The IPCC’s muddled definitions of climate change

In my first post, I criticised Peter Stott for muddling the IPCC’s definition of climate change. It seems that I owe Stott an apology: it’s not he who got the definitions confused, it’s the IPCC itself.

I gave a link to the IPCC’s definition of climate change, from the 2007 AR4 synthesis report. This states that

Climate change in IPCC usage refers to a change in the state of the climate that can be identified (e.g. using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. It refers to any change in climate over time, whether due to natural variability or as a result of human activity.

So it’s quite clear that when the IPCC says climate change, it means either man-made or natural change. And this is what the IPCC studies, since of course CC = “climate change”. The closest thing I can find to a definition in AR5 is Chapter 1 page 5, which again refers to any change, regardless of cause.

But hang on. There’s another document called “Principles Governing IPCC Work”. This says

The role of the IPCC is to assess on a comprehensive, objective, open and transparent basis the scientific, technical and socio-economic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.

So now it appears that the IPCC is only concerned with man-made climate change! This was probably the statement Peter Stott was referring to.

Related confusion arose in a twitter conversation between Richard Tol, Andy Revkin and Roger Pielke Jr:

The link leads to a 2005 paper by Pielke, Misdefining ‘‘climate change’’: consequences for science and action,  which draws attention to the confusion between the narrow definition used by the UNFCC and the broader one used by the IPCC, and also notes the “schizophrenic”  internal inconsistency of definitions within the IPCC.

The reference here to WGII and a note refers to the recently leaked WGII report, see this Bishop Hill thread, where Hilary Ostrov comments on a footnote,

[2] Attribution of observed impacts in the WGII AR5 links responses of natural and human systems to climate change, not to anthropogenic climate change, unless explicitly indicated.

This of course is in contradiction with the second blockquote above, that says the IPCC’s role is to assess the impacts of human-induced climate change.

What a shambles.

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10 thoughts on “The IPCC’s muddled definitions of climate change

  1. How does the UK Department of Energy and Climate Change define climate change?

    “Climate Change
    The process of changing weather patterns caused by the increased number of greenhouse gases in the global atmosphere as a result of human activity since the beginning of the Industrial Revolution.”

    from – ’A guide to carbon offsetting for the public sector’ – Department of Energy and Climate Change

    http://gps.cabinetoffice.gov.uk/sites/default/files/contracts/DECC%20guide%20to%20carbon%20offsetting.pdf

  2. As I had noted almost three years ago, Mike Hulme once wrote

    … the idea of climate change is so plastic…

    The conflation and confusion we see nowadays from the IPCC may (or may not) be what Hulme had in mind! But such “plasticity”, IMHO, is certainly a distraction from the “bottom line”: After 20+ years, there is no empirical evidence to support the claim that human-generated CO2 is the “primary cause” of whatever might (or might not!) be occurring.

    All of the above aside, I believe there are other “factors” one needs to remind oneself to take into account.

    From what I’ve seen over the last four years, an increase in “science by press release” compounds the problem (and perhaps deliberately so – she says, somewhat skeptically!)

    Even if the underlying “adopted” – i.e. not necessarily examined – full monty WG reports were to be fault-free (well, at least 97% fault-free), the distillation of the “message(s)”, i.e. Report–>SPM—>Press Release–>Media Churning is often so far removed from whatever might be the more measured and nuanced “assessment” of “the science” as to be virtually unrecognizable.

    Not to mention the carefully crafted and culled “Headline” statements for lazy media communicators!

    That’s one side of this plastic coin. The other side is that while all of the above can be said to be “hidden in plain view”, so to speak, the “negotiators” at the annual UNFCCC confabs are always working with a completely different (and very narrow) “definition” of climate change, i.e. only “human caused”.

    Whether these UNFCCC honchos and negotiators have taken the time to read (and understand!) even the relevant SPM(s) – let alone the full monty – doesn’t seem to matter, does it?! “Climate change” can mean only one thing in their books: It is all human-caused and it’s greatest threat to the future of the planet (unless we send megabucks).

    I’ve read a fair number (well, far more than I could ever have dreamed of four years ago!) of UNFCCC (and its multitude of ever-growing acronymic offspring) drafts and papers and who knows what.

    And I have yet to see a single one which acknowledges this (convenient – and perhaps even deliberate?!) definition discrepancy, which may (or may not!) derive from planned “plasticity”!

    Hilary [stepping down from soapbox!]

  3. I think there is reason to doubt this is “just” a bureaucratic oversight. Having two definitions is just too convenient. For example, when surveying to get “the consensus” they can use the broader definition to get wider agreement and then when referencing the agreement point to the narrow definition. Like an evolutionary system, there is reason these apparently non-adaptive mistakes survive.

  4. Correction: Sorry, the IPCC specializes in triple-A confusion. So when I wrote:

    Even if the underlying “adopted” …

    I really should have written “Even if the underlying “accepted” …

    For the record, in IPCC-speak, as I have noted in the past (e.g. here):

    “acceptance” of IPCC Reports at a Session of the Working Group or Panel signifies that the material has not been subject to line by line discussion and agreement, but nevertheless presents a comprehensive, objective and balanced view of the subject matter.

    How one can “accept” a document that requires no discussion (which strongly suggests that one might skip the reading thereof) is somewhat beyond my comprehension. But I digress …

    “adoption” of IPCC Reports is a process of endorsement section by section (and not line by line) used for the longer report of the Synthesis Report as described in section 4.3 and for Overview Chapters of Methodology Reports.

    “approval” of IPCC Summaries for Policymakers signifies that the material has been subjected to detailed, line by line discussion and agreement.

  5. The source of the problem is the UN Framework Confention on Climate Change (UNFCCC) redefining “climate change” from the scientific/linguistic definitions to meaning only change due to anthropogenic causes. See:

    Source: UNBIS Thesaurus

    Term definition:
    1. “Climate change” means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods

    2. Refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use. Note that the Framework Convention on Climate Change (UNFCCC), in its Article 1, defines “climate change” as: “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”. The UNFCCC thus makes a distinction between “climate change” attributable to human activities altering the atmospheric composition, and “climate variability” attributable to natural causes

    3. Any change in climate over time, whether due to natural variability or as a result of human activity. This usage differs from that in the United Nations Framework Convention on Climate Change (UNFCCC), which defines “climate change” as: “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”

    4. The climate of a place or region is changed if over an extended period (typically decades or longer) there is a statistically significant change in measurements of either the mean state or variability of the climate for that place or region. (Changes in climate may be due to natural processes or to persistent anthropogenic changes in atmosphere or in land use. Note that the definition of climate change used in the United Nations Framework Convention on Climate Change is more restricted, as it includes only those changes which are attributable directly or indirectly to human activity.) (UN/ISDR, 2004)

    Notes:
    Definition 1 taken from Convention, Article 1, para 2.

    Definition 2 taken from Climate change 2001: the scientific basis: contribution of Working Group I to the third assessment report of the Intergovernmental Panel on Climate Change. Appendix I. Glossary. (http://www.grida.no/climate/ipcc_tar/wg1/518.htm)

    Definition 3 taken from Climate change 2001: impacts, adaptation, and vulnerability: contribution of Working Group II to the third assessment report of the Intergovernmental Panel on Climate Change. Annex B. Glossary of Terms. (http://www.grida.no/climate/ipcc_tar/wg2/689.htm)

  6. Coincidentally, an article by Tim Ball at WUWT also discusses the IPCC’s muddled definition of climate change, calling it a “major deception”, see Pingback above.

  7. David is correct. The IPCC’s mandate comes from the UNFCCC, whose definitions, and whose concerns, are important. Confusion arises when scientists, including those inside the IPCC, think that IPCC activity is scientific and concerns scientific issues. For instance, McIntyre’s longstanding calls to approach paleoclimate studies from an engineering perspective cannot be carried out by the IPCC because its objectives are not to do so. Which other scientific discipline requires a single, official, international, intergovernmental synthesis of science?

    (Actually, some medical disciplines do. In histopathology, for instance, there are international disease-criteria defining expert compilations of existing evidence, carried out by … the World Health Organization. It has seen success to varying degrees in different disciplines. It has been a tremendous success in hematopathology, for instance, but not so in others. The larger benefits however, are from standardization of terminology and advancement of the ‘cutting edge’.)

  8. – And the undefined Consensus that unsurveyed scientists working in aspects of climate science are supposed to agree on ?
    Surprising that warmists never seem to write one down, you’d think it’d belong on the front page of any report, but I can’t find it written down anywhere.
    – show me that definition.

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