Getting rid of the spurious blips - another look at global sea surface temperatures

Kevin Cowtan | Source: U York

Once again, Kevin Cowtan has brought his skills to climate science, working with Robert Rohde and Zeke Hausfather. They decided to explore those pesky ups and downs in the temperature record, which a lot of people (scientists mostly) have expressed concerns about. This new paper is largely addressing bucket bias in sea surface temperature and is very detailed. Taken with his other work on temperature records, this has to cement Kevin Cowtan's place among the "serious climate nerds" (h/t ykw!)

A hybrid check on sea surface temperature bias corrections

The authors analysed sea surface temperature, the main source of the temperature blips, from a new perspective. Their analysis can be seen mainly as a check of the bias corrections used in other sea surface temperature records. Instead of reanalysing data from ships and buoys, they compared weather stations on the coast and on islands with the measurements taken on ships when they passed close to the coast. They subjected this to further analysis and called the result a hybrid SST (sea surface temperature).

I can only imagine how much work this must have entailed. There are hints in the paper. Not only did they get the temperature records from land and nearby sea, they made adjustments in their analysis to compensate for the fact that with global warming, the land surface is warming faster than the sea surface, plus more.

They used their results to assess the bias correction that needs to be made when the sources for sea surface temperature changed, such as from buckets to engine intake, and to buoys (see below). The end result was a different check on sea surface temperatures and additional evidence that:

• Some of the odd blips in the temperature records were not what actually happened - particularly the upward WWII blip and the drop down around 1910
• The NOAA sea surface temperature record from 1997 onwards is probably closest to reality. On the other hand, the Cowtan17 analysis indicates ERSST v4 is too warm in the earliest years (1860 to 1900 or so) and too cool in the early 20th century (1910 to late 1930s).
• Climate models reflect reality even more closely than previous records suggest. 

There's an excellent article on Kevin Cowtan's website which explains the research, and accompanying provisos. The paper and supporting information contain a lot more detail, including all the ifs and buts and maybes. Co-author Zeke Hausfather has a  Twitter thread about the paper, too.

Challenges in the historical record of sea surface temperature

The authors begin by pointing out that getting a record of sea surface temperature is more challenging in many ways than putting together land temperature records. The difficulty with sea surface temperature is that information sources change much more than those on land.

On the land, apart from getting as many records together as possible (thank you CRU and other early collectors, and more recently ISTI), the main issues to contend with are adjusting for changes in instrument design and location. Location changes can be identified from station records or inferred from abrupt changes in the record compared with neighbouring records. Technological change hasn't happened all that often in the past 150 years or so. The main ones include the introduction of the Stevenson screen way back, and the more recent shift to automatic weather stations with resistance probes replacing mercury thermometers.

On the sea, the problems include the different sources for temperature readings: buckets of differing materials being dipped into the sea, engine room intakes, sensors on the ships hull and, more recently, drifting buoys and satellites. Within all that, scientists have to account for things like changes in the height of ship decks, interruptions to the consistency of records caused by world wars (where the data source changed from predominately merchant ships to predominately naval vessels), and more. The marvel is that researchers have worked through all these difficulties and developed records of sea surface temperature going back many decades.

Questionable peaks and troughs in the SST records - WWII and all that

One period about which most scientists who've worked on the subject have had most issue with are the years of the second world war (WWII). Some data sets show a peak in temperature that has not been easily explained by weather or climate change phenomena. In addition, previous records show a drop in the temperature around 1910 that looks a bit odd. In this paper, the authors did not find the spike that exists in ERSST v5 and to a lesser extend in HadSST3. Neither did they find the drop in temperature in the early 1900s.

In the top chart below, the hybrid record is shown in blue. The different series are a bit hard to distinguish so you might want to click on the image to enlarge it.

Figure 1 | Comparison of the coastal hybrid temperature reconstruction (using all coastal stations and fitting the global mean of the coastal temperature differences only) to co-located data from HadSST3 and ERSSTv5 for the period 1850-2016. Spatial coverage is that of HadSST3 for all of the records, with coastal cells weighted by ocean fraction.The shaded region is the 95% confidence region for the HadSST3 anomalies including combined bias adjustment and measurement and sampling errors. The lower panel shows the adjustment applied to the raw data in the HadSST3 and coastal hybrid records. A comparison with the ERSSTv4 ensemble is shown in Figure S7. Source: Cowtan 17 Figure 12.

To help see the difference, the chart below compares the Cowtan17 hybrid record with NOAA's ERSST v4 record. As discussed, the two are very similar in the most recent decades, but differ much more in the period prior to the early 1940s.

Figure 2 | Comparison of coastal hybrid temperature reconstruction to the ERSSTv4 ensemble. The dotted line is the ensemble median, while the shaded region is the 95% range of the ERSSTv4 1000 member ensemble from Huang et al (2016). DOI: 10.1175/JCLI-D-15-0430.1 . Source: Cowtan17 supporting information Figure S7

The table below highlights further that the Cowtan17 analysis is closer to the NOAA data set for the period after WWII since 1997 than it is to the Hadley record (HadSST3). The trend of HadSST3 is lower than that found in Cowtan17 and ERSST v4.

Table 1: Trend in sea surface temperature since 1997. Source: Cowtan17 Supporting Information Table S2.

The analysis supports the CMIP5 models

Another thing the analysis suggests is that there is less of a difference between observations and the blended mean from CMIP5 model runs. This is shown in the chart below, from Kevin Cowtan's briefing paper, where the green line is the CMIP5 blended mean.

Figure 3 | Comparison of global temperature records based on either the UK Met Office sea surface temperature record (HadSST3), or our coastal hybrid record. The smoothed records are compared to the average of climate model simulations from the CMIP5 project. The lower panel shows the differences between each set of observations and the models. Source: Kevin Cowtan's blog article.

Constraints and provisos

The authors of Cowtan17 show a lot of restraint and go into quite a bit of discussion of uncertainties and provisos. They present their findings not as the be all and end all of temperature reconstruction, but as a suggestion of where to investigate further. Kevin Cowtan wrote in his briefing:

However we do not necessarily trust our new record, because of the assumptions we had to make in constructing it. The most important result of our work may therefore be to identify places where extra attention should be given to addressing problems in the existing sea surface temperature records. A secondary result is that caution is required when trying to draw conclusions about any differences between the models and the observations, whether it be to identify internal cycles of the climate system or problems in the models, because the differences that we do see are mostly within the range of uncertainty of the observations.

Just the same, this paper has a lot of merit, looks at the data differently, and shows that the spurious peaks and troughs from years gone by may indeed be out of whack. It also supports the records in recent times, which seems to me to add weight to their findings.

What deniers are saying about Cowtan17

Nothing. At least nothing at WUWT or anywhere else that I've seen. Either they all missed the paper because it came out in the holidays, or they haven't figured out what to say about it.

References and further reading

Cowtan, K., Robert Rohde, and Zeke Hausfather. "Evaluating biases in Sea Surface Temperature records using coastal weather stations." Quarterly Journal of the Royal Meteorological Society (2017). DOI: 10.1002/qj.3235 (pdf here)

• Evaluating biases in Sea Surface Temperature records using coastal weather stations - overview, briefing document, links to methods and data and more from Kevin Cowtan
• Twitter thread from Zeke Hausfather

The winner is NOAA - for global sea surface temperature

There's a new paper out that shows that, contrary to what you'll read on denier blogs, NOAA's latest version of global sea surface temperature is probably the best and most accurate around. It's the closest to observations, when you compare it to measurements from moored and floating buoys, Argo floats and radiometer-based satellite records of sea surface temperature.

Umpteen denier protests

Lamar Smith

You might remember how climate hoax conspiracy theorists, professional disinformers and other deniers protested loud and long when NOAA scientists published a paper about the revised NOAA temperature data. The US House Committee on Science, Space, and Technology, led by arch denier Lamar Smith, harassed NOAA endlessly with subpoena after subpoena. A lot of the changes to the NOAA temperature record were a result of a new version of the global sea surface temperature data set, known as Extended Reconstructed Sea Surface Temperature, or ERSST v4. The papers on that were published in February 2015 (see below). The protests only came, though, in June 2015 when there was a paper by Karl et al. That paper pushed denier buttons because it challenged the so-called "hiatus". You can read about Karl15 here, and the paper itself is here.

Explaining different results for climate sensitivity and the low bias

This was a month late at WUWT but better late than never I suppose.  WUWT's current leading blog writer, Eric Worrall, has written about a paper published last month in Nature Climate Change (archived here). The authors, Mark Richardson, Kevin Cowtan, Ed Hawkins and Martin B. Stolpe, had a look at how temperature records are sampled. They found that slower warming regions are preferentially sampled, which means that observations are biased low.

The authors reported that after adjusting for biases, and using observations, the transient climate response (TCR) is 1.66 °C with a 5% to 95% range of 1.0 to 3.3 °C. This is consistent with that derived from climate models considered in the AR5 IPCC report.

Paul Homewood and Christopher Booker are wrong about global surface temperatures

For some odd reason, arch-science denier Christopher Booker has been getting some play in the media. He's been broadcasting false claims about the surface temperature records.

Every so often a science denier will scour the temperature records to unearth some that have been adjusted upwards. They'll then shout to the world "fraud" "scam" "it's all a hoax". What I've never seen from any denier is them scouring the records for temperatures adjusted downwards. That would totally spoil their propaganda.

This sort of thing happens from time to time, often when the UN is meeting to discuss action on global warming. The timing of the denier attacks in this case coincide with the UN meeting in Geneva.

Anthony Watts blows his dog whistle to round up the cosmic ray lynch mob

Ha ha ha. This is hilarious. There's an article by Anthony Watts on his climate science denier blog WUWT where he writes (archived here):

A peer reviewed Nuccitelli smackdown
Posted on June 19, 2014 by Anthony Watts
Reply to “Comment on ‘Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change’ by Dana Nuccitelli et al.”

Anthony copies the abstract of the reply to the comment but nothing else apart from the above and a link to the reply. He leaves it up to readers to try to find the original paper, figure out who wrote it and see if they can lay their hand on the comment. (The reply was published a month ago, so Anthony is losing his touch.)

Click "read more" to read the rest :)

Silly chart day at WUWT - from Jan Zelman

In the umpteenth protest at Cowan and Way (2013) at WUWT (archived here), I came across the chart below.

Source: A fake sceptic at WUWT called Jan Zelman

It's got to be one of the silliest charts I've seen.  The chart is described as being an amalgam of the temperature at twenty weather stations in Antarctica.  Where those stations are located there is barely a clue. It's certainly not a gridded data set representing Antarctica as a whole. We're told it includes three stations in the interior.  But where the rest are who knows.  There is no attempt to distinguish between Western and Eastern Antarctica.  But even leaving that aside, even if you made the assumption that this was somehow representative of a continent with vastly different climatic zones (which I doubt), what I thought was really funny was:

• the line drawn from 2005 to the present and the bold statement that it's cooling - and yet 2007 and 2011 are the two hottest years in the chart.  And the fourth hottest year since 1997 was in 2009.  So three of the four hottest years have been since 2005.
• it's put up to "prove" that Cowtan and Ways' conclusions regarding the Arctic are wrong.  And it's at the opposite end of the world!

Silliest WUWT chart comparisons

The chart above is a long way short of being the silliest ever at WUWT.  Those would have to include the charts that Anthony doesn't dare draw from the words that are written because they are just too, too silly.  Like this one derived from David "funny sunny" Archibald's work:

And the charts from denier Don Easterbrook, where he variously reckons the temperature on the top of the Greenland ice sheet "correlates" with surface temperature of the entire world or is the same as. And denier Don's "predictions" of global surface temperature like the one  below:

Or maybe this one from Anthony Watts, copied from the wacky "journalist" Christopher Booker fits in there somewhere too. I've added some notes to illustrate just how silly it is.

More on Cowtan and Way

You can read Cowtan and Way here - it's now open access.  And if you want to see it explained, as well as an article here at HotWhopper, there have been quite a few other/better articles about it, for example:

• SkepticalScience.com, co-authored by the authors Kevin Cowtan and Robert Way with Dana Nuccitelli
• Zeke Hausfather at the Yale Forum on Climate Change and the Media
• The Carbon Brief by Roz Pidcock
• Stefan Rahmstorf at RealClimate.org
• Bart Verheggen on his blog My View on Climate Change
• Victor Venema at his blog Variable Variability

From the WUWT comments

A small sample from the scientific illiterates at WUWT. (Archived here.)

Like most of the fake sceptics who comment at WUWT, RichardLH hasn't the first clue about Cowtan and Way when he foolishly says:

December 4, 2013 at 3:18 am
I would have been much more impressed that Cowtan & Way had got something of interest if they had managed to align the two data sets they were using (UAH and HadCRUt4) before they did any of their infilling.

The fact that we still have not achieved even that small measure of agreement to date says an awful lot about climate science.

The two data sets are supposed to be representative of the same ‘Global Temperature over time’ after all.

First off, his comment misses the whole point of the paper.  Secondly, the two data sets are not representative of "the same" - one is land and ocean surface the other is varying heights in the troposphere. Thirdly, let's compare UAH global lower troposphere with HadCRUT4 global surface temperature anomalies.  Contrary to what Richard implies, they are not so different are they.

michael hart says he wonders what's the point because when the ice blocks move around the surface temperature in the Arctic will change - or something:

December 4, 2013 at 3:34 am
I keep wondering if I’m missing something critical. If you use kriging to infer absent data-points from near by (or not so near by) data points, how does that work in a dynamical system? I could see the value maybe where one was inferring, say, ore concentration in geological deposits, because the ore will still likely be there when you go to dig it up.

But when, for example, ice melts and/or moves elsewhere under the influence of wind-/currents-/salinity-/temperature-changes, what can you learn about the system by kriging as though the variables are fixed or vary in a constant and predictable manner? Or is learning about a dynamical system not the point of the exercise?

AndyG55 says he wishes the world would stop warming.  Don't we all!  He thinks the world will stop warming if we stop measuring the temperature.

December 4, 2013 at 2:54 am

“The future of science, democracy and the genuine environmental movement depends on the end of the AGW inanity. Get out of the way.”

Well said Konrad.. It is WELL PAST time that this myth was destroyed.. and the funding stopped.

Once the funding stops, people like KR can get on with their lives (without climate funds) and stop trying to defend the indefensible.

---

Kevin Cowtan and Robert G. Way (2013), Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends, Quarterly Journal of the Royal Meteorological Society, http://dx.doi.org/10.1002/qj.2297

It's utter nutter day at the WUWT nuttery, now with the Potty Peer

Christopher Monkton prides himself on his utter nuttery.   Anthony Watts loves utter nutters.  He puts up lots of articles by them.  Today we've had:

• Anthony Watts himself arguing that UHI has affected some temperature readings in the remote regions of the Arctic because of "human warmth" - see here
• Steve "mad, mad, mad" Goreham writing that "climate change is dominated by natural, not man-made factors" - see here
• Christopher Monckton writing about his offensive stunt that got him permanently banned from UNFCC processes, faking that he was the "honorary delegate from Burma".

Christopher writes a really, really silly article (archived here and updated) about the recent paper by Cowtan and Way.  He seems to be arguing that the paper doesn't do something that it never claimed to have done in the first place but which, according to the potty peer it should have done.  In other words, the potty peer has built a strawman so he can knock it down.

Nick Stokes demolishes Christopher's nonsense nicely quoting Christopher:

November 20, 2013 at 1:31 am

“The fundamental conceptual error that Cowtan & Way had made lay in their failure to realize that large uncertainties do not reduce the length of The Pause: they actually increase it.”

I’d like to see a quote where C&W are making that conceptual error. In fact, the “length of the Pause” as formulated here is a skeptics construct, and you won ‘t see scientists writng about it.

The period of “no statistically significant increase” is a meaningless statistical test. Rejecting the null hypothesis can lead to useful conclusions; failing to reject does not. It means the test failed.

Yes, HADCRUT takes account of the missing data in its uncertainty estimate, but does not correct for the bias in the trend. That’s what C&W have done.

If you bother to read the archived WUWT article (updated here), you'll notice that Christopher doesn't dispute the findings of Cowtan and Way.  So far I've yet to see anyone dispute it at WUWT, other than Anthony Watts.  And even he seems to be of two minds about it.

Update

I've updated the archive.  Watch out for the "absurd" pontifications of the batty duke (physics teacher rgbatduke who takes a very large number of words to display his profound ignorance of climate), the "genetic" fudgery  of ferd berple and RussR's comment (that I overlooked), in which he pointed out that Christopher argues that AGW continues:

Before long, therefore, another El Niño will arrive, the wind and the thermohaline circulation will carry the warmth around the world, and The Pause – at least for a time – will be over.

Science deniers use a flawed discarded IPCC chart, but accept Cowtan and Way (for the most part)

Science deniers have resorted to once again using a flawed discarded chart from an earlier draft of the AR5 IPCC report.  This time to consider the new paper by Cowtan and Way, which I've already written about here.

The denialati didn't have to use a flawed, discarded chart.  Though it's kind of cute that they've finally found something produced by the IPCC which they like.  Most of the time science deniers reject everything from the IPCC but when it comes to something the IPCC has rejected, they suddenly decide they'll embrace it.

Which discarded IPCC chart do science deniers hang onto so tenaciously? No, it's not the discarded chart showing short term projections (to 2015) for "Estimated changes in the observed globally and annually averaged surface temperature (in °C) since 1990 compared with the range of projections from the previous IPCC assessments".  It's the discarded IPCC chart showing short term projections (to 2015) for which "the focus is now on the range of selected scenario projections from AR4".

Not only do the deniers want to use a discarded chart, they want to use a discarded chart that uses older AR4 CMIP3 models (see below), not the discarded chart using CMIP5 models used by AR5.

One thing though, it looks as if some of the deniers have accepted some actual climate science.  Anthony Watts and Stephen McIntyre seem to have accepted Cowtan and Way.

Deniers refuse to see the envelope

It not all roses though.  Some of the science deniers reject what their chosen discarded chart purports to represent.  (I hope you're still able to follow the denier trail heading down their convoluted topsy turvey denier pathway.)The chart itself has grey shading (see below) that depicts the "90% uncertainty estimate due to observational uncertainty and internal variability based on the HadCRUT4 temperature data for 1951-1980".

Anthony Watts, probably because it's beyond him, writes a headline: simply copies and pastes a teeny bit from The Auditor's blog (CA archived here), writing (WUWT archived here):

In the context of IPCC SOD FIgure 1.5 (or similar comparison of models and observations), CW13 is slightly warmer than HadCRUT4 but the difference is small relative to the discrepancy between models and observations; the CW13 variation is also outside the Figure 1.5 envelope.

Well, first of all the fake sceptics are using a flawed chart to misrepresent the data.  Secondly, it's not "outside" the 90% envelope even on the flawed chart.

Oh boy! They really are a sad desperate bunch of scallywags, aren't they.

Just so you can see why science deniers use a rejected and flawed chart, this is the chart rejected by the IPCC but which the Auditor chose to depict:

Below is the closest chart in the final AR5 draft of the IPCC WG1 report, showing AR4 and CMIP3 projections out to a more realistic 2035.  Observations are within the range depicted by the models:

Source: IPCC AR5 TFE.3 Figure 1 page TS-96

And here, for comparison are temperature projections using the latest AR5 CMIP5 projections:

Source: IPCC AR5 TFE.3 Figure 1 page TS-96

Science denier's cannot help themselves...

I went to The Auditor's blog and read this (archived here):

That there are continuing defects in HadCRU methodology should hardly come as a surprise to CA readers. 

It reads like a denier interpretation, emphasising the words "continuing defects".  It's true that HadCRUT still doesn't provide for the Arctic properly.  Cowtan and Way call it a "bias" in their abstract. It's acknowledged by scientists that HadCRUT is biased because of the way HadCRUT is constructed.  Because of the gaps in the coverage particularly in the Arctic.  The fact that Cowtan and Way used a hybrid of different temperature sources shows that their method is not straightforward and I don't expect it would be easy to incorporate all the measures they used into a monthly update of HadCRUT.  Hopefully a reader will shed more light on that.

The Auditor then wrote this, which Anthony Watts omitted:

Attempts to reconcile and/or explain discrepancies between HadCRU and GISS also seem worthwhile to me.

I would not accept any praise coming from The Auditor.  It's not worth a brass razoo.  I'd only accept praise from scientists who specialise in studying the global surface temperature anomaly.  And there's plenty of praise to go around for Cowtan and Way from scientific sources without having to take any notice of the denialati.

Filling gaps in global surface temperature coverage

In any case, Cowtan and Way didn't do the work to reconcile or explain discrepancies between HadCRUT and GISTemp.  The reason they did the work was to fill in the gaps in global surface temperature coverage.  The results are what they are.

Here again is the video explaining the research and showing where the gaps are, the before and after Cowtan and Way:

The following is an excerpt from an article co-authored by Kevin Cowtan, Robert Way and Dana Nuccitelli at SkepticalScience.com (my bold italics):

The study, authored by Kevin Cowtan from the University of York and Robert Way from the University of Ottawa (who both also contribute to Skeptical Science), notes that the Met Office data set only covers about 84 percent of the Earth's surface. There are large gaps in its coverage, mainly in the Arctic, Antarctica, and Africa, where temperature monitoring stations are relatively scarce. ...

...Dr. Cowtan is an interdisciplinary computational scientist who recognized some potential solutions to this temperature coverage gap problem.

"Like many scientists, I'm an obsessive problem solver. Sometimes you see a problem and think 'That's mine, I can make a contribution here'"

The article goes on to describe how Cowtan and Way filled the gaps in coverage:

In their paper, Cowtan & Way apply a kriging approach to fill in the gaps between surface measurements, but they do so for both land and oceans. In a second approach, they also take advantage of the near-global coverage of satellite observations, combining the University of Alabama at Huntsville (UAH) satellite temperature measurements with the available surface data to fill in the gaps with a 'hybrid' temperature data set. They found that the kriging method works best to estimate temperatures over the oceans, while the hybrid method works best over land and most importantly sea ice, which accounts for much of the unobserved region.
Both of their new surface temperature data sets show significantly more warming over the past 16 years than HadCRUT4. This is mainly due to HadCRUT4 missing accelerated Arctic warming, especially since 1997.

It's been warming!

And the result was that the rate of increase in surface temperature between 1997 and 2012 turns out to be greater than that depicted by both HadCRUT4 and GISTemp.

Cowtan & Way investigate the claim of a global surface warming 'pause' over the past 16 years by examining the trends from 1997 through 2012. While HadCRUT4 only estimates the surface warming trend at 0.046°C per decade during that time, and NASA puts it at 0.080°C per decade, the new kriging and hybrid data sets estimate the trend during this time at 0.11 and 0.12°C per decade, respectively.

From the WUWT comments

Below are a few of the comments from Anthony Watts WUWT article (archived here).  Although Stephen McIntyre seems to accept the findings, most of Anthony Watts' WUWT rabble can't bring themselves to do so.

R Taylor gets what is "supposed to be" backwards.  I guess R Taylor hasn't heard of Arctic amplification and says:

November 18, 2013 at 2:15 pm
Pity the polar data, tortured into an inadequate confession. After all, greenhouse theory says the tropical troposphere is supposed to warm first and fastest.

catweazle666 is plain weird and thinks that if the surface heats up it must mean the oceans don't, and says:

November 18, 2013 at 2:30 pm
What happened to all the heat that was hiding deep in the oceans?
How did it suddenly migrate to the Arctic – retrospectively too, apparently.
Clearly this is groundbreaking new scientific theory!

prjindigo cannot cope with any new scientific findings and decides that knowledge is a "fake religion" and says:

November 18, 2013 at 2:36 pm
So one man’s BS doesn’t match another’s? Its starting to look like the data sets are all fake religions.

Ugh! Tedious Bob Tisdale promises another lengthy impenetrable boring cut and paste from his endless wrong diatribes and says:

November 18, 2013 at 3:00 pm
Darn, Steve M beat me to the apparent 2005 breakpoint in the difference between the HADCRUT and Cowart and Ray (2013) data. My versions are here:
http://bobtisdale.files.wordpress.com/2013/11/figure-44.png
My post will hopefully be finished tomorrow and I’ll explain why that’s odd…among other things the warmistas have overlooked.

ROM says he's gone and made a fool of himself at Lucia's blog, apparently not realising that the Cowtan and Way analysis is from 1979 to 2012.  Nor does he understand that the purpose of the study was not to come to a predefined outcome.  It was done to fill in the gaps in the coverage.  The findings were what they were.  You'll see that ROM equates discovering new knowledge with being raped.  What a nutter!

November 18, 2013 at 3:12 pm
I have just posted this on Lucia’s “The Blackboard”

As a humble member of the public who is expected to pay for most of this climate science research guff and who as a member of that low life uninformed public who are expected to lay down and be data raped by every passing wannabe climate scientist, it seems to me that the finangling [ I could use some quite unprintable language to describe this ] of the data where no data exists to get a result that ensures that what is seen to be happening in the climate, isn’t according to the non existent data.

In this case attempting to dispel the idea that there is a “Pause” in the warming using some fancy and argued about statistical techniques applied to that non existent data taken from a region where there are almost no records to justify the claim there isn’t a Pause of over 16 years running in the climb in global temperatures.

So why is it that this particular statistical lash-up couldn’t also be applied to those 20 years of supposed increasing temperatures from 1978 to 2007, a period which is only 4 years longer than the Pause and on which 20 years the entire global warming meme / ideology is based.
Using Cowtan & Way’s statistical techniques and the same identical data base of temperatures it could probably be proven that there was no increase in global temperatures during that 20 years of supposed warming.

milodonharlani is a purist denier.  He doesn't "believe" the science (excerpt):

November 18, 2013 at 5:53 pm
The models aren’t based upon either physics or observations. They’re based upon GIGO assumptions not in evidence, indeed contrary to all actual observations & physical evidence.

Dumb Scientist does a terrific job of informing the denialati and responding to their questions at WUWT, copping a fair bit of flak in the process (archived here).

---

Kevin Cowtan and Robert G. Way (2013), Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends, Quarterly Journal of the Royal Meteorological Society, http://dx.doi.org/10.1002/qj.2297

Anthony Watts' protest about Cowtan, Way and the Arctic

Anthony Watts has found something new to protest (archived here).  It's an interesting paper by Kevin Cowtan and Robert G Way published in the Quarterly Journal of the Royal Meteorological Society.

The Arctic is warming at about eight times the pace of the rest of the planet

The paper has been described and discussed in various places.  What the researchers did was take a novel approach to work out recent temperature changes in parts of the world where there are gaps in the data.  Here is a report from ScienceDaily.com:

An interdisciplinary team of researchers say they have found 'missing heat' in the climate system, casting doubt on suggestions that global warming has slowed or stopped over the past decade.

Observational data on which climate records are based cover only 84 per cent of the planet -- with Polar regions and parts of Africa largely excluded.

Now Dr Kevin Cowtan, a computational scientist at the University of York, and Robert Way, a cryosphere specialist and PhD student at the University of Ottawa, have reconstructed the 'missing' global temperatures using a combination of observations from satellites and surface data from weather stations and ships on the peripheries of the unsampled regions.

The new research published in the Quarterly Journal of the Royal Meteorological Society shows that the Arctic is warming at about eight times the pace of the rest of the planet. Previous studies by the UK Met Office based on the HadCRUT4 dataset, which only covers about five-sixths of the globe, suggest that global warming has slowed substantially since 1997. The new research suggests, however, that the addition of the 'missing' data indicates that the rate of warming since 1997 has been two and a half times greater than shown in the Met Office studies. Evidence for the rapid warming of the Arctic includes observations from high latitude weather stations, radiosonde and satellite observations of temperatures in the lower atmosphere and reanalysis of historical data.

A member of the Department of Chemistry at York, Dr Cowtan, whose speciality is crystallography, carried out the research in his spare time. This is his first climate paper.

He says: "There's a perception that global warming has stopped but, in fact, our data suggests otherwise. But the reality is that 16 years is too short a period to draw a reliable conclusion. We find only weak evidence of any change in the rate of global warming."

Robert Way adds: "Changes in Arctic sea ice and glaciers over the past decade clearly support the results of our study. By producing a truly global temperature record, we aim to better understand the drivers of recent climate change."

More about the research

There are some very readable discussions about the paper at:

• realclimate.org by Stefan Rahmstorf
• skepticalscience.com by the authors, Kevin Cowtan and Robert Way, with Dana Nuccitelli
• Variable Variability by Victor Venema - with lots more links
• Arctic Sea Ice Blog by Neven

The authors used a statistical technique known as kriging to interpolate data from neighbouring sites that have temperature observations to determine the temperature in between.  Here is how Wikipedia describes kriging:

The basic idea of kriging is to predict the value of a function at a given point by computing a weighted average of the known values of the function in the neighborhood of the point. The method is mathematically closely related to regression analysis. Both theories derive a best linear unbiased estimator, based on assumptions on covariances, make use of Gauss-Markov theorem to prove independence of the estimate and error, and make use of very similar formulae. They are nevertheless, useful in different frameworks: kriging is made for estimation of a single realization of a random field, while regression models are based on multiple observations of a multivariate dataset.

Kriging was also used by the Berkeley Earth Surface Temperature team. What was novel about this research was that the authors also used a hybrid method, combining satellite data and surface data.  They found by testing that the hybrid method gave the most accurate results over land and sea ice, whereas kriging was best over open oceans.

It's all a bit too much for Anthony Watts and his band of fake skeptics

Anthony would discount any reasonable discussion of the paper as being too sciency.  He managed to find a denier slant proffered by Judith Curry (archived here). And he did find some words of his own to help get his crew fired up (archived here):

Breathless interpreters of Cowtan & Way claim that by doing the same with satellite data instead of tortured surface data, Voilà “the pause” disappears.

It looks as if Anthony didn't read the paper or any discussion of it.  If he had, he would have seen that the authors used both satellite and surface data.  I guess he didn't watch the video he posted, either.  Here it is:

Judith Curry shows her ignorance - and she has researched the Arctic

Over at Judith Curry's blog (archived here), Kevin Cowtan, one of the authors, explains, rather nicely and politely, that (my hyperlinks):

Dear Dr Curry
Thank you for you comments. We indeed hope that one of the results of our paper will be to stimulate a vigorous discussion in this area.

With respect to kriging across land ocean boundaries, we note that this is a problem in the paper. Can I draw your attention to our update memo [Sou: I think Kevin is referring to this] in which we test separate reconstruction of the land and ocean data before blending, which is in our view a better approach. To do this properly would require access to the HadCRUT4 land ensemble which is not currently distributed, but with the CRUTEM4 data (which lacks some corrections) the results of blending pre- or post-reconstruction is almost indistinguishable, even under different ice-coverage assumptions. (There is no reason why this must be the case, it is a result of the distribution of the unobserved regions). Dynamically changing ice is more difficult, and you can’t do it with anomalies as you don’t know what kind of bias you introduce when changing a cell from land to ocean, so we’ll have to leave that problem to the BEST team.

Most interesting is the issue of the UAH data over Antarctica. We’ve recently been looking at this with respect to both Vostok, and the Bromwich 2012 Byrd reconstruction. Byrd particularly interesting – it sits on a cell boundary and is remarkably well modelled by the cell to the north in the hybrid reconstruction. The cell to the south models the year-to-year variations, but not the long term trend. We’ve made some preliminary analysis of what is going on based on differencing North-South transects in the UAH data. Some regions show no significant changes, whereas others show large changes in either direction around 2000. I hope to write this up as another update, and maybe Dr Christie will be able to shed more light on the issue, although I’m afraid everything takes a long time when you’re doing it in your spare time.

So it may be that kriging is a better approach for Antartica, especially with remediated data from some of the isolated stations – Byrd is critical here, and I want to do some detailed comparisons with BEST too. Against that, the holdout tests actually favour the hybrid approach for most of the existing station locations, including the SP.

Having said all of that, the difference between the hybrid and kriging reconstructions of Antarctica is only really significant around 1998, so it doesn’t greatly affect our conclusions. And the Arctic is sufficiently small that the two reconstructions are very similar. Most of the Arctic coverage bias also arises in the NH winter, when the Rigor result is most relevant.

If I may appeal to your own expertise, there would seem to be a parallel between our results and those of Cohen et al 2012 (doi:10.1088/1748-9326/7/1/014007). Do you think there is a plausible connection? November 13, 2013 at 4:23 pm 

Robert Way added some comments of his own in response to Judith Curry's complaints (my bold, with Judith Curry's comments in italics ).

First, Kriging. Kriging across land/ocean/sea ice boundaries makes no physical sense. While the paper cites Rigor et al. (2000) that shows ‘some’ correlation in winter between land and sea ice temps at up to 1000 km, I would expect no correlation in other seasons.

Response [1] Actually in the paper we show through rigorous cross-validation tests (see Table 1; Table 2; Figure 3) that kriging is an effective approach for estimating temperatures, even across boundaries. However the hybrid approach performs better than any other method at reconstructing high latitude temperatures (see Figure 3 – cross validation) even at distances of 1650 km). In the case of sea ice this hypothesis has been tested (see Figure 4) where it is shown that kriging from land regions outperforms kriging from ocean cells.

Second, UAH satellite analyses. Not useful at high latitudes in the presence of temperature inversions and not useful over sea ice (which has a very complex spatially varying microwave emission signature). Hopefully John Christy will chime in on this.

Response [2] As indicated in the response to the 1st comment – we have tested the methodology adopted in this study against both held-out observations and against grounded/floating buoys in the Arctic ocean, often located on sea ice. The results of our study indicate that the performance of the hybrid method is reasonable over ice (Figure 4; Figure S5).

We also provide an attempt at showing the impacts of changing sea ice conditions on the reconstruction. Although not available in the supplemental information we have also tested the method in Antarctic against the reconciled Byrd station located in one of the most icebound, isolated places on the planet. The results of this test show very reasonable performance with the hybrid method.

Third, re reanalyses in the Arctic. See Fig 1 from this paper [Sou: the paper Judith cites is one of hers published in 2002], which gives you a sense of the magnitude of grid point errors for one point over an annual cycle. Some potential utility here, but reanalyses are not useful for trends owing to temporal inhomogeneities in the datasets that are assimilated.

Response [3] Since the paper in question was published there have been significant advances in reanalysis methods. In particular, 4-D methods such as those employed by ERA-Interim have shown to be much more reliable in the Arctic and Antarctic. There are a series of papers by James Screen at Exeter which delves into many of these issues and examines the performance of reanalysis products in both the Arctic and Antarctic. I would suggest that Dr. Curry take a bit of time to have a look at the results of some of these studies. That being said the paper does not use reanalysis to infill temperatures, nor do we use it with the kriging, reanalysis is simply presented as an additional source of evidence in additional to satellites, radiosondes and isolated weather stations which show that the Arctic is rapidly warming. Physical evidence is also available in the form of sea ice reduction and glacier changes as well as melt records from high Arctic ice caps. There is a wealth of literature supporting the conclusions that the Arctic is warming rapidly and this relationship (Arctic Amplification) is clear in the paleorecords.  November 13, 2013 at 4:31 pm

Judith, having mispelt Robert's family name throughout (Wray instead of Way) posts a reply immediately under Robert's but for some reason decides to call him James and then, for no reason at all, says she doesn't believe him.  (Yeah, I went 'huh?' too).  Judith also said she doesn't know of any reanalysis studies done by James Screen despite her having done some recent research on the general topic.

James, thanks for stopping by and engaging here. I agree that there is evidence of warming in the Arctic, however, I remain unconvinced that your methods are verified in any meaningful way for surface temperatures of open water and sea ice in the Arctic Ocean. I see no reference to papers by James Screen in your paper, I don’t know what papers you are referring to. I have recently done a comprehensive literature survey regarding in situ surface temperature and surface flux measurements in the Arctic Ocean (for a grant proposal). I have not seen any recent studies evaluating reanalyses using these data sets. November 13, 2013 at 6:56 pm

So much for Judith's research skills! I would have said that a ten second Google Scholar search would have saved Judith Curry a certain amount of embarrassment, except that she has never shown any sign of being embarrassed by her bloopers.

From the WUWT comments

I'll leave interested readers to do any further reading with the links I've provided above.  Let's just see what the various members of the WUWT brigade have to say (archived here).

Judge starts the ball rolling and maybe got up Anthony's nose a bit by pointing out that he mimicked Judith Curry's mis-spelling of Robert Way's name (which Anthony later corrected) and says:

November 14, 2013 at 9:32 am
Way not Wray – “Robert G. Way”

omnologos points out that it can't be warming everywhere.  Someone is probably wrong.  Thing is, I don't think the Cowtan and Way necessarily claims to account for all the difference between the models and the other global temperature data sets, but I could be wrong:

November 14, 2013 at 9:35 am
Just like Kloor has shown it’s ridiculous now for alarmists to do their regular ambulance chasing at every hurricane or drought, likewise scientists should stop claiming to have found the missing heat in the most convenient of places, namely where nobody can get much reasonable data from (it was the depths of the ocean, not it’s the most remote of the North Pole).

There are also many other problems with this pausebuster. Have the scientists involved deliberately misled the IPCC by telling nobody about what was incoming two months later? If they are right, isn’t Dear Kev wrong about the oceans?

If they are right, then people claiming that there was a pause (based on non-infilled data)were right, and Dana and SkS wrong in dismissing the pause.

Also if the North Pole puts the trend back to expected values, this means the recent warming is becoming more and more northern-polar than global.

Furthermore this would be yet another AGW miracle, with values magically going back to be exactly as expected.
Etc etc.

Kev-in-Uk says he can't stomach science:

November 14, 2013 at 9:36 am
Here we go again – more data from the ‘middle of nowhere’, literally! I dunno whether I can stomach to watch the method video. Someone tell me if it makes sense, and if I can use the same methodology to magic money into my bank account, as there is none there at present!

Paul Homewood, recently of super-typhoon infamy, hasn't bothered reading anything about the paper but agrees that it's been getting very warm in the Arctic lately.  He says:

November 14, 2013 at 9:42 am
Even GISS figures with their 1200km smoothing (right or wrong) show the same pause as the other sets, so they cannot argue the poles are being ignored.
Indeed, take out the poles from the GISS dataset, and I would imagine you would end up with a cooling trend.

tWISTERdATA says:

November 14, 2013 at 9:44 am
Lots of sciency talk. Lets just simplify: “We made stuff up.”

Then tWISTERdATA posting again, this time as tornadomark, decided he could improve on his previous comment and says:

November 14, 2013 at 9:45 am
Lots of Sciencey talk. Here’s the bottom line: “We made stuff up to support the cause.”

Salvatore Del Prete makes believe he knows something about science and says:

November 14, 2013 at 9:48 am
Filling in data is worse then doing nothing.

Eliza says she doesn't know why WUWT bothers with sciency stuff (maybe it should stick to paranoid conspiracy theories) and says:

November 14, 2013 at 10:15 am
I dont’ know why such drivel (The paper) even gets mentioned here.

Ian W just knows all those scientists are wrong and so is the Royal Society of Meteorology and all the reviewers.  He lets everyone know why all the scientists are wrong.  A change in temperature tells you nothing, he cries, and proceeds to build a heated strawman (excerpt):

November 14, 2013 at 1:05 pm
Water does not scatter the infrared it absorbs it. Thus it raises the heat content of the air without raising its temperature. That is the enthalpy of the air (its heat capacity) increases as the humidity increases.

Mosher and all the other non-engineers are averaging temperature are thus averaging the wrong metric. They should be measuring heat content in kilojoules per kilogram. After all isn’t the ‘global warming hypothesis’ about trapping heat – you can’t trap temperature Steven can you?
So as davidmhoffer says it requires almost no heat at all to raise the temperature of a volume of dry arctic air at minus 30C by one degree, but a large amount of energy is required to raise the temperature of a similar volume of 90% humidity equatorial Pacific air by one degree because the humid air enthalpy is so much higher. Yet you ‘highly trained climate scientists’ average the temperature of these volumes of air to measure heat???

For that reason alone the Cowtan and Way should have been thrown out at peer review.

Gunga Din lightens the mood and says:

November 14, 2013 at 1:13 pm
So………….the missing heat is hiding in the cold?

 Steven Mosher and Nick Stokes chime in with some science stuff, much to the disgust of the WUWT-ers.  For example, Nick Stokes writes:

November 14, 2013 at 1:32 pm

“At first glance, this seems an admirable and reasonable goal, but one should always be wary of trying to create data where there is none, something we learned about in Steig et al’s discredited paper on the supposed Antarctic warming.”

Steig’s paper was not discredited, and particularly not his method of fitting satellite-derived EOFs to station data to infill. His critics Ryan et al used the same method. They used more EOFs, which gave an improvement.

Whenever you calculate a space average from sampled data, there is an implied assumption that the samples are representative of data in between. That’s not just climate science, it’s for any continuum analysis. The average is justified by interpolation. Any form of rational interpolation is better than leaving areas out.

Even a couple of fake sceptics concede the point Nick Stokes made. Mark Bofill says:

November 14, 2013 at 1:45 pm
I’m often critical of Nick but I’ve got to say I think he’s got a point here. I haven’t read the paper (with my limited grasp of the science it wouldn’t make all that much difference if I did) but from what I’ve gathered so far from the discussions about it I’m thinking this paper is probably pretty solid. Perfect? No, but it’s probably a step in the right direction.

Louis doesn't understand how scientific knowledge grows and says:

November 14, 2013 at 2:02 pm
If climate scientists accept this paper, won’t they be admitting that they have been calculating the average global temperature wrong all this time? If they could make such a big mistake in how they estimated polar temperatures, doesn’t that open the door to the possibility of other major mistakes in their methodology? Do they really want to admit that the science isn’t so settled after all?

The paranoid arrive a bit late to the WUWT playground.  Dolphinhead says:

November 14, 2013 at 2:05 pm
I’m guessing this is another of those papers that will be used by politicians as if it was written on tablets of stone and will be quoted as the reason why we must continue to de-industrialise the West.

Philip Peake is sad that the scientists don't take heed of all the fake experts at WUWT and says:

November 14, 2013 at 2:12 pm
The sad thing here appears to be using data which is not understood.
The even sadder thing, is that a (supposedly) respected journal and its expert reviewers didn’t catch that.

Janice Moore gets up a head of steam and as one of seven posts in a row, all of them meaningless, shouts (excerpt):

November 14, 2013 at 7:23 pm:
...This stupid paper (given that it reveals ANY truth) does at least indicate that the IPCC models which projected Arctic cooling are even WORSE than we already knew that they were ……….which isn’t saying much …………………. which makes this paper just a piece of junk.  As someone above aptly said: THEY ARE JUST MAKING IT UP AS THEY GO. Pitiful.

That about covers it, unless you're a glutton for punishment and want to read more WUWT comments - archived here.

---

Kevin Cowtan and Robert G. Way (2013), Coverage bias in the HadCRUT4 temperature series and its impact on recent temperature trends, Quarterly Journal of the Royal Meteorological Society, http://dx.doi.org/10.1002/qj.2297