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« Science as a public enterprise | Main | Piling on »
Tuesday
Jun052012

Large-scale temperature trends

This is a guest post by Rob Wilson. It addresses some concerns I raised when I spoke in St Andrews the other week. I had discussed Climategate and the lack of trust this engendered and then went on to briefly cover other issues that made me uncomfortable. In particular, I mentioned the tendency of corrections to the temperature records to produce cooling in the nineteenth century and warming in the twentieth, and the recent lack of warming.

In light of Myles’ and other comments w.r.t. instrumental data, I thought this might be a good time to quickly try and address some of Andrew’s observations that he made in his talk at St Andrews in April.

I had hoped to write a guest post along with colleagues from the Met Office showing temperature trends along with AR4 projections, but I already see the summer running away and what spare time I have, I would rather concentrate on a series of later guest posts focussing on dendroclimatology. So below, I concentrate only on temperature trends in the HADCRU and HADSST data-sets. Thanks to Ed Hawkins and John Kennedy for providing feedback.

There were two issues that Andrew raised:

  1. That updates of large scale temperature data-sets appear to depress 19th century and raise 21st century temperature values.
  2. That over the last decade or so, there had been a flattening off in temperature trends.

At the time, I could not comment on either as I had not looked at the new data-sets in detail.

So – the following link will take you to a series of figures that compares CRUTEM3 and 4 (land temperatures) and HADSST2 and 3 (SST) for northern and southern extra-tropics (ET) and tropical (TROP) latitudinal bands. References at end.

http://www.st-andrews.ac.uk/~rjsw/ftp/TempTrends.htm

For those of you who want to check and replicate my plots, the data can be easily accessed from the Met office website:

http://www.metoffice.gov.uk/hadobs/hadcrut3/

http://www.metoffice.gov.uk/hadobs/hadcrut4/

http://www.metoffice.gov.uk/hadobs/hadsst2/

http://www.metoffice.gov.uk/hadobs/hadsst3/

or perhaps an even more user friendly site is:

http://climexp.knmi.nl

I have purposely not added trend lines, or smoothing functions and have just plotted the temperature anomalies (w.r.t. 1961-1990).

I am not going to describe trends in exhaustive detail, but really want to address Andrew’s two main concerns.

Older vs newer temperature data-sets

There has been little change in the NH ET input data-sets. The major changes I am aware of are some early instrumental corrections of temperature data-sets in the Greater Alpine Region. However, this is only a small number of records in the extensive NH data-set so does not impact the large scale mean series. For those interested, the Alpine data-set correction is detailed here:

Böhm R, Jones PD, Hiebl J, Frank D, Brunetti M, Maugeri M (2010) The early instrumental warm-bias: a solution for long central European temperature series 1760 – 2007. Climatic Change 101, 41-67.

http://www.slf.ch/fe/landschaftsdynamik/dendroclimatology/Publikationen/index_DE/Bohm_2010_ClimCha.pdf

For TROP and southern hemisphere ET land temperatures, the major changes are in the 19th century which reflects the addition of newly digitized station records – probably mainly from Australia. Early instrumental temperatures are always going to be less certain and there is less data.

Changes in the late 20th century appear to be minimal.

w.r.t. SST, again little difference between HADSST2 and 3 in the ET NH.

The period of greatest difference in the TROP SST data is around the post 1940’s period which are related to biases in HADSST2 w.r.t. an “uncorrected change from engine room intake measurements

(US ships) to uninsulated bucket measurements (UK ships) at the end of the Second World War.” These have been adjusted in HADSST3. For those interested, the relevant paper is:

Thompson et al. (2008) A large discontinuity in the mid-twentieth century in observed global-mean surface temperature. Nature 453, 646-649

http://www.roberts.cmc.edu/159/2009%20Combined%20pdfs/Feb%2010%202009.pdf

For the southern hemisphere ET SSTs, we again see similar corrections in the 1940s as in the tropical SSTs, but interestingly, the HADSST3 are actually marginally “colder” in the recent period than HADSST2. I only highlight this to show that correction can go both ways.

As a final note, correction for homogeneity biases in temperature record is very important and if you want more information on the basic theory, a really good review paper is:

Peterson,T.C. et al, (1998). “Homogeneity adjustments of in situ atmospheric climate data: a review.” International Journal of Climatology, 18 1493-1517

http://www.st-andrews.ac.uk/~rjsw/PalaeoPDFs/Peterson-etal-1998.pdf

 

The recent flattening of temperature trends

As for the recent flattening. Well this appears to vary markedly. For NH ET winter temperatures, there is clearly an “eye-ball” flattening in winter temperatures, but likewise, a continued increase in summer temperatures. Tropical land temperatures appear to show continued warming for all seasons, but tropical SST records could be argued to have flattened. SH ET land temperatures is a little mixed – perhaps a flattening in summer, but still increasing in spring and autumn.

Statistically, due to internally forced multi-decadal variability expressed in all of these records and the fact that we are “at the end of the time-series”, I think it is really very difficult to “quantify” a flattening or even a continued increase. Yes, we can fit linear trend lines to the latter end of the time-series, but with the known naturally forced decadal variability expressed in these data-series, I personally think that such exercises are really not very helpful. This issue will simply become clearer over the next 10-20 years............but should we wait until we have statistical certainty?

Final thought

So – my take home message. Let’s not generalise too much. The newer HADCRU4 and HADSST3 data-series are incrementally improved data-sets using new data and utilising corrections related to robust theory and methods. Many on this blog will disagree with this statement, but all I can urge is please read the papers below. Much effort is focussed on the uncertainties and biases in these records. I do not see a systematic change (between old and new) to cooling (warming) of early (late) large scale instrumental series – rather I see improved data-sets (HADCRU4 and HADSST3) with well documented uncertainties.

As for temperature trends, in the same way that it does not really matter if the medieval period was warmer or cooler than today, it does not really matter if a particular seasonal time series shows an increase or flattening in temperatures. What MATTERS is that we need to understand the drivers of these changes. Natural or anthropogenic (or a mix of both). CO2 cannot explain all trends since the 1850s, but likewise internal dynamics (PDO, ENSO, NAO etc) or changes in the sun or large-scale volcanic events cannot alone explain the variability in climate.

References:

Jones, P. D., D. H. Lister, T. J. Osborn, C. Harpham, M. Salmon, and C. P. Morice (2012), Hemispheric and large-scale land surface air temperature variations: An extensive revision and an update to 2010,

J. Geophys. Res., 117, D05127, doi:10.1029/2011JD017139.

http://www.metoffice.gov.uk/hadobs/crutem4/CRUTEM4_accepted.pdf

Kennedy J.J., Rayner, N.A., Smith, R.O., Saunby, M. and Parker, D.E. (2011b). Reassessing biases and other uncertainties in sea-surface temperature observations since 1850 part 1: measurement and sampling errors. J. Geophys. Res., 116, D14103, doi:10.1029/2010JD015218

http://www.metoffice.gov.uk/hadobs/hadsst3/part_1_figinline.pdf

Kennedy J.J., Rayner, N.A., Smith, R.O., Saunby, M. and Parker, D.E. (2011c). Reassessing biases and other uncertainties in sea-surface temperature observations since 1850 part 2: biases and homogenisation. J. Geophys. Res., 116, D14104, doi:10.1029/2010JD015220

http://www.metoffice.gov.uk/hadobs/hadsst3/part_2_figinline.pdf

Morice, C. P., J. J. Kennedy, N. A. Rayner, and P. D. Jones (2012), Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 dataset, J. Geophys. Res., doi:10.1029/2011JD017187, in press.

http://www.metoffice.gov.uk/hadobs/hadcrut4/HadCRUT4_accepted.pdf

 

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Reader Comments (190)

What MATTERS is that we need to understand the drivers of these changes. Natural or anthropogenic (or a mix of both). CO2 cannot explain all trends since the 1850s, but likewise internal dynamics (PDO, ENSO, NAO etc) or changes in the sun or large-scale volcanic events cannot alone explain the variability in climate.

I'm not a climate scientist but I came from the generation that was taught to question 'authority' ...
http://wattsupwiththat.com/2012/06/04/sun-and-clouds-are-sufficient/

Jun 5, 2012 at 8:23 AM | Unregistered CommenterStreetcred

It's nice to read a guest post on these two issues but this is not very convincing response to my scepticism of climate science. Rob, you've said Bish was querying the changed temp records to show a warming in the 21st C. His own comment shows he's referring to the 20th. Being inaccurate from the word go does not augur well. Later you write "it doesn't really matter if the medieval warm period was warmer than today". Speak for yourself. It does matter. If the medieval warm period was warmer than now it follows that CO2 present then cannot have been as high as now from mankind's emissions because we were emitting so much less then. So if CO2 was less present then than now then the current CO2-is-causing-global-warming-and-we-need-a-carbon-tax-to-move-to-a-low-carbon-economy-to-mitigate-warming argument is logically unsupportable. I am here in Oz and we are facing a CO2 tax starting 1 July to mitigate the warming that CO2 has apparently caused. A tax on something that has never been taxed ever before. Can you and your Met office colleagues not see how profoundly disagreeable it is to have climate scientists just fob off critical logical issues like this? As I noted at the start of this comment it's great you've posted but my goodness, the gulf between how you think and how I think is vast.

[BH adds. Don't draw conclusions from what Rob has said about 21st century vs me saying the 20th. We're both just talking about "the end of the record" if you like]

Jun 5, 2012 at 8:25 AM | Unregistered CommenterWB

It easy to lose the detail in the overall database, the specific adjustments are harder to explain such as

http://wattsupwiththat.com/2012/05/03/has-the-crutem4-data-been-fiddled-with/

If we had explanations for why these changes were made it would be better, more pointedly why are these changes not publically documented right from the start.

Jun 5, 2012 at 8:55 AM | Registered CommenterBreath of Fresh Air

WB said "the gulf between how you think and how I think is vast" - not only different in thought!

There is also another dimension to this and that is the preservation of one's funding!

Jun 5, 2012 at 8:55 AM | Unregistered CommenterConfusedPhoton

Slightly O/T but the series around

http://chiefio.wordpress.com/2012/06/02/ghcn-v1-vs-v-north-america-region-4/

might be of interest

Jun 5, 2012 at 8:58 AM | Unregistered CommenterAnother Ian

When will these people learn what the rest of the real science community have know for centuries, you do not adjust data. You cannot adjust data, there is no justification for adjusting the data.

Adjusting data for any reason is a 'criminal offense' in real science. You collect, collate, analyse the data. That's it. The more people like Betts, Thompson et al write the more corrupted the data looks to us scientists.

It is impossible to know for certain the type or amount of adjustment, or even the direction, that would be required for old temperatures to be the same as new. They are what they are, PLEASE, LEAVE THEM ALONE.

Jun 5, 2012 at 8:58 AM | Unregistered Commenterstephen richards

or perhaps an even more user friendly site is:

Update
Apologies BOFA you got the link up while I was still searching.

Jun 5, 2012 at 9:05 AM | Registered CommenterLord Beaverbrook

Hmm, who to trust? CRU, or Chiefio? No contest.

So, tell us how many of the adjustments have been past up present down. Now tell us how likely that proportion of the whole is, if there was anything fair going on.

And above all, once you have lost the trust, you cannot easily get it back. Certainly not by shouting louder or re-asserting the same old stuff. The impression is that anything which fits the agenda is included, anything which does not fit is ignored or suppressed. One could disprove that by listing all the CRU output which doesn't support CAGW. Sound of crickets...

Jun 5, 2012 at 9:07 AM | Unregistered CommenterRhoda

The MWP is a real thorn in the side for the alarmists. The current tack is to grudgingly acknowledge that it may have been real after all but dismiss it as being irrelevant. Sorry but some of us are keeping track of the pea and attach great significance to the MWP. Anyone who dismisses it as irrelevant clearly has an agenda that is grounded in considerations other than the science and logic.

Statements such as
"I think it is really very difficult to “quantify” a flattening or even a continued increase" and
"I personally think that such exercises are really not very helpful. This issue will simply become clearer over the next 10-20 years............but should we wait until we have statistical certainty?"
only go to reinforce my suspicion of those who now seem to be reluctantly acknowledging that the science is NOT settled but cannot bring themselves to actually say it.

Jun 5, 2012 at 9:21 AM | Unregistered CommenterTC

"but should we wait until we have statistical certainty...."

Pascal's Wager is spotted yet again! Believe, because the chances that disbelief will send you to eternal damnation are very small, but the payoff is so huge that no matter how small they are, belief is the only rational course.

We need to be certain enough to make the proposed course of action rational. You cannot get around this. Imagine this form of argument in medical cases.

Proposer: Lets dose the entire male population over 50 with statins to lower heart disease rates.

Reply: There is no reason to think it will work, and in fact there is some reason to think it will raise rather than lower death rates in that population.

Proposer: But should we wait till we have statistical certainty when the life and death of all men over 50 in the UK is at stake?

Reply: Yes, that is exactly why we should wait, not for statistical certainty whatever that is, but for enough evidence to persuade us that its a reasonable course of action.

These guys are amazing. Not only can't they do statistics, they can't even think straight.

Jun 5, 2012 at 9:40 AM | Unregistered Commentermichel

Rob Wilson's home page at Edinburgh University states:

I am currently funded through the European Union on a project entitled, "Millennium - European Climate of the last Millennium. The Millennium project is a multidisciplinary consortium of more than 40 European universities and research Institutes, with the aim of answering a single question:

Does the magnitude and rate of 20th Century climate change exceed the natural variability of European climate over the last millennium?


Why is all this taxpayers money being spent if "it does not really matter if the medieval period was warmer or cooler than today"?

Jun 5, 2012 at 9:43 AM | Unregistered CommenterPhillip Bratby

Like Rhoda above, I place greater trust in chiefio`s analyses (see another Ian above for link) than climate scientists on the official payroll. The latter have failed the fundamental test - that of public scrutiny; chiefio has demonstrated that part of the reported increase is the result of station selection.

Jun 5, 2012 at 9:55 AM | Unregistered Commenteroldtimer

Like Rhoda above, I place greater trust in chiefio`s analyses (see another Ian above for link) than climate scientists on the official payroll. The latter have failed the fundamental test - that of public scrutiny; chiefio has demonstrated that part of the reported increase is the result of station selection.

Jun 5, 2012 at 9:55 AM | Unregistered Commenteroldtimer

Nice to see you posting Rob, and look forward to more. As we all know negative feedback is much better for us than positive feedback, so I'm going to give you a little negative feedback in the hope that it will improve your next postings. I found the post rambling, it didn't get to the point but provided us with loads of information which I suppose you thought would help us understand what's happened. it may do for some people but it hasn't for me, so maybe I'm looking for an answer to a different question, a question that seems so simple to answer I'd be surprised if you couldn't do it in a paragraph. Well two questions actually, both reasonably simple to answer. Let me put them to you:

1. There are constant adjustments being made to the past temperature records. While I can see a reason to adjust data at the time of taking the measurements, for say satellite orbit variations, or urban heat island effects, once those adjustments are made then the data goes into the record. Now in the 19th century there were probably adjustments but of a less sophisticated kind. So the people who made the adjustments are dead, and we have no record of what they were, so the 19th century data is the same as it was in the the 19th century, it hasn't changed. We have no information that would allow us to go back and change the records so the records shouldn't be changed. So what possible explanation can there be, in simple terms for adjusting historical data records? I don't see it in your post.

2. Do you not think that the whole thing is like the Monty Python dead parrot sketch, where the shopkeeper knocks the parrot and tells the customer the parrot's just moved and isn't dead, and the customer telling him it was dead and he has just seen the shopkeeper knock it to make it move? You know, you're telling us humans have warmed the planet we're pointing out that there's nothing unusual going on and you're reducing historical temperatures and we're saying we've seen you.

Jun 5, 2012 at 9:58 AM | Unregistered Commentergeronimo

The real additional logical fallacy in the call to action is this. Let us suppose that high cholesterol levels are correlated with heart disease rates. Does it follow that if we reduce cholesterol levels we will either lower heart disease rates or reduce death rates?

No. We have to do studies and prove it. And in this particular case, what we discover is that when we add cholesterol lowering drugs to statins, we raise death rates compared to just statins. We discover that when we use cholesterol lowering drugs on their own, death rates from causes other than heart disease rise. Biology is complicated. So public policy requires us not only to prove that A is associated with and arguably causes B, it also requires us to prove that working on A in some prescribed way is both safe and effective.

It may seem obvious that lowering CO2 emissions and ppm will produce cooling. Show us where in the historical record that has occurred. Show the evidence that its a safe and effective. And this is not logically the same as showing that the rise in temps since 1850 is plausibly the result of rises in CO2 ppm. This is an independent policy prescription which has to be evaluated on its merits.

Jun 5, 2012 at 9:59 AM | Unregistered Commentermichel

You say:

As for temperature trends, in the same way that it does not really matter if the medieval period was warmer or cooler than today, it does not really matter if a particular seasonal time series shows an increase or flattening in temperatures. What MATTERS is that we need to understand the drivers of these changes.

You’re saying here that it doesn’t matter what the changes are, we just need to understand what’s causing them.

That’s nonsense.

Jun 5, 2012 at 9:59 AM | Unregistered Commentergeoffchambers

With "climatology" becoming the South Sea Bubble of academia - there's a risk of being submerged in the vast number of competing data sets.

For non climatologically-inclined, simple minded souls like me; if Rob Wilson is following this - could he put my mind at rest by commenting on this overlay of Steve Goddard's showing Hansen's US temperature record adjustments made between 1999 and 2000.

http://stevengoddard.wordpress.com/2012/05/16/tormented-hansen-in-the-months-before-he-corrupted-the-us-temperature-record/

Jun 5, 2012 at 10:16 AM | Registered CommenterFoxgoose

I often wonder what the homogeneity-adjusted data for the 5th/6th of June 1944 would look like.

Meteorologischen Durch Technik

Jun 5, 2012 at 10:18 AM | Unregistered CommenterAnoneumouse

"The major changes I am aware of are some early instrumental corrections of temperature data-sets in the Greater Alpine Region. However, this is only a small number of records in the extensive NH data-set so"

I wouldn't be so sure. The same group at ZAMG is responsible for the RAOBCORE corrections to the rawisonde data globally, so it should be looked at very carefully. One point I never understood in the raobcore is that for many stations the dates of correction do not correspond to the date for instrument replacement, so the main reason for discrepancies is lost.

I am also aware that the magnitude and sign for the Alpine data correction is always in the same direction, à la NIWA, producing always present warming, whatever the past fluctuations. Here an example: http://img411.imageshack.us/img411/3471/tcorrectedzamg.png
I have shaded the station name and actual values, because I am pretty sure that the person that gave me the data would run into trouble. Why don't they publish the uncorrected data?

Jun 5, 2012 at 10:18 AM | Registered CommenterPatagon

Awhile back Richard Betts pointed at the following MO page to explain the HadCRUT3 /Arctic issues hence the need for HadCRUT4:-

“Global-average annual temperature forecast”

http://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/long-range/glob-aver-annual-temp-fc

At the bottom of the page is:-

Figure 3: The difference in coverage of land surface temperature data between 1990-1999 and 2005-2010. Blue squares are common coverage. Orange squares are areas where we had data in the 90s but don't have now and the few pale green areas are those where we have data now, but didn't in the 90s. The largest difference is over Canada.

Could somebody from the MO explain why did the MO not have the 2005-2010 Canadian land surface temperature data? Were they closed? If they have been could somebody please point me in the right direction? Are they now back online?

Why would we have them now and in the 90s but not in-between? Are they included/excluded by choice if so is it possible to clarify the mechanism? Without clarification of such changes it is difficult to understand how any trends in the data can be representative.

Many, many thanks for the post, still reading through (v.short of time), apologies if the above is covered, hopefully get to it later or could somebody point me to the relevant paper/ref?

TIA

Jun 5, 2012 at 10:26 AM | Registered CommenterGreen Sand

"CO2 cannot explain all trends since the 1850s, but likewise internal dynamics (PDO, ENSO, NAO etc) or changes in the sun or large-scale volcanic events cannot alone explain the variability in climate."

But internal dynamical changes could alter circulation patterns which then effect cloud cover. This could fully explain temperature changes. Not saying that that is the explanation, but odd how he neglected to mention it, eh?

Jun 5, 2012 at 10:37 AM | Unregistered CommenterWill Nitschke

"CO2 cannot explain all trends since the 1850s, but likewise internal dynamics (PDO, ENSO, NAO etc) or changes in the sun or large-scale volcanic events cannot alone explain the variability in climate."

So we know and can measure every forcing in the climate system Rob? Is that true, or are you assuming their are no unknown unknowns?

Jun 5, 2012 at 11:05 AM | Unregistered Commentergeronimo

"This issue will simply become clearer over the next 10-20 years............but should we wait until we have statistical certainty?" Agreed - time will settle the issue. But your parenthetical question is not fair. We have not waited. We have undertaken major initiatives towards reducing carbon emissions. Other 'we' have not done so much (Chinese, Americans, Indians, Brazilians). Australian 'we' are about to do something though with a carbon tax (but their little puff of CO2 is hardly here or there). Canadian 'we' are doing their tar sands thing. German 'we' have lots of solar cells though shutting down nuclear because of Fukushima. Eurozone is falling apart (maybe) - German 'we' blamed for that as well. EU 'we' trying to keep the eurozone together and funding your research. Jolly good.

Jun 5, 2012 at 11:16 AM | Unregistered CommenterPeter Mott

geronimo "unknown unknowns"

Isn't the IPCC mantra "well we can't think of any other cause - so it must be Carbon dioxide"

Jun 5, 2012 at 11:34 AM | Unregistered CommenterConfusedPhoton

Hasn't Steve McIntyre done things about SSTs and the insulated/uninsulated bucket adjustments & was non-too inpressed by them?

Jun 5, 2012 at 12:55 PM | Unregistered CommenterAdam Gallon

Stephen Richards,

I agree with your comments 100%. If you adjust the data, it ain't science.

Jun 5, 2012 at 1:20 PM | Unregistered Commenterdrcrinum

Rob Wilson

I have a couple of points; I'd be interested in your thoughts:

First, on the substance of your post. I don't know the details of what Andrew asked about. However, as far as I can tell, you've chosen a very particular source of temperature data to assess whether "updates of large scale temperature data-sets appear to depress 19th century and raise 21st century temperature values". You concluded that the adjustments weren't large, were justified and weren't systematically in one direction.

Elsewhere on this thread, other data sets have been advanced which seem to show much more significant adjustments, with less apparent justification and which seem to be systematic in just the way Andrew was concerned about.

It would need a survey of all adjustments to all temperature data sets to avoid the risk of "cherry-picking" (or at any rate, accusations thereof) on either side. As far as I know there's no single publicly available data set which sets out the adjustments made to all the temperature series.

Now these series are claimed to be of the utmost importance for assessing AGW, its economic impact and appropriate actions (see eg Myles Allen's recent contribution). They are possibly the most economically significant data ever gathered, yet it seems none of the organisations responsible for the data sets has published a simple list of all the adjustments which have been made to all the data sets.

If I've got that wrong, and there is such a comprehensive list of adjustments, do let me know. Otherwise, how can the lack of such a publicly available list be justified?

Second, on your remarks:

"As for temperature trends, in the same way that it does not really matter if the medieval period was warmer or cooler than today, it does not really matter if a particular seasonal time series shows an increase or flattening in temperatures. What MATTERS is that we need to understand the drivers of these changes."


I'd second Geoff Chamber's comments: "You’re saying here that it doesn’t matter what the changes are, we just need to understand what’s causing them."

As Geoff implies, your stance really doesn't make sense. It seems likely that if there was an MWP, climate models may find it hard to account for it. On the other hand, if modellers do find some means to make an MWP, they may find that the same means accounts for some of the recent warming. Similarly, if the recent apparent fall in the rate of increase of temps (I put it no more strongly than that) wasn't predicted, it indicates that something is wrong, possibly seriously so, with the models.

In both cases, MWP and recent history, the facts are crucial to assessing the status of the models. You won't know that you've misunderstood the "climate drivers" unless you know that the climate has been driven in a different direction to where models say it should have gone.

Jun 5, 2012 at 1:22 PM | Unregistered CommenterSimon Anthony

I think that there are known problems with measuring temperatures, like radiative heating depending on the housing, rawisonde inexpensive thermometers, location, ventilation, etc.

However, the corrections are even more uncertain than the original data, and for that reason raw data should always be available, together with a replicable correction procedure. Error bars should be bigger than the correction factor in most cases.

The fact that so many corrections are predictably in favour of the consensus hypothesis is very worrying.

Jun 5, 2012 at 1:58 PM | Registered CommenterPatagon

Rob Wilson needs to respond to Phillip Bratby. Why does he now say "it does not really matter if the medieval period was warmer or cooler than today" when he was/is(?) part of a ~40 institute project funded by the EU that said:

"Reconstructing the climate of the past is important because it will allow us to say whether the warming seen in recent years is really unusual."

?

http://137.44.8.2/ (the Millennium Project - they seemed to have lost their domain name)

Jun 5, 2012 at 3:00 PM | Unregistered Commenterclimatebeagle

Myles Allen also tried to convince us that the MWP was unimportant and I challenged him on that as I challenge Rob now.
The MWP (like all the other "named" climatic events) is vitally important because we are being asked to pauperise ourselves and destroy western civilisation on the basis that the current warming is unprecedented. If the MWP was warmer than the present, or was at least no colder, then AGW theory begins to look a little threadbare. It is essential, as we have been told numerous times, that we "get rid of the Mediaeval Warm Period".
It is for the same reason that MBH98 was so vital and why the hockey stick became the poster child for TAR and AR4. (I don't care how few times it was mentioned; it was the context in which it was used and promoted that was important). Finally there was some scientific evidence that 20th century warming was unprecedented, at least for the last 1000 years. The fact that data were dubious and the method even more so was irrelevant — you know what they say about lies and how long it takes truth to get its boots on.
And to cap it all we now find that Rob Wilson is up to his neck in EU-funded research to establish whether the warming seen in recent years is really unusual. Presumably the answer is contained in the idea that it doesn't matter whether it's warm or cold or getting warmer or getting colder it's why it's getting warm or cold that matters.
Colour me unconvinced.

Jun 5, 2012 at 3:22 PM | Registered CommenterMike Jackson

Stephen Richards said it all, in his comment (as drcrinum has already pointed out, in his comment). Just refuse to have anything to do with these fatally mauled datasets (and the same goes for Hanson's GISS data, for the same reason). "Adjusting" data is saying "the science is settled" in the strongest, and most obnoxious, way to other scientists. It is a criminal offense to honest scientists. Geronimo's point #2, earlier, is also appropo.

Jun 5, 2012 at 3:34 PM | Unregistered CommenterHarry Dale Huffman

On 'Further thoughts on Carbon Taxes' I have explained MDGNN's ideas on Tallbloke, also being developed by Claes Johnson. The outcome as far as this thread is concerned is that if they are right and the models exaggerate GHG warming [MDGNN thinks indirect thermalisation at clouds may explain Miskolczi's constant IR optical depth], natural effects are much more important.

The present temperature and OHC plateau means natural cooling >= incremental GHG-AGW. Since tsi on its own can't explain this, it's probably from cloud area convolved with albedo.Thus the Earthshine project shows an increase of albedo by 1% since 1998, or about 3% greater cloud albedo.

This is equivalent to ~ 2.4 W/m^2 reaching the Earth's surface and lower atmosphere. The response of the oceans is the rate controlling factor and so far it's just the North Atlantic that's cooling: http://bobtisdale.files.wordpress.com/2012/01/figure-102.png

This localised fall in OHC has to arise from the Arctic melt ending. This is apparently proven by recent 1930s Greenland data: http://tallbloke.wordpress.com/2012/05/30/greenland-glaciers-unprecedented-retreat-similar-to-1930s-warming/#more-6572

The land glaciers retreated further then than now but sea melt has been greater now presumably because SST is higher. From the 1940s we reverted to cold winters and OHC fell. Our winters are getting colder and OHC is falling. Last week was the coldest Stockholm June day for 86 years. Canberra ACT had its coldest May in 50 years. 7.00 am Perth WA on 24th May, coldest in a Century.

As for the mechanism, there is plenty of evidence showing now and in palaeo times that phytoplankton blooms cause temporary regional warming and the mechanism is probably higher [CCN] reducing cloud area/albedo. When the blooms die off, the process reverses. To this one must add the new Little Ice Age unstable jet streams: http://www.youtube.com/watch?v=Y8QviKVMtE8&feature=youtu.be

CO2-AGW as the main influence cannot explain such cooling including today's UK's snow >2,400 feet.

Jun 5, 2012 at 3:43 PM | Unregistered Commenterspartacusisfree

Vineyards in Yorkshire were only possible because the Vikings, and before them the Romans, came across in their bloody SUVs, beltching all that CO2 and causing globull warming.

Don't you guys know anything?

Jun 5, 2012 at 4:17 PM | Unregistered CommenterRoger Longstaff

Jun 5, 2012 at 9:21 AM | TC
"The MWP is a real thorn in the side for the alarmists."

"As for temperature trends, in the same way that it does not really matter if the medieval period was warmer or cooler than today"

It looks like Rob is willing to concede that the MWP was warmer than today as it doesn't affect his argument and isn't of any importance to his work. So can we just make the assumption that it was for other arguments sake.

I do agree we would like to know what caused the MWP and the very similar looking 1910-1940 and 1970-2000 warming periods. I assume CO2 warming advocates advocate different attributions for the 2 20th century periods. I'm also interested in what the main cause of the MWP was (and the LIA)

Jun 5, 2012 at 4:21 PM | Unregistered CommenterRob Burton

Jun 5, 2012 at 4:17 PM | Roger Longstaff

"Vineyards in Yorkshire were only possible because the Vikings...."

Roger, if you are in the area I'd recommend a visit to the Leventhorpe vineyard on the edge of Leeds. The owner is amazingly enthusiastic and will give you a good idea on the difficulties of growing vines in Yorkshire. I think it is still the most northerly vineyard in the country.

Jun 5, 2012 at 4:33 PM | Unregistered CommenterRob Burton

Rob Wilson - If I have understood correctly, the charts you present compare one homogenised and gridded version of an index to another.

From the perspective of an observer, my understanding is that the 2011 ICO ruling requiring UEA to release ungridded, yet previously adjusted, station data in response to J Jones' FOI request does not alter the position on unadjusted data as published on the Met Office sites FAQ page:
//
"Land surface climate station records - frequently asked questions

3)Why is there no comprehensive copy of the underlying data?

The data set of temperatures, which are provided as a gridded product back to 1850, was largely compiled in the 1980s and 1990s when it was technically difficult and expensive to keep multiple copies of the database.

For IT infrastructure of the time this was an exceedingly large database and multiple copies could not be kept at a reasonable cost. There is no question that anything untoward or unacceptable, in terms of best practices at the time, occurred."
//
Have I understood this correctly - there is no archive of original data? Without an audit trail to original data, how do you know that there are no issues such as those that Paul Homewood identifies in GHCN?:

http://notalotofpeopleknowthat.wordpress.com/2012/03/14/reykjavik-temperature-adjustments/

I have read para 4.2.1 of the Peterson paper you linked and, IMO, it is worryingly subjective.

Jun 5, 2012 at 4:54 PM | Unregistered Commenternot banned yet

Quite often people get very emotive with references like “what about your grand children”. Well if you really want to look after your grand children start holding present day scientists to their responsibilities.

It is the inherent responsibility of this generation of scientist to ensure that those yet to come will have pure unadulterated raw data upon which to base their yet to be defined decisions.

It is far from apparent that this will be the case.

If there is one thing that this, the first generation of climate scientists, can do to aid homo sapiens understand their climate then it is is to secure the unadulterated raw data. At this infant stage in the development it could be that the establishment of good sound raw data is far more important than hypothetical solutions.

Jun 5, 2012 at 5:01 PM | Registered CommenterGreen Sand

Contrast

"This issue will simply become clearer over the next 10-20 years......." "What MATTERS is that we need to understand the drivers of these changes. Natural or anthropogenic (or a mix of both). CO2 cannot explain all trends since the 1850s, but likewise internal dynamics (PDO, ENSO, NAO etc) or changes in the sun or large-scale volcanic events cannot alone explain the variability in climate."

with

Statement from the UK science community 10 December 2009

"We, members of the UK science community, have the utmost confidence in the observational evidence for global warming and the scientific basis for concluding that it is due primarily to human activities. The evidence and the science are deep and extensive. They come from decades of painstaking and meticulous research, by many thousands of scientists across the world who adhere to the highest levels of professional integrity. That research has been subject to peer review and publication, providing traceability of the evidence and support for the scientific method.

The science of climate change draws on fundamental research from an increasing number of disciplines, many of which are represented here. As professional scientists, from students to senior professors, we uphold the findings of the IPCC Fourth Assessment Report, which concludes that 'Warming of the climate system is unequivocal' and that 'Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations"

one of the many signatories was a Dr Rob Wilson of St Andrews University.

Is it just me or do we seem to be going backwards in our understanding of 'the drivers of these changes'?

Jun 5, 2012 at 5:21 PM | Unregistered CommenterDolphinhead

"We, members of the UK science community, have the utmost confidence in the observational evidence for global warming and the scientific basis......'

Yet the 2009 Trenberth Energy budget adds to SW energy transformed at the surface heat double that energy claiming it's confirmed by pyrgeometers when in reality, for a normal temperature gradient it's zero..

This appears to be about the biggest experimental fail in History.

Jun 5, 2012 at 5:33 PM | Unregistered Commenterspartacusisfree

Rob, despite my filippant remarks I will visit Leventhorpe - thank you, I had no idea about it.

To make a further flippant remark - warm periods are really not very good for us - we get invaded! First the Romans and then the Normans. During the Dark Ages (King Arthur et al) and the (LIA) middle ages (Good Queen Bess who saw orf the Armada) we scattered our foes to the four winds. I am getting really confused about this correlation and causation stuff!

Jun 5, 2012 at 5:55 PM | Unregistered CommenterRoger Longstaff

When I compare HADCET summer to UK Summer to HADCRUT3 or HADCRUT4 I think "Who the hell do they think they are"?

UK Tmax Summer:

http://i48.tinypic.com/2jee645.jpg

HADCET summer

http://sunshinehours.wordpress.com/2012/05/14/hadcet-june-july-and-august-trend-for-350-years-is-a-measly-009c-per-decade/

Where is this mythical warming that shows up in HADCRUT3 or HADCRUT4 but doesn't show up in UK summer temperatures.

Jun 5, 2012 at 6:57 PM | Unregistered CommenterBruce

I have mixed feelings about the post by Rob Wilson. I am grateful to him for giving us some explanations and for his comments. However, I strongly reject a large number of his claims. Many of these are covered above, so I won't repeat them here.

The thing that irritates me most is that the author and many of his colleagues state that the climate changes cannot be explained by natural events alone. There are many papers that say that that climate changes can be explained by natural events. (Many of these have been reviewed by P Gosselin and others).

I find it amazing that in an embrionic science where the level of understanding is obviously close to zilch, we have scientists reaching conclusions about what is causing climate change through a process of elimination. The eliminated factors seem to have features in common; they are most obvious ones to influence the climate, such as solar effects and clouds, they are very poorly understood and therefore we don't know how to put them in the models. Furthermore, we can't influence them and therefore they are never going to fuel a funding gravy train.

Even the CO2 effect is harmless without the assumed massive positive feedback from water vapour. There now papers that show that the feedback is actually strongly negative.

I'm afraid that all of this reinforces my feeling that AGW is more of a religion (based on faith) and the scientific search for truth has no place in its thinking.

Jun 5, 2012 at 7:50 PM | Unregistered CommenterSchrodinger's Cat

Hi Folks,

To those who state that adjusting data is a criminal offense to honest scientists, isn't science, or that it categorically should never ever be done, or some similar statement, I give you the GUM: The guide to the expression of uncertainty in measurements.

http://www.bipm.org/en/publications/guides/gum.html

In the document
http://www.bipm.org/utils/common/documents/jcgm/JCGM_100_2008_E.pdf

I would particularly draw your attention to section 3.2.3

"3.2.3 Systematic error, like random error, cannot be eliminated but it too can often be reduced. If a systematic error arises from a recognized effect of an influence quantity on a measurement result, hereafter termed a systematic effect, the effect can be quantified and, if it is significant in size relative to the required accuracy of the measurement, a correction (B.2.23) or correction factor (B.2.24) can be applied to compensate for the effect."

Also of relevance is Annex D, section D.3. (The "true" value and the corrected value) or, for those who don't like words, but do like pictures, D.6 has a nice pictorial representation.

The GUM "establishes general rules for evaluating and expressing uncertainty in measurement that are intended to be applicable to a broad spectrum of measurements." Its development was supported by:

BIPM: Bureau International des Poids et Mesures
IEC: International Electrotechnical Commission
IFCC: International Federation of Clinical Chemistry
ISO: International Organization for Standardization
IUPAC: International Union of Pure and Applied Chemistry
IUPAP: International Union of Pure and Applied Physics
OlML: International Organization of Legal Metrology

I also offer a personal anecdote from particle physics in which subject, the energy of jets of hadrons are often systematically undermeasured by calorimeters necessitating a correction factor, or adjustment to the data, which is based (brace yourselves) on a computer model of the detector.

For something a little more climatic, the papers by Christy et al. describe the process of turning voltages on detectors that are sensitive to radiances at certain microwave frequencies into estimates of global atmospheric temperatures. The process involves systematic adjustments for detector temperature and orbital drift amongst others.

I believe a sound rule is to preserve the raw data, but in calculating useful measures from the readings, adjustments are admissable.

Jun 5, 2012 at 8:01 PM | Unregistered CommenterNebuchadnezzar

Nebuchadnezzar

Cracking post! Thanks.

Jun 5, 2012 at 8:32 PM | Unregistered CommenterBBD

Raw data must be preserved, it is the only true record of the measurements and observations. I have no problem with data being manipulated, provided the raw data is also shown or referenced. The changes in the data should be clearly shown in order that others can decide whether the adjustments are justified or not.

If anyone changes the raw data in a non-transparent way, especially in a direction that supports his agenda, it becomes less like science and more like deception and fraud.

Jun 5, 2012 at 8:42 PM | Unregistered CommenterSchrodinger's Cat

Rob and Nebuchadnezzar (8:01 PM), as far as I understand one problem in this situation, it seems to be a more transparent/trustworthy/reliable method for many "outsiders" if the public (apparently many "outsiders") could knew for example what was done precisely, and how, when or why the adjustments were done (There is the same question with regard to the code(s), data, all measurements,... module(s).). Do you agree?

Jun 5, 2012 at 8:49 PM | Unregistered CommenterSeptember 2011

It has been shown several times on the net (and I have done the calculation myself too) that for the GHCN data the corrections applied to the data over the period 1910 onwards have a slope upwards of around 0.3 degC per century. Two very simple questions:

1. Why would we believe the approximately 0.8 degC warming over the 20th century is caused by man when (a) half of it occured prior to 1940 when CO2 effects were unimportant (although that point is slowly being erased in the "story" put forward by AGW supporters) and (b) when 0.3 deg of it is the "corrections" to the data

2. Please explain in simple terms why a global temperature measurement over 100 years should require a systematic correction over time. For what? The only systematic physical effect I can think of is UHI and that would require the oppoiste slope correction. Why would a thermometer in 1910 and a thermometer in 1950 require different averge corrections across the entire global average of the data set?

Jun 5, 2012 at 9:02 PM | Unregistered CommenterThinkingScientist

Greetings.
Sorry I have not replied earlier, but the end of term is a rather busy time w.r.t. exam board meetings and degree classification calculations etc. I will try and make some brief responses below to anything I feel I can make comment to. Remember, I am a data user (w.r.t. instrumental data) and used this opportunity to look at the new data-sets. Essentially, I wanted to address Andrew’s two points and I hope I have done so. I do not see a systematic relative depressing of 19th century temperatures or a raising of late 20th/early 21st century temperatures. Also trends in the recent period (whether a flattening of a continued rise) appear to vary with season and latitudinal band.

I will not make comments to any links to other blog posts. If individuals have alternative hypotheses, then they should write a paper and submit to an appropriate journal. Yes, I KNOW, there is a conspiracy to bury alternate theories, but forgive me if, in a slightly flippant way, I ignore such statements.

Re. my comment w.r.t. the Medieval Period. If we are talking globally (or northern hemisphere at least), I do not believe we can state confidently (at 95% C.L.) that it was warmer or cooler than present. It was a warm period and to make a comparison with the present period, we need much more data for 1000 years ago. There is obviously a lot of distrust on this blog of the hundreds of instrumental data-series used for the large scale temperature composite records like CRUTEM4 etc, so we certainly need to be much more cautious with our statements when utilising 10-30 “noisy” proxy records for the medieval. At local scales there are many records that show a warmer medieval than present but there are also others that show cooler conditions.

Re. stephen Richards. I am sorry, but adjustment of these data is important, but where possible, I would agree that non-adjusted data-series should also be made available as well as the “corrected” homogenised records. Maybe someone from the Met Office can comment here. I certainly would be interested to see a CRUTEM4 equivalent using data-sets that had minimal or no corrections. I would not be surprised if the error bars were greater but the final global time series post 1880 would look quite similar.

Re. TC – yes – the MWP is perhaps a thorn in the side of the community, but not in the way you state. At the moment, large scale proxy composites and models do not agree pre ~1300. I think that is a real concern and needs to be addressed. The same models however, do model very well the 1300-present period.

Re. Will Nitschke and Geronimo – I am not a modeller but I do believe w.r.t. internal forcing and some feedbacks (e.g. clouds), the models might well struggle, but please don’t quote me on that (you probably will!). Please note that as some of you here don’t want your taxes wasted on climate research, my only conclusion is that these individuals don’t want further study in trying to understand the complexities of the climate system. This would be foolish I think.

Re. “not banned yet”. Individual station data (corrected and non-corrected) can be access from the GHCN (http://www.ncdc.noaa.gov/ghcnm/) which I think can be more easily accessed from the “monthly station data” link at http://climexp.knmi.nl. The problem with many GHCN records is that they do not all come up to present. This link
http://www.metoffice.gov.uk/hadobs/crutem4/data/download.html
may provide information on the theoretical availability of individual stations used in CRUTEM4.

Re. Dolphinhead. I stand by my signing of the Statement from the UK science community 10 December 2009.

Re. Schrodinger's Cat. Please feel free to send me PDFs or links (Google me at St Andrews) of the studies you mention w.r.t. natural forcing explaining temperature trends for the last few centuries. You may not believe it, but I do have an open mind.

Lastly, some of you are a prickly bunch and I will try and keep my responses measured. However, some of the personal e-mails sent to me today would be rather embarrassing to some of you if I posted them on BH. So let’s please keep this civil. I can accept that some/many of you are rather sceptical, but insults will not help the discourse.
Rob

Jun 5, 2012 at 9:17 PM | Unregistered CommenterRob Wilson

In reply to Rob Burton @ 4.33 pm

These appear to be the most Northerly vineyards in the country

http://www.ryedalevineyards.co.uk/

according to Bing Maps they are 37.5 miles by road from Woodlesford in a North Easterly direction

Jun 5, 2012 at 9:27 PM | Unregistered Commenterrockchicken

Nebuchadnezzar

Systematic error only has meaning in controlled experiments. We are talking atmospheric temperature recording methodology wherein there is/was no standardization, no calibration, no siting uniformity, no instrument uniformity, no calibration, no quality control, differences in altitude, no recording uniformity, etc., with scant to neglible records from the polar regions. The raw data used to construct the temperature record would be laughed out of existence in any other scientific field. To take such data and then manipulate it or adjust it is not only arbitrary, it is absurd. Additionally, atmospheric temperature has little meaning with respect to heat content without consideration of humidity, a parameter totally lacking from the discussion.

And just for your information, if you take the "unadjusted raw data" from only US stations that were in continuous operation (continuous reporting) from 1900 to 2000, then one finds absoluting no warming at all = completely flat. http://wattsupwiththat.com/2011/10/24/unadjusted-data-of-long-period-stations-in-giss-show-a-virtually-flat-century-scale-trend/

Jun 5, 2012 at 9:41 PM | Unregistered Commenterdrcrinum

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