[ExI] IPCC errors: facts and spin

Emlyn emlynoregan at gmail.com
Thu Feb 18 04:29:05 UTC 2010

Apologies if this has turned up before. I haven't read AR4 (because
I'm not a masochistic freak), so have to take this mostly on face
value. It seems reasonable though.

If I were to level any criticism at the IPCC report based on this, it
would be at the process; this laborious effort to coordinate the input
of thousands of volunteers to make several dense books, which then
inevitably have some problems, seems like a poor approach in the
modern world. Surely an online collaborative approach, with the
ability to amend (bug fix) would be vastly superior??


IPCC errors: facts and spin

Currently, a few errors –and supposed errors– in the last IPCC report
(“AR4″) are making the media rounds – together with a lot of
distortion and professional spin by parties interested in discrediting
climate science.  Time for us to sort the wheat from the chaff: which
of these putative errors are real, and which not? And what does it all
mean, for the IPCC in particular, and for climate science more

Let’s start with a few basic facts about the IPCC.  The IPCC is not,
as many people seem to think, a large organization. In fact, it has
only 10 full-time staff in its secretariat at the World Meteorological
Organization in Geneva, plus a few staff in four technical support
units that help the chairs of the three IPCC working groups and the
national greenhouse gas inventories group. The actual work of the IPCC
is done by unpaid volunteers – thousands of scientists at universities
and research institutes around the world who contribute as authors or
reviewers to the completion of the IPCC reports. A large fraction of
the relevant scientific community is thus involved in the effort.  The
three working groups are:

Working Group 1 (WG1), which deals with the physical climate science
basis, as assessed by the climatologists, including several of the
Realclimate authors.

Working Group 2 (WG2), which deals with impacts of climate change on
society and ecosystems, as assessed by social scientists, ecologists,

Working Group 3 (WG3) , which deals with mitigation options for
limiting global warming, as assessed by energy experts, economists,

Assessment reports are published every six or seven years and writing
them takes about three years. Each working group publishes one of the
three volumes of each assessment. The focus of the recent allegations
is the Fourth Assessment Report (AR4), which was published in 2007.
Its three volumes are almost a thousand pages each, in small print.
They were written by over 450 lead authors and 800 contributing
authors; most were not previous IPCC authors. There are three stages
of review involving more than 2,500 expert reviewers who collectively
submitted 90,000 review comments on the drafts. These, together with
the authors’ responses to them, are all in the public record.

Errors in the IPCC Fourth Assessment Report (AR4)

As far as we’re aware, so far only one–or at most two–legitimate
errors have been found in the AR4:

Himalayan glaciers: In a regional chapter on Asia in Volume 2, written
by authors from the region, it was erroneously stated that 80% of
Himalayan glacier area would very likely be gone by 2035. This is of
course not the proper IPCC projection of future glacier decline, which
is found in Volume 1 of the report. There we find a 45-page, perfectly
valid chapter on glaciers, snow and ice (Chapter 4), with the authors
including leading glacier experts (such as our colleague Georg Kaser
from Austria, who first discovered the Himalaya error in the WG2
report).  There are also several pages on future glacier decline in
Chapter 10 (“Global Climate Projections”), where the proper
projections are used e.g. to estimate future sea level rise. So the
problem here is not that the IPCC’s glacier experts made an incorrect
prediction. The problem is that a WG2 chapter, instead of relying on
the proper IPCC projections from their WG1 colleagues, cited an
unreliable outside source in one place. Fixing this error involves
deleting two sentences on page 493 of the WG2 report.

Sea level in the Netherlands: The WG2 report states that “The
Netherlands is an example of a country highly susceptible to both
sea-level rise and river flooding because 55% of its territory is
below sea level”. This sentence was provided by a Dutch government
agency – the Netherlands Environmental Assessment Agency, which has
now published a correction stating that the sentence should have read
“55 per cent of the Netherlands is at risk of flooding; 26 per cent of
the country is below sea level, and 29 per cent is susceptible to
river flooding”. It surely will go down as one of the more ironic
episodes in its history when the Dutch parliament last Monday derided
the IPCC, in a heated debate, for printing information provided by …
the Dutch government. In addition, the IPCC notes that there are
several definitions of the area below sea level. The Dutch Ministry of
Transport uses the figure 60% (below high water level during storms),
while others use 30% (below mean sea level). Needless to say, the
actual number mentioned in the report has no bearing on any IPCC
conclusions and has nothing to do with climate science, and it is
questionable whether it should even be counted as an IPCC error.

Some other issues

African crop yields: The IPCC Synthesis Report states: “By 2020, in
some countries, yields from rain-fed agriculture could be reduced by
up to 50%.” This is properly referenced back to chapter 9.4 of WG2,
which says: “In other countries, additional risks that could be
exacerbated by climate change include greater erosion, deficiencies in
yields from rain-fed agriculture of up to 50% during the 2000-2020
period, and reductions in crop growth period (Agoumi, 2003).”  The
Agoumi reference is correct and reported correctly. The Sunday Times,
in an article by Jonathan Leake, labels this issue “Africagate” – the
main criticism being that Agoumi (2003) is not a peer-reviewed study
(see below for our comments on “gray” literature), but a report from
the International Institute for Sustainable Development and the
Climate Change Knowledge Network, funded by the US Agency for
International Development. The report, written by Morroccan climate
expert Professor Ali Agoumi, is a summary of technical studies and
research conducted to inform Initial National Communications from
three countries (Morocco, Algeria and Tunisia) to the United Nations
Framework Convention on Climate Change, and is a perfectly legitimate
IPCC reference.

It is noteworthy that chapter 9.4 continues with “However, there is
the possibility that adaptation could reduce these negative effects
(Benhin, 2006).”  Some examples thereof follow, and then it states:
“However, not all changes in climate and climate variability will be
negative, as agriculture and the growing seasons in certain areas (for
example, parts of the Ethiopian highlands and parts of southern Africa
such as Mozambique), may lengthen under climate change, due to a
combination of increased temperature and rainfall changes (Thornton et
al., 2006). Mild climate scenarios project further benefits across
African croplands for irrigated and, especially, dryland farms.”
(Incidentally, the Benhin and Thornton references are also “gray”, but
nobody has complained about them. Could there be double standards
amongst the IPCC’s critics?)

Chapter 9.4 to us sounds like a balanced discussion of potential risks
and benefits, based on the evidence available at the time–hardly the
stuff for shrill “Africagate!” cries. If the IPCC can be criticized
here, it is that in condensing these results for its Synthesis Report,
important nuance and qualification were lost – especially the point
that the risk of drought (defined as a 50% downturn in rainfall)
“could be exacerbated by climate change”, as chapter 9.4 wrote –
rather than being outright caused by climate change.

Trends in disaster losses: Jonathan Leake (again) in The Sunday Times
accused the IPCC of wrongly linking global warming to natural
disasters. The IPCC in a statement points out errors in Leake’s
“misleading and baseless story”, and maintains that the IPCC provided
“a balanced treatment of a complicated and important issue”. While we
agree with the IPCC here, WG2 did include a debatable graph provided
by Robert Muir-Wood (although not in the main report but only as
Supplementary Material). It cited a paper by Muir-Wood as its source
although that paper doesn’t include the graph, only the analysis that
it is based on. Muir-Wood himself has gone on record to say that the
IPCC has fairly represented his research findings and that it was
appropriate to include them in the report. In our view there is no
IPCC error here; at best there is a difference of opinion. Obviously,
not every scientist will always agree with assessments made by the
IPCC author teams.

Amazon forest dieback: Leake (yet again), with “research” by skeptic
Richard North, has also promoted “Amazongate” with a story regarding a
WG2 statement on the future of Amazonian forests under a drying
climate.  The contested IPCC statement reads: “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).”  Leake’s problem is with the Rowell and Moore reference, a WWF

The roots of the story are in two blog pieces by North, in which he
first claims that the IPCC assertions attributed to the WWF report are
not actually in that report. Since this claim was immediately shown to
be false,  North then argued that the WWF report’s basis for their
statement (a 1999 Nature article by Nepstad et al.) dealt only with
the effects of logging and fire –not drought– on Amazonian forests. To
these various claims Nepstad has now responded, noting that the IPCC
statement is in fact correct. The only issue is that the IPCC cited
the WWF report rather than the underlying peer-reviewed papers by
Nepstad et al. These studies actually provide the  basis for the
IPCC’s estimate on Amazonian sensitivity to drought. Investigations of
the correspondence between Leake, scientists, and a BBC reporter (see
here and here and here) show that Leake ignored or misrepresented
explanatory information given to him by Nepstad and another expert,
Simon Lewis, and published his incorrect story anyway. This “issue” is
thus completely without merit.

Gray literature: The IPCC cites 18,000 references in the AR4; the vast
majority of these are peer-reviewed scientific journal papers. The
IPCC maintains a clear guideline on the responsible use of so-called
“gray” literature, which are typically reports by other organizations
or governments. Especially for Working Groups 2 and 3 (but in some
cases also for 1) it is indispensable to use gray sources, since many
valuable data are published in them: reports by government statistics
offices, the International Energy Agency, World Bank, UNEP and so on.
This is particularly true when it comes to regional impacts in the
least developed countries, where knowledgeable local experts exist who
have little chance, or impetus, to publish in international science

Reports by non-governmental organizations like the WWF can be used (as
in the Himalaya glacier and Amazon forest cases) but any information
from them needs to be carefully checked (this guideline was not
followed in the former case). After all, the role of the IPCC is to
assess information, not just compile anything it finds.  Assessment
involves a level of critical judgment, double-checking, weighing
supporting and conflicting pieces of evidence, and a critical
appreciation of the methodology used to obtain the results. That is
why leading researchers need to write the assessment reports – rather
than say, hiring graduate students to compile a comprehensive
literature review.

Media distortions

To those familiar with the science and the IPCC’s work, the current
media discussion is in large part simply absurd and surreal.
Journalists who have never even peeked into the IPCC report are now
outraged that one wrong number appears on page 493 of Volume 2. We’ve
met TV teams coming to film a report on the IPCC reports’ errors, who
were astonished when they held one of the heavy volumes in hand,
having never even seen it. They told us frankly that they had no way
to make their own judgment; they could only report what they were
being told about it. And there are well-organized lobby forces with
proper PR skills that make sure these journalists are being told the
“right” story. That explains why some media stories about what is
supposedly said in the IPCC reports can easily be falsified simply by
opening the report and reading. Unfortunately, as a broad-based
volunteer effort with only minimal organizational structure the IPCC
is not in a good position to rapidly counter misinformation.

One near-universal meme of the media stories on the Himalaya mistake
was that this was “one of the most central predictions of the IPCC” –
apparently in order to make the error look more serious than it was.
However, this prediction does not appear in any of the IPCC Summaries
for Policy Makers, nor in the Synthesis Report (which at least partly
explains why it went unnoticed for years). None of the media reports
that we saw properly explained that Volume 1 (which is where
projections of physical climate changes belong) has an extensive and
entirely valid discussion of glacier loss.

What apparently has happened is that interested quarters, after the
Himalyan glacier story broke, have sifted through the IPCC volumes
with a fine-toothed comb, hoping to find more embarrassing errors.
They have actually found precious little, but the little they did find
was promptly hyped into Seagate, Africagate, Amazongate and so on.
This has some similarity to the CRU email theft, where precious little
was discovered from among thousands of emails, but a few sentences
were plucked out of context, deliberately misinterpreted (like “hide
the decline”) and then hyped into “Climategate”.

As lucidly analysed by Tim Holmes, there appear to be a few active
leaders of this misinformation parade in the media. Jonathan Leake is
carrying the ball on this, but his stories contain multiple errors,
misrepresentations and misquotes. There also is a sizeable contingent
of me-too journalism that is simply repeating the stories but not
taking the time to form a well-founded view on the topics. Typically
they report on various “allegations”, such as these  against the IPCC,
similar to reporting that the CRU email hack lead to “allegations of
data manipulation”. Technically it isn’t even wrong that there were
such allegations. But isn’t it the responsibility of the media to
actually investigate whether allegations have any merit before they
decide to repeat them?

Leake incidentally attacked the scientific work of one of us (Stefan)
in a Sunday Times article in January. This article was rather biased
and contained some factual errors that Stefan asked to be corrected.
He has received no response, nor was any correction made. Two British
scientists quoted by Leake – Jonathan Gregory and Simon Holgate –
independently wrote to Stefan after the article appeared to say they
had been badly misquoted. One of them wrote that the experience with
Leake had made him “reluctant to speak to any journalist about any
subject at all”.

Does the IPCC need to change?

The IPCC has done a very good job so far, but certainly there is room
for improvement. The review procedures could be organized better, for
example. Until now, anyone has been allowed to review any part of the
IPCC drafts they liked, but there was no coordination in the sense
that say, a glacier expert was specifically assigned to double-check
parts of the WG2 chapter on Asia. Such a practice would likely have
caught the Himalayan glacier mistake. Another problem has been that
reports of all three working groups had to be completed nearly at the
same time, making it hard for WG2 to properly base their discussions
on the conclusions and projections from WG1. This has already been
improved on for the AR5, for which the WG2 report can be completed six
months after the WG1 report.

Also, these errors revealed that the IPCC had no mechanism to publish
errata. Since a few errors will inevitably turn up in a 2800-page
report, obviously an avenue is needed to publish errata as soon as
errors are identified.

Is climate science sound?

In some media reports the impression has been given that even the
fundamental results of climate change science are now in question,
such as whether humans are in fact changing the climate, causing
glacier melt, sea level rise and so on. The IPCC does not carry out
primary research, and hence any mistakes in the IPCC reports do not
imply that any climate research itself is wrong. A reference to a poor
report or an editorial lapse by IPCC authors obviously does not
undermine climate science. Doubting basic results of climate science
based on the recent claims against the IPCC is particularly ironic
since none of the real or supposed errors being discussed are even in
the Working Group 1 report, where the climate science basis is laid

To be fair to our colleagues from WG2 and WG3, climate scientists do
have a much simpler task. The system we study is ruled by the
well-known laws of physics, there is plenty of hard data and
peer-reviewed studies, and the science is relatively mature. The
greenhouse effect was discovered in 1824 by Fourier, the heat trapping
properties of CO2 and other gases were first measured by Tyndall in
1859, the climate sensitivity to CO2 was first computed in 1896 by
Arrhenius, and by the 1950s the scientific foundations were pretty
much understood.

Do the above issues suggest “politicized science”, deliberate
deceptions or a tendency towards alarmism on the part of IPCC? We do
not think there is any factual basis for such allegations. To the
contrary, large groups of (inherently cautious) scientists attempting
to reach a consensus in a societally important collaborative document
is a prescription for reaching generally “conservative” conclusions.
And indeed, before the recent media flash broke out, the real
discussion amongst experts was about the AR4 having underestimated,
not exaggerated, certain aspects of climate change. These include such
important topics as sea level rise and sea ice decline (see the sea
ice and sea level chapters of the Copenhagen Diagnosis), where the
data show that things are changing faster than the IPCC expected.

Overall then, the IPCC assessment reports reflect the state of
scientific knowledge very well. There have been a few isolated errors,
and these have been acknowledged and corrected. What is seriously
amiss is something else: the public perception of the IPCC, and of
climate science in general, has been massively distorted by the recent
media storm. All of these various “gates” – Climategate, Amazongate,
Seagate, Africagate, etc., do not represent scandals of the IPCC or of
climate science. Rather, they are the embarrassing battle-cries of a
media scandal, in which a few journalists have misled the public with
grossly overblown or entirely fabricated pseudogates, and many others
have naively and willingly followed along without seeing through the
scam. It is not up to us as climate scientists to clear up this mess –
it is up to the media world itself to put this right again, e.g. by
publishing proper analysis pieces like the one of Tim Holmes and by
issuing formal corrections of their mistaken reporting. We will follow
with great interest whether the media world has the professional and
moral integrity to correct its own errors.

PS. A new book by Realclimate-authors David Archer and Stefan
Rahmstorf critically discussing the main findings of the AR4 (all
three volumes) is just out: The Climate Crisis. None of the real or
alleged errors are in this book, since none of those contentious
statements plucked from the thousands of pages appeared to be “main
findings” that needed to be discussed in a 250-page summary.

PPS. Same thing for Mike’s book Dire Predictions: Understanding Global
Warming, which bills itself as “The illustrated guide to the findings
of the IPCC”. Or Gavin’s “Climate Change: Picturing the Science” –
which does include a few pictures of disappearing glaciers though!


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