In addition to doing my bit to promote Olle's book (Buy it! Read it! Act on it!) I can't help but also pride myself on having a tiny, tiny role in its conception: I have had the great privilege of reading and commenting upon drafts of the text. Here is just one example of the kind of reflections that the book's extensive and multi-faceted content stirred in me (to be absolutely clear: these are my thoughts, inspired by Olle's discussion; they do not reflect the text itself).
I don't think it is at all obvious to discuss AGW * as a (solely or largely) ethical or moral dilemma! And it's not clear to me that it should be considered an especially hard problem, either. There are many practical problems, to be sure; but they are just that: practicalities.
"The perfect moral storm" is a grievous misnomer. It seems to imply that there are major obstacles to agreeing (in principle) on what should be done when, in fact, it refers to a confluence of aggravating circumstances when it comes to acting accordingly.
The tragedy of the commons isn't an ethical problem, but rather a practical one. Sure, there are ethical considerations regarding how we, as a society, should calculate and weigh different interests and risks. But, again, "moral competence" appears to denote only the ability or desire to act consistent with any reasonable calculus.
I believe that a failure to distinguish between what should (or could) be done, and what people seem willing (or eager) to do, is highly counter-productive. It leads to "moral hazard"; in effect providing people with a perfect alibi for doing nothing; for not acting constructively, and in accordance with everything they actually know - or are told - to be right (and absolutely necessary).
(*) Anthropogenic Global Warming