TWO recent, widely publicised reports by the government's scientific advisory agencies on climate change have sought to raise alarm yet again about global warming.
With the world having warmed slightly during the late 20th century, CSIRO, the Bureau of Meteorology and the Climate Commission all advocate that this warming was caused mainly by industrial emissions of carbon dioxide, and that the continuation of emissions unchecked will cause dangerous warming of 3C-4C by 2100.
However, these and other climate agencies are now encountering a public that is increasingly aware of the lack of factual evidence for dangerous warming, and of the speculative nature of the arguments advanced in its favour.
For example, many people now understand that there is no direct evidence that 20th-century warming was caused mostly by carbon dioxide increase; that the late 20th-century warming has been followed by a 15-year temperature standstill in the face of continuing increases in carbon dioxide; and that the models that project alarming future warming are inadequate.
The dangerous warming hypothesis is embodied in the complex climate models that CSIRO and others use to predict the future climate.
But when the model predictions are tested against the latest high-quality data from our best instruments, they are seen to have comprehensively failed.
For example, the models predicted increasing global air temperatures (the measured rises have been much less than predicted), increasing ocean temperatures (there has been no change since 2003, when we started measuring it properly with Argo ocean-diving buoys) and the presence of a hot spot caused by humidity and cloud feedback at heights of 8km-12km in the tropical atmosphere (entirely absent).
The last item is especially important because it shows that the crucial amplification assumed by the modellers and which is responsible for two-thirds of the predicted warming (yes, only one-third is directly due to carbon dioxide) simply does not exist.
Finding that the estimated historic increase in carbon dioxide was not enough to cause dangerous warming on its own, the modellers guessed that atmospheric water vapour would amplify, by a factor of three, any initial carbon dioxide-forced warming.
That this assumed amplification is present in the models but not in reality explains why the models consistently overestimate recent warming.
What then should our government be making of all this?
Well, the government appears to take advice on global warming and climate change from a wide range of sources, which include the UN Intergovernmental Panel on Climate Change, Australian government agencies (CSIRO, BOM), state-based greenhouse or climate-change bodies, rent- seekers from many university climate-related research groups, business lobby groups and consultants and, finally, large environmental lobby organisations (Australian Conservation Foundation, Greenpeace, WWF). Phew.
The reality is, though, that all of these groups and organisations take their lead from, and support the views of, the IPCC (a political body that is unaccountable to Australian citizens).
Their starting assumption is therefore that human-caused global warming exists, that it is dangerous and that the way to avert the danger is to "decarbonise" the planet. The many agencies and groups giving advice are, in fact, just providing multiple conduits for the same repetitive, alarmist message, which derives ultimately from the same IPCC source.
Since the government's carbon tax legislative package passed the Senate last October, Australian press coverage of the global warming issue has been muted, doubtless partly signifying that there have been few government media releases that address the topic since the Senate decision.
That situation changed with a jolt during the week starting on March 12, when a wide variety of news media carried stories about CSIRO's Cape Grim air pollution monitoring station in Tasmania, followed later in the week by publicity for new reports on global warming by CSIRO/BOM and the Climate Commission.
In effect, the week revealed a co-ordinated and highly successful public relations campaign by three of the organisations involved in giving advice on climate change in Australia, with support and advance knowledge among some media editors and reporters. The aim was to rekindle the fast-fading fear of global warming alarm among the general public.
Very little scientific balance or analysis was provided during this week-long barrage of tired, speculative and highly controversial assertions about supposedly dangerous global warming.
Rather than being a new state of affairs, this assault in favour of warming alarmism by Australian climate agencies follows many similar propaganda blitzes during the past 10 years.
As experienced scientists, we have just completed a detailed assessment of the recent reports, which has been added to the list of earlier independent audits of IPCC and Australian reports at Quadrant Online (Google "global warming: an essential reference").
Our analysis of the "new" reports finds that they provide no evidence that dangerous global warming is occurring; nor that human carbon dioxide emissions will cause such warming in future; nor that recent Australian climate-related events lie outside normal climate variability; nor that reducing carbon dioxide emissions will have any discernible impact on future climate.
Therefore, Australian public policies regarding dangerous climate change, sea-level rise and other climatic hazards are based on inadequate scientific advice, which is shackled to the shortcomings of inadequate computer model projections.
The climate models are incompatible with the measured data. In recent decades the model predictions have significantly exceeded the measured temperature rise.
In science, data trumps theory. If data and theory disagree, as they do here, scientists go with the data and revise their hypothesis.
But in politics the opposite is true, for authority figures and political correctness reign supreme. In which context government climate scientists, Western governments and numerous influential lobby groups all strongly support the idea of dangerous global warming, despite the strong contrary evidence.
We conclude that an obvious and urgent need exists for the government to reassess its climate hazard policies. A good starting point would be to implement an unbiased review of the evidence.
Bob Carter is a geologist specialising in paleontology and marine geology. David Evans is a computer modeller and was a consultant to the Australian Greenhouse Office, 1999-2005. Stewart Franks is an associate professor of environmental engineering at the University of Newcastle. William Kininmonth headed Australia's National Climate Centre at the Bureau of Meteorology, 1986-98.