Judith,
One aspect of the "consensus" as promulgated by the IPCC that you might want to consider is that there is some indication that even the "insiders" differ on their <em>interpretation</em> of the word.
Yet, for the most part, they remain <em>deafeningly silent</em> when it is taken up and - in effect - used as a cudgel by the media and by activist organizations whose pronouncements are far more likely to reach the public than any of the science upon which this "consensus" is supposedly based.
For example, as I had <a href="http://hro001.wordpress.com/2010/06/18/honey-i-shrunk-the-consensus/" rel="nofollow">observed</a> in June 2010, Mike Hulme wrote (my bold -hro):
<blockquote>“Claims such as ’2,500 of the world’s leading scientists have reached a <strong>consensus</strong> that human activities are having a significant influence on the climate’ are disingenuous.
“That particular <strong>consensus judgement</strong>, as are many others in the IPCC reports, <strong>is reached by only a few dozen experts</strong> in the specific field of detection and attribution studies; other IPCC authors are experts in other fields.”</blockquote>
Approximately a year later, as I had documented in (what has become a "dangling") <a href="http://hro001.wordpress.com/2011/07/31/a-conversation-with-an-ipcc-coordinating-lead-author/" rel="nofollow">Conversation with an IPCC coordinating lead author</a>, I was advised that (again, my bold -hro]:
it is this line-by-line approval process [of the SPM] that results in the <strong>actual consensus</strong> that the IPCC is famous for, and which is sometimes misunderstood. The consensus is not a consensus among all authors about every issue assessed in the report; <strong>it is a consensus among governments about the summary for policymakers.</strong>
Yet, as I had noted in that same post, to the best of my knowledge neither of these IPCC "insiders" (or any others, for that matter!) has taken the step of <em>correcting</em> the very public pronouncements of (for example and again, my bold):
Oreskes (in <em>Science</em>, Dec. 2004):
<blockquote>"The <strong>scientific consensus</strong> is clearly expressed in the reports of the Intergovernmental Panel on Climate Change (IPCC). [...] IPCC states unequivocally that the <strong>consensus of scientific opinion</strong> [...]"</blockquote>
Greenpeace (July 20, 2010):
<blockquote>Scientific consensus
There is, in fact, a <strong>broad and overwhelming scientific consensus</strong> that climate change is occurring, is caused in large part by human activities (such as burning fossil fuels), and if left unchecked will likely have <strong>disastrous consequences.</strong></blockquote>
Union of Concerned Scientists (March 7, 2011):
<blockquote>Scientific Consensus on Global Warming
Scientific societies and scientists have released statements and studies showing the growing <strong>consensus on climate change science</strong>. A common objection to taking action to reduce our heat-trapping emissions has been uncertainty within the scientific community on whether or not global warming is happening and if it is caused by humans. However, <strong>here is now an overwhelming scientific consensus</strong> that global warming is indeed happening and humans are contributing to it.</blockquote>
And, as recently as a few days ago, Adam Corner had concluded an essay by noting:
<blockquote><a href="http://talkingclimate.org/communicating-climate-change-where-next/" rel="nofollow">Communicating climate change: where next?</a>
Without a focus on better communication, the danger is that the gap between the <strong>scientific and the social consensus</strong> on climate change will continue to grow.</blockquote>
In your post, (which I very much liked, btw!) you have asked for suggestions regarding the "way forward".
This may seem somewhat "radical" from a conservative "diagnostician" such as I; but, IMHO, perhaps a good first step would be to <em>excise</em> this foggy, mythical, shape-shifting "consensus" from the ongoing debate.
IOW, I wholeheartedly endorse your conclusion that:
<blockquote>It is time to abandon the concept of consensus in favor of open debate [...]</blockquote>
Hilary [stepping down from "anti-consensus" soapbox ;-)]
