"Independent confirmation of global land warming without the use of station temperatures†," by Gilbert P. Compo et al., GRL (2013); DOI: 10.1002/grl.50425

Geophysical Research Letters, (2013); DOI: 10.1002/grl.50425

Independent confirmation of global land warming without the use of station temperatures

1. Gilbert P. Compo^1,2,*, 
2. Prashant D. Sardeshmukh^1,2, 
3. Jeffrey S. Whitaker²,
4. Philip Brohan³, 
5. Philip D. Jones^4,5, and 
6. Chesley McColl^1,2

Abstract

[1] Confidence in estimates of anthropogenic climate change is limited by known issues with air temperature observations from land stations. Station siting, instrument changes, changing observing practices, urban effects, land cover, land use variations, and statistical processing have all been hypothesized as affecting the trends presented by the Intergovernmental Panel on Climate Change and others. Any artifacts in the observed decadal and centennial variations associated with these issues could have important consequences for scientific understanding and climate policy. We use a completely different approach to investigate global land warming over the 20th century. We have ignored all air temperature observations and instead inferred them from observations of barometric pressure, sea surface temperature, and sea-ice concentration using a physically-based data assimilation system called the 20th century Reanalysis. This independent dataset reproduces both annual variations and centennial trends in the temperature datasets, demonstrating the robustness of previous conclusions regarding global warming.

Link to abstract:  http://onlinelibrary.wiley.com/doi/10.1002/grl.50425/abstract

"Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 dataset" by Colin P. Morice et al., JGR (2012) in press; doi:10.1029/2011JD017187

Journal of Geophysical Research, (2012); doi:10.1029/2011JD017187

Quantifying uncertainties in global and regional temperature change using an ensemble of observational estimates: The HadCRUT4 dataset

Colin P. Morice, John J. J. Kennedy, Nick A. Rayner and Philip Douglas Jones

Abstract

Recent developments in observational near-surface air temperature and sea-surface temperature analyses are combined to produce HadCRUT4, a new dataset of global and regional temperature evolution from 1850 to the present. This includes the addition of newly digitised measurement data, both over land and sea, new sea-surface temperature bias adjustments and a more comprehensive error model for describing uncertainties in sea-surface temperature measurements. An ensemble approach has been adopted to better describe complex temporal and spatial interdependencies of measurement and bias uncertainties and to allow these correlated uncertainties to be taken into account in studies that are based upon HadCRUT4. Climate diagnostics computed from the gridded dataset broadly agree with those of other global near-surface temperature analyses. Fitted linear trends in temperature anomalies are approximately 0.07 degC/decade from 1901 to 2010 and 0.17 degC/decade from 1979 to 2010 globally. Northern/southern hemispheric trends are 0.08/0.07 degC/decade over 1901 to 2010 and 0.24/0.10 degC/decade over 1979 to 2010. Linear trends in other prominent near-surface temperature analyses agree well with the range of trends computed from the HadCRUT4 ensemble members.

Received 18 November 2011; accepted 20 February 2012.

Citation: Morice, C. P., J. 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.agu.org/pubs/crossref/pip/2011JD017187.shtml 

"Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010" by Phil D. Jones et al., JGR 117 (2012) doi:10.1029/2011JD017139

Journal of Geophysical Research, 117 (2012) D05127; doi:10.1029/2011JD017139


Hemispheric and large-scale land-surface air temperature variations: An extensive revision and an update to 2010


P. D. Jones, D. H. Lister, T. J. Osborn, C. Harpham, M. Salmon and C. P. Morice


Received 8 November 2011, revised 17 January 2012, accepted 17 January 2012, published 14 March 2012.


Abstract

[1] This study is an extensive revision of the Climatic Research Unit (CRU) land station temperature database that has been used to produce a grid-box data set of 5 latitude 5  longitude temperature anomalies. The new database (CRUTEM4) comprises 5,583 station records of which 4,842 have enough data for the 1961–1990 period to calculate or estimate the average temperatures for this period. Many station records have had their data replaced by newly homogenized series that have been produced by a number of studies, particularly from National Meteorological Services (NMSs). Hemispheric temperature averages for land areas developed with the new CRUTEM4 data set differ slightly from their CRUTEM3 equivalent. The inclusion of much additional data from the Arctic (particularly the Russian Arctic) has led to estimates for the Northern Hemisphere (NH) being warmer by about 0.1 C for the years since 2001. The NH/Southern Hemisphere (SH) warms by 1.12 C/0.84 C over the period 1901–2010. The robustness of the hemispheric averages is assessed by producing five different analyses, each including a different subset of 20% of the station time series and by omitting some large countries. CRUTEM4 is also compared with hemispheric averages produced by reanalyses undertaken by the European Centre for Medium-Range Weather Forecasts (ECMWF): ERA-40 (1958–2001) and ERA-Interim (1979–2010) data sets. For the NH, agreement is good back to 1958 and excellent from 1979 at monthly, annual, and decadal

time scales. For the SH, agreement is poorer, but if the area is restricted to the SH north of 60 S, the agreement is dramatically improved from the mid-1970s.

Citation: 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.

Kerry Emanuel: Science Self-Corrects Even When Scientists Don't

Science Self-Corrects Even When Scientists Don't

by Kerry Emanuel, National Association of Scholars, December 19, 2011

The National Association of Scholars was formed largely to counter an erosion of scholarship originating in the political left and driven by an ideological commitment to advancing certain agendas at the expense of the free and open inquiry we once took for granted. It is therefore both ironic and distressing to find some of its members in sympathy with an equally disturbing and just as ideologically driven campaign against scholarship that can only be characterized as a war on science. The latest example is the egregious piece published recently by H. Sterling Burnett. It closely follows what has become a template for the conservative campaign against climate science:

1.      Tar an entire scholarly endeavor with the alleged crimes of a few

2.      Endlessly repeat allegations long after they have been proven false

3.      Falsely attribute to scientists extremist statements originating outside science

4.      Claim that the existence of minority opinions obviates the need to take risk seriously

5.      Attribute ulterior motives to scientists while ignoring the rather obvious motives of their critics

6.      Claim that the lack of existence of easy solutions justifies ignoring or discrediting science

As Dr. Burnett notes, the latest release of hacked emails, sometimes known as “Climategate II,” involves largely the same “cabal” as the first round; indeed, they were harvested at the same time but deliberately withheld so as to have an optimum negative impact on the recently concluded climate talks in Durban. As they contain little new information, however, they have had minimal influence. 

To be sure, some of the hacked messages are decidedly unflattering to their authors. I agree with Dr. Burnett that the requests to destroy emails or to hide data are completely out of line with the ideals of free and open inquiry that constitute a key cornerstone of scholarship. (Fortunately, various inquiries into the matter ascertained that no emails were destroyed in response to this request; nor is it possible to hide publicly funded data.) These are not defensible statements and no scientist I know would subscribe to them. But it is at this point that massive leveraging begins. We know something is amiss when Burnett claims that “the e-mails show the scientists involved to be violating their professional ethics with the result that climate science in particular and science as an institution more generally is brought into question” (emphasis mine). This represents a fundamental lack of understanding of how science actually works. It is simply naïve to imagine that science can only work if all its practitioners are models of virtue; it works because the enterprise as a whole is self-correcting, not because individuals are. Error, whatever its source, is a constant feature of research and advances are made only because results are constantly being tested by others. The land-temperature data that Phil Jones is best known for working on have been pored over by many groups, including most recently that of the Berkeley physicist Richard Muller – a strong critic of Jones’s efforts – and found to be robust. It is also consistent with records of sea surface temperature, which are based on entirely independent measurements.

From here, Burnett descends into repetition of false allegations. His claims that scientists destroyed raw data, that peer-review was undermined or that scientists employed “tricks” intended to deceive have been shown over and over again to be false, but those intent on undermining climate science hope that they will nonetheless gain currency by endless repetition. Burnett also falsely claims that researchers argue that “the science is settled”; no scientist in his right mind would ever claim that about any scientific finding. It is a claim made frequently by politicians and environmentalists, not climate scientists.

Imagine for a moment that some hacker gained access to thousands of emails exchanged among members of your profession. Can you honestly and confidently assert that none of these would reveal unprofessional behavior? Would the existence of such invalidate all the work you yourself and your profession as a whole is devoted to?  The holier-than-thou moral preening so abundantly evident in recent attacks on climate science has a singular purpose: to discredit a scientific endeavor whose findings are seen as lending support to policies advocated by Al Gore, environmentalists, the far left, and others that conservatives find distasteful. Perhaps because scientists are such easy targets, it’s easier to discredit them than engage policies that deal with climate change. At root, this is simple cowardice.

I am a scientist, a member of this organization, and someone who regards himself as conservative. I believe that our grandchildren will remember our generation not for its grand and overhyped exposés of a handful of climate scientists but for our failure to honestly and openly confront the risks that threaten their wellbeing, of which our attempts to discredit climate science are but one symptom.

Kerry Emanuel is a professor of atmospheric science at the Massachusetts Institute of Technology. He is the author of Divine Wind: The History and Science of Hurricanes, (2005, OxfordUniversity Press). In May 2006 he was named one of Time Magazine's "Time 100: The People Who Shape Our World."

http://www.nas.org/polArticles.cfm?doc_id=2325

The Guardian: The leaked CRU climate science emails – and what they mean

The leaked climate science emails – and what they mean

Following the publication this week of 5,000 hacked climate emails, we look at what was happening in those exchanges

• Fresh round of hacked climate science emails leaked online

• by Juliette Jowit, guardian.co.uk, November 24, 2011
• 
  
• 

A 'drunken' forest in Alaska – a phenomenon caused by the permafrost melting beneath the trees. Photograph: Ashley Cooper/Corbis

"Observations do not show rising temperatures throughout the tropical troposphere unless you accept one single study and approach and discount a wealth of others. This is just downright dangerous."

• Peter Thorne, research scientist, Met Office Hadley Centre, to Phil Jones, UEA, 4 February 2005 (email 1939)

Thorne's email repeatedly criticises the then-current draft of a report for the US Climate Change Science Programme (CCSP, now the Global Change Research Program) for over-simplifying or even dismissing the uncertainty about temperature rises in the atmosphere. This reflects badly on the authors, but also demonstrates that there are climate scientists who are critical of ignoring contradictory evidence and are not afraid to speak their minds. As urged by Thorne, the final report said: "The new evidence in this Report -- model-to-model consistency of amplification results, the large uncertainties in observed tropospheric temperature trends, and independent physical evidence supporting substantial tropospheric warming (such as the increasing height of the tropopause) -- favors the second explanation. However, the large observational uncertainties that currently exist make it difficult to determine whether or not models still have significant errors. Resolution of this issue requires reducing these uncertainties."

"Getting people we know and trust [into the IPCC report team] is vital."

• Phil Jones, UEA, to Kevin Trenberth, NCAR, 15 September 2004 (email 714)

In an earlier email in the thread, Jones refers to two scientists he does not "trust." He does not say why, but does not say because he does not agree with them. He and Trenberth discuss a huge range of names as possible contributors, from several countries, and are keen to widen the net.

"Mike, the figure you sent is very deceptive ... there have been a number of dishonest presentations of model results by individual authors and by IPCC."

• Tom Wigley, University Corporation for Atmospheric Research, US, to Michael Mann, Penn State University, US, and others, 14 October 2009 (email 2884)

Wigley is referring to a graph on the Real Climate blog by climate scientist Gavin Schmidt. On Wednesday Schmidt responded, again on the blog, saying he "disagreed (and disagree) with Wigley," and replied at the time to say so. The general allegation about dishonest presentations is uncomfortable, but these are often scientifically difficult judgements, and are being argued out.

"The trick may be to decide on the main message and use that to guide what's included and what is left out."

• Jonathan Overpeck, University of Arizona, to Ricardo Villalba, IANIGLA-CONICET, Argentina, 16 December 2004 (email 4755)

Overpeck is advising Villalba on how to edit something down to a half-page summary, in which context his advice looks less conspiratorial. Notably, he goes on immediately to say: "For the IPCC, we need to know what is relevant and useful for assessing recent and future climate change. Moreover, we have to have solid data – not inconclusive information."

"I find myself in the strange position of being very skeptical of the quality of all present reconstructions, yet sounding like a pro-greenhouse zealot here!"

• Keith Briffa, UEA, to Edward Cook (probably Edward R Cook at the Earth Institute, Columbia University), 20 January 2005 (email 2009)

Briffa explained to the Guardian: "I am trying to reinforce the request to my co-author to provide a strongly critical review of the draft text. I believed that I had taken account of the considerable uncertainties in the evidence when producing the draft and still came to the conclusion that the late 20th century was unusually warm." This explanation is backed up by the email thread, in which he writes: "Really happy to get critical comment here." Not in keeping with the idea that the scientists were only interested in opinions that agreed with theirs.

Waspishly, Briffa does also suggest however that another climate scientist, Kevin Trenberth, is "extremely defensive and combative when ever criticized about anything because he figures that he is smarter than everyone else and virtually infallible." That does not make Trenberth unique!

"We're choosing the periods to show warming."

• Phil Jones, UEA, to Kevin Trenberth, NCAR, and others, 21 December 2004 (email 2775)

On the surface this was one of the more damaging excerpts. But Jones explained at briefing in London on Wednesday that he was referring to the colour scheme and scales on graphs showing temperature records from 1901 to 2005 – the last century – and 1970 to 2005 – the period for which satellite records are available. "Those periods show warming. They were not pre-selected to show warming," he added.

"My most immediate concern is to whether to leave this statement ["the last two decades of the 20th century were probably the warmest of the last millennium"] in or whether I should remove it in the anticipation that by the time of the 4th assessment report we'll have withdrawn this statement."

• Peter Stott, Met Office Hadley Centre, to Phil Jones and others, 8 September 2004 (email 4923)

Stott is preparing for a meeting with the ecologist David Bellamy, who has publicly called global warming "poppycock," and is being cautious about not overstating the evidence in case ongoing research shows it to be untrue. In the event the IPCC report in 2007 still suggests they were the warmest decades, despite the previous extra research.

"We don't really want the bullshit and optimistic stuff that Michael has written ..."

• Phil Jones, UAE, to Jonathan Overpeck, Arizona University, 8 February 2008 (email 3062)

Jones is referring to new research by Michael Schultz of the University of Bremen – not, as many at first assumed, Michael Mann. Jones said on Wednesday he was not confident enough in Schultz's early work on a new way of reconstructing ancient climate through the oceans. Interestingly, Jones's email then asks Overpeck to write something and adds: "What we want is good honest stuff, warts and all, dubious dating, interpretation marginally better etc."

"The results for 400 ppm [parts per million carbon in the atmosphere] stabilization look odd in many cases ... As it stands we'll have to delete the results from the paper if it is to be published."

• Rachel Warren, UEA, to Rita Yu, UEA, 19 August 2008 (email 310)

This is a clear illustration of the danger of people posting excerpts online using ellipsis (...). What Warren actually wrote was: "The results for 400ppm stabilization look odd in many cases as I have commented before. I would like to try to understand why, before we finish the paper. As it stands we'll have to delete the results from the paper if it is to be published." Warren has seen an anomoly in Yu's results; Yu is a PhD student and she is being asked to give more detail before an unexplained anomoly is written up in a journal paper.

"What if climate change appears to be just mainly a multidecadal natural fluctuation? They'll kill us probably ..."

Tommy Wills, Swansea University to the mailing list for tree-ring data forum ITRDB, 28 Mar 2007 (email 1682)

Wils' email is part of an exchange about whether and how to respond to climate sceptic criticisms. It appears to be a point made for more for rhetorical effect than anything else. As one contributor on the blog Quark Soup by David Appell put it: "Well, at least they considered it as an option."

"There shouldn't be someone else at UEA with different views [from "recent extreme weather is due to global warming"] – at least not a climatologist."

• Phil Jones, UEA, to Melissa Murphy, UEA, 23 Aug 2004 (email 1788)

The TV programme Tonight with Trevor Macdonald is going to feature a colleague of Jones, David Viner, arguing that (then) recent extreme weather was a result of global warming. Jones is responding to a request via the press office for another member of the Climatic Research Unit to appear making the opposite argument. Jones is arguing it would "look odd" if two people with opposite views were from the same department and suggests the TV production team "could easily dredge someone up" from elsewhere.

"I doubt the modelling world will be able to get away with this much longer."

• Tim Barnett, Scripps Institution of Oceanography, US, to Gabi Hegerl, Duke University, US, 18 May 2007 (email 850)

This is during a discussion about information a group of scientists wants to request from climate modellers to improve their understanding of the models – and presumably improve the models themselves. Barnett says getting forcing data is "a must" because many climate models, when tested against history, produced results close to observed temperatures, despite making different assumptions about "forcing" (probably radiative forcing, the net difference between heat radiation entering the earth's atmosphere and leaving it).

"All models are wrong."

• Phil Jones, UEA, to Timothy Carter, Finnish Environment Institute, 11 Mar 2004 (email 4443)

Jones's statement would be dynamite if he was referring to all climate models. Actually, he said on Wednesday, he was referring to new attempts to average existing models, which he did not believe were complex enough. The UEA said that those early averaging models were not subsequently published because of continuing concerns.

http://www.guardian.co.uk/environment/2011/nov/24/leaked-climate-science-emails

ScienceInsider: Son of Climategate: 5,000 new UEA e-mails released, Phil Jones responds

Son of Climategate: 5000 New UEA E-mails Released, Jones Responds

by Sara Reardon, ScienceInsider, November 23, 2011

LONDON—There's nothing really new in a second massive cache of e-mails that hackers have released from the University of East Anglia's (UEA's) Climate Research Unit, U.K., scientists at the center of the controversy said today. The university hasn't finished going through the 5,000 e-mails, but "nothing so far leads me to believe it raises issues not raised two years ago," UEA Vice-Chancellor Edward Acton said at a London press conference. "Different phrases, same issues."

And research unit director Phil Jones said that he was "not embarrassed" by anything so far, but might be as more tidbits of his discussions with colleagues come out.

The new cache of 5,000 e-mails (apparently 39,000 pages when printed) was released yesterday as a torrent hosted anonymously on a Russian server and is now available on a searchable database. It's being touted as more smoking gun evidence that UEA's Jones and colleagues working in climate science conspired to cover up data, engineer which papers made it through peer review, and, most damningly, avoid Freedom of Information (FOI) requests. But Jones described the released e-mails as "heavily cherrypicked." And the hackers, still unknown after two years of police investigation, aren't quite scraping the bottom of the barrel yet; there are reportedly 220,000 e-mails left in their horde, and they appear to be promising to release more. They released a first batch in 2009, sparking a furor dubbed "Climategate" that has sparked a number of investigations, all of which have cleared the researchers of wrongdoing.

Crowdsourcing climate bloggers have flagged phrases from the new e-mails that appear to show the scientists massaging data, such as this one:

<2775> Jones: I too don't see why the schemes should be symmetrical. The temperature ones certainly will not as we're choosing the periods to show warming.

Jones, however, says that the conversation refers to color schemes, highlighting trend data dating back from 1901 that had already been published in a previous report.

Other e-mails deal with the more serious issue of Jones telling his colleagues to delete their e-mails in advance of a FOI request. (He has previously been exonerated of wrongdoing in this regard.) One of the most damning:

<2440> Jones: I've been told that IPCC is above national FOI Acts. One way to cover yourself and all those working in AR5 would be to delete all emails at the end of the process.

Asked about that, Jones said someone had told him that IPCC was immune to FOI rules but he now acknowledges that as "wrong" (as in incorrect). He said he was just "sending concerns I had with FOI." He added that outsiders didn't need to see the excruciating detail that goes into writing a multiauthor report, arguing that skeptics of climate science could misuse the back-and-forth. "Why do they need to know who wrote each sentence in each paragraph?" he said. "They're scientific discussions."

Although the various investigations after the 2009 leak cleared Jones and UEA of wrongdoing, Acton admitted that "our knuckles were collectively rapped over FOI." The university has since addressed the recommendations made by multiple inquiries, and turned over data to requesters. But under current U.K. FOI law, "there are no guidelines on info that might be in public interest," he said. Acton said a current working group in Parliament is trying to draw a line between what information in a university employee's e-mail account is considered subject to FOI requests and what is considered personal.

Numerous e-mails in the new batch, particularly from Michael Mann of Pennsylvania State University, make reference to a "cause:" apparently, persuading the public and policy makers of the reality of global warming. Jones said those weren't from him. "There are those who think there is a cause," he said. "I can see where Mike Mann is coming from. It's not something I agree with him on."

But the rumor mill may be disappointed to learn that e-mails purported to show a deteriorating relationship between Jones and Mann don't. One e-mail, reading "We don't really want the bullshit and optimistic stuff that Michael has written," was actually in reference to another scientist named Michael Schulz, said Jones

Apparently hoping for a silver lining in the latest dump (and the promised future ones), Acton says that he hopes that it will "throw more light on the perpetrator." But he was unable to say what the Norfolk police have come up with so far. The police statement itself simply said that it was "of interest" to their investigation.

In other parts of the world, concerns are rising about the police investigation. "If this happened surrounding nuclear arms talks, we would have the full force of the Western world's intelligence community pursuing the perpetrators. And yet, with the stability of our climate hanging in the balance with these international climate treaty negotiations, these hackers and their supporters are still on the loose. It is time to bring them to justice," U.S. Representative Ed Markey (D-MA) said in a statement yesterday. And information obtained by the BBC under a FOI request showed that "over the past 12 months, [police] have spent precisely £5,649.09 on the investigation. … All of that was disbursed back in February; and all but £80.05 went on 'invoices for work in the last six months.' "

In a statement, UEA made its own suspicions clear: 

These emails have the appearance of having been held back after the theft of data and emails in 2009 to be released at a time designed to cause maximum disruption to the imminent international climate talks [the U.N. conference in Durban, South Africa, next week].

http://news.sciencemag.org/scienceinsider/2011/11/son-of-climategate-5000-new-uea.html 

Phil Jones: Warming since 1995 is now Statistically Significant

Phil Jones - Warming Since 1995 is now Statistically Significant

by dana1981, Skeptical Science, June 14, 2011

As all Skeptical Science readers are undoubtedly aware, in February of 2010, Phil Jones was asked some loaded questions in an interview with the BBC.  Several of the questions were gathered from "climate sceptics," and Jones' answer to the second one has been widely re-published and distorted:

"Do you agree that from 1995 to the present there has been no statistically-significant global warming?"

"Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12 °C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods."

Why choose 1995 as the starting point in this question?  Well, that is the closest year for which the answer to this loaded question is "yes."  From 1994 to 2009, the warming trend in the HadCRUT dataset was statistically significant at the 95% confidence level (CL).  It's also worth noting that there's nothing magical about the 95% CL -- it's simply the most commonly-used interval in scientific research, but it's also true that the HadCRUT 1995-2009 trend was statistically significant at a 93% confidence level. 

In other words, using Jones' data, we could say with 93% confidence that the planet had warmed since 1995.  Nevertheless, this did not stop numerous mainstream media outlets like Fox News claiming that Phil Jones had said global warming since 1995 was "insignificant" -- a grossly incorrect misrepresentation of his actual statements.  The Daily Mail warped the truth even further, claiming Jones had said there was no global warming since 1995.  These media outlets turned 93% confidence of warming into "no warming". 

Furthermore, the HadCRUT dataset excludes portions of the Arctic where there are no temperature stations.  The Arctic also happens to be the fastest-warming part of the planet.  NASA's GISTemp,whose data analysis extrapolates for the Arctic temperatures using the nearest temperature stations, did find a statistically significant warming trend at the 95% CL from 1995 to 2009.  So not only are the "skeptics" cherrypicking the start date, they're also cherrypicking a dataset which doesn't cover the whole planet.

Deep Climate has detailed the history of the 1995 cherrypicked starting point.  It appears to have originated with an email from Richard Lindzen to Anthony Watts, which was subsequently published in a post on WattsUpWithThat (WUWT):

Look at the attached.  There has been no warming since 1997 and no statistically significant warming since 1995.  Why bother with the arguments about an El Nino anomaly in 1998?  (Incidentally, the red fuzz represents the error ‘bars’.)

Best wishes,

Dick

Luboš Motl made a similar argument in December 2009 using UAH satellite data, which was also published on WUWT.  Two months later, the question was posed to Phil Jones in the BBC interview, which suggests strongly that it originated from Motl, Lindzen, and/or Watts.  Regardless of the source, what really matters is that the question was based on a cherrypicked starting date, and on a somewhat arbitrary statistical confidence level, and that the media subsequently distorted Jones' response.

In January 2009, Tamino at Open Mind analyzed the data after removing the influence of exogenous factors like El Niño, volcanic eruptions, and solar variation from the temperature data.  Tamino concluded that "until 2001 the warming is statistically significant" (Figure 1).

Figure 1. HadCRUT3v estimated warming rates from the plotted date to Present with 2-sigma error bars, using exogenous factor-compensated temperature data (Open Mind).

Another year has passed since the original BBC interview, and in a new BBC article, Jones notes that the HadCRUT warming trend since 1995 is now statistically significant.

"Basically what's changed is one more year [of data]. That period 1995-2009 was just 15 years -- and because of the uncertainty in estimating trends over short periods, an extra year has made that trend significant at the 95% level which is the traditional threshold that statisticians have used for many years.

"It just shows the difficulty of achieving significance with a short time series, and that's why longer series -- 20 or 30 years -- would be a much better way of estimating trends and getting significance on a consistent basis."

As Jones notes, and as scientists like Lindzen and Motl should very well know, trying to assess trends in the noisy global temperature data over periods as short as 10-15 years is pointless.  There's just too much short-term noise, which if you're going to look at such short-term data, you at least need to attempt to filter out first, as Tamino did.

So to sum up, a cherrypicked starting date chosen by a couple of "skeptics" (Lindzen and Motl) and published by a "skeptic" blog (WUWT) was picked up and passed along in the form of a loaded question to Phil Jones in the BBC interview.  Phil Jones' answer was subsequently (and predictably) grossly distorted by various media outlets, who turned 93% confidence of global warming into "no global warming." 

In reality, the HadCRUT warming trend since 1995 was statistically significant above the 90% CL, the GISTemp warming trend (which does not exclude the Arctic) was significant at the 95% CL, and by removing short-term effects, even HadCRUT has been significant at the 95% CL since 2000.  One year later, we can now say that the HadCRUT warming trend since 1995 is statistically significant at the 95% CL, even including the exogenous factors.

Unfortunately, the main consequence of this sequence of events was that much of the public was misinformed by media articles claiming that global warming since 1995 was "insignificant" or non-existent, which are both factually incorrect statements.  Misleading the public may well have been the goal of those individuals who originally cherrypicked the 1995 starting date and the HadCRUT dataset, and if so, they succeeded.  And not surprisingly, Anthony Watts continues to mislead his readers, claiming Phil Jones' comments are "an about face...From the “make up your mind” department," when in reality Jones' comments have been consistent and accurate throughout.

This reactions to this story have revealed a number of media outlets whose aim is not to accurately inform their readers with regards to the climate, but rather to misinform them.

http://www.skepticalscience.com/phil-jones-warming-since-1995-significant.html

Richard Black, BBC: Global warming since 1995 is 'now significant'

Global warming since 1995 'now significant'
by Richard Black, Environment correspondent, BBC News, June 10, 2011

Phil Jones's comments last year have become a touchstone for climate "sceptics."

Climate warming since 1995 is now statistically significant, according to Phil Jones, the UK scientist targeted in the "ClimateGate" affair.

Last year, he told BBC News that post-1995 warming was not significant -- a statement still seen on blogs critical of the idea of man-made climate change.

But another year of data has pushed the trend past the threshold usually used to assess whether trends are "real."

Dr Jones says this shows the importance of using longer records for analysis.

By widespread convention, scientists use a minimum threshold of 95% to assess whether a trend is likely to be down to an underlying cause, rather than emerging by chance.

If a trend meets the 95% threshold, it basically means that the odds of it being down to chance are less than one in 20.

Last year's analysis, which went to 2009, did not reach this threshold; but adding data for 2010 takes it over the line.

"The trend over the period 1995-2009 was significant at the 90% level, but wasn't significant at the standard 95% level that people use," Professor Jones told BBC News.

"Basically what's changed is one more year [of data]. That period 1995-2009 was just 15 years -- and because of the uncertainty in estimating trends over short periods, an extra year has made that trend significant at the 95% level which is the traditional threshold that statisticians have used for many years.

"It just shows the difficulty of achieving significance with a short time series, and that's why longer series -- 20 or 30 years -- would be a much better way of estimating trends and getting significance on a consistent basis."

Professor Jones' previous comment, from a BBC interview in Febuary 2010, is routinely quoted -- erroneously -- as demonstration that the Earth's surface temperature is not rising.

Globally consistent

The dataset that Professor Jones helps to compile -- HadCRUT3 -- is a joint project between the Climatic Research Unit (CRU) at the University of East Anglia (UEA), where he is based, and the UK Met Office.

Phil Jones is back at the scientific helm of CRU, though relieved of administrative leadership

It is one of the main global temperature records used by bodies such as the Intergovernmental Panel on Climate Change (IPCC).

HadCRUT shows a warming 1995-2010 of 0.19 °C -- consistent with the other major records, which all use slightly different ways of analysing the data in order to compensate for issues such as the dearth of measuring stations in polar regions.

Shortly before the UN climate summit in Copenhagen, Phil Jones found himself at the centre of the affair that came to be known as "ClimateGate," which saw the release of more than 1,000 emails taken from a CRU server.

Critics alleged the emails showed CRU scientists and others attempting to subvert the usual processes of science, and of manipulating data in order to paint an unfounded picture of globally rising temperatures.

Subsequent enquiries found the scientists and their institutions did fall short of best practice in areas such as routine use of professional statisticians and response to Freedom of Information requests, but found no case to answer on the charges of manipulation.

Since then, nothing has emerged through mainstream science to challenge the IPCC's basic picture of a world warming through greenhouse gas emissions.

And a new initiative to construct a global temperature record, based in, Berkeley, California, whose funders include "climate sceptical" organisations, has reached early conclusions that match established records closely.

http://www.bbc.co.uk/news/science-environment-13719510