To add some substance on top of my comments (and you're right to call me on that Andrew), the argument that because we cannot explain the dynamics within a rigorous framework does *not* necessarily suggest that the theory is wrong - just that given our current data it is the most effective theoretical argument available.
That is to say, the fact that we cannot predict an occurence does not mean that we cannot develop working theories that elucidate the underlying issues.
As Don says, the models that have been built do a fairly good job at describing phenomena based on past data. That means our job is to take data and turn it into empirical evidence for a particular theory.
What has occured to date is that frameworks have been built, data has been submitted to them and the evidence that was generated was enough to convince those whose *responsibility* it is to be skeptical that global warming does in fact exist and it is due to human environmental abuse.
In my experience, climatologists, biologists, activists, etc, are not so invested in the idea that Earth is doomed that they will support global warming in the face of bad science.
For a more complete discussion of this issue, please read this article by a former professor of mine whose focus is on philosophy of science and engineering epistemology (he's in the philosophy faculty at Tufts but is actually the most famous and respected engineer on the faculty there - in his "professional life" he is one of the world's most famous experts in turbo engines). The book he reviews is precisely about the burden of proof in the debate over the causes of the hole in the Ozone layer.
Here's a quick quote:
"Standards of evidence when risk is central can be very different from standards of evidence in either comparatively finished science or science in the early stages of theory construction
These differing standards can be a serious source of continuing confusion in disputes over such matters as ozone depletion. Indeed, they clearly have been so in respect to global warming. A consensus among scientists can form because the evidence strongly supports the promise of a theory. Those who think that their vested interests may be adversely affected by policies based on this evidence can always invoke the standard of finished science to argue for delay. And all the while the policy question is best viewed as a balance of risks against gains, given currently available information."
talli
PS
To further support Don's thesis that not everyone who argues we are facing an environmental crisis is a raving leftist. EO Wilson, in fact, is quite controversial given his socio-biological theories which to many on the Left sound dangerously racist.