A study in 2007 showed that the forest gets greener when it rains less. A new study, by Samanta et al. in Geophysical Research Letters shows that the earlier work was flawed. Aided by an apparently rather careless press release, this is being used as evidence that the Amazon is less sensitive to rainfall changes than the IPCC claimed. But the Samanta et al. paper actually does not address the central questions at all. It only addresses whether a single anomalous rainfall year had an impact that is measureable and interpretable from a satellite sensor. The conclusion is that they could not detect a change. As noted in a commentary from Simon Lewis, University of Leeds, “the critical question is how these forests respond to repeated droughts, not merely single-year droughts.”

Lewis – a broadly published expert on tropical forests – makes a number of additional important points in his commentary below. Bottom line: IPCC gets it right as usual.

—————
Guest Commentary by Simon Lewis, University of Leeds, UK

The new Samanta et al. study uses sensors on satellites to assess the colour of the rainforest canopy in the dry season of the year 2005, compared to the dry seasons of the years 2003 and 2004. More detected green colour in 2005 may suggest that the forest is being more productive (more green leaves photosynthesising), or more brown colours may suggest leaves dying and less productivity, than the previous years. The results show that 2005 was little different to the previous years, despite the strong drought.

This is important new information, as in 2007, a paper using broadly the same satellite-based method showed a strong ‘greening-up’ of the Amazon in 2005, suggesting tolerance to drought (Saleska et al. 2007, Science). The new study shows that those results were not reproducible, but also highlight the extreme caution that should be attached to satellite studies generally in this field, with instruments in space collecting data which is then used to infer subtle changes in the ecology of tropical forests.

In contrast to the 2007 paper, Oliver Phillips, myself, and others, published a paper in Science last year, using ground observations from across the Amazon, showing that while the 2005 drought did not dramatically change the growth of the trees compared to a normal year, as Samanta et al. also show, the deaths of trees did increase considerably. The new study of Samanta et al. does not contradict the Phillips et al. study, which itself shows the Amazon is vulnerable to drought via impacts on tree mortality. The Phillips et al. paper showed that remaining Amazon forest trees changed from absorbing nearly 2 billion tonnes of CO₂ from the atmosphere annually over recent decades, as tree growth has been exceeding mortality, to being a large, but temporary, source of over 3 billion tonnes, from the elevated tree mortality associated with the 2005 drought event.

The evidence for the possibility of a major die-back of the Amazon rainforest is due to two factors,

1. That climate change induced decreases in rainfall in the dry season occur, and

2. The trees cannot tolerate these reductions in rainfall.

The Samanta paper does not directly address the first point; this is addressed using global circulation models (of which some, but not all, show a strong drying trend for the east of the Amazon over the 21st century). The second point is only addressed in a limited way. The critical question is how these forests respond to repeated droughts, not merely single-year droughts. The forests are of course able to withstand these single droughts (otherwise there would be no rainforest!) — it is their ability to survive an increased frequency of the most severe droughts that is critical to answer. Drought experiments, where a roof is built under the forest canopy to reduce rainfall, show that most forest trees survive a single year’s intense drought, in agreement with the ground observations in the 2005 drought, but can’t persist with repeated years of drought. The Samanta study does not address this point at all.

In conclusion, the new Samanta et al. study lends further weight to the emerging picture of the impact of the 2005 drought: that tree growth was relatively unaffected, but tree mortality increased, contributing temporarily to accelerating the rate of climate change, rather than as usual reducing it, via additions of carbon to the atmosphere from the dead trees. The mortality was far from catastrophic, but the impact on the carbon cycle was globally significant. This is hardly the ‘no impact’ of the 2005-drought on the forest suggested in various news reports.

I should add that there is considerable uncertainty associated with the models suggesting decreases in rainfall, and uncertainty as to how Amazon forests may react (especially when one considers the impacts of deforestation, logging, and fire combined with climate change impacts). But this uncertainty is being chipped away at by scientists, a task in which the Samanta et al. paper assists.

Oddly, the Boston University press release to accompany the paper was titled, “New study debunks myths about Amazon rain forests”. The opening line runs: “A new NASA-funded study has concluded that Amazon rain forests were remarkably unaffected in the face of once-in-a-century drought in 2005, neither dying nor thriving, contrary to a previously published report and claims by the Intergovernmental Panel on Climate Change.” So, have scientists, myself included, been peddling myths? Have respected journals being publishing them? Have the IPCC? The answer is no, no and no.

The reality is that the IPCC have largely ignored the papers on the model results of decreasing rainfall in the east of the Amazon, and the diverse evidence used to assess the sensitivity of these forests to such rainfall reductions. There are a couple of lines in IPCC Working Group I (“New coupled climate-carbon models (Betts et al., 2004; Huntingford et al., 2004) demonstrate the possibility of large feedbacks between future climate change and vegetation change, discussed further in Section 7.3.5 (i.e., a die back of Amazon vegetation and reductions in Amazon precipitation).”). And in Working Group II there is a now infamous single sentence:

“Up to 40% of the Amazonian forests could react drastically to even a slight reduction in precipitation; this means that the tropical vegetation, hydrology and climate system in South America could change very rapidly to another steady state, not necessarily producing gradual changes between the current and the future situation (Rowell and Moore, 2000).”

The statement is not as carefully worded as it should be, and incorrectly referenced, but basically scientifically correct and defensible with recourse to the peer-reviewed literature available at the time. Rainforest persists above a threshold of rainfall, below which one finds savanna. If this threshold is crossed a landscape dominated by rainforest can ‘flip’ to savanna. Therefore a ’slight’ reduction can lead to a ‘dramatic’ reaction. Of course, evidence of a shift to a new lower rainfall climate regime is needed, and evidence of large areas of forest close to that rainfall threshold would be required for the IPCC statement to be reasonable; there is ample published evidence for both.

Overall the conclusions in the IPCC 2007 Fourth Assessment Report are strengthened (because the anomalous result of the Saleska et al. 2007 paper appear to be at fault), not weakened, by the new Samanta et al. study as their press release implies.

Dear RealClimate team:

I have a background in biology and studied at post-grad level in the area of philosophy of science. For the last few years, I have been working on a book about the logic of argument used in debates between creationists and evolutionists.

About a year ago I decided it was time to properly educate myself about climate science. Being perhaps a little too influenced by Harry M Collins’ “The Golem” (and probably too much modern French philosophy!), I was definitely predisposed to see group-think, political and cultural bias in the work of climatologists.

On the whole, though, I tried hard to follow the principles of genuine skepticism, as I understood them.

Obviously, there are plenty of ill-considered opinions to be found either side of any issue, but only the most ignorant person could fail to see the terrible intellectual gulf between the quality of so-called skeptic sites and those defending the science behind the AGW thesis.

What convinced me, though, is that the arguments made by a few sites like yours are explicit and testable. In particular, it is useful that RealClimate sticks to the science as much as possible. It has been a lot of hard work to get here, but I am now at a point where I understand the fundamentals of climate science well enough to articulate them to others.

For my part, I am grateful to you guys. I hope it gives you some small amount of satisfaction to know that your work can convert readers who really were skeptics in the beginning. I use the word ’skeptic’ carefully – the one thing most commonly absent from the so-called ’skeptics’ is authentic skepticism.

By the way, my book is an attempt to categorise the various logical errors people fall into when they search for arguments to support a conclusion to which they have arrived at a priori. It will now have a few chapters on global warming.

All the best,

First, although the temperature scenarios of IPCC project a maximum warming of 6.4 ºC (Table SPM3), the upper limit of sea level rise has been computed assuming a warming of 7.6 ºC. Second, the IPCC chose to compute sea level rise up to the year 2105 rather than 2100 – just to add that extra bit of alarmism. Worse, the IPCC report shows that over the past 40 years, sea level has in fact risen 50% less than predicted by its models – yet these same models are used uncorrected to predict the future! And finally, the future projections assume a massive ice sheet decay which is rather at odds with past ice sheet behaviour.

Some scientists within IPCC warned early that all this could lead to a credibility problem, but the IPCC decided to go ahead anyway.

Now, the blogosphere and their great media amplifiers are up in arms. Heads must roll!

Unthinkable? Indeed. I am convinced that IPCC would never have done this.

The North Sea (see Stefan’s photostream on Flickr)

But here is what actually did happen.

In its latest report, the IPCC has predicted up to 59 cm of sea level rise by the end of this century. But realclimate soon revealed a few problems.

First, although the temperature scenarios of IPCC project a maximum warming of 6.4 ºC (Table SPM3), the upper limit of sea level rise has been computed for a warming of only 5.2 ºC – which reduced the estimate by about 15 cm. Second, the IPCC chose to compute sea level rise up to the year 2095 rather than 2100 – just to cut off another 5 cm. Worse, the IPCC report shows that over the past 40 years, sea level has in fact risen 50% more than predicted by its models – yet these same models are used uncorrected to predict the future! And finally, the future projections assume that the Antarctic ice sheet gains mass, thus lowering sea level, rather at odds with past ice sheet behaviour.**

Some scientists within IPCC warned early that all this could lead to a credibility problem, but the IPCC decided to go ahead anyway.

Nobody cared about this.

I mention this because there is a lesson in it. IPCC would never have published an implausibly high 3 meter upper limit like this, but it did not hesitate with the implausibly low 59 cm. That is because within the IPCC culture, being “alarmist” is bad and being “conservative” (i.e. underestimating the potential severity of things) is good.

Note that this culture is the opposite of “erring on the safe side” (assuming it is better to have overestimated the problem and made the transition to a low-carbon society a little earlier than needed, rather than to have underestimated it and sunk coastal cities and entire island nations). Just to avoid any misunderstandings here: I am squarely against exaggerating climate change to “err on the safe side”. I am deeply convinced that scientists must avoid erring on any side, they must always give the most balanced assessment they are capable of (and that is why I have often spoken up against “alarmist” exaggeration of climate science, see e.g. here and here).

Why do I find this IPCC problem far worse than the Himalaya error? Because it is not a slip-up by a Working Group 2 author who failed to properly follow procedures and cited an unreliable source. Rather, this is the result of intensive deliberations by Working Group 1 climate experts. Unlike the Himalaya mistake, this is one of the central predictions of IPCC, prominently discussed in the Summary for Policy Makers. What went wrong in this case needs to be carefully looked at when considering future improvements to the IPCC process.

And let’s see whether we learn another lesson here, this time about society and the media. Will this evidence for an underestimation of the climate problem by IPCC, presented by an IPCC lead author who studies sea level, be just as widely reported and discussed as, say, faulty claims by a blogger about “Amazongate”?

p.s. Recent sea level results. A number of broadly based assessments have appeared since the last IPCC report, which all conclude that global sea level rise by the year 2100 could exceed one meter: The assessment of the Dutch Delta Commission, the Synthesis Report of the Copenhagen Climate Congress, the Copenhagen Diagnosis report as well as the SCAR report on Antarctic Climate Change. This is also the conclusion of a number of recent peer-reviewed papers: Rahmstorf 2007, Horton et al. 2008, Pfeffer et al. 2008, Grinsted et al. 2009, Vermeer and Rahmstorf 2009, Jevrejeva et al. 2010 (in press with GRL). The notable exception – Siddall et al. 2009 – was withdrawn by its authors after we revealed numerical errors on Realclimate. This is a good example of self-correction in science (in stark contrast with the climate sceptics’ practice of endlessly perpetuating false information). Rather bizarrely, Fox News managed to turn this into the headline “More Questions About Validity of Global Warming Theory“.

** About the numbers stated above. Regarding the actual IPCC AR4 numbers, adjust the IPCC upper estimate of 59 cm by adding 15 cm to make it apply to 6.4 ºC warming (not just 5.2 ºC) and 5 cm to make it go up to 2100 (not just 2095). That gives you 79 cm. Add 50% to adjust for the underestimation of past sea level rise and you get 119 cm.
For the hypothetical case at the start of this post, just introduce similar errors in the other direction. Let’s add 31 cm by going up to 7.6 ºC and the year 2105 (in fact that is “conservative” but it gives a nice round number, 150 cm). Now assume you have a model compared to which actual sea level is rising 50% slower (rather 50% faster): now you’re at the 3 meters mentioned above. For details, see The IPCC sea level numbers.

The paper by Judith Lean (2010) has the character of a review article, summarizing past studies on the relationship between solar forcing and climate. The main message from her article is that the solar forcing probably plays a modest role for the global warming over the last 100 years (10% or less). It’s a nice overview, but I miss treatment of uncertainties.

Her analysis is based on the HadCRUT3 data, and I wonder if she would get similar results if she chose the GISTEMP or NCDC instead. The choice may in particular be relevant for the discussion of the temperatures after 1998.

Personally, I regard the data on solar activity before 1900 as quite uncertain too. The reason is that there are strange things happening to the solar cycle length in the shift from the 19th to the 20th century. Hence, any analysis based on the past centuries is uncertain because of suspect data quality in the early part of the record. Lean mentions that proxy-based records are uncertain, however.

Another source of uncertainty stems from the analysis itself – a regression analysis with chaotic data can easily yield misleading results. Gavin and I showed in a recent paper that multiple regression can produce strange results when applied to the global mean temperature and a number of forcings.

In other words, I think the reader may get the wrong impression from Lean (2010) that the link between solar activity and climate is better established than the data and methods suggest. Especially when she discusses forecasts for the near future (eg. for year 2014) – I fear that such a discussion can be misinterpreted and misused. However, that’s my view, and it does not necessarily mean that her paper is incorrect – quite the opposite, I think her main conclusions are sound (Her estimate of the solar contribution to the global warming over past century – 10% or less – is in good agreement with the figure Gavin and I got in our analysis).

The positive side is that the paper is probably clearer and more accessible without all these caveats. I also think she makes an interesting point when she discusses ‘fundamental puzzles’ associated with claims of strong solar role in terms of the past warming. She puts this into the context of climate sensitivity, arguing that it would imply that Earth’s climate be insensitive to well-measured increases in GHG concentrations and simultaneously excessively sensitive to poorly known solar brightness changes. Furthermore, Lean argues that it would also require that the Sun’s brightness increased more in the past century than at any time in the past millennium – a situation not readily supported by observations.

The paper of Calogovic et al. (2010) is a follow-up of a recent paper by Svensmark et al. (2009), looking into the claim that the cloud water content drops after a Forbush event. Their work involved estimating cosmic ray fluxes for the whole planet, and comparing it to local cloud information derived from satellites. They concluded that the Forbush events had no detectable effect on the clouds.

Moreover, they also argued that the analysis of Svensmark et al. (2009) gave unreliable results since it included a Forbush event on January 20, 2005 which was accompanied by a strong solar proton event. However, they did not explain explicitly why such proton events would disturb the measurements, but referred to another study by Laken et al. (2009) in Geophysical Research Letter. Laken et. al. only discusses the proton events briefly, and refers to a study by Fluckiger et al. (2005), who state that “The cosmic ray ground level enhancement (GLE) on January 20, 2005 is ranked among the largest in years, with neutron monitor count rates increased by factors of more than 50″.

But there is no reference to proton events in Fluckiger et al. (2005), so I’m not convinced that proton events will invalidate the analysis of Svensmark et al. (2009). Perhaps I’m missing something? Anyway, this is only a minor detail, and the rest of the analysis of Calogovic et al. (2010) seems more convincing. Their conclusion is supported by Kulmala et al. (2010): “galactic cosmic rays appear to play a minor role for atmospheric aerosol formation events, and so for the connected aerosol-climate effects as well”. Kulmala’s group in Finland boasts many world-renowned aerosol physicists.

The study by Kulmala et al. (2010) was based on near-ground measurements of aerosols, magnetic field, cosmic rays, sunlight intensity (solar radiation), and ionization over a 13-year long period (~1 solar cycle). They also used airborne Neutral cluster and Air Ion Spectrometer, LIDAR and Forward Scattering Spectrometer Probe measurements. They failed to detect any correlation between cosmic ray ionization intensity and atmospheric aerosol formation.

Feulner and Rahmstorf address a speculation stated by Lean: the possibility of solar forcing countering anthropogenic global warming. Their paper examines the effect a solar grand minimum (low solar activity similar to that inferred for the Maunder Minimum) would have on the global mean temperature by 2100. By accounting for a corresponding reduction in forcing for the future in a climate model study, they conclude that the effect is negligible (less than 0.3K compared to 3.7 – 4.5K if the SRES A1b or A2 emission scenarios were assumed).

So what can we learn from these articles? What we see is how science often works – increases in knowledge by increments and independent studies re-affirming previous findings, namely that changes in the sun play a minor role in climate change on decadal to centennial scales. After all, 2009 was the second-warmest year on record, and by far the warmest in the southern hemisphere, despite the record solar minimum. The solar signal for the past 25 years is not just small but negative (i.e. cooling), but this has not noticeably slowed down global warming. But there are also many unknowns remaining, and the largest uncertainties concern clouds, cloud physics, and their impact on climate. In this sense, I find it ironic that some people still rely on the cosmic rays argument as their strongest argument against AGW – it does involve poorly known clouds physics!

The statement calls for increased transparency, and expresses concerns about the public confidence in science if the transparency is absent. The IoP statement, however, fails to note that the issue of transparency is far more general applicable than just to mainstream climate science. It should also involve the critics of climate change, as noted by New Scientist.

The statement also fails to clarify what level of transparency they expect the climate scientists to reach. Which scientific discipline should we use as a role model? I know of none that is more transparent than climate science, and in large part that s due to the IPCC. Ironically, without this transparency, the climate-change deniers would not get as much ammunition. For instance, note how the attacks on the NASA GISTEMP product have become more vehement in recent months even though the code base and data have been available for years and clearly demonstrate that the criticisms are bogus.

Another question arises is whether the IoP follows its own recommendations in its own publications?

The statement of the IoP was made on the behalf of its 36000 members, but as a member of IoP myself, this came as a surprise. According to the Guardian, there was only a small group of people behind this, and other IoP members was obviously not very impressed. The IoP did, however, make a second statement after their initial one was misrepresented by the climate-change deniers (there is some confusion about versions).

The irony of this affair is that the IoP will not disclose who were responsible for the original statement, thus not living up to the standards they set for others.

Furthermore, it’s a paradox that the IoP based the statement on stolen private e-mail exchanges, while putting disclaimers about confidentiality, especially as it asks people to delete any e-mail before they go astray:

This email (and attachments) are confidential and intended for the addressee(s) only. If you are not the intended recipient please notify the sender, delete any copies and do not take action in reliance on it…

Transparency is essential for trust and confidence in science – as in all matters – but claims about lack of transparency are easy to make. It’s another question whether the alleged lack of transparency in climate science has had any impact on anyone’s ability to verify the science.

Update
‘Concerns raised over Institute of Physics climate submission‘ in Physics World

[Note: Edited Toyota velocities to reflect relative radiative forcings of anthropogenic CO₂ and methane. David]

For some background on methane hydrates we can refer you here. This weeks’ Science paper is by Shakhova et al, a follow on to a 2005 GRL paper. The observation in 2005 was elevated concentrations of methane in ocean waters on the Siberian shelf, presumably driven by outgassing from the sediments and driving excess methane to the atmosphere. The new paper adds observations of methane spikes in the air over the water, confirming the methane’s escape from the water column, instead of it being oxidized to CO₂ in the water, for example. The new data enable the methane flux from this region to the atmosphere to be quantified, and they find that this region rivals the methane flux from the whole rest of the ocean.

What’s missing from these studies themselves is evidence that the Siberian shelf degassing is new, a climate feedback, rather than simply nature-as-usual, driven by the retreat of submerged permafrost left over from the last ice age. However, other recent papers speak to this question.

Westbrook et al 2009, published stunning sonar images of bubble plumes rising from sediments off Spitzbergen, Norway. The bubbles are rising from a line on the sea floor that corresponds to the boundary of methane hydrate stability, a boundary that would retreat in a warming water column. A modeling study by Reagan and Moridis 2009 supports the idea that the observed bubbles could be in response to observed warming of the water column driven by anthropogenic warming.

Another recent paper, from Dlugokencky et al. 2009, describes an uptick in the methane concentration in the air in 2007, and tries to figure out where it’s coming from. The atmospheric methane concentration rose from the preanthropogenic until about the year 1993, at which point it rather abruptly plateaued. Methane is a transient gas in the atmosphere, so it ought to plateau if the emission flux is steady, but the shape of the concentration curve suggested some sudden decrease in the emission rate, stemming from the collapse of economic activity in the former Soviet bloc, or by drying of wetlands, or any of several other proposed and unresolved explanations. (Maybe the legislature in South Dakota should pass a law that methane is driven by astrology!) A previous uptick in the methane concentration in 1998 could be explained in terms of the effect of el Nino on wetlands, but the uptick in 2007 is not so simple to explain. The concentration held steady in 2008, meaning at least that interannual variability is important in the methane cycle, and making it hard to say if the long-term average emission rate is rising in a way that would be consistent with a new carbon feedback.

Anyway, so far it is at most a very small feedback. The Siberian Margin might rival the whole rest of the world ocean as a methane source, but the ocean source overall is much smaller than the land source. Most of the methane in the atmosphere comes from wetlands, natural and artificial associated with rice agriculture. The ocean is small potatoes, and there is enough uncertainty in the methane budget to accommodate adjustments in the sources without too much overturning of apple carts.

Could this be the first modest sprout of what will grow into a huge carbon feedback in the future? It is possible, but two things should be kept in mind. One is that there’s no reason to fixate on methane in particular. Methane is a transient gas in the atmosphere, while CO₂ essentially accumulates in the atmosphere / ocean carbon cycle, so in the end the climate forcing from the accumulating CO₂ that methane oxidizes into may be as important as the transient concentration of methane itself. The other thing to remember is that there’s no reason to fixate on methane hydrates in particular, as opposed to the carbon stored in peats in Arctic permafrosts for example. Peats take time to degrade but hydrate also takes time to melt, limited by heat transport. They don’t generally explode instantaneously.

For methane to be a game-changer in the future of Earth’s climate, it would have to degas to the atmosphere catastrophically, on a time scale that is faster than the decadal lifetime of methane in the air. So far no one has seen or proposed a mechanism to make that happen.

References

Westbrook, G., et al, Escape of methane gas from the seabed along the West Spitsbergen continental margin, GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15608, doi:10.1029/2009GL039191, 2009

Their figure neatly demonstrates the different issues:

The upper line is often what is referred to as the ‘climate change commitment’ (for instance Wigley, 2005). This is the warming you get if we keep CO₂ (and other GHG and pollutant levels) constant at today’s values. (Technically, the figure shows the case staying at year 2000 values). In such a scenario, the planet still has a radiative imbalance, and the warming will continue until the oceans have warmed sufficiently to equalise the situation – giving an additional 0.3 to 0.8ºC warming over the 21st Century. Thus the conclusion has been that because of climate inertia, further warming is inevitable.

However, constant concentrations of CO₂ imply a change in emissions – specifically an immediate cut of around 60 to 70% globally and continued further cuts over time. Matthews and Weaver make the point that this is a little arbitrary and that the true impact of climate inertia would be seen only with emissions cut to zero. That is, if we define the commitment as the consequence only of past emissions, then you should set future emissions to zero before you calculate it. This is a valid point, and the consequence of that is seen in the lower lines in the figure.

CO₂ concentrations would start to fall immediately since the ocean and terrestrial biosphere would continue to absorb more carbon than they release as long as the CO₂ level in the atmosphere is higher than pre-industrial levels (approximately). And subsequent temperatures (depending slightly on the model you are using) would either be flat or slightly decreasing. With this definition then, there is no climate change commitment because of climate inertia. Instead, the reason for the likely continuation of the warming is that we can’t get to zero emissions any time soon because of societal, economic or technological inertia.

That is an interesting reframing of an issue that comes up all the time in discussions of adaptation and mitigation. This is because it demonstrates that adaptation (over and above what is necessary to reduce vulnerabilities to current climate conditions) is unnecessary if mitigation is dramatic enough.

However, the practical implication of this reframing is small. We are clearly not going to get to zero emissions any time soon, and even the 60-70% cuts required to stabilise concentrations initially seem a long way off. Thus as a practical matter, it doesn’t really matter whether the inertia is climatic or societal or technological or economic because the globe will continue to warm under all realistic scenarios (what we do have a possible control over is the magnitude of that warming). Thus further adaptation measures will still be needed.

Part 2 of a series discussing the recent Guardian articles

A recent story by Fred Pearce in the February 9th online edition of the Guardian (“Victory for openness as IPCC climate scientist opens up lab doors”) covers some of the more publicized aspects of the last 14 years of my scientific career. I am glad that Mr. Pearce’s account illuminates some of the non-scientific difficulties I have faced. However, his account also repeats unfounded allegations that I engaged in dubious professional conduct. In a number of instances, Mr Pearce provides links to these allegations, but does not provide a balanced account of the rebuttals to them. Nor does he give links to locations where these rebuttals can be found. I am taking this opportunity to correct Mr. Pearce’s omissions, to reply to the key allegations, and to supply links to more detailed responses.

Another concern relates to Mr. Pearce’s discussion of the “openness” issue mentioned in the title and sub-title of his story. A naïve reader of Mr. Pearce’s article might infer from the sub-title (“Ben Santer had a change of heart about data transparency…”) that my scientific research was not conducted in an open and transparent manner until I experienced “a change of heart”.

This inference would be completely incorrect. As I discuss below, my research into the nature and causes of climate change has always been performed in an open, transparent, and collegial manner. Virtually all of the scientific papers I have published over the course of my career involve multi-institutional teams of scientists with expertise in climate modeling, the development of observational datasets, and climate model evaluation. The model and observational data used in my research is not proprietary – it is freely available to researchers anywhere in the world.

The 1995 IPCC Report: The “scientific cleansing” allegation

Mr. Pearce begins by repeating some of the allegations of misconduct that arose after publication (in 1996) of the Second Assessment Report (SAR) of the Intergovernmental Panel on Climate Change (IPCC). These allegations targeted Chapter 8 of the SAR, which dealt with the “Detection of Climate Change, and Attribution of Causes”. The IPCC SAR reached the historic finding that “The balance of evidence suggests a discernible human influence on global climate”. Information presented in Chapter 8 provided substantial support for this finding.

I served as the Convening Lead Author (CLA) of Chapter 8. There were three principal criticisms of my conduct as CLA. All three allegations are baseless. They have been refuted on many occasions, and in many different fora. All three allegations make an appearance in Mr. Pearce’s story, but there are no links to the detailed responses to these claims.

The first allegation was that I had engaged in “scientific cleansing”. This allegation originated with the Global Climate Coalition (GCC) – a group of businesses “opposing immediate action to reduce greenhouse gas emissions”.

In May 1996, a document entitled “The IPCC: Institutionalized ‘Scientific Cleansing’?” was widely circulated to the press and politicians. In this document, the Global Climate Coalition claimed that after a key Plenary Meeting of the IPCC in Madrid in November 1995, all scientific uncertainties had been purged from Chapter 8. The GCC’s “scientific cleansing” allegation was soon repeated in an article in Energy Daily (May 22, 1996) and in an editorial in the Washington Times (May 24, 1996). It was also prominently featured in the World Climate Report, a publication edited by Professor Patrick J. Michaels (June 10, 1996).

This “scientific cleansing” claim is categorically untrue. There was no “scientific cleansing”. Roughly 20% of the published version of Chapter 8 specifically addressed uncertainties in scientific studies of the causes of climate change. In discussing the “scientific cleansing” issue, Mr. Pearce claims that many of the caveats in Chapter 8 “did not make it to the summary for policy-makers”. This is incorrect.

The Summary for Policymakers (SPM) of the IPCC SAR is four-and-a-half pages long. Roughly one page of the SPM discusses results from Chapter 8. The final paragraph of that page deals specifically with uncertainties, and notes that:

“Our ability to quantify the human influence on global climate is currently limited because the expected signal is still emerging from the noise of natural variability, and because there are uncertainties in key factors. These include the magnitude and patterns of long term natural variability and the time-evolving pattern of forcing by, and response to, changes in concentrations of greenhouse gases and aerosols, and land surface changes”.

Contrary to Mr. Pearce’s assertion, important caveats did “make it to the summary for policy-makers”. And the “discernible human influence” conclusion of both Chapter 8 and the Summary for Policymakers has been substantiated by many subsequent national and international assessments of climate science.

There were several reasons why Chapter 8 was a target for unfounded “scientific cleansing” allegations. First, the Global Climate Coalitions’s “scientific cleansing” charges were released to the media in May 1996. At that time, Cambridge University Press had not yet published the IPCC Second Assessment Report in the United States. Because of this delay in the Report’s U.S. publication, many U.S. commentators on the “scientific cleansing” claims had not even read Chapter 8 – they only had access to the GCC’s skewed account of the changes made to Chapter 8. Had the Second Assessment Report been readily available in the U.S. in May 1996, it would have been easy for interested parties to verify that Chapter 8 incorporated a fair and balanced discussion of scientific uncertainties.

Second, the “pre-Madrid” version of Chapter 8 was the only chapter in the IPCC Working Group I Second Assessment Report to have both an “Executive Summary” and a “Concluding Summary”. As discussed in the next section, this anomaly was partly due to the fact that the Lead Author team for Chapter 8 was not finalized until April 1994 – months after all other chapters had started work. Because of this delay in getting out of the starting blocks, the Chapter 8 Lead Author team was more concerned with completing the initial drafts of our chapter than with the question of whether all chapters in the Working Group I Report had exactly the same structure.

The reply of the Chapter 8 Lead Authors to the Energy Daily story of May 22, 1996 pointed out this ‘two summary’ redundancy, and noted that:

“After receiving much criticism of this redundancy in October and November 1995, the Convening Lead Author of Chapter 8 decided to remove the concluding summary. About half of the information in the concluding summary was integrated with material in Section 8.6. It did not disappear completely, as the Global Climate Coalition has implied. The lengthy Executive Summary of Chapter 8 addresses the issue of uncertainties in great detail – as does the underlying Chapter itself.”

The removal of the concluding summary made it simple for the Global Climate Coalition to advance their unjustified “scientific cleansing” allegations. They could claim ‘This statement has been deleted’, without mentioning that the scientific issue addressed in the deleted statement was covered elsewhere in the chapter.

This was my first close encounter of the absurd kind.

The 1995 IPCC Report: The “political tampering/corruption of peer-review” allegation

The second allegation is that I was responsible for “political tampering”. I like to call this “the tail wags the dog” allegation. The “tail” here is the summary of the Chapter 8 results in the IPCC Summary for Policymakers, and the “dog” is the detailed underlying text of Chapter 8.

In November 1995, 177 government delegates from 96 countries spent three days in Madrid. Their job was to “approve” each word of the four-and-a-half page Summary for Policymakers of the IPCC’s Working Group I Report. This was the report that dealt with the physical science of climate change. The delegates also had the task of “accepting” the 11 underlying science chapters on which the Summary for Policymakers was based. “Acceptance” of the 11 chapters did not require government approval of each word in each chapter.

This was not a meeting of politicians only. A number of the government delegates were climate scientists. Twenty-eight of the Lead Authors of the IPCC Working Group I Report – myself included – were also prominent participants in Madrid. We were there to ensure that the politics did not get ahead of the science, and that the tail did not wag the dog.

Non-governmental organizations – such as the Global Climate Coalition – were also active participants in the Madrid meeting. NGOs had no say in the formal process of approving the Summary for Policymakers. They were, however, allowed to make comments on the SPM and the underlying 11 science chapters during the first day of the Plenary Meeting (November 27, 1996). The Global Climate Coalition dominated the initial plenary discussions.

Most of the plenary discussions at Madrid focused on the portrayal of Chapter 8’s findings in the Summary for Policymakers. Discussions were often difficult and contentious. We wrestled with the exact wording of the “balance of evidence” statement mentioned above. The delegations from Saudi Arabia and Kuwait argued for a very weak statement, or for no statement at all. Delegates from many other countries countered that there was strong scientific evidence of pronounced a human effect on climate, and that the bottom-line statement from Chapter 8 should reflect this.

Given the intense interest in Chapter 8, Sir John Houghton (one of the two Co-Chairs of IPCC Working Group I) established an ad hoc group on November 27, 1996. I was a member of this group. Our charge was to review those parts of the draft Summary for Policymakers that dealt with climate change detection and attribution issues. The group was placed under the Chairmanship of Dr. Martin Manning of New Zealand, and included delegates from the U.S., the U.K., Canada, Kenya, the Netherlands, and New Zealand. Sir John Houghton also invited delegates from Saudi Arabia and Kuwait to participate in this ad hoc group. Unfortunately, they did not accept this invitation.

The ad hoc group considered more than just the portions of the Summary for Policymakers that were relevant to Chapter 8. The Dutch delegation asked for a detailed discussion of Chapter 8 itself, and of the full scientific evidence contained in it. This discussion took place on November 28, 1996.

On November 29, 1996, I reported back to the Plenary on the deliberations of the ad hoc group. The Saudi Arabian and Kuwaiti delegations – who had not attended any of the discussions of the ad hoc group, and had no first-hand knowledge of what had been discussed by the group – continued to express serious reservations about the scientific basis for the detection and attribution statements in the Summary for Policymakers.

On the final evening of the Madrid Plenary Meeting, debate focused on finding the right word to describe the human effect on global climate. There was broad agreement among the government delegates that – based on the scientific evidence presented in Chapter 8 – some form of qualifying word was necessary. Was the human influence “measurable”? Could it be best described as “appreciable”, “detectable”, or “substantial”? Each of these suggested words had proponents and opponents. How would each word translate into different languages? Would the meaning be the same as in English?

After hours of often rancorous debate, Bert Bolin (who was then the Chairman of the IPCC) finally found the elusive solution. Professor Bolin suggested that the human effect on climate should be described as “discernible”.

Mr. Pearce – who was not present at the Madrid Plenary Meeting – argues that the discussion of human effects on climate in the IPCC Summary for Policymakers “went beyond what was said in the chapter from which the summary was supposedly drawn”. In other words, he suggests that the tail wagged the dog. This is not true. The “pre-Madrid” bottom-line statement from Chapter 8 was “Taken together, these results point towards a human influence on climate”. As I’ve noted above, the final statement agreed upon in Madrid was “The balance of evidence suggests a discernible human influence on global climate”.

Is “suggests” stronger than “points towards”? I doubt it. Is “The balance of evidence” a more confident phrase than “Taken together”? I don’t think so.

The primary difference between the pre- and post-Madrid statements is that the latter includes the word “discernible”. In my American Heritage College Dictionary, “discernible” is defined as “perceptible, as by vision or the intellect”. In Merriam-Webster’s Online Dictionary, one of the three meanings of the verb “discern” is “to recognize or identify as separate and distinct”. Was the use of “discernible” justified?

The answer is clearly “yes”. Chapter 8 of the IPCC’s Second Assessment Report relied heavily on the evidence from a number of different “fingerprint” studies. This type of research uses rigorous statistical methods to compare observed patterns of climate change with results from climate model simulations. The basic concept of fingerprinting is that each different influence on climate – such as purely natural changes in the Sun’s energy output, or human-caused changes in atmospheric levels of greenhouse gases – has a unique signature in climate records. This uniqueness becomes more apparent if one looks beyond changes averaged over the entire globe, and instead exploits the much greater information content available in complex, time-varying patterns of climate change.

Fingerprinting has proved to be an invaluable tool for untangling the complex cause-and-effect relationships in the climate system. The IPCC’s Second Assessment Report in 1995 was able to draw on fingerprint studies from a half-dozen different research groups. Each of these groups had independently shown that they could indeed perceive a fingerprint of human influence in observed temperature records. The signal was beginning to rise out of the noise, and was (using Merriam-Webster’s definition of “discern”) “separate and distinct” from purely natural variations in climate.

Based on these fingerprint results, and based on the other scientific evidence available to us in November 1995, use of the word “discernible” was entirely justified. Its use is certainly justified based on the scientific information available to us in 2010. The “discernible human influence” phrase was approved by all of the 177 delegates from 96 countries present at the Plenary Meeting – even by the Saudi and Kuwaiti delegations. None of the 28 IPCC Lead Authors in attendance at Madrid balked at this phrase, or questioned our finding that “the balance of evidence suggests a discernible human influence on global climate”. The latter statement was cautious and responsible, and entirely consistent with the state of the science. The much more difficult job of trying to quantify the size of human influences on climate would be left to subsequent IPCC assessments.

Mr. Pearce’s remarks suggest that there is some substance to the “political tampering” allegation – that I was somehow coerced to change Chapter 8 in order to “reflect the wording of the political summary”. This is untrue. There was no political distortion of the science. If Mr. Pearce had been present at the Madrid Plenary Meeting, he would have seen how vigorously (and successfully) scientists resisted efforts on the part of a small number of delegates to skew and spin some of the information in the Summary for Policymakers.

The key point here is that the SPM was not a “political summary” – it was an accurate reflection of the science. Had it been otherwise, I would not have agreed to put my name on the Report.

A reader of Mr. Pearce’s article might also gain the mistaken impression that the changes to Chapter 8 were only made in response to comments made by government delegates during the Madrid Plenary Meeting. That is not true. As I’ve mentioned above, changes were also made to address government comments made during the meeting of the ad hoc group formed to discuss Chapter 8.

Furthermore, when I first arrived in Madrid on November 26, 1995, I was handed a stack of government and NGO comments on Chapter 8 that I had not seen previously. I had the responsibility of responding to these comments.

One reason for the delay in receiving comments was that the IPCC had encountered difficulties in finding a Convening Lead Author (CLA) for Chapter 8. To my knowledge, the CLA job had been turned down by at least two other scientists before I received the job offer. The unfortunate consequence of this delay was that, at the time of the Madrid Plenary Meeting, Chapter 8 was less mature and polished than other chapters of the IPCC Working Group I Report. Hence the belated review comments.

The bottom line in this story is that the post-Madrid revisions to Chapter 8 were made for scientific, not political reasons. They were made by me, not by IPCC officials. The changes were in full accord with IPCC rules and procedures (pdf). Mr. Pearce repeats accusations by Fred Seitz that the changes to Chapter 8 were illegal and unauthorized, and that I was guilty of “corruption of the peer-review process”. These allegations are false, as the IPCC has clearly pointed out.

The 1995 IPCC Report: The “research irregularities” allegation

The third major front in the attack on Chapter 8 focused on my personal research. It was a two-pronged attack. First, Professor S. Fred Singer claimed that the IPCC’s “discernible human influence” conclusion was entirely based on two of my own (multi-authored) research papers. Next, Professor Patrick Michaels argued that one of these two papers was seriously flawed, and that irregularities had occurred in the paper’s publication process. Both charges were untrue.

On July 25, 1996, I addressed the first of these allegations in an email to the Lead Authors of the 1995 IPCC Report:

“Chapter 8 references more than 130 scientific papers – not just two. Its bottom-line conclusion that “the balance of evidence suggests a discernible human influence on global climate” is not solely based on the two Santer et al. papers that Singer alludes to. This conclusion derives from many other published studies on the comparison of modelled and observed patterns of temperature change – for example, papers by Karoly et al. (1994), Mitchell et al. (1995), Hegerl et al. (1995), Karl et al. (1995), Hasselmann et al. (1995), Hansen et al. (1995) and Ramaswamy et al. (1996). It is supported by many studies of global-mean temperature changes, by our physical understanding of the climate system, by our knowledge of human-induced changes in the chemical composition of the atmosphere, by information from paleoclimatic studies, and by a wide range of supporting information (sea-level rise, retreat of glaciers, etc.). To allege, as Singer does, that “Chapter 8 is mainly based on two research papers” is just plain wrong”.

In the second prong of the attack, Professor Michaels claimed that a paper my colleagues and I had published in Nature in 1996 had been selective in its use of observational data, and that our finding of a human fingerprint in atmospheric temperature data was not valid if a longer observational record was used. Further, he argued that Nature had been “toyed with” (presumably by me), and coerced into publishing the 1996 Santer et al. Nature paper one week prior to a key United Nations meeting in Geneva.

My colleagues and I immediately addressed the scientific criticism of our Nature paper by Michaels and his colleague Chip Knappenberger. We demonstrated that this criticism was simply wrong. Use of a longer record of atmospheric temperature change strengthened rather than weakened the evidence for a human fingerprint. We published this work in Nature in December 1996. Unfortunately, Mr. Pearce does not provide a link to this publication.

Since 1996, studies by a number of scientists around the world have substantiated the findings of our 1996 Nature paper. Such work has consistently shown clear evidence of a human fingerprint in atmospheric temperature records.

Disappointingly, Professor Michaels persists in repeating his criticism of our paper, without mentioning our published rebuttal or the large body of subsequently published evidence refuting his claims. Michaels’ charge that Nature had been “toyed with” was complete nonsense. As described below, however, this was not the last time I would be falsely accused of having the extraordinary power to force scientific journals to do my bidding.

A Climatology Conspiracy? More “peer-review abuse” accusations

Mr. Pearce also investigates a more recent issue. He implies that I abused the normal peer-review system, and exerted pressure on the editor of the International Journal of Climatology to delay publication of the print version of a paper by Professor David Douglass and colleagues. This is not true.

The Douglass et al. paper was published in December 2007 in the online edition of the International Journal of Climatology. The “et al.” included the same Professor S. Fred Singer who had previously accused me of “scientific cleansing”. It also included Professor John Christy, the primary developer of a satellite-based temperature record which suggests that there has been minimal warming of Earth’s lower atmosphere since 1979. Three alternate versions of the satellite temperature record, produced by different teams of researchers using the same raw satellite measurements, all indicate substantially more warming of the Earth’s atmosphere.

The focus of the Douglass et al. paper was on post-1979 temperature changes in the tropics. The authors devised what they called a “robust statistical test” to compare computer model results with observations. The test was seriously flawed (see Appendix A in Open Letter to the Climate Science Community: Response to A “Climatology Conspiracy?”). When it was applied to the model and observational temperature datasets, the test showed (quite incorrectly) that the model results were significantly different from observations.

As I have noted elsewhere, the Douglass et al. paper immediately attracted considerable media and political attention. One of the paper’s authors claimed that it represented an “inconvenient truth”, and proved that “Nature, not humans, rules the climate”. These statements were absurd. No single study can overturn the very large body of scientific evidence supporting “discernible human influence” findings. Nor does any individual study provide the sole underpinning for the conclusion that human activities are influencing global climate.

Given the extraordinary claims that were being made on the basis of this incorrect paper, my colleagues and I decided that a response was necessary. Although the errors in Douglass et al. were easy to identify, it required a substantial amount of new and original work to repeat the statistical analysis properly.

Our work went far beyond what Douglass et al. had done. We looked at the sensitivity of model-versus-data comparisons to the choice of statistical test, to the test assumptions, to the number of years of record used in the tests, and to errors in the computer model estimates of year-to-year temperature variability. We also examined how the statistical test devised by Douglass et al. performed under controlled conditions, using random data with known statistical properties. From their paper, there is no evidence that Douglass et al. considered any of these important issues before making their highly-publicized claims.

Our analysis clearly showed that tropical temperature changes in observations and climate model simulations were not fundamentally inconsistent – contrary to the claim of Douglass and colleagues. Our research was published on October 10, 2008, in the online edition of the International Journal of Climatology. On November 15, 2008, the Douglass et al. and Santer et al. papers appeared in the same print version of the International Journal of Climatology.

In December 2009, shortly after the public release of the stolen emails from the University of East Anglia’s Climatic Research Unit, Professors David Douglass and John Christy accused me of leading a conspiracy to delay publication of the print version of the Douglass et al. paper. This accusation was based on a selective analysis of the stolen emails. It is false.

In Mr. Pearce’s account of this issue, he states that “There is no doubt the (sic) Santer and his colleagues sought to use the power they held to the utmost…” So what are the facts of this matter? What is the “power” Fred Pearce is referring to?

• Fact 1: The only “power” that I had was the power to choose which scientific journal to submit our paper to. I chose the International Journal of Climatology. I did this because the International Journal of Climatology had published (in their online edition) the seriously flawed Douglass et al. paper. I wanted to give the journal the opportunity to set the scientific record straight.
• Fact 2: I had never previously submitted a paper to the International Journal of Climatology. I had never met the editor of the journal (Professor Glenn McGregor). I did not have any correspondence or professional interaction with the editor prior to 2008.
• Fact 3: Prior to submitting our paper, I wrote an email to Dr. Tim Osborn on January 10, 2008. Tim Osborn was on the editorial board of the International Journal of Climatology. I told Dr. Osborn that, before deciding whether we would submit our paper to the International Journal of Climatology, I wanted to have some assurance that our paper would “be regarded as an independent contribution, not as a comment on Douglass et al.” This request was entirely reasonable in view of the substantial amount of new work that we had done. I have described this new work above.
• Fact 4: I did not want to submit our paper to the International Journal of Climatology if there was a possibility that our submission would be regarded as a mere “comment” on Douglass et al. Under this scenario, Douglass et al. would have received the last word. Given the extraordinary claims they had made, I thought it unlikely that their “last word” would have acknowledged the serious statistical error in their original paper. As subsequent events showed, I was right to be concerned – they have not admitted any error in their work.
• Fact 5: As I clearly stated in my email of January 10 to Dr. Tim Osborn, if the International Journal of Climatology agreed to classify our paper as an independent contribution, “Douglass et al. should have the opportunity to respond to our contribution, and we should be given the chance to reply. Any response and reply should be published side-by-side…”
• Fact 6: The decision to hold back the print version of the Douglass et al. paper was not mine. It was the editor’s decision. I had no “power” over the publishing decisions of the International Journal of Climatology.

This whole episode should be filed under the category “No good deed goes unpunished”. My colleagues and I were simply trying to set the scientific record straight. There was no conspiracy to subvert the peer-review process. Unfortunately, conspiracy theories are easy to disseminate. Many are willing to accept these theories at face value. The distribution of facts on complex scientific issues is a slower, more difficult process.

Climate Auditing – Close Encounters with Mr. Steven McIntyre

Ten days after the online publication of our International Journal of Climatology paper, Mr. Steven McIntyre, who runs the “ClimateAudit” blog, requested all of the climate model data we had used in our research. I replied that Mr. McIntyre was welcome to “audit” our calculations, and that all of the primary model data we had employed were archived at Lawrence Livermore National Laboratory and freely available to any researcher. Over 3,400 scientists around the world currently analyze climate model output from this open database.

My response was insufficient for Mr. McIntyre. He submitted two Freedom of Information Act (FOIA) requests for climate model data – not for the freely available raw data, but for the results from intermediate calculations I had performed with the raw data. One FOIA request also asked for two years of my email correspondence related to these climate model data sets.

I had performed these intermediate calculations in order derive weighted-average temperature changes for different layers of the atmosphere. This is standard practice. It is necessary since model temperature data are available at specific heights in the atmosphere, whereas satellite temperature measurements represent an average over a deep layer of the atmosphere. The weighted averages calculated from the climate model data can be directly compared with actual satellite data. The method used for making such intermediate calculations is not a secret. It is published in several different scientific journals.

Unlike Mr. McIntyre, David Douglass and his colleagues (in their International Journal of Climatology paper) had used the freely available raw model data. With these raw datasets, Douglass et al. made intermediate calculations similar to the calculations we had performed. The results of their intermediate calculations were similar to our own intermediate results. The differences between what Douglass and colleagues had done and what my colleagues and I had done was not in the intermediate calculations – it was in the statistical tests each group had used to compare climate models with observations.

The punch-line of this story is that Mr. McIntyre’s Freedom of Information Act requests were completely unnecessary. In my opinion, they were frivolous. Mr. McIntyre already had access to all of the information necessary to check our calculations and our findings.

When I invited Mr. McIntyre to “audit” our entire study, including the intermediate calculations, and told him that all the data necessary to perform such an “audit” were freely available, he expressed moral outrage on his blog. I began to receive threatening emails. Complaints about my “stonewalling” behavior were sent to my superiors at Lawrence Livermore National Laboratory and at the U.S. Department of Energy.

A little over a month after receiving Mr. McIntyre’s Freedom of Information Act requests, I decided to release all of the intermediate calculations I had performed for our International Journal of Climatology paper. I made these datasets available to the entire scientific community. I did this because I wanted to continue with my scientific research. I did not want to spend all of my available time and energy responding to harassment incited by Mr. McIntyre’s blog.

Mr. Pearce does not mention that Mr. McIntyre had no need to file Freedom of Information Act requests, since Mr. McIntyre already had access to all of the raw climate model data we had used in our study (and to the methods we had used for performing intermediate calculations). Nor does Mr. Pearce mention the curious asymmetry in Mr. McIntyre’s “auditing”. To my knowledge, Mr. McIntyre – who purports to have considerable statistical expertise – has failed to “audit” the Douglass et al. paper, which contained serious statistical errors.

As the “Climategate” emails clearly show, there is a pattern of behavior here. My encounter with Mr. McIntyre’s use of FOIA requests for “audit” purposes is not an isolated event. In my opinion, Mr. McIntyre’s FOIA requests serve the purpose of initiating fishing expeditions, and are not being used for true scientific discovery.

Mr. McIntyre’s own words do not present a picture of a man engaged in purely dispassionate and objective scientific inquiry:

“But if Santer wants to try this kind of stunt, as I’ve said above, I’ve submitted FOI requests and we’ll see what they turn up. We’ll see what the journal policies require. I’ll also see what DOE and PCDMI administrators have to say. We’ll see if any of Santer’s buddies are obligated to produce the data. We’ll see if Santer ever sent any of the data to his buddies”

(Steven McIntyre; posting on his ClimateAudit blog; Nov. 21, 2008).

My research is subject to rigorous scrutiny. Mr. McIntyre’s blogging is not. He can issue FOIA requests at will. He is the master of his domain – the supreme, unchallenged ruler of the “ClimateAudit” universe. He is not a climate scientist, but he has the power to single-handedly destroy the reputations of exceptional men and women who have devoted their entire careers to the pursuit of climate science. Mr. McIntyre’s unchecked, extraordinary power is the real story of “Climategate”. I hope that someone has the courage to tell this story.

Benjamin D. Santer

John D. and Catherine T. MacArthur Fellow
San Ramon, California
February 22, 2010*

*These remarks reflect the personal opinions of Benjamin D. Santer. They do not reflect the official views of Lawrence Livermore National Laboratory or the U.S. Department of Energy. In preparing this document, I would like to acknowledge the assistance of Tom Wigley, Myles Allen, Kristin Aydt, Graham Cogley, Peter Gleckler, Leo Haimberger, Gabi Hegerl, John Lanzante, Mike MacCracken, Gavin Schmidt, Steve Sherwood, Susan Solomon, Karl Taylor, Simon Tett, and Peter Thorne.

We highlight issues with three of the articles below, which revisit a number of zombie arguments that have been doing the rounds of the sceptic blogs for years. Two follow-up pieces will deal with two further parts of the series. Hopefully some of the more egregious factual errors can be fixed as part of a ‘group experiment‘ in improving the stories, though the larger misconceptions probably can’t be (and readers should feel free to use this information to comment on the articles directly). Why the Guardian is asking for group input after the stories were published instead of before is however a puzzle. Some of the other pieces in this series are fine, which makes the ones that get it so wrong all the more puzzling. The errors consist of mistakes in the basic science, misunderstandings of scientific practice, more out of context quotes and some specific issues that are relatively new. (In the text below, quotes from the articles are in italics).

Part 3: Hockey Sticks

Some of the more egregious confusions and errors were in the third part of the series. In this part, a number of issues that were being discussed among the paleo-community in 1999 were horribly mixed up. For instance, there was a claim that arguments on the zeroth-order draft of the 2001 IPCC report were based on Briffa’s reconstruction showed the 11th century as being almost as warm as the 20th century, while Mann’s graph found little sign of the earlier warming. But this is simply untrue since at the time Briffa’s curve only went back to 1400 AD (not the 11th Century) and the discussions had nothing to do with the medieval warm period, but rather the amount of multi-decadal variability in the three different reconstructions then available. This was corrected in the online edition, but the description of the dispute in the article is still very confused.

That discussion was conflated with a completely separate April 1999 issue based on a disagreement about a perspectives piece in Science (which appeared as Briffa and Osborn, 1999) and which was in any case amicably resolved.

That discussion is then further confused with the discussions about the framing of the SPM text which despite Pearce claiming that ‘the emails reveal how deeply controversial it was at the time, did not get discussed in the emails at all. And while the article claimed that the uncertainty was not discussed in the IPCC report, the discussion in Chapter 2 was actually quite extensive.

Part 5: Chinese weather stations

This piece concerns the response of Phil Jones at CRU to a FOI request for data that had been used in a 1990 paper on the urban heat island (UHI). This now-20 year old paper was an early attempt to try and assess the possible magnitude of the UHI impact on the global temperature records. (Note that this is not the same as thinking that UHI does not exist).

Starting from the headline “Leaked climate change emails scientist ‘hid’ data flaws” on down, the article is full of misrepresentations. To start with, the data in question (and presumably it’s flaws) were not hidden by anyone, but rather had been put on the CRU server in 2007 response to a FOI request. Hardly ‘hidden’. Exactly contrary to the truth of the matter, the article incorrectly asserted that ‘Jones withheld the information requested under freedom of information laws’.

These data assumed a much greater importance later in 2007 when they were used for a completely unsubstantiated claim of ‘fabrication’ and ‘fraud’ against Wei-Chyung Wang (a co-author on the paper) at SUNY Albany by a certain Douglas Keenan. These charges were found by the university to be baseless in 2009 and the matter was dropped. However, the Guardian noted that a couple of the emails mentioned the issue, and that one in particular had Tom Wigley asking Phil Jones about the situation. Curiously enough, Phil Jones’ response was not part of the archive, and Wigley’s current thoughts on the subject (presumably that have been informed by Jones’ answers) were not reported.

Pearce describes this conversation saying that ‘new information brought to light today indicates at least one senior colleague had serious concerns about the affair‘. However, Tom Wigley has subsequently passed on later conversations to me showing very clearly that he did not support Keenan’s allegations of ‘fabrication’ and the implication that he does here are very misleading. Indeed, the statement that ‘Tom Wigley, harboured grave doubts about the cover-up‘ is completely false. There was no ‘cover-up’; the email was written two years after the data had been posted online.

The line in the 1990 paper that has apparently caused the furore is the following:

“The stations were selected on the basis of station history: we chose those with few, if any, changes in instrumentation, location or observation times.”

For fraud to have been proven, it would have been necessary to show that Wang – at the time of the 1990 paper – deliberately misled in the line as it was written. It would not be enough to show that the statement was mistaken because of incomplete histories available to him at that time, nor that some stations had in fact moved. The statement is a declaration of a good faith effort to pick suitable stations. Instead, you would have to demonstrate that Wang was aware of substantial and important moves that
made a material difference and deliberately concealed this fact. And for this there is absolutely no evidence. Keenan’s assumption of fabrication is merely that, an assumption.

Wigley’s ‘grave doubts’ were a suggestion that the key line be rewritten as

“Where possible, stations were chosen on the basis of station histories and/or local knowledge: selected stations have relatively few, if any, changes in instrumentation, location, or observation times”

A change that doesn’t undermine the paper in the slightest, and would hardly be likely to set the blogosphere aflame.

Quite frankly this whole allegation is absurd – why would anyone do this? All the authors involved have written many papers on the problems in the temperature record and on Urban Heat Islands in general, and even in China. Indeed the story here is that information was provided under FOI rules, and that it was not used to constructively examine the science, but rather to provide ammunition for baseless accusations that led to pointless university inquiries into alleged misconduct. That might be a good reason for why FOI requests are now being viewed with suspicion.

Other claims that this ‘may yet result in a significant revision of a scientific paper that is still cited by the UN’s top climate science body‘ . and that ‘what data is available suggests that the findings are fundamentally flawed‘ are simply made up. The findings of the 1990 paper was that UHI was unlikely to be contaminating the global temperature records in any significant way has been upheld by any number of additional studies in the 20 years since it was published. Oceans are not warming because of UHI, spring is not coming earlier because of UHI, and indeed, glaciers are not melting because of UHI (they are of course melting, recent news reports notwithstanding). No evidence of significant UHI contamination was found by Parker (2004, 2006), the record from GISTEMP which applies a different UHI correction than HadCRUT does not differ substantially at the global or regional scale. Other studies by Peterson, Jones, and others all show similar results. Even the more recent analyses of the Chinese stations themselves and even in an environment where urbanisation is happening faster than ever, UHI effects are still small (Jones et al, 2008).

As an aside, Keenan has made a cottage industry of accusing people of fraud whenever someone writes a paper of which he disapproves. He has attempted to get the FBI to investigate Mike Mann, pursued a vendetta against a Queen’s University Belfast researcher, and has harassed a French graduate student with fraud accusations based on completely legitimate choices in data handling. More recently Keenan, who contacted Wigley after having seen the email mentioned in the Pearce story, came to realise that Wigley was not in agreement with his unjustified allegations of ‘fraud’. In response, Keenan replied (in an email dated Jan 10, 2010) that:

.. this has encouraged me to check a few of your publications: some are so incompetent that they seem to be criminally negligent.


Sincerely, Doug

This kind of knee-jerk presumption of misconduct (and criminal misconduct at that) when people disagree with you has no place in the scientific discourse, and serves only to poison scientific debate. Indeed, Jones adds in one of the emails: “I’d be far happier if they would write some papers and act in the normal way. I’d know how to respond to that”. For the Guardian to dignify this kind of behaviour – especially after the charges had been investigated and dismissed – is unconscionable and a public apology should be forthcoming to Jones, Wigley and Wang.

Part 6: Peer review

The discussion of peer review is the most replete with basic misconceptions about the scientific process. Pearce appears to conflate any rejection of a paper or even a negative review for any reason as a prima facie case of mainstream climate scientists … censoring their critics. But in none of the cases highlighted were anyone’s view ‘censored’. To have your opinion published in peer-reviewed literature is not some fundamental right – it is a privilege that depends on your ability to do the analysis and the marshal the logical arguments and data to support your point.

Pearce, surprisingly for someone who has been on a science beat for a long time, states that peer review is the supposed gold standard of scientific merit. This is not the case at all. As we’ve outlined in many articles, peer review is just a first (necessary) step towards scientific acceptance and as the number of badly flawed papers that do appear in the literature attest, it is no guarantee of merit. For it to work of course there need to be some standards that should ideally be met, and this will lead to the rejection of some submissions. Thus automatically equating rejections of bad submissions with squashing of ‘dissent’ is like assuming that anyone who gets an F on a test is being unfairly discriminated against.

Pearce also declares that the mere act of reviewing a paper that is critical of your own work is mired in ‘conflicts of interest that would not be allowed in most professions‘. This is wrong on multiple levels. First of all, peer review of the literature is hardly unique to climate science, and so his claim about improper conflicts of interest is an accusation against the whole of science, not just climatology. Secondly, he confuses the role of the reviewer with that of the editor. Editors often solicit reviews of a critical comment directly from those being criticised, since that is often the easiest way to judge whether the critique is substantive. That is not the same as giving the right of veto to the criticised authors since, of course, it’s the editor’s job to weigh the different reviews from different sources, and use their own judgment as to the merits of the critique. Not asking the original authors for comment can certainly be (and has been) problematic and unfair to them. The problems most often arise – such as in Soon and Baliunas (2003) or McIntyre and McKitrick (2003;2005) when the criticised authors are not involved at all.

In the cases mentioned in this article, there is absolutely no evidence of unfair discrimination. Indeed, in one case of a submission by Lars Kamel, the reasons for rejection are obvious and Pearce appears not to know what the criteria for acceptance even are. He states that “the finding sounded important, but his paper was rejected by Geophysical Research Letters (GRL) that year“. But papers are not accepted or rejected because a finding ’sounds important’, but because that finding is backed up by analysis and logic while acknowledging the prior work on the topic. In this case, the author did not “however, justify that conclusion with any data or analysis“, and so a rejected manuscript would have been very likely, regardless of who the reviewers were. Similarly, the assumption that “some would have recommended publication” purely because it called into question previous work is unsupportable as a general rule. Filling the literature with papers ‘just asking questions’ that ’sound important’ but not demonstrating any actual results is a recipe for wasting everyone’s time with poorly thought out, and even mendacious, critiques of mainstream science from HIV-denial to perpetual motion machines. Papers in the technical literature are not just opinion.

Pearce also assumes (without evidence) that Kamel was discriminated against because Jones “would certainly have been aware of Kamel’s [negative] views about mainstream climate research“. But why should this be assumed? Most scientists (luckily) go through their whole career without wasting their time investigating and cataloguing the cranks in their field. Some climate sceptics get addressed here on RC a fair bit, but it would be a big mistake to think that these people, particularly the more obscure ones, are the subject of water cooler conversations at climate research labs across the world. Indeed, I can find no reference to Kamel on RC at all and I was unaware of his peculiar views until this story emerged. Why Jones should be assumed to omniscient on this topic is unclear.

Pearce quotes McIntyre discussing “CRU’s policies of obstructing critical articles in the peer-reviewed literature” slowing the resolution of unspecified “issues”. This is simply disingenuous – what papers have been obstructed that would have resolved what issues? We are unaware of any such papers, and certainly none from McIntyre. Prior therefore to declaring that “evidence, flawed though it might be, is actively being kept out of the journals” it behoves Pearce to actually find such evidence. Otherwise, the simple non-appearance of these mythical critiques is apparently proof of the corruption of the peer review process.

As an additional example of problematic practice, Pearce highlights a June 2003 email from Keith Briffa, who as an editor ‘emailed fellow tree-ring researcher Edward Cook, a researcher at Lamont-Doherty Earth Observatory in New York, saying: “Confidentially I now need a hard and if required extensive case for rejecting [an unnamed paper] to ­support Dave Stahle’s and really as soon as you can.”‘. However, without context this is meaningless. People often sign reviews and this could well have been a second go around on a particular paper whose first round reviews would have been seen by everyone concerned. Briffa (like many editors) can have a feeling that a paper should be rejected for multiple reasons but would like to have the reasons gone into in some detail, mostly for the benefit of the authors. This is one reason why reviewing bad papers is so much more work than good ones. Quoting this as if it absolutely demonstrated bad faith or misconduct is simply a smear.

Pearce then accuses Cook of some unjustified quid-pro-quo because he wanted to use some of Briffa’s data to assess the practical implications of a new analysis technique, that Pearce interprets as “attacking his own tree-ring work“. However, this too is a misreading. The work in question has subsequently been revised and the authors themselves have said that the current submission is improved over the initial submission. It goes along with the overall point made above, that pure criticism is not particularly useful – it is much better to demonstrate that some technical point actually matters. This is what Cook appears to be asking for help to demonstrate.

The article then moves on to the issue of the 2003 Soon and Baliunas paper in Climate Research. Pearce nowhere acknowledges that it is (and was) widely regarded as a complete failure of the peer review system. Six (very independent minded) editors resigned from the journal because of the publisher’s inaction on tightening up peer review standards and even the publisher himself declared that the paper’s conclusions were not supported by the data or analysis of the authors. Is this not germane?

Pearce suggests that the reaction to the demonstrably low standards at Climate Research involved “improper pressure“. This has no validity whatsoever. The suggestion was made that maybe people should not submit work to the journal or cite work that appeared there. But how can a suggestion made among colleagues and not transmitted more widely be ‘pressure’ of any sort? People have their impressions about journals determined by many factors, and if they are seen to be publishing bad papers, that will be noted. Compare the reputations of Science and E&E for instance. Which would you rather be published in if you had a good paper?

The one email that Pearce declares “means what it seems to mean” refers to the declaration (along with exclamation point) that Jones would “redefine peer-review!” rather than include two flawed papers in the AR4 report. But it should be obvious that no-one gets to redefine what ‘peer reviewed’ means, and the exclamation point underlines the fact that this was hyperbole. The two papers referred to (McKitrick and Michaels, 2004; Kalnay and Cai, 2003)) were indeed discussed in Chapter 2 of AR4 as the contributing lead author of that chapter Trenberth rightly pointed out. As an aside neither have stood the test the time.

The problem with lapses in peer review (which will inevitably occur) is that they are sometimes systematic, indicating a more institutional problem instead of simply an unfortunate combination of poor reviewers and a busy editor. This appeared to occur at Geophysical Research Letters over the period 2005-2006. There was a string of bad papers published – ones that did not properly support their conclusions and made basic errors in the science. For instance, Douglass and Knox (2005), Douglass, Patel and Knox (2005), Douglass, Pearson and Singer (2004), Douglass, Pearson, Singer, Knappenberger, and Michaels (2004), and Loáiciga (2006).

Science is indeed a ’self-correcting’ process, but someone has to do that correcting, and scientists do get frustrated when they have to spend weeks dealing with the aftermath of bad papers in the media and putting together the comments that almost every single one of these papers generated. (For amusement and for an example of the lack of standards being talked about, look at the response of Bjornsson et al to the Douglass, Patel and Knox paper).

Are scientists supposed not to notice these patterns? Or never discuss them among colleagues? The implication that the mere discussion of the situation is somehow a corruption of the peer review process is completely unjustified. Peer review only holds the status it does because scientists are on guard against failures in the system and try to correct them when they occur.

Update: Coincidentally, David Adams on the Guardian makes many of the same points as we do.

In two follow-up pieces we will host a letter from Ben Santer on Part 7 and on the skewed reporting of the ‘Yamal‘ issue in Part 9.

Here on RC, we have developed a wiki, to which I also would like to bring the reader’s attention. Furthermore, I want to remind the readers about other useful web sites, listed at our blog roll.