I would say if there is a source it would be human. If enough people hate you and wish you harm, maybe that brings bad karma.
Interesting point of view. Do you feel there is a critical number of haters for a curse to take effect, or is there a sliding scale? Is it purely a "quantity" thing, or does it vary depending on the scale of the hate - i.e. does one person seriously hating you cause the same level of curse to fall on you as ten people vaguely disliking you? (Not implying those are actual numbers, but you see what I mean).
As far as weather disasters, are we making more intense weather because of our pollution? If this is true this would also be a self inflicted curse.
Not really, not in the sense that most people would use the term. Because if the weather disasters are a natural effect of pollution, then "hate" (as you imply above) would not be a feature at all. The same weather effects would occur if we polluted to the same level and loved everyone, as if we polluted to the same level and really hated everyone.
So I'm confused now - are you suggesting the weather effects are the natural and logical and scientific result of particular industrial processes? Originally you suggested it was some kind of karmic thing that was happening because of the US' treatment of some races, and thus (presumably) would be happening even if pollution was zero?
Good thing about curses is they go away when you learn your lesson, don't you think. You know make amends and say I'm sorry.
Do they? I suppose if you believe they are the direct result of an action then possibly - if weather comes from pollution, then cease pollution and you cease the weather. But if we're talking some kind of karmic effect from people hating you, then would the curse effect cease immediately? What if the person still hates you even AFTER you've said sorry? Do you believe the curse would stop, or keep going?