Sure, as you say, kamma is not the only factor in causing unpleasant feelings. And I'm certainly not arguing that a Tsumami happens as the result of kamma. But as I understand it, being born in, or moving to, a Tsunami-prone region, may well be...
And, of course, going back to Bhikkhu Bodhi's talk, if one accepts that human-induced global warming is happening, then it is clearly, by definition, a result of human action (setting aside the technicalities of what is vipaka).
I guess we could save a bit of time if we were able to read the old thread on E-Sangha where Retro (among others) went through the same discussion.