I would call that consequences, not a curse.
This is how I see it as well. Inasmuch as someone's own actions cause their downfall, I think that the word 'curse' only applies in a colloquial sense. A claim of retaliation coming from a supernatural source actually muddies the picture, as many of the victims of major disasters (e.g. small children) simply could not have behaved so badly as to invite such a tragic fate upon themselves. If this were a genuine form of divine justice at play here, I'd expect to see the karma targeting more people in and behind the halls of power and fewer schoolkids.
Unfortunately, due to instability in planetary climate and continued population growth, I fear that we're likely to see a corresponding increase in the number and severity of disasters worldwide.