Why global targets to reduce emissions won’t work
In November 2005 the Australian Academy of Science (AAS) invited me to a “President’s Soiree” to discuss the topic “Integrative climate science, economics and sociology.” According to the invitation sent to the Academy’s Canberra Fellows, “The choice of topic has been stimulated in part by the [recently-released] House of Lords report [on “The Economics of Climate Change”]. Attached to the Academy’s invitation was the Abstract of the Report, the conclusion of which read:
We are concerned that the international negotiations on climate change reduction will be ineffective because of the preoccupation with setting emissions targets … We urge the [UK] Government to take a lead in exploring alternative ‘architectures’ for future Protocols, based perhaps on agreements on technology and its diffusion.
As the only non-scientist present at the gathering, I was grateful to President Jim Peacock for allowing me to try and explain the reasoning underlying the unanimous recommendations of the all-Party Lords Committee Report.
I was also able to draw the expert audience’s attention to a recent Policy Paper that had been published by the Academy of the Social Sciences in Australia (ASSA) under the title “Uncertainty and Climate Change: The Challenge for Policy”. In this Paper three leading scholars (meteorologist John Zillman, economist Warwick McKibbin and political scientist Aynsley Kellow) explained why “An in-depth understanding of the nature and significance of … uncertainties is essential for the formulation of properly informed national and international action on the greenhouse issue.”
In the course of a friendly discussion, Dr Peacock contested my view that experts had a duty to try to convey this understanding to governments, interest groups and the wider community. He argued that governments wanted clear and simple statements about the need for action, and that the admission of the inherent uncertainty blunted the capacity to win support for urgent implementation of mitigation policies.
The evidence suggests that Jim Peacock was right. Although the ASSA Policy Paper was widely circulated – including to members of Federal Parliament, Government departments, educational institutions, NGOs nationally and internationally, libraries and the media – it attracted virtually no attention. The Lords Committee Report suffered a similar fate, being dismissed by the UK Government and ignored in the Stern Report.
By contrast, the prevailing scientific opinion on climate change tends to take the form of strongly worded assertions about the urgency of the problem and, at least by implication, the self-evident character of solutions.
For example, in an op-ed published in The Australian on 7 February 2007 under the stark headline “On the Edge of Global Calamity”, Dr Peacock’s successor as President of the AAS, Professor Kurt Lambeck, asserted that the “basic facts” underpinning the just-released Fourth Assessment Report of the IPCC (AR4) were “undeniable, indisputable and confirmed by the best minds the world can bring to bear on the subject”.
It is true that some basic facts about climate science are undeniable and indisputable, but there is no need for an intergovernmental Panel of 200 governments and hundreds of lead authors and expert reviewers to establish those.
Interestingly, however, none of the AAS’s four most senior Fellows in climate-related disciplines (Dr Garth Paltridge, elected 1980; Dr Angus McEwan, elected 1982; Professor Graham Farquhar, elected 1988; and Dr Graeme Pearman, elected 1989) had roles either as lead authors or reviewers of the report that was the subject of Professor Lambeck’s op-ed. Yet these same four were the only Fellows of AAS who were members of the interdisciplinary Study Team which produced the valuable Joint Academies report Climate Change Science: Current Understanding and Uncertainties in 1995. It can no longer be assumed, if it were ever true, that all of the ‘best minds’ in climate change science are participating in the IPCC process.
I hesitate to correct the President of the AAS on a point of fact, but his statement that “the fraction of annually emitted CO2 absorbed by the oceans is … now down to 37 per cent” does not square with the estimates from the standard source: the Global Carbon Project (GCP). The GCP proportion shows marked annual fluctuations but it has been continuously below 37 per cent for the entire 50-year period of the series, with the exception of the three years 1964 to 1966.
Of course the GCP’s estimates of oceanic absorption of CO2 expressed as a fraction of the same year’s emissions may be substantially astray: they depend in part upon the denominator – global CO2 emissions. And even the more reliable component of anthropogenic CO2 emissions (those arising from the combustion of fossil fuels) is subject to large uncertainties.
In one of the media releases supporting the most recent GCP update, one principal of the Project was quoted as saying that the uncertainty of the estimate for China could be as much as 20%, which is equivalent to more than the total fossil fuel emissions of all but three other countries (the US, Russia and India). At the same time, in a different media release, another GCP principal was quoted as saying that “Forests and oceans – the Earth’s natural sinks – absorbed 54% of the CO2 emissions since 2000, down by 3% compared to 1959-2000.” The truth is that the large uncertainties in both numerator and denominator preclude firm conclusions, even about the direction of change.
There are formidable measurement, verification and enforcement issues that stand in the way of any internationally-agreed scheme of binding emissions reduction targets. That is why the Lords Committee advocated “wholly different, and more promising, approaches based on a careful analysis of the incentives that countries have to agree to any measures adopted.” In the meantime, Australia should not commit itself to the large costs and inefficiencies of an emissions trading scheme of the kind that is currently before the Parliament.
Ian Castles is a Visiting Fellow at the Crawford School of Economics and Government at the Australian National University. He is a former Secretary of the Australian Department of Finance, Head of the Australian Bureau of Statistics and Executive Director of the Academy of the Social Sciences in Australia.