Before human-caused global warming can become an economic problem, it first has to be identified by scientific study as a dangerous hazard for the planet, distinct from natural climate change.

This notwithstanding, a number of distinguished economists have recently written compendious papers or reports on the issue, for example Nicholas Stern (2006) and William Nordhaus (2007); in Australia, Ross Garnaut is currently undertaking a similar analysis. These persons, and many other public commentators and politicians as well, have indicated that they accept that there is a scientific consensus that dangerous, human-caused global warming is occurring, as set by the views and advice of the Intergovernmental Panel on Climate Change (IPCC).

The IPCC is the United Nations body whose first chairman, John Houghton, wrote in 1994 that ‘unless we announce disasters, no one will listen’. From that point forward, it was obvious that IPCC pronouncements needed to be subjected to independent critical analysis; in fact, the opposite has happened, and increasingly the world’s press and politicians have come to treat IPCC utterances as if they were scribed in stone by Moses. This is a reflection, first, of superb marketing by the IPCC and its supporting cast of influential environmental and scientific organisations; second, of strong media bias towards alarmist news stories in general, and global warming political correctness in particular; and, third, of a lack of legislators and senior bureaucrats possessed of a sound knowledge of even elementary science, coupled with a similar lack of science appreciation throughout the wider electorate – our societies thereby becoming vulnerable to what can be termed ‘frisbee science’, i.e. spin.

Having decided around the turn of the 20th century that ‘the science was settled’, for the IPCC said so, politicians in industrialized societies and their economic advisors started to implement policies that they assured the public would ‘stop global warming’, notably measures to inhibit the emission of the mild greenhouse gas carbon dioxide into the atmosphere. However, the acronym GIGO (garbage in, garbage out) that has long been applied to computer modelling endeavours applies also to economic studies that purport to give policy advice against the threat of future climate change. For the reality is that no-one can predict the specific way in which climate will change in the future, beyond the general statement that multi-decadal warming and cooling trends, and abrupt climatic changes, are all certain to continue to occur. . . .

. . . This is an economics journal, and as a scientist I am clearly not the appropriate person to discuss the economics of the global warming issue were there any need to do so. But I have argued above that sound science understanding is an essential prerequisite to any meaningful economic analysis, and that we have not yet attained such an understanding, least of all as represented by IPCC advice. Therefore, the best service that I can render to readers is to alert them to the danger of wasting their time and talent – as many economists already have – in erecting rigorous economic models on the basis of fanciful or voodoo climate science. My paper will concentrate, then, not on economics but on presenting a critical account of the scientific arguments that have been claimed as evidence for dangerous, human-caused global warming.