The role of the IPCC is to assess climate change not advocate Kyoto

The Australian Senate's Environment, Communications, Information Technology and the Arts Legislation Committee has recently released its Report on the Kyoto Protocol Ratification Bill 2003 (No.2).

On the specific subject of the Inquiry, the Committee divided along party lines: the Report recommended that the Bill for ratification of the Protocol not be proceeded with, and a Dissenting Report from the Australian Labor Party, Australian Democrats and Australian Greens recommended that it be "proceeded with forthwith".

On the more fundamental issues, however, there was near-unanimity.

The Committee stated that the most recently accepted report by the Intergovernmental Panel on Climate Change (IPCC) had "predicted" a doubling or tripling of atmospheric levels of carbon dioxide by 2100 and had found that this "will" lead to global warming of between 1.4 and 5.8 degrees Celsius. There was bipartisan support for "the proposition that the problem of global warming is real and one that cannot be ignored", and for the concomitant need "to substantially reduce greenhouse gas emissions in order to stabilise atmospheric concentrations of those gases".

These views were shared by all groups that made submissions to the Inquiry. The Report said that those groups that opposed ratification of the Protocol were "united in the belief that climate change is a serious issue, warranting global attention, so that the impacts of climate change on humankind can be avoided or minimised"; and that the groups in favour of ratification "point to the enormity of the climate change scenario facing the world".

The general impression conveyed by the Report - and, to an even greater extent, by the Dissenting Report - is that it has been established that human-induced climate change poses an extremely serious problem which demands urgent countervailing action in the form of negotiated emissions reductions, either under the Kyoto Protocol or some successor instrument.

But this is far from being the case. To begin with, the IPCC's Third Assessment Report, which the Senate Committee Report describes as "the most recent generally accepted authoritative statement on climate change", produced "projections" - not "predictions" - of future greenhouse gas concentrations and global temperatures.

The distinction is crucial. Dr. John Zillman, Australia's Principal Delegate to the Panel since 1993, made clear in an address in March 2003 that the projections in the IPCC's Report are "nothing more than 'what if?' assessments", and "are not, in any sense, to be regarded as predictions of actual future climate".

In the same address, Dr. Zillman said the question of how global greenhouse warming will manifest itself at the national, regional or local level "is, at present, completely unanswerable". He recognised, however, that "we do have sufficient information ... to develop the techniques that would enable us to begin to evaluate the benefits and costs [of future climate change for individual states or regions of Australia] once we are in a position to produce estimates (i.e. predictions rather than scenarios) of global greenhouse gas concentrations for the century ahead".

Dr. James Hansen, Head of the NASA Goddard Institute of Space Studies (GISS), has recently produced a "lay person's emissions graph" in order to show that it is highly misleading to interpret the IPCC's projections of future carbon dioxide emissions as if they are predictions (see the second graph, labelled Figure 15). Hansen's comments on this Figure include the observation that "The IPCC scenarios that extend far off-scale (high) are impractical to show in entirety with a linear scale, but they do not need to be shown as they are unrealistic".

Dr. Hansen's previous graph (Figure 14) enables the Senate Committee's statement that the IPCC had "predicted" a doubling or trebling of carbon dioxide concentrations to be placed in a more balanced perspective. It shows that the build-up of these concentrations under the "alternative scenario" developed by Hansen and his colleagues at GISS would be substantially slower than under any of the IPCC scenarios.

James Hansen is not a climate sceptic. In fact, an extract from one of his recent papers (co-authored with 27 of his colleagues at GISS) was cited in the Australian Greenhouse Office publication Climate Change: an Australian Guide to the Science and Potential Impacts (December 2003) in support of the view that global warming is attributable to human influences:

Hansen et al (2002) used the GISS model to explore the effect on global temperature of various natural and anthropogenic forcings. They conclude that the observed global temperature change during the last 50 years is primarily the result of these forcings. They also note that the ocean temperatures lag behind these forcings, such that additional global warming of about 0.5 degrees C is already "in the pipeline". (p. 26)

Most readers would infer from this that Dr Hansen and his colleagues were acutely concerned about the dire prospects for the planet arising from the prospective warming in the present century and a further warming which would still be "in the pipeline" in 2100. But nothing could be further from the truth. Under Hansen's alternative scenario, the maximum projected global warming above 2000 levels would be only about 1 degree C. This increase, which is projected to occur between 2125 and 2150, is far below that projected in any of the IPCC scenarios.

The study of past and prospective climate forcings that was cited in the AGO Guide had been foreshadowed in a companion paper by Hansen in the leading journal Climatic Change (52: 435-440, 2002) under the significant title "A Brighter Future". In the latter paper, Hansen explicitly rejected the claim that the actions needed to avoid a "gloom and doom scenario" were "economically wrenching", and argued that, on the contrary, they "made sense independent of global warming".

A striking chart in "A Brighter Future" shows that the greenhouse gas climate forcing that Hansen and his colleagues now project for 2050 under their "alternative scenario" is no greater than the forcing that had been projected for 2010 under a GISS scenario (styled "business as usual" or "fast growth") that had been published at about the time of Hansen's influential appearance before a US Senate Committee on 23 June 1988. Hansen's evidence received extensive media coverage and contributed to the wave of concern about global warming that led to the establishment of the IPCC later that year.

Hansen is critical of "the IPCC predilection for exaggerated growth rates of population, energy intensity and pollution", and of its "failure to emphasise data". He gives a number of reasons for believing that the IPCC scenarios are "unduly pessimistic", and questions whether those scenarios are necessary or even plausible. He argues that "global warming can be slowed, and stopped, with practical actions that yield a cleaner healthier atmosphere", and argues that the focus of international action, at least in the short run, should be directed towards the reduction of air pollution through concerted efforts to develop and share clean technologies.

Hansen contends that this approach would unite the interests of developed and developing countries, and that the benefits (not least in the saving of human lives) would accrue immediately rather than in 100 years.

In a hearing before a US Senate Committee in May 2001, Hansen was asked whether he felt that his results had been reviewed and properly considered as part of the IPCC process He responded as follows:

No. IPCC's size and review procedures make it inherently lethargic, so responding to a mid-2000 paper is difficult. However, the real problem is probably the close binding between the IPCC and the Kyoto Protocol discussions. Kyoto excludes consideration of air pollution (such as tropospheric ozone and black carbon), for example, so IPCC basically ignores these topics and downgrades them. The only IPCC "review" of our paper was by the IPCC leaders ... who saw our paper as potentially harmful to Kyoto discussions ... When I had difficulty publishing a response in Nature, I wrote an open letter that is available at http://naturalscience.com/ns/letters/ns_let25.html.

My experience with the IPCC has been regrettably similar. I met the Panel's newly-elected Chairman, Dr. Rajendra Pachauri, during his first official visit to Australia in July 2002. At his invitation, I wrote to him to outline criticisms I had made of the economic work of the IPCC, especially its emissions scenarios. He assured me that my concerns were being taken seriously, and that my letters had been made available to all members of the IPCC Bureau. In October 2002, Professor David Henderson, a former Head of the Economics and Statistics Department of the OECD, wrote to Dr. Pachauri to support my criticisms.

At the IPCC's invitation, Henderson and I gave presentations to an IPCC Expert Meeting in Amsterdam in January 2003. Here and subsequently, we argued that the economic aspects of the Panel's work needed to be placed on a professionally sounder basis.

So far as I know, none of the papers presented at the expert meeting has been published by the IPCC. Our criticisms have been published in the journal Energy & Environment, and have been rejected in intemperate articles in the same journal by teams of authors involved in the work on emissions scenarios for the IPCC. In December 2003 the IPCC itself issued a special press release dismissing our arguments. It described Henderson and me as "so-called 'two independent commentators'" and as originators of "some disinformation [that] has been spread questioning the scenarios".

Meanwhile the Panel has published a 340-page volume entitled Integrating Sustainable Development and Climate Change in the IPCC Fourth Assessment Report (pdf, 162Kb), being the proceedings of an Expert Meeting held in Sri Lanka in March 2003. The volume purports "to communicate the latest results on the topic to the lead authors of the IPCC fourth assessment report (AR4) and the general scientific community". Although five of the six editors are members of the IPCC Bureau, the "latest results" include a repetition of several of the "material errors" to which I had drawn attention in my letters to Dr Pachauri in August 2002, which had been sent to all members of the Bureau at his direction. Most of the papers fall lamentably short of the minimum standards that could reasonably be expected in the publications of a scientific body.

Underlying the IPCC's unprofessional way of dealing with its critics is a perception of the Panel's role that does not sit easily with what were, at least until recently, widely accepted views of the proper role of science in relation to the political processes.

James Hansen's concerns about the "close binding between the IPCC and the Kyoto Protocol discussions" have already been mentioned. Comments made by Dr. Pachauri soon after his election to the chairmanship of the IPCC 12 months later serve to reinforce those concerns. According to a BBC report, the new chairman said that there was a need for a dialogue on what commitments nations should make in a second wave after Kyoto: "I think that the science must provide a compelling reason and a logic to take those steps, and this is what I hope the IPCC will be able to do in the future."

There are disturbing signs that the IPCC has increasingly seen its role as that of providing scientific justification for the maintenance of divisive Kyoto-style emissions restrictions, rather than of providing an objective assessment. Dr. Zillman has recently expressed the view that the IPCC has now become "cast more in the mode of supporting than informing policy development" (Bulletin of the Australian Meteorological and Oceanographic Society, 2003, vol. 16:85).

I am not competent to assess the full implications of Hansen's "alternative scenario". But it is a matter of public record that, four years after its publication, this radical proposal, which - if valid - has far-reaching implications for the appropriate policy response to the prospect of global climate change in the coming decades, has not been considered by the IPCC. Meanwhile, Hansen's papers and statements have become increasingly critical of the Panel's modus operandi.

The IPCC's failure to consider the Hansen "alternative scenario" and its dismissal of the Castles and Henderson critique are disturbing signs that the Panel's role in the assessment of the science of climate change has now become subservient to its role in supporting a specific policy agenda.