Wednesday, August 01, 2007


What Consensus?

The claim of “consensus” rests almost entirely on an inaccurate and now-outdated single-page comment in the journal Science entitled The Scientific Consensus on Climate Change (Oreskes, 2004). In this less than impressive “head-count” essay, Naomi Oreskes, a historian of science with no qualifications in climatology, defined the “consensus” in a very limited sense, quoting as follows from IPCC (2001) – “Human activities … are modifying the concentration of atmospheric constituents … that absorb or scatter radiant energy. … most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations.”

...There is no scientific consensus on how much the world has warmed or will warm; how much of the warming is natural; how much impact greenhouse gases have had or will have on temperature; how sea level, storms, droughts, floods, flora, and fauna will respond to warmer temperature; what mitigative steps – if any – we should take; whether (if at all) such steps would have sufficient (or any) climatic effect; or even whether we should take any steps at all.

...According to Dr. Peiser, fewer than one-third of the papers analyzed by Oreskes either explicitly or implicitly endorsed the “consensus”, contrary to Oreskes’ assertion that the figure was 75%. In addition, 44 abstracts focused on the natural as opposed to anthropogenic causes of climate change, and did not include any direct or indirect link or reference to human actitivies, carbon dioxide or other greenhouse gas emissions, let alone anthropogenic forcing of recent climate change. More than half of the abstracts did not mention anthropogenic climate change at all and could not, therefore, reasonably be held to have commented either way upon the “consensus” as defined by Oreskes.

...Oreskes’ essay is now outdated. Since it was published, more than 8,000 further papers on climate change have been published in the learned journals. In these papers, there is a discernible and accelerating trend away from unanimity even on her limited definition of “consensus”. Schulte (2007: submitted) has brought Oreskes’ essay up to date by examining the 539 abstracts found using her search phrase “global climate change” between 2004 (her search had ended in 2003) and mid-February 2007. Even if Oreskes’ commentary in Science were true, the “consensus” has moved very considerably away from the unanimity she says she found. Dr. Schulte’s results show that about 1.5% of the papers (just 9 out of 539) explicitly endorse the “consensus”, even in the limited sense defined by Oreskes. Though Oreskes found that 75% of the papers she reviewed explicitly or implicitly endorsed the “consensus”, Dr. Schulte’s review of subsequent papers shows that fewer than half now give some degree of endorsement to the “consensus”.

...The outright scaremongers are led by James Hansen, a donor of thousands of dollars to the re-election campaigns of Al Gore and John Kerry. He showed Congress a graph in 1988 that set the trend for wildly-exaggerated projections of future global temperature. The graph presented three scenarios, the most extreme of which had no basis in the scientific literature or in previously-observed trends. Politicians at that time treated the graph with respect because it had been generated by a computer. Yet the model which generated the graph, still in use by Hansen and the UN today, continues to contain “flux adjustments” – i.e. fudge-factors – many times greater than the very small perturbations which the model is supposed to predicting.


John Nicklin said...

I'm glad someone did an update to Oreskies. What acceptance it gets will be interesting since it seems to take the "consensus" myth to task.

Count Iblis said...

This is old news. Peiser's study was already debunked some time ago. He has admitted that he made mistakes.

racoon said...

How typical of count Iblis...rather than address the substantive argument, attack the person, repeat the global warming dogma mantra.

This is my first post to this blog, and I would like to express my thanks for the no-nonsense scientific approach it exemplifies