Since its founding more than 20 years ago, the Intergovernmental Panel on Climate Change (IPCC) can claim many important accomplishments to its credit. First among these are the periodic assessments of our understanding of the nature, origin, and impact of observed changes in the world’s climate. Also among its significant contributions has been the sustaining of a global focus on climate change.

Indeed IPCC has provided the framework for a continued and rather remarkable international conversation on climate research both among scientists and policymakers. In many ways IPCC, with its massive, far-flung, and decentralised network of scientists along with the governments represented on the panel, represents a significant social innovation.

For these and other contributions, the IPCC was one of the recipients of the Nobel Peace Prize in 2007.

In response to some sustained criticism and a heightened level of public scrutiny of the Fourth Assessment Report, the United Nations and IPCC asked the InterAcademy Council (IAC) to assemble a committee to review the processes and procedures of the IPCC and make recommendations for change that would enhance the authoritative nature of the IPCC reports.

Our review was undertaken amid a flurry of interesting, very public discussions surrounding aspects of IPCC’s fourth assessment that raised concerns in some quarters regarding the continuing credibility of the IPCC assessments themselves and the processes and procedures underlying them.

Among the critical contributions to this international discourse was a report from the Netherlands Environmental Assessment Agency on issues of concern in the report of Working Group II and the associated Summary for Policy Makers. Similar but more muted concerns followed publication of the Third Assessment Report in 2001.

On the other hand, many groups of scientists have insisted that whatever the failings in certain aspects of IPCC’s massive assessment, the key findings of the most recent IPCC assessment remain, as the Netherlands Environmental Assessment Agency concluded, unaffected. In the United States, the National Research Council came to the same conclusion after the third assessment and again more recently.

Scientific debates have always involved controversies over the value and importance of particular classes of evidence, and this can be expected to continue. Moreover, all scientific knowledge always contains some level of uncertainty and any actions based on scientific evidence inevitably involves an assessment of risk and a process of risk management.

Finally, given the dependence of major facets of IPCC assessments on vast data collections and complex models whose parameters are especially difficult to assess independently, risk assessments are especially challenging.

However, as the resulting controversies gained some momentum, they tended to expand beyond the IPCC assessments and raise issues ranging from the proper role of science (and scientists) in policymaking to the dangers of ‘group think’ or consensus building as a general proposition.

Unlike much of the current debate, the focus of this review is on the processes and procedures that support and give structure to IPCC’s very distinctive assessments. Our task was to broadly assess the processes and procedures of the IPCC and make recommendations on how they might be improved in order to enhance the quality and authoritative nature of future assessments.

As I consider IPCC as an organisation, it seems to me that its large decentralised worldwide network of scientists is the source of both its strength and its continuing vitality. However, climate science has become so central to important public debates that accountability and transparency must be considered as a growing obligation, and this alone would require revisiting IPCC’s processes and procedures.

In fact IPCC has shown itself to be an adaptive organisation in the past in the sense that it has adjusted the processes and procedures surrounding its assessments, both in response to scientific developments and as a result of lessons learned over the years. I expect that it will continue to do so and that the fifth assessment is certain to reflect some continuing change.

Nevertheless its overall management and governance structure has not been modified, and in my view this has made it less agile and responsive than it needs to be.

The intersection of climate science and public policy is certain to remain a controversial arena for some time as so many competing interests are at stake, including the interests of future generations and the diverse interests of different nations, regions, and sectors of society around the world.

Moreover, thoughtful controversy will remain a critical ingredient in stimulating further developments on the scientific frontier relating to our understanding of evolving climate conditions, their impact and the possible responses of policy makers.

Indeed climate science is a collective learning process as data are accumulated, interpreted, and used to construct models, and as alternative hypotheses are tested until we have increased confidence in our measurements and models and as a subset of ideas survive careful testing and competing explanations are eliminated.

I hope that the progress of climate science in all of these dimensions may slowly remove some of the uncertainties that continue to impede our fuller understanding of global climate change.

In my judgment, IPCC can continue to remain a very valuable resource, provided it can continue to highlight both what we believe we know and what we believe is still unknown and to adapt its processes and procedures in a manner that reflects both the dynamics of climate science and the needs of public policy for the best possible understanding of changing global climate, its impacts, and possible mitigation initiatives.

-- Harold T Shapiro is chair of the InterAcademy Council's review committee