every scientific study myself, I have to rely on research conducted by others in order to advance my knowledge. So, I have to mentally assign a degree of credibility to the papers I read, and to the authors of those papers. I’m much more willing to accept the findings of well-credentialed authors publishing in reputable, peer-reviewed journals. For the same reason, I am inclined to accept the information reported at RC based on the scientific reputations of the contributors. I know full well,however, that any given statement, or any given conclusion, by any of the RC contributors could be partially or completely wrong. But, I have far more confidence in their statements than I do of many of the authors at other climate science websites. Ro