This article reviews and extends the continuing debate on the treatment of economic issues by the Intergovernmental Panel on Climate Change (IPCC). Following an introduction, it has four main parts. Section 2, with its accompanying Annex 1, deals with one of the leading technical issues in the debate. It argues that, contrary to IPCC-related sources and some other analysts, exchange rates should not enter into measures or projections of output (real GDP). Section 3, in conjunction with Annexes 2 and 3, reviews again the projections of GDP and emissions that emerge from the IPCC's Special Report on Emissions Scenarios (SRES). It brings out in particular some confusions that have entered into the IPCC process and the arguments deployed in its defence. Section 4 lists the main weaknesses of the SRES, which are not a matter of the specific projections that it makes. These weaknesses cast doubt on the Panel's decision to use the SRES as a point of departure for its Fourth Assessment Report which is now in course of preparation. Section 5 considers the IPCC process as a whole. Attention is drawn again to the mishandling of economic evidence in IPCC documents and by the United Nations Environment Programme which is one of the IPCC's two parent agencies. New evidence of the professionally unrepresentative status of the IPCC milieu is cited from two sources: the Expert Meeting on Emissions Scenarios convened by the IPCC in January 2005; and the proceedings of the House of Lords Select Committee on Economic Affairs which has just reviewed 'economic aspects of climate change'. The IPCC's dismissive response to independent critics, as illustrated in Annex 3, means that its handling of economic issues can be improved only if its member governments take action. Effective action will require in particular the involvement of the central economic departments of state: these will have to show greater awareness of what is at stake than Her Majesty's Treasury in its evidence to the Select Committee. More broadly, and going beyond economic aspects, it is high time to put in question the IPCC's status as a monopoly provider of information to governments on issues relating to climate change.