I don't like this decision, but I'm working with it for the moment. It is a mentor decision, and I've not been part of that discussion.
I will say one thing...
I don't believe this is actually the problem, and have said so previously. After all, we don't have a vulcanoligist on staff either.
The real problem is that too many people just don't trust what the scientists say. I appreciate I have not been part of mentor discussions, but even so.... I think trying to address the matter by finding a single authority figure won't work well.
We get all kinds of strange assertions about scientists who are opposed to the mainstream of climate science; but in fact all actual working climate scientists, including those who have definite differences with the overwhelming majority of scientific opinion (Lindezen, Spencer, Christy, Svensmark, Douglass, etc), still do not have the same level of extreme skepticism of the fundamentals that pervades public discussion. It is not necessary to be a professional to follow this.
It has been really hard to try and give clear accessible accounts of even very uncontroversial basics, in response to a widespread level of skepticism that (in my opinion) merely debases the normal understanding of legitimate scientific skepticism. Skepticism is a good thing. A lot of what is called skepticism is better seen as credulous naivety. But how can you help people past that without causing offense?
This DOES make it very hard for the mentors, I acknowledge. But in my view the problem has been much worse than it needs to be; and having a working climate scientist to moderate discussions would not be at all well received by the people who are raising much of the ruckus. They don't trust climate scientists now.
Given the problem mentors have had finding a workable solution, I am for the time being content with this decision. I am hopeful this may be a break from what has been disruptive, rather than a final and complete finish to this topic; but we'll have to see. For the time being, the decision is to close debate, and I accept that.
At the same time, I think this topic is deeply rooted in basic physics, and there is a wide spread desire of many people to get a better educational introduction to the issues. It ought to be something physicsforums could help with; but it may be no bad thing to stop for a bit and take stock.
I think there is a wide spread desire by many forum members to have a way to continue to talk about this topic. Given this, I'm hoping the mentors will continue to be open to looking at ways to manage the debate, even though for the time being they are apparently burned out with it. I'll be continuing to try and work towards a way of handing this difficult topic, while submitting to the decision of the mentors for this new policy at the present time.
Ideally, I would like to keep a forum where we can discuss the open questions which are raised within the body of working scientists, which does include ideas at some variance with the majority view. Science has always had this tolerance of minority views and dissent, as long as they continue to work within the normal scientific process. Some views are merely silly, and it would be nice to avoid distraction from the extremes. Some views are legitimate minority alternatives, and still science in good standing.
The main task of physicsforums is education in the process of science, as it is practiced. Obviously, physicsforums will continue to provide that service, in all kinds of fields. This one topic has presented difficulties, and I gather no-one really likes what it has come to.
Cheers -- sylas