One misgiving about running a climate model on the mac is that I don't trust linux to handle the Mac's fans to keep the mac cool. Apparently, there is even more to it. The mac also will throttle memory bandwidth if the ram gets too hot (see technote TN2156). Whether or not a Linux install not targeted to a Mac would handle these issues, I don't know.
All those worries seem to be moot, however. I managed to get the model running within Leopard. The next few posts will concern some of the details of how this was accomplished.