NZ Environment Court, Cromwell, July 28-29, 2008








1.1   I, ROBERT MERLIN CARTER, Adjunct Research Professor of James Cook University, Townsville, Queensland 4811, Australia, make oath and say that I make this witness statement at the request of lawyers acting for appellant Roch Patrick Sullivan in the matter of an appeal under section 120 of the Resource Management Act 1991 that lies before the Environment Court (ENV-2007-CHC-307).


1.2   I confirm that I have read the Code of Conduct for Expert Witnesses in the Environment Court (Consolidated Practice Note 2006), and that my statement of evidence has been prepared in accord with the principles and practices specified therein.




2.1   Since 2000 I have been Adjunct Research Professor in the Marine Geophysical Laboratory and School of Earth Sciences, James Cook University, and also for a period Adjunct Research Professor in the School of Environmental and Earth Sciences, University of Adelaide.


2.9   My research career has been supported by grants from competitive public research agencies, especially the Australian Research Council (ARC), from whom I have received a Special Investigator Award. I receive no research funding from special interest organisations such as environmental groups, energy companies or government departments




3.1   In this evidence the term “climate change” is used in conformity with its general scientific meaning, as also adopted by the IPCC. Thereby, the term refers to the sum of all changes in climate, howsoever caused. The qualified terms “natural climate change” and “human-caused climate change” are used when they need to be distinguished, though these terms are in general relevant only in description of very recent climate history, i.e., that which has occurred since the industrial revolution.


3.2   The term “climate change” is defined in the Resource Management Act (RMA) as:

a change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and that is in addition to natural climate variability observed over comparable time periods”.


3.3   It is difficult to conduct a meaningful scientific discussion with reference to this definition, because (i) it refers to attribution rather than evidence; (ii) it does not define who is to do the attributing; (iii) it only considers change that is caused by human greenhouse gas emissions (there are other human effects on climate); and (iv) no evidential distinction has ever been demonstrated between natural and human-caused climate change at the global scale, and the phenomenon referred to is therefore unmeasurable.


3.4   The following acronyms are used throughout:


3AR      Third Assessment Report (of the IPCC)

4AR      Fourth Assessment Report (of the IPCC)

GCM     General Circulation Model (computer climate model)

IPCC     Intergovernmental Panel on Climate Change

SPM      Summary for Policymakers (of the IPCC)




4.1   My evidence will show that a human effect on global climate change has not yet been distinguished and measured. Meanwhile, global temperature change is occurring, as it always naturally does, and a phase of cooling has succeeded the mild late 20th century warming.


4.2   My conclusions are:


·        No human global climate signal has yet been measured. It is therefore likely that the human signal lies embedded within the variability of the natural climate system.

·       The science of climate change is far from settled. Meanwhile, there is no compelling evidence that human-caused climate change poses a strong future danger.

·       The available scientific data, and proved relationships, do not justify the belief that carbon dioxide emission controls can be used as a means of “managing” or “stopping” future climate change.

·      The projections (which are not predictions) of computer modellers must be assessed against the best available empirical science.

·        As is the case for other natural planetary hazards, policies to cope with climate change should be based upon adaptation to the change as it happens - whether warming or cooling - including appropriate mitigation of undesirable socio-economic effects.




5.1   The issue of dangerous human-caused global warming is a complex one. It can be assessed meaningfully only against our knowledge of natural climate change, which is incomplete and in some regards even rudimentary.

5.2   There is no Theory of Climate, in the sense that there is a Theory of Gravitation or Relativity. Therefore no computer model, let alone the unvalidated General Circulation Models (GCMs) that are employed, for example, by the Intergovernmental Panel on Climate Change (IPCC), can accurately predict future global or regional climate.

5.3   Furthermore, science does not operate by consensus. To assert – as many do – that IPCC advice on climate change represents a consensus scientific view that should necessarily be acted upon is a statement about sociology and politics, not about science.


5.4   In these circumstances, extreme caution is required for public authorities that are charged with environmental planning or safeguard for matters in which global warming is claimed to be a factor. It is vital that such bodies base their determinations on evidence-based, not speculative or virtual reality, science, and that they strive to appraise the evidence in a balanced manner. All sides of the global warming issue (and there are many more than the two caricatured in the media) must be presented fairly and given equal consideration.


5.5   Hereafter, this evidence comprises (i) A  summary of the global warming issue, (ii) A commentary on the Witness Statement of Dr David Wratt; and (iii) Conclusions.


The commentary considers the following topics: (i) Over-reliance on IPCC advice; (ii) Presumption that additional atmospheric carbon dioxide is harmful; (iii) Reliance upon unvalidated computer modelling; (iv) Failure to consider recent evidence;  (v) Over-reliance on circumstantial evidence; and (vi) Unsupportable conclusions.







6.1   A balanced summary of the global warming issue as it relates to human societies might read as follows.


“Climate changes naturally all the time. Human activities have an effect on the local climate, for example in the vicinity of cities (warming) or near large areas of changed land usage (warming or cooling, depending mainly upon the changed albedo*). Logically, therefore, humans must have an effect on global climate also. This notwithstanding, a distinct global human signal has not yet been identified within the variations of the natural climate system, to the degree that we cannot even be certain whether the signal is one of warming or cooling. Though it is true that many scientists anticipate on theoretical grounds that human warming is the more likely, no strong evidence exists that any such warming would ipso facto be dangerous.


The gentle global warming that probably occurred in the late 20th century falls within previous natural rates and magnitudes of warming and cooling, and is prima facie unalarming, especially when consideration is given to the likelihood that the historic ground temperature records used to delineate the warming are warm-biased by the urban heat island and other effects. Once corrected for non-greenhouse climate agents such as El Ninos and volcanic eruptions, the radiosonde (since 1958) and satellite (since 1979) records of atmospheric temperature show little if any recent warming and certainly none of untoward magnitude. 


Atmospheric carbon dioxide is indeed a greenhouse gas, but the empirical evidence shows that the warming effect of its increase at the rates of modern industrial emission and accumulation is minor, given an assumed pre-industrial atmospheric level of about 280 ppm and noting the established logarithmic relationship between gas concentration increases and warming. As one such empirical test, it can be noted that no significant increase in global average temperature has now occurred since 1998 despite an increase in carbon dioxide over the same 8 years of about 15 ppm (5%).


Putative human influence aside, it is certain that natural climate change will continue into the future, sometimes driven by unforced internal variations in the climate system and at other times forced by factors that we do not yet understand. The appropriate public policy response is, first, to monitor climate accurately in an ongoing way; and, second, to respond and adapt to any changes - both warmings and the likely more damaging coolings - in the same way that we cope with other natural events such as droughts, cyclones, earthquakes and volcanic eruptions.


In dealing with the certainties and uncertainties of climate change, the key issue is prudence. The main certainty is that natural climate change will continue, and that some of its likely manifestations – sea-level rise and coastal change in particular locations, for example – will be expensive to adapt to. But adapt we must and will. Adaptation will not be aided by imprudent restructuring of the world’s energy economy in pursuit of the chimera of “stopping” an alleged dangerous human-caused climate change that can neither be demonstrated nor measured”.


(*albedo is a technical term that means reflectivity)


6.2   This quotation is drawn from a published critique of the widely promulgated Stern Report on the economics of climate change, of which I am the senior author (Carter, De Freitas, Goklany, Holland & Lindzen, 2007). The analysis in the paper demonstrates that the Stern Report rests upon naïve science and speculative computer modelling, to a degree that vitiates the economic conclusions that are drawn.


6.3   A fuller discussion of many of the pros and cons of global warming, and an explanation of the alarmism that attends public debate on the issue, is provided in the review paper by Carter (2007).


6.4   Similar comments and advice to those contained in the quotation above appear in a letter written to the Secretary General of the United Nations by 103 professional persons in December, 2007 (Attachment A). The distinguished list of signatories to this letter includes many winners of awards, medals and prizes in meteorology, climatology or cognate subdisciplines, and 24 are Emeritus Professors. Unlike scientists associated with the United Nations Intergovernmental Panel on Climate Change, who are bound by the “cabinet solidarity” principle to the politically nuanced advice that is contained in IPCC’s Summary for Policymakers, the signatories of the UN letter – as those of the Manhatten Declaration (below), and the authors of the scientific papers that I refer to hereafter - provide their judgements independent of anything other than scientific merit.

6.5   Another recent public statement on climate change, the Manhatten Declaration, was first declared at a Climate Change meeting in New York in March, 2008 (Attachment B). The Declaration has now attracted more than 1,100 signatories (International Climate Science Coalition, 2008), of whom 187 (at the time of writing) are persons highly qualified in climate or a cognate science.


6.6   Summary


Science truth is not determined by head counts. Nonethless, there is now overwhelming documented evidence that a large number of responsible, highly qualified  professional scientists and economists do not accept that the advice given by the IPCC is accurate enough to carry exclusive influence in setting climate policies. The considered views of such a large body of expert people cannot simply be wished away.




7.0.1   I have been provided with, and read, a copy of the evidence of Dr David Wratt, presented on behalf of Meridian Energy Ltd. Dr Wratt, who bases his advice largely on IPCC opinions, has put similar arguments many times previously. They have been critically assessed in an analysis provided by Auer et al. (2006) to the Royal Society of New Zealand.


7.0.2   I make the following comments on Dr Wratt’s evidence. Other argumentation and supporting references for the topics covered below are provided by Auer et al. (2006), Carter (2007), Carter et al. (2007) and NIPCC (2008).


7.1.0   Over-reliance upon IPCC advice


7.1.1   In paras. 10-12, Dr Wratt outlines the history of the IPCC, and the remainder of his evidence rests almost exclusively upon statements made by that organisation. Only 3 of more than 40 references that he cites are from sources other than the IPCC, and more than 60% (28) of the citations are to the IPCC Summary for Policymakers (SPM).


7.1.2   In this context, Dr Wratt has failed to adequately inform the court about the widely known inadequacies of the IPCC procedures, and about the political nature of the advice to governments that is contained in the IPCC’s SPM. Before release, this document is approved, line by line, by government appointed functionaries. Though based upon recommendations from qualified scientists - and resting in part on the substantive IPCC science review volume - the SPM, which is the primary source for policy formulation, carries a heavy political overlay.


7.1.3   Furthermore, over many years, severe and mostly unrebutted criticisms have been made of even the science processes and procedures used by the IPCC. These criticisms, many of which are detailed by McLean (2007a, b; 2008), include the following.


7.1.4   That the IPCC operates a deeply flawed “peer review” process, which is hostile to any criticism of the presumption of dangerous human influence on global climate. Scientists who have participated in IPCC review procedures have complained that they are corrupted by:

Ÿ    a failure to incorporate valid critical comments made by some expert reviewers;

Ÿ    chaotic editorial techniques, which have included the preparation and release of a new draft report whilst its first draft was still being reviewed;

Ÿ    in the final stage of review of a Summary for Policymakers, incorporating changes desired by government bureaucrats without recourse to expert scientific assessment; and

Ÿ    an inadequate and dismissive attitude towards informed criticism.

7.1.5   Wegman (2006), who conducted a review for the US Congress of a particularly controversial piece of IPCC 3AR science (Michael Mann’s now infamous “hockey stick” curve of recent climate change)  listed as his first review recommendation that:

Especially when massive amounts of public monies and human lives are at stake, academic work should have a more intense level of scrutiny and review.  It is especially the case that authors of policy-related documents like the IPCC report, ’Climate Change 2001: The Scientific Basis’, should not be the same people as those that constructed the academic papers”.

 7.1.6   Overall, the IPCC uses the term “peer review” to describe a procedure that differs greatly from the conventionally understood meaning of the term. The problem is well summarised by von Storch (2005), who writes:

"The IPCC has failed to ensure that the assessment reports, which shall review the existing published knowledge and knowledge claims, should have been prepared by scientists not significantly involved in the research themselves. Instead, the IPCC has chosen to invite scientists who dominate the debate about the considered issues to participate in the assessment. This was already in the Second Assessment Report a contested problem, and the IPCC would have done better in inviting other, considerably more independent scientists for this task. Instead, the IPCC has asked scientists like Professor Mann to review his own work. This does not represent an "independent" review."


7.1.7   A related matter is the repetitious promulgation of misleading IPCC participant statistics; for example, of the 3,750 persons that Dr Wratt (para. 12) lists as participating in or approving the IPCC’s 4AR recommendations, just 51 scientists participated in the completion and final approval of the recent SPM for 4AR.

7.1.7   In a recent study, McLean (2008) reports that out of the 62 expert reviewers of the critical Chapter 9 of the 4AR, “Understanding and Attributing Climate Change”, 55 had conflicting or vested interest. In fact,
McLean was only able to identify 7 prima facie impartial reviewers, which is a very different number to 3,750.


7.1.8   The succinct advice of Sir Charles Fleming, one of New Zealand's greatest conservationists and natural scientists, on such pressure tactics was (Fleming, 1986):


"Any body of scientists that adopts pressure group tactics is endangering its status as the guardian of principles of scientific philosophy that are worth conserving".


7.1.9   During the preparation of 3AR and 4AR, a number of meritorious scientists who were involved expressed their dissatisfaction with IPCC process, in particular, what they saw as political interference in the preparation of IPCC reports. In one high profile case, on January 15, 2005, Dr Chris Landsea, an acknowledged leading expert on hurricanes/cyclones, withdrew his participation in IPCC. In resigning, Dr Landsea (2005) said:


“I personally cannot in good faith continue to contribute to a process that I view as both being motivated by pre-conceived agendas and being scientifically unsound”.


7.1.10   For the purposes of developing projections of future climate change, in 3AR the IPCC developed a number of alternative socio-economic scenarios for future world energy use. These scenarios, which feed into all climate projections made by the IPCC, have been shown to be both unrealistic and deeply flawed (Castles & Henderson, 2003). Yet these same inadequate economic scenarios have been used as the basis for the climate predictions made in the recent 4AR.


7.1.11   The IPCC exhibits an overdependence on climate projections made by unvalidated GCM computer models (see section 7.3 below).

7.1.12   The IPCC has adopted a qualititative scale of probability terms (which are deployed by Dr Wratt throughout his statement) that has no rigorous basis. IPCC terms such as “likely (>66% probable)” and “very likely (>90% probable)” have no actual statistical meaning, but instead represent only considered opinions. This is because the IPCC provides no empirical evidence that events predicted to have a >66% probability have indeed occurred at least two times out of three in the past.

The use of such terminology is highly misleading, and represents sociology not science.

7.1.13   In its reports, the IPCC often implies an inverted null hypothesis, whereby any observed global warming is presumed to be human-caused unless it can be shown otherwise. Because both the rate and magnitude of recent warmings fall within the bounds of previous natural climate variations, the correct null hypothesis is that global climate changes are presumed to be natural unless and until specific evidence is forthcoming for human causation. Despite the expenditure of much money and great research effort, not least by IPCC-related scientists, to date no such evidence has been forthcoming;


7.1.14   Considering these and other IPCC deficiencies, in 2006 an authoritative UK House of Lords Committee concluded that:

“We can see no justification for an IPCC procedure which strikes us as opening the way for climate science and economics to be determined, at least in part, by political requirements rather than by evidence. Sound science cannot emerge from an unsound process”, adding also that “we are concerned that there may be political interference in the nomination of scientists to the IPCC”.

7.1.15   Summary


New Zealand’s interests are not well served by relying exclusively on the advice of such a flawed international body as the IPCC, whose processes it cannot control. Instead, public policies on climate change would best be determined by expert advice that is tailored to the country’s regional geography, and is based less on computer models and more on the best empirical science and pragmatic economic reality.


7.2.0   Presumption that additional atmospheric carbon dioxide is harmful


7.2.1   In paras. 14-15, Dr Wratt describes how atmospheric carbon dioxide levels have increased by about 100 ppm from their pre-industrial levels, largely as a result of human activities. Throughout the rest of his evidence, Dr Wratt presumes that these increased, and still increasing, human emissions of carbon dioxide will cause dangerous climatic warming.


7.2.2   There is no dispute that atmospheric carbon dioxide levels have increased materially in the recent past, and that human emissions are one of the major sources for this increase. Nor is there any disagreement that carbon dioxide is a greenhouse gas that exerts a mild initial global warming effect. Beyond that, there is no agreement at all amongst scientists as to the magnitude of this warming effect once all likely feedback loops are considered. Relevant points include the following.

7.2.3   When governments, the public and the media discuss “carbon policy” or “reducing greenhouse gases”, they have in mind carbon dioxide. Even educated persons mostly have no idea (i) that the overwhelmingly dominant greenhouse gas is water vapour; or (ii) that, as a minor greenhouse gas, carbon dioxide is less than 4% of total greenhouse gases; or (iii) that human emissions then represent just a tiny portion (~3%) of that 4%. One recent estimate is that the human production of carbon dioxide (7.2 Gt/C/yr; IPCC, 2007) is more than four times less than the combined error (32 Gt) on the estimated carbon dioxide production from all other sources. A perspective that follows is that even were human emissions to be reduced to zero, the difference would be lost amongst other uncertainties in the global carbon budget (Ball, 2008). What is presently missing from the public debate, then - and not provided either by computer model outputs - is an appreciation of both the small scale (in context) of human emissions, and the range of uncertainty in the carbon budget.


7.2.4   A logarithmic relationship exists between the addition of carbon dioxide to the atmosphere and radiative heating, which causes each incremental amount of carbon dioxide to exert a lesser heating effect (IPCC, 2001). Post-industrial increases in greenhouse gases, including the 100 ppm increase in carbon dioxide, are estimated to have already caused about 75% of an anticipated 10 C of warming (Lindzen, 2006), so that all that remains to occur for a doubling of carbon dioxide is additional warming of an insignificant few tenths of a degree.

7.2.5   IPCC models, which invoke a positive feedback loop from water vapour, predict much greater increases up to 6.40 C for a doubling in carbon dioxide (IPCC, 2001, 2007). These calculations take numerical account of only positive feedback effects, especially that of increasing water vapour, and neglect negative feedback loops such as the generation of additional (reflective) low cloud cover. Alternative calculations by independent scientists suggest an increase of only 0.3-1.00 C for a doubling of carbon dioxide (e.g., Idso, 2001; Schwarz, 2007).


7.2.6   During natural climate cycling, changes in temperature PRECEDE the parallel changes in carbon dioxide (Mudelsee, 2001). Thus carbon dioxide cannot be the primary driver of global temperature change.

7.2.7   Carbon dioxide reached levels similar to today’s only a few thousand years ago, in the early Holocene (Kouwenberg et al., 2005). Prior to that, in earlier geological epochs, atmospheric carbon dioxide attained levels of 1000 ppm or more without known untoward environmental effects (e.g., Haworth et al., 2005).


7.2.8   The assumption that higher levels of carbon dioxide are, of themselves, harmful is most unlikely to be true. For it should be considered, first, that any mild warming caused by enhanced carbon dioxide is likely to be of net climatic benefit (cf. section 7.4.3 below); and, second, that higher atmospheric carbon dioxide both enhances plant growth and aids the efficiency of water use (Eamus, 1996; Robinson et al., 1998; Saxe et al., 1998), i.e. enhanced carbon dioxide is of net benefit for both biodiversity and food production.


7.2.9   Summary


Considering this evidence, the conclusion is inescapable that further increases of atmospheric carbon dioxide are likely to cause, at the most, slight warming; no case has been demonstrated that such warming, ipso facto, will be dangerous, indeed it is most likely to be beneficial (cf. 7.4.3 below).


7.3.0   Reliance upon unvalidated computer modelling


7.3.1   In para. 20, Dr Wratt reports that IPCC 4AR modelling projects a “best estimate for global average warming at the end of this century” for the lowest SRES emissions marker scenario B1 (i.e. 600 ppm carbon dioxide) of 1.80 C. In paras. 21- 23, Dr Wratt discusses other computer projections for such climate-related phenomena as sea-level rise, snow and ice cover, changing pH of the oceans, heat waves, precipitation and cyclone frequency.


7.3.2   This raises the question as to why - despite being correctly labelled as “projections” - these virtual reality computer imaginings are throughout Dr Wratt’s evidence nonetheless treated as if they were accurate climate “predictions” or “forecasts”.  


7.3.3   IPCC labels its computer model outputs of future temperature as projections precisely in order to highlight the fact that they are not skilled predictions of climate in 2100.  For example, none of the IPCC models were able to forecast the now-known path of the global average temperature statistic between 1990 and 2007, and they remain unvalidated.

7.3.4   Validation of a model, in the sense used by computer engineers, requires rigorous testing that demonstrates a capacity to forecast future behavior of the modelled system to a specified, satisfactory level of accuracy. No such procedure is known to have been carried out for any of the climate models used by the IPCC. Furthermore, it appears that no IPCC document, including 4AR, discusses the validation of their GCM  models,  and neither does the word “validation” appear in the Glossary of IPCC 4AR (2007).


7.3.5   That deterministic GCMs are unable to accurately predict future climate, at both global and especially regional level, is not a matter of opinion. Rather, that fact is well understood by the practitioners of deterministic computer modelling themselves, as is indicated by the following quotations selected from amongst a wide range of available similar statements.


7.3.6   Senior IPCC scientist and modelling expert Kevin Trenberth (2007) comments:


"There are no (climate) predictions by IPCC at all. And there never have been". Instead, there are only "what if" projections of future climate that correspond to certain emissions scenarios”.

According to Trenberth, "None of the models used by IPCC is initialised to the observed state and none of the climate states in the models corresponds even remotely to the current observed climate”. GCMs "do not consider many things like the recovery of the ozone layer, for instance, or observed trends in forcing agents" and "the state of the oceans, sea ice and soil moisture has no relationship to the observed state at any recent time in any of the IPCC models”.

"There is neither an El Nino sequence nor any Pacific Decadal Oscillation that replicates the recent past; yet these are critical modes of variability that affect Pacific rim countries and beyond . . . the starting climate state in several of the models may depart significantly from the real climate owing to model errors" and "regional climate change is impossible to deal with properly unless the models are initialised".

GCMs "assume linearity" which "works for global forced variations, but it cannot work for many aspects of climate, especially those related to the water cycle . . . the science is not done because we do not have reliable or regional predictions of climate".

7.3.7   Distinguished meteorologist, and former director of the World Meteorological Organization, John Zillman (2003) is of the view that:


"The most important question - should global warming proceed as the IPCC reports suggest - is how will warming be manifest at the national, regional and local level, and what would that mean for each of us? I believe this question is, at present, completely unanswerable".


7.3.8   Expert climate modellers McCracken, Smith & Janetos (2004)  say:

"We strongly agree that much more reliable regional climate simulations and analyses are needed. However, at present ...... such simulations are more aspiration than reality".

7.3.9   Finally, senior NIWA scientist, and IPCC representative, Dr. Jim Renwick, recently stated (2007):

"Climate prediction is hard, half of the variability in the climate system is not predictable, so we don't expect to do terrifically well”.

Dr Renwick was responding to an audit showing that the long term climate forecasts issued by NIWA were accurate only 48 per cent of the time. In other words, one can do just as well by flipping a coin.


7.3.10   It is not a coincidence that the Australian CSIRO, which provides one of the model outputs used by the IPCC, puts the following disclaimer on its climate modelling consultancy studies (e.g., Walsh et al., 2002):

“This report relates to climate change scenarios based on computer modelling. Models involve simplifications of the real processes that are not fully understood. Accordingly, no responsibility will be accepted by CSIRO or the QLD government for the accuracy of forecasts or pre- dictions inferred from this report or for any person's interpretations, deductions, conclusions or actions in reliance on this report.


7.3.11   Summary


Deterministic computer models do not produce predictive outputs that are suitable for direct application in policy making. Yet it is on the outputs of such unrealistic, unvalidated computer models that Dr Wratt’s evidence almost entirely relies.

It is clearly inappropriate to use projections of unskilled computer models for planning purposes as if they were predictions of future climate. Rather, environmental planning should be based upon the relevant real world, empirical data.


7.4.0   Failure to consider recent evidence


7.4.1   The cutoff date for publication of material to be included in the IPCC 4AR working group reports was May 2005. Globally, several billion US dollars are spent on climate change research each year, which produces prodigious published results. The IPCC 4AR assessment report that Dr Wratt relies so heavily on in his evidence is already materially outdated because it does not cover the last 3 years of this published science.


7.4.2   In the event - and in contrast to the oft repeated assertion that the science of climate change is ‘settled’- data accumulation and significant new peer-reviewed research since 4AR has cast even more doubt on the hypothesis of dangerous human-caused global warming than already existed in 2005 (see, e.g., NIPCC, 2008). Of various matters arising from this that might be discussed, the most germane is the behavior of global temperature itself.



7.4.3   The generally acknowledged phase of mild late 20th century global warming terminated in 1998. This warming phase was followed first by stasis, and then, since 2002, by cooling (Keenlyside et al., 2008; d’Aleo, 2008a) (Fig. 1). Ocean temperatures have also been cooling since 2003 (Willis et al., 2008) (Fig. 2). Dr Wratt makes no mention of these coolings in his evidence, but presumes instead that global warming is proceeding (e.g. para. 20).







7.4.4   Such changes in temperature trends are an established part of the multi-decadal cyclicity that is apparent throughout climate history. Such cycling relates at least partly to the phases of known climatic oscillations such as the Pacific Decadal Oscillation (e.g. NASA, 2008; McLean, 2007c), which in turn are likely driven by solar variations and not carbon dioxide increase.

7.4.5   The sun is currently in a quiescent state between solar cycles 23 and 24. The average length of a solar cycle is 11.1 years, and it is observationally established that cycles longer than this average are followed by later cyles of lesser intensity, and, commensurately, a cooling climate. Solar cycle 23 has now extended almost 2 years past the average duration, which points to continued and possibly even severe near future cooling (e.g., Clilverd et al., 2006; Archibald, 2007; Schatten & Pesnell, 2007; d’Aleo, 2008b).


7.4.6   It also bears repeating here that there was nothing unusual about the gentle late 20th century warming, which fell well within the rates and magnitudes of earlier known climatic warming episodes (e.g., Carter, 2007).

7.4.7   Dr Wratt (para. 17) makes play with the fact that “Eleven of the twelve years before the IPCC report was published (1995-2008) ranked among the 12 warmest years in instrumental records”. The suggestion that meaningful judgements about climate change can be made on the basis of the instrumental records alone (i.e. about 150 years of record, which represents 5 climate data points) is disingenuous. When a climate record of adequate length is examined – i.e. one at least tens of thousands of years in length - and multidecadal cycling is considered, it becomes obvious that it is no more surprising that many warm years cluster around and just after the 1998 climatic peak than it is that the warmer parts of each day generally occur between 11 am and 3 pm.

7.4.8   Including the warming that occurred in the early part of the century, the overall 20th century climate record is consistent with recovery from the severe Little Ice Age, combined with natural multidecadal climate cycling.

7.4.9   The IPCC has asserted (2001, p. 61) that:


"The fact that the global mean temperature has increased since the late 19th century and that other trends have been observed does not necessarily mean that an anthropogenic effect on the climate system has been identified. Climate has always varied on all time-scales, so the observed change may be natural. A more detailed analysis is required to provide evidence of a human impact."

Considering all the evidence, including that published in the three years since the completion of the 4AR report, this statement remains true.


7.4.10   Summary


The IPCC 4AR report is already materially out of date. In particular, global temperature records show that no significant warming has occurred since 1998 and that cooling has occurred in both the ocean and atmosphere since 2002. Over those same time periods, human emissions of carbon dioxide have continued to rise. Human causation for measurable, let alone dangerous, temperature increase is therefore unlikely, and at this time remains entirely speculative.


7.5.0   Over-reliance on circumstantial evidence


7.5.1   Earth is a dynamic planet. Its systems are constantly changing, and its lithosphere, biosphere, atmosphere and oceans incorporate many complex, homoeostatic, buffering mechanisms. Changes occur in all aspects of local climate, all the time and all over the world. Geological records show that climate also changes continually through deep time. Change is what climate does, and the ecologies of the natural world change concomitantly, in parallel.

7.5.2   Dr Wratt (paras. 21-23) and the IPCC analyse many and varied aspects of earth’s natural systems that are asserted to be controlled by, or linked to, human-caused climate change. These include, inter alia, changes in atmospheric composition, atmospheric aerosol load, global and regional ice volume, the frequency and intensity of storms, patterns of precipitation and drought, sea-level and the ranges of individual organisms and their ecological habitats.

7.5.3   Such matters are all topics for proper concern, as a result of which they are being subjected to intensive current research. However, to date no empirical study has been able to establish a certain link between changes in any of these things and human-caused global warming, i.e. to overturn the null hypothesis that particular changes are natural.


7.5.4   More details regarding most of these matters, and references, are contained in Auer et al. (2006), Carter (2007), Carter et al. (2007) and NIPCC (2008).

7.5.5   Summary

The various lines of indirect evidence for “climate change” adduced by the IPCC are consistent with natural change. Evidence for human attribution of observed changes in such features as storm intensity, global ice volume and sea-level change is at best circumstantial. Despite intensive research, no necessary connection with human causation has been established for any major global climate-related phenomenon. Conversely, and consistent with the null hypothesis, plausible natural explanations exist for all changes that have been described so far. 


7.6.0   Unsupportable conclusions


 Dr Wratt provides six conclusions to his evidence. In my opinion, the first five of these are unsupported by any convincing empirical evidence.



Global action to reduce greenhouse gas emissions is required as a matter of urgency to prevent dangerous interference in the planet’s climate and ecosystems” (Wratt, 43).


Neither Dr Wratt, nor the IPCC publications on which he heavily relies, provide empirical data that human greenhouse emissions are likely to cause dangerous interference with Earth’s climate. Though it is true that this view is held by the IPCC, it is equally true that the view is decisively rejected by very many qualified and distinguished scientists (section 6, above).



Warming of the climate system is now unequivocal, and most of the observed increase in global average temperature since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations” (Wratt, 44).


In reality, (i) both global atmospheric and ocean temperature are declining (7.4.3, above); (ii) a specific component of climate change that might stem from human greenhouse gas emissions has neither been identified or measured (6.1, above); and (iii) no empirical evidence exists that human emissions are causing dangerous warming (7.2.9, above).



Continued greenhouse gas emissions at or above current rates would cause further warming and induce many changes in the global system” (Wratt, 45).


In reality, and considering all likely feedbacks, (i) it is unknown whether measurable “further warming” will be produced by continuing human greenhouse emissions (7.2.2, above); and (ii) should human-caused warming occur to the degree that there are changes in the global system, some of these changes will be benefits and some will be disbenefits: Dr Wratt provides no appraisal of the balance of these effects, nor, so far as I am aware, has any such accurate appraisal ever been undertaken.



In order to prevent serious impacts on natural and managed systems from climate change it will be necessary to substantially reduce global emissions of carbon dioxide and other greenhouse gases” (Wratt, 46).


Presuming that “climate change” means “human-caused climate change”, no empirical evidence has been provided that human greenhouse emissions are causing “serious” environmental impacts (7.2.7, above), nor that emission curtailment would carry any identifiable environmental benefit (7.2.8, above).



Renewable energy, including energy generation from wind farms, is an important part of the climate change mitigation portfolio both globally and in New Zealand, since it reduces demand for energy generation by greenhouse gas-emitting thermal power plants” (Wratt, 47).


This is a generalization for which no quantitative evidence is provided. For example, what amount of global warming will be prevented, in degrees C, by the construction of the Project Hayes windfarm? Further, in calculating any such perceived “benefit”, account must be taken of the emissions that will be generated by the construction and operation of the necessary ~500 MW backup power station, a consideration that is not mentioned anywhere in Dr Wratt’s evidence.


7.6.6. In addition to Dr Wratt’s evidence, I have also given consideration to the evidence of Mr Gurnsey (Ministry for the Environment) where it touches on climate change.

7.6.7   Mr Gurnsey asserts that:


Over the past decade, climate change has emerged as the major environmental impact of energy use. Climate change is real, and it is happening” (Gurnsey, 23).


It is unclear whether Mr Gurney is referring to natural or human-caused climate change, nor whether he is referring to local or global change. The second sentence is certainly true with respect to natural global climate change; equally, in the sense of it being measurable, the sentence is not true for global human-caused change. These deep ambiguities are troubling, and make it difficult to attribute any value to the accompanying statements.


7.6.8   Mr Gurnsey also asserts that:


Our economy and lifestyle are particularly vulnerable to the impacts of global climate change”, and that “…..our national interests could be threatened by a changing climate”.


Presuming that Mr Gurnsey is referring to human-caused climate change, I am unaware of any published research that can credibly sustain the first of these remarks. On the other hand, it is certainly true for all nations that natural climate change, be it severe warming or severe cooling, represents a potential hazard. The appropriate response, as for similar natural hazards like earthquakes and volcanic eruptions, is one of adaptation to climate change as and when it occurs. For there is no empirical evidence that reducing human greenhouse emissions will have a measurable effect on global climate.


7.6.9    Summary


Few, if any, of the conclusions reached in evidence by Dr Wratt and Mr Gurnsey regarding dangerous human-caused climate change from human carbon dioxide emissions are substantiated by empirical data.




8.1   A human effect on global climate change has not yet been distinguished and measured. Meanwhile, global temperature change is occurring, as it always naturally does, and a phase of cooling has succeeded the mild late 20th century warming.


8.2   Independent scientists who have considered the matter carefully do not deny that human development can have an effect on local climate, nor that the sum of such local effects represents a hypothetical global signal. The key questions to be answered, however, are: (i) can any human global signal be measured, and, if so, (ii) does it represent, or is it likely to become, dangerous change outside of the range of natural variability?

No human global climate signal has yet been measured. It is therefore likely that the human signal lies embedded within the variability of the natural climate system.


8.3   That human-caused climate change will be dangerous is under strong dispute amongst equally well qualified scientific groups. The null hypothesis, which is yet to be contradicted, is that observed changes in climate or climate-related phenomena are natural unless and until it can be shown otherwise.

The science of climate change is far from settled. Meanwhile, there is no compelling evidence that human-caused climate change poses a strong future danger.

8.4   No measurable environmental benefits have been shown to be conferred by actions taken under the Kyoto Protocol, nor can they be predicted to result from carbon dioxide emission restrictions more generally. On the other hand, the social and economic disbenefits of governments deploying such instruments are now reported daily in the media.

The available scientific data, and proved relationships, do not justify the belief that carbon dioxide emission controls can be used as a means of “managing” or “stopping” future climate change.

8.5   Bowen (2005) has well written:


"Science is based upon empiricism - the objective observation of natural phenomena, and the attempt to encompass them in classifications, models and theories of ever-expanding scope. This enormously important principle of the Enlightenment still needs affirming. The principle is under threat, from those of every religious and political persuasion and from those of none, who seek to impose their world view upon scientific enquiry. Science is not more important than morality. But without

empiricism, there can be no science".

The projections (which are not predictions) of computer modellers must be assessed against the best available empirical science.


8.6   Study of the geological record of climate reveals many instances of natural changes of a speed and magnitude that would be hazardous to human life and economic well being should they be revisited upon today’s planet. Many of these changes are unpredictable, even in hindsight. That such natural changes will occur again in the future, both coolings and warmings, is certain.


To focus on the chimera of human-caused greenhouse warming while ignoring the real threats posed by the natural variability of the climate system itself is self-delusory. Instead, the reality that global climate is currently cooling, and will both warm and cool again in the future, needs to be recognized. As is the case for other unpredictable and dangerous natural events like earthquakes and volcanic eruptions, it is futile to try to “prevent” climate change.

As is the case for other natural planetary hazards, policies to cope with climate change should be based upon adaptation to the change as it happens - whether warming or cooling - including appropriate mitigation of undesirable socio-economic effects.


Professor R.M. Carter

June 19, 2008


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